AS3649 2500mA High Current LED Flash Driver 1 General Description 2 Key Features The AS3649 is an inductive high efficient DCDC step up converter with two current sources. The DCDC step up converter operates at a fixed frequency of 4MHz and includes soft startup to allow easy integration into noise sensitive RF systems. The two current sources can operate in flash / torch or video light modes. High efficiency 4MHz fixed frequency DCDC Boost converter The AS3649 includes flash timeout, overvoltage, overtemperature, undervoltage and LED short/open circuit protection functions. A TXMASK/TORCH function reduces the flash current in case of parallel operation to the RF power amplifier and avoids a system shutdown. Alternatively this pin can be used to directly operate the torch light directly. If the TXMask function is not used, it can be used as a hardware torch input (programmable). Automatic current adjustment for low battery voltage A hardware NTC pin can be used to measure the LED temperature with the ADC and to automatically reduce the LED current if a temperature threshold is exceeded. 2 The AS3649 is controlled by an I C interface and has a hardware reset pin ON. Setting ON=0 resets the AS3649. Interface input voltage levels are 1.8V compliant. The AS3649 is available in a space-saving WL-CSP package measuring only 2.06x2.02x0.6mm and operates over the -30C to +85C temperature range. with soft start allows small coils - Stable even in coil current limit LED current adjustable up to 2x1000mA(2x1250mA with current boost) or 2000mA and automatic load balancing for two LEDs PWM operation for lower output current for reliable light output of the LED; can run at 31.5kHz to avoid audible noise Protection functions: Automatic Flash Timeout timer to protect the LED(s) Overvoltage and undervoltage Protection Overtemperature Protection LED short/open circuit protection ADC to measure LED temperature NTC to automatically reduce the flash current if the LED temperature is too high (programmable level) 2 I C Interface with hardware reset pin Available in tiny WL-CSP Package, 16 balls 0.5mm pitch, 2.06x2.02x0.6mm package size 3 Applications Flash/Torch for mobile phones Figure 1. Typical Operating Circuit $%&'( &' ! )*+ ,+( www.ams.com/AS3649 " "! .+ (01$ $$$$$$$$%%% $$$$$$$$&%%% AS3649 #" !$/ .* ! 1.0-2 " &' #"! * 1 - 39 AS3649 Datasheet - P i n A s s i g n m e n t s 4 Pin Assignments Figure 2. Pin Assignments (Top View) AS3649 " " ! # !#$" !#$" 4.1 Pin Description Table 1. Pin Description for AS3649 1 Pin Number Pin Name A1 PGND2 Power ground; make a short connection between all GND balls A2 PGND1 Power ground; make a short connection between all GND balls A3 VIN A4 ON B1 SW2 DCDC converter switching node - make a short connection to SW1 / coil LDCDC B2 SW1 DCDC converter switching node - make a short connection to SW2 / coil LDCDC B3 NTC LED temperature sensor input (NTC) for LED overtemperature protection B4 TXMASK/TORCH Description Positive supply voltage input - connect to supply and make a short connection to input capacitor CVIN and to coil LDCDC Hardware reset input; an active low signal resets the registers of AS3649 and enters shutdown 2 (and I C lines SDA and SCL are in high-Z), active high allows to operate the device Function 1: Connect to RF power amplifier enable signal - reduces currents during flash to avoid a system shutdown due to parallel operation of the RF PA and the flash driver 2 Function 2: Operate torch current level without using the I C interface to operate the torch 2 without need to start a camera processor (if the I C is connected to the camera processor C1 VOUT2 DCDC converter output capacitor - make a short connection to CVOUT / VOUT1 C2 VOUT1 DCDC converter output capacitor - make a short connection to CVOUT / VOUT2 www.ams.com/AS3649 1.0-2 2 - 39 AS3649 Datasheet - P i n A s s i g n m e n t s Table 1. Pin Description for AS3649 1 Pin Number Pin Name Description C3 SCL serial clock input for I C interface C4 SDA serial data input/output for I C interface (needs external pullup resistor) D1 LED_OUT2 Flash LED current source D2 LED_OUT1 Flash LED current source D3 AGND Analog ground; make a short connection between all GND balls D4 STROBE Digital input with pulldown to control strobe time for flash function 2 2 1. Final pinout subject to change - now only used to count number of pins www.ams.com/AS3649 1.0-2 3 - 39 AS3649 Datasheet - A b s o l u t e M a x i m u m R a t i n g s 5 Absolute Maximum Ratings Stresses beyond those listed in Table 2 may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 5 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 2. Absolute Maximum Ratings Parameter Min Max Units VIN to GND -0.3 +7.0 V STROBE, TXMASK/TORCH, SCL, SDA, ON, NTC to GND -0.3 VIN + 0.3 V SW1/2, VOUT1/2, LED_OUT1/2 to GND -0.3 +7.0 V VOUT1/2 to SW1/2 -0.3 voltage between AGND, PGND1/2 pins 0.0 Input Pin Current without causing latchup -100 Comments max. +7V V Note: Diode between VOUT1/2 and SW1/2 0.0 V short connection required +100 +IIN mA Norm: EIA/JESD78 Continuous power dissipation 1470 mW PT at 70C Continuous power dissipation derating factor 20 mW/C PDERATE ESD HBM 2000 V Norm: JEDEC JESD22-A114F ESD CDM 500 V Norm: JEDEC JESD 22-C101E Continuous Power Dissipation (TA = +70C) 1 2 Electrostatic Discharge Temperature Ranges and Storage Conditions Junction to ambient thermal resistance 50 C/W For more information about thermal metrics, see application note AN01 Thermal Characteristics Junction Temperature +150 C Internally limited (overtemperature protection), max. 20000s 3 Storage Temperature Range -55 +125 C Humidity 5 85 % Non condensing +260 C according to IPC/JEDEC J-STD-020 Body Temperature during Soldering Moisture Sensitivity Level (MSL) MSL 1 Represents a max. floor life time of unlimited 1. Depending on actual PCB layout and PCB used measured on demoboard; for peak power dissipation during flashing see document 'AS3649 Thermal Measurements' 2. PDERATE derating factor changes the total continuous power dissipation (PT) if the ambient temperature is not 70C. Therefore for e.g. TAMB=85C calculate PT at 85C = PT - PDERATE * (85C - 70C) 3. Measured on AS3649 demoboard. www.ams.com/AS3649 1.0-2 4 - 39 AS3649 Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s 6 Electrical Characteristics VVIN = +2.7V to +4.4V, TAMB = -30C to +85C, unless otherwise specified. Typical values are at VVIN = +3.7V, TAMB = +25C, unless otherwise specified. Table 3. Electrical Characteristics Symbol Parameter Condition Min Typ Max Unit 3.7 4.4 V General Operating Conditions VVIN Supply Voltage Pin VIN 2.7 VVINREDUCED_ Supply Voltage AS3649 functionally working, but not all parameters fulfilled 2.5 2.7 4.4 5.5 ISHUTDOWN Shutdown Current TXMASK/TORCH=L, STROBE=L, ON=L, VVIN<3.7V 1.0 2.0 A ISTANBY Standby Current Interface active, TXMASK/TORCH=L, STROBE=L VVIN<3.7V 1.0 10 A TAMB Operating Temperature 25 85 C FUNC 1 -30 Application Efficiency LCOIL=0.6H@3A, LESR=60m, LED_OUT1,2=2000mA, (DCDC and current source) tFLASH<300ms, VFLED=3.7V tFLASH Flash Duration V 83 VVIN>3.3V, TAMB<85C, ILED_OUT<2000mA If TAMB or ILED_OUT is reduced or VVIN is increased, longer flash times are allowed. For longer flash durations, see section Current Reduction by VIN Measurements in Flash Mode and Diagnostic Pulse on page 15 % 300 ms 5.5 V DCDC Step Up Converter VVOUT DCDC Boost output Voltage (pin VOUT1/2) RPMOS On-resistance DCDC internal PMOS switch 45 m RNMOS On-resistance DCDC internal NMOS switch 47 m fCLK Operating Frequency All internal timings are derived from this oscillator VVOUT5V DCDC Boost output Voltage (pin VOUT1/2) Constant voltage mode operation const_v_mode (see page 30)=1 2.8 -7.5% 4.0 +7.5% 5.0 MHz V Current Sources VLED LED forward voltage ILED_OUT LED_OUT1/2 current combined Two flash LEDs, ILED_OUT<2x1000mA 2.8 3.32 4.0 V Single flash LED, ILED_OUT<1800mA 2.8 3.32 4.4 V 0 2000 mA 0 2000 mA 2 mA VVIN>3.3V, coil_peak=11b, LCOIL=0.6H@3.4A, LESR=60m coil SPM3012T-1R0M, tFLASH<300ms dual flash LED, current_boost=0 single flash LED ILED_OUT_BO LED_OUT1/2 current combined Dual flash LED, current_boost=1 0 2500 ILED_OUT LED_OUT1/2 current source accuracy Otherwise -7 +7 % ILED_OUT=500mA...800mA, 0C<TJ<100C -5 +5 % OST 2 ILED_OUT RAMP ILED_OUT RIPPLE LED_OUT1/2 ramp time LED_OUT current ripple www.ams.com/AS3649 Rampup initiated by I C command 730 s Rampup started by STROBE 530 s Full range Ramp-down 500 s ILED_OUT = 1000mA 40 mAPP 1.0-2 5 - 39 AS3649 Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s Table 3. Electrical Characteristics (Continued) Symbol VILED_COMP VILED_COMP _BOOST Parameter Condition Min Minimum voltage between pin VOUT1/2 and LED_OUT1/ LED_OUT current source 2 for operation of the current source with current_boost=0 voltage compliance VILED_COMP with current_boost=1 Typ Max Unit 230 mV 290 mV LLED_CONNECT LED connection inductance Represents a maximum connection length of 10cm (LED ION connection and ground return path) 100 nH V Protection and Fault Detection Functions (see page 12) VVOUTMAX ILIMIT VVOUT overvoltage protection Current Limit for coil LDCDC (Pin SW) measured at 25% PWM 3 duty cycle DCDC Converter Overvoltage Protection Default value maximum 40000s lifetime operation in overcurrent limit VLEDSHORT Flash LED short circuit detection voltage TOVTEMP Overtemperature Protection TOVTEMPHYS T tFLASHTIMEO UT VUVLO Undervoltage Lockout VIN_LOW_VOLTA Battery Low Voltage Protection GE 5.3 5.6 coil_peak=00b 2.25 2.5 2.75 coil_peak=01b 2.61 2.9 3.19 coil_peak (see page 23)=10b 3.0 3.3 3.63 coil_peak=11b 3.3 3.7 4.1 Voltage measured between pins LED_OUT1,2 and GND A 1.2 V 144 C 5 C Junction temperature Overtemperature Hysteresis Flash Timeout Timer 5.0 Can be adjusted with register flash_timeout (page 26) 4 1124 ms Accuracy -7.5 +7.5 % Falling VVIN 2.25 2.5 V Rising VVIN Defined by vin_low_v - see Current Reduction by VIN Measurements in Flash Mode and Diagnostic Pulse on page 15 2.4 VUVLO VUVLO VUVLO +0.05 +0.1 +0.15 V 3.03.47 +2.5% V -2.5% Protection and Fault Detection Functions - NTC INTC VNTC_TH NTC Current Source Threshold for overtemperature Adjustable by ntc_current (page 25) in 40A steps Range 40 600 A I - accuracy V(NTC) <= 1.7V -7 +7 % -5 +5 A If ntc_on (page 25)=1 and the voltage on NTC drops below VNTC_TH, any flash/torch or pwm operation of LED_OUT is stopped 4 1.0 V 10 bits ADC Resolution 0 full scale NTC 0.0 2.2 V VIN 0.0 5.5 V % full scale ADC Code Range ADC input range; channel selected by adc_channel (page 27) TJUNC (AS3649 junction temperature) Accuracy ADC measurement accuracy www.ams.com/AS3649 see Table 6 C NTC -1.5 +1.5 TJUNC (-30C...150C) -8 +8 TJUNC (0C...85C) -5 +5 1.0-2 C 6 - 39 AS3649 Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s Table 3. Electrical Characteristics (Continued) Symbol Parameter Condition Min VIH High Level Input Voltage VIL Low Level Input Voltage Pins ON, SCL, SDA. and TXMASK/TORCH VIHFLASH High Level Input Voltage VILFLASH Low Level Input Voltage Typ Max Unit 1.26 VVIN V 0.0 0.54 V 0.84 VVIN V 0.0 0.54 V Digital Interface Pin STROBE. VOL Low Level Output Voltage Pin SDA, IOL=3mA ILEAK Leakage current Pins ON, SCL, SDA IPD Pulldown current to GND tDEBTORCH TORCH debounce time tDEBTXMASK TXMASK debounce timer 5 -1.0 Pins STROBE and TXMASK/TORCH 0.0 0.3 V +1.0 A 36 6.3 9 A 11.7 1.5 ms s 2 I C mode timings - see Figure 3 on page 8 fSCLK SCL Clock Frequency 0 tBUF Bus Free Time Between a STOP and START Condition 1.3 s tHD:STA Hold Time (Repeated) 6 START Condition 0.6 s 400 kHz tLOW LOW Period of SCL Clock 1.3 s tHIGH HIGH Period of SCL Clock 0.6 s tSU:STA Setup Time for a Repeated START Condition 0.6 s tHD:DAT Data Hold Time tSU:DAT 7 0 Data Setup Time 8 100 tR Rise Time of Both SDA and SCL Signals 20 + 0.1CB 300 ns tF Fall Time of Both SDA and SCL Signals 20 + 0.1CB 300 ns tSU:STO Setup Time for STOP Condition 0.6 CB Capacitive Load for Each Bus Line CI/O I/O Capacitance (SDA, SCL) CB -- total capacitance of one bus line in pF 0.9 s ns s 400 pF 10 pF 1. To improve efficiency at low output currents, the active part of the internal switching transistor PMOS is reduced in size to 1/5 its original size. This reduces the current required to drive the PMOS transistor and therefore improves overall efficiency at low output currents. 2. The maximum current driving capability depends on supply voltage VVIN, LED forward voltage and coil peak current limit. 3. Due to slope compensation of the current limit, ILIMIT changes with duty cycle - see Figure 16 on page 11. 4. Accuracy defined in % of current setting and in absolute value (A), accuracy values have to be added together 5. A pulldown current of 36A is equal to a pulldown resistor of 42k at 1.5V 6. After this period, the first clock pulse is generated 7. A device must internally provide a hold time of at least 300ns for the SDA signal (referred to the VIHMIN of the SCL signal) to bridge the undefined region of the falling edge of SCL. 8. A fast-mode device can be used in a standard-mode system, but the requirement tSU:DAT = to 250ns must then be met. This is automatically the case if the device does not stretch the LOW period of the SCL signal. If such a device does stretch the LOW period of the SCL signal, it must output the next data bit to the SDA line tR max + tSU:DAT = 1000 + 250 = 1250ns before the SCL line is released. www.ams.com/AS3649 1.0-2 7 - 39 AS3649 Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s 6.1 Timing Diagrams 2 Figure 3. I C mode Timing Diagram SDA tBUF tLOW tR tHD:STA tF SCL tHD:STA tSU:STA tHD:DAT STOP tHIGH tSU:DAT REPEATED START START www.ams.com/AS3649 tSU:STO 1.0-2 8 - 39 AS3649 Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s 7 Typical Operating Characteristics VVIN = 3.7V, TA = +25C (unless otherwise specified) Figure 4. DCDC Efficiency vs. VVIN Figure 5. Application Efficiency (PLED/PVIN) vs. VVIN 90 100 95 85 85 Efficiency % Efficiency % 90 80 75 80 75 70 ILED = 2500mA, VFLED=3.55V (2 LEDs) 70 ILED = 2500mA, VFLED=3.55V (2 LEDs) ILED = 2000mA, VFLED=3.45V (2 LEDs) ILED = 2000mA, VFLED=3.45V (2 LEDs) 65 ILED = 1600mA, VFLED=3.7V (1 LED) 65 ILED = 1600mA, VFLED=3.7V (1 LED) ILED = 1600mA / dcdc_skip_enable=0 ILED = 1600mA / dcdc_skip_enable=0 ILED = 1000mA, VFLED=3.45V (1 LED) ILED = 1000mA, VFLED=3.45V (1 LED) 60 60 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 2.8 4.4 3.0 3.2 Input Voltage (V) Figure 6. Battery Current vs. VVIN 3.6 3.8 4.0 4.2 4.4 Figure 7. Efficiency at low currents (298mA/100mA) 4.0 90 limited by 3.7A peak current setting 3.5 85 3.0 80 2.5 75 Efficiency % Battery Current [A] 3.4 Input Voltage (V) 2.0 1.5 1.0 65 60 ILED = 2500mA, VFLED=3.55V (2 LEDs) ILED = 2000mA, VFLED=3.45V (2 LEDs) ILED = 1600mA, VFLED=3.7V (1 LED) ILED = 1600mA / dcdc_skip_enable=0 ILED = 1000mA, VFLED=3.45V (1 LED) 0.5 70 ILED = 298mA/1LED DCDC Efficiency ILED = 298mA/1LED Application Efficiency 55 ILED = 100mA x 2 LEDs DCDC Efficiency ILED = 100mA x 2 LEDs Application Efficiency 0.0 50 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 2.8 Input Voltage (V) Figure 8. ILED Startup (ILED_OUT=1.0A) www.ams.com/AS3649 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 Input Voltage (V) Figure 9. IVIN, ILED Startup (ILED_OUT=800mA) 1.0-2 9 - 39 AS3649 Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s Figure 10. ILED vs. VVIN 3.0 LED Current [A] 2.5 Figure 11. VOUT / ILED_OUT ripple, ILED_OUT = 2x1.0A limited by 3.7A peak current setting 2.0 1.5 1.0 ILED = 2500mA, VFLED=3.55V (2 LEDs) 0.5 ILED = 2000mA, VFLED=3.45V (2 LEDs) ILED = 1600mA, VFLED=3.7V (1 LED) ILED = 1000mA, VFLED=3.45V (1 LED) 0.0 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 Input Voltage (V) Figure 12. Diagnostic Pulse Operation Figure 13. TxMask operation waveform (ILED, IVIN) VVIN=3.62V vin_low_v=3.47V Figure 14. Timeout Timer www.ams.com/AS3649 Figure 15. NTC operation (overtemperature triggered) 1.0-2 10 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n 8 Detailed Description The AS3649 is a high performance DCDC step up converter with internal PMOS and NMOS switches. Its output is connected to one or two flash 1 LEDs with two internal current sources and hardware LED temperature protection using an external NTC. The device is controlled by the pins 2 SDA and SCL in I C mode and includes a hardware reset input ON. The actual operating mode like standby, torch light, indicator or flash mode, can then be chosen by the interface. If not in standby mode, the device automatically enters shutdown and resets all registers by setting pin ON=0. The AS3649 includes a fixed frequency DCDC step-up with accurate startup control. Together with the current source (on LED_OUT1/2) it includes several protection and safety functions. 8.1 Internal Circuit Diagram Figure 16. Internal Circuit Diagram ! " $% "! ( ' & M ,- . / * N M M (&+ (,- -K,(,# % )*(+) (,-( & " "! ,R # " # "! N'Q( # " # "! QQ&P' (K&P' . # (# / * " -+''.- (& + -K, (( ' O . "! % 0" # 8.2 Softstart / Soft ramp down During startup and ramp down the LED current is smoothly ramped up and ramped down. If the DCDC converter goes out of regulation (measured by monitoring the voltage across the current sources), the ramp up is temporarily stopped in order for the DCDC to return to 2 regulation . 1. If two LEDs are connected, it is possible to operate each of the two LEDs individually as the LED current can be selected individually. 2. The actual value of the LED current setting can be readout by the register led_current_actual (see page 31) to allow the camera processor to adopt to the actual operating conditions. www.ams.com/AS3649 1.0-2 11 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n 8.3 4/1MHz Operating Mode Switching and Pulse Skipping 3 If freq_switch_on (see page 29)=1 and if led_current1>=40h or led_current2>=40h and current_boost=0, the DCDC converter always operates in PWM mode (exception: PFM mode is allowed during startup) to reduce EMI in EMI sensitive systems. For high duty cycles close to 100% ontime (maximum duty cycle) of the PMOS, the DCDC converter can switch into a 1MHz operating mode and maximum duty cycle to improve 4 efficiency for this load condition . The DCDC converter returns back to its normal 4MHz operating frequency when load or supply conditions change. Due to this switching between two fixed frequencies the noise spectrum of the system is exactly defined and predictable. If improved efficiency is required, the fixed switching between 4MHz / 1MHz can be disabled by freq_switch_on (see page 29)=0. In this case pulseskip will be used. The modes are selected according to Table 4: Table 4. 4/1MHz switching and pulseskip operating modes freq_switch_on dcdc_skip_enable led_current1>=40h or led_current2>=40h 0 0 4MHz forced PWM operation (no 1MHz operation, no pulseskip) 0 1 4MHz, pulse skipping allowed, no 1MHz operation 1 0 1 1 4MHz/1Mhz forced PWM operation, 1 pulseskip not allowed led_current1<40h and led_current2<40h 4MHz forced PWM operation (no 1MHz operation, no pulseskip) 4MHz, pulse skipping allowed, no 1MHz operation 1. If current_boost=1, freq_switch_on is set to `0'. The internal circuit for switching between these two frequencies is shown in Figure 17 (for simplicity only a single current source is shown): Figure 17. Internal circuit of 4MHz/1MHz selection AS3649 ! $ " #$# %&'#!( $ , 1! # )** +,- ./ &31#$1" 121! Note: If the voltage on VOUT1/2 exceeds VVOUTMAX, the DCDC will always skip pulses to limit the output voltage. 8.4 Protection and Fault Detection Functions The protection functions protect the AS3649 and the LED(s) against physical damage. In most cases a Fault register bit is set, which can be 2 2 readout by the I C interface. The fault bits are automatically cleared by a I C readout of the fault register. Additionally the DCDC is stopped and 5 6 the current sources are disabled by resetting mode_setting=00 and txmask_torch_mode=00. 3. Set register dcdc_skip_enable (see page 28)=1 if 4MHz forced operation shall be used below this LED current. 4. Efficiency compared to a 4MHz only DCDC converter forced to operate with minimum duty cycle. www.ams.com/AS3649 1.0-2 12 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n 8.4.1 Overvoltage Protection In case of no or a broken LED(s) at the pin LED_OUT1/2 and an enabled DCDC converter, the voltage on VOUT1/2 rises until it reaches 7 VVOUTMAX (overvoltage condition) and the voltage across the current source is below low_vds ., the DCDC converter is stopped, the current 8 9 sources are disabled and the bit fault_ovp (see page 29) is set . In a dual LED configuration for the AS3649, if a single open LED is detected, this LED is disabled, fault_ovp is set and the device continuous operation with the other LED. Note: In PWM operating mode (mode_setting=01b), open LED detection is disabled (and fault_ovp is not set). The output voltage will nevertheless be kept below VVOUTMAX. 8.4.2 Short Circuit Protection After the startup of the DCDC converter, the voltage on LED_OUT1/2 is continuously monitored and compared against VLEDSHORT if the LED 10 11 current is above 27.5mA (current_boost=0), 34.3mA (current_boost=1) , (see Figure 18). If the voltage on the LED (VFLED = LED_OUT1/2) stays below VLEDSHORT, the DCDC is stopped (as a shorted LED is assumed), the current sources are disabled and the bit fault_led_short (see page 29) is set. In a dual LED configuration for the AS3649, if a single shorted LED is detected, this LED is disabled, fault_led_short is set and the device continuous operation with the other LED. Note: In PWM operating mode (mode_setting=01b), short circuit protection is disabled. Figure 18. Short LED Detection !!$ % & ! ' !"! ## 8.4.3 Overtemperature Protection The junction temperature of the AS3649 is continuously monitored. If the temperature exceeds TOVTEMP, the DCDC is stopped, the current sources are disabled (instantaneous) and the bit fault_overtemp (see page 29) is set (but the operating mode mode_setting is not changed). The 12 driver is automatically re-enabled once the junction temperature drops below TOVTEMP-TOVTEMPHYST. 8.4.4 TXMASK event occurred If during flash, TXMASK current reduction is enabled (see TXMASK on page 15, configured by txmask_torch_mode=01) and a TXMASK event happened (pin TXMASK/TORCH=1), the fault register bit fault_txmask (see page 28) is set. 5. Applies for all faults except TXMASK event occurred 6. Except for TXMASK event occurred and Overtemperature Protection 7. If overvoltage is reached, but none of the low_vds comparator(s) triggers, VOUT1/2 is still regulated below VVOUTMAX. 8. In indicator or low current PWM mode (mode_setting (see page 26)=01) the register fault_ovp is not set under an overvoltage conditions. The output voltage is nevertheless kept below VVOUTMAX. 9. In constant voltage mode (5V generation, register bit const_v_mode=1) this fault is disabled. 10.To avoid errors in short LED detection for LEDs with a high leakage current 11. The LED short circuit protection is disabled in indicator mode (or low current mode using PWM) (mode_setting on page 26=01b) 12.In constant voltage mode (const_v_mode=1) the DCDC will not be automatically re-enabled. www.ams.com/AS3649 1.0-2 13 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n 8.4.5 Flash Timeout If the flash is started a timeout timer is started in parallel. If the flash duration defined by the STROBE input (strobe_on=1 and strobe_type=1, see Figure 25 on page 18) exceeds tFLASHTIMEOUT (adjustable by register flash_timeout (see page 26)), the DCDC is stopped and the flash current sources (on pin LED_OUT1/2) are disabled (ramping down) and fault_timeout is set. If the flash duration is defined by the timeout timer itself (strobe_on = 0, see Figure 23 on page 17), the register fault_timeout is set after the flash has been finished. 8.4.6 Supply Undervoltage Protection If the voltage on the pin VIN (=battery voltage) is or falls below VUVLO, the AS3649 is kept in shutdown state and all registers are set to their default state. 8.4.7 NTC - Flash LED Overtemperature Protection The ntc_on (see page 25)=1, the flash LED is protected by the AS3649 using an internal comparator connected to NTC and an current source controlled by ntc_current (see page 25) (VNTC_TH, INTC as shown in Figure 16, "Internal Circuit Diagram," on page 11); once it is triggered, the DCDC is stopped, the current sources are disabled (instantaneous) and the bit fault_ntc (see page 28) is set. As the external NTC cannot measure the LED temperature in real time during a high current flash pulse (the duration from heating up of the LED until the NTC recognizes a too hot LED is usually too long), it is advisable to measure the LED temperature before the flash pulse (with the ADC (see page 19) and ntc_current (see page 25)) and judge how much current can be driven through the LED (to be estimated depending on LED heat sink and is usually specified by the LED manufacturer). 8.5 Operating Mode and Currents The output currents and operating mode currents are selected according to the following table: Table 5. Operating Mode and Current Settings ON, SCL, SDA TXMASK/TORCH STROBE X X X X X 0 X 1 X 2 ON=1; I C commands are accepted on pins SCL and SDA mode_s etting (see page 26) ON=0 AS3649 Configuration Operating Mode and Currents Condition Mode LED_OUT1/2 Output current X Shutdown All registers are reset to their default values 0 standby 0 external torch mode LED current is defined by the 6LSB bits of led_current1 and led_current2 txmask_torch_mode (see page 23) not 10 00 txmask_torch_mode =10 txmask_torch_mode =10 1 X X 01 indicator mode or 2 low current pwm mode LED current is defined by the 6LSB bits (bits 5...0) of led_current1 and led_current2 pwm modulated defined by register inct_pwm (31.5kHz: 1/16...4/16) or 7.9kHz: 1/ 64...3/64) X X 10 torch light mode LED current is defined by the 6LSB bits (5...0) of led_current1 and led_current2 X X strobe_on (see page 28) = 0 X 0->1 strobe_on = 1 and strobe_type (see page 28) = 0 11 X 1 www.ams.com/AS3649 strobe_on = 1 and strobe_type = 1 2 flash mode; flash duration defined by flash_timeout (see page 26) LED current is defined by led_current1 and led_current2 - the current can be flash mode; reduced during flash, see Flash Current Reductions below flash duration defined by STROBE input; timeout defined by flash_timeout 1.0-2 14 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n 1. The MSB bit of this register not used to protect the LED; therefore the maximum torch light current = 1/4 * the maximum flash current 2. The low current mode is a general purpose PWM mode to drive less current through the LED in average, but keep the actual pulsed current in a range where the light output from the LED is still specified. As only the 6 LSBs of led_current1 and led_current2 is used the maximum current is limited to 1/4 of the maximum flash current. Always keep led_current1 >= led_current2. 8.5.1 Flash Current Reductions TXMASK. Usually the flash current is defined by the register led_current1 and led_current2. If the TXMASK/TORCH input is used and (configured by txmask_torch_mode=01), the flash current is reduced to flash_txmask_current if TXMASK/TORCH=1. Current Reduction by VIN Measurements in Flash Mode and Diagnostic Pulse. Due to the high load of the flash driver and the ESR of the battery (especially critical at low temperatures), the voltage on the battery drops. If the voltage drops below the reset threshold, the system would reset. To prevent this condition the AS3649 monitors the battery voltage and keeps it above vin_low_v as follows: If the voltage on VIN before the flash is below vin_low_v, the DCDC is not started at all. Otherwise during flash, if the voltage on VIN drops below the threshold defined by vin_low_v, the flash current is reduced (or ramping of the current is stopped during flash current startup) and status_uvlo is set. The timing for the reduction of the current is 2s/LSB current change. During the flash pulse the actual used current can be readout by the register led_current_actual. After the flash pulse the minimum current can be readout by the register led_current_min - this allows to adjust the camera sensitivity (gain or iso-settings) for the subsequent flash pulse (e.g. when using a pre-flash and a main flash pulse). The internal circuit for low voltage current reductions are shown in Figure 19: Figure 19. Low Voltage Current Reduction Internal Circuit +/ , + -. ! ###! $& $ &' (&) * # # ,# #. . ,# #) www.ams.com/AS3649 AS3649 1.0-2 ! )*#.,1 .0 +# +# 15 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n A mobile phone camera flash system can trigger a diagnostic flash and a main-flash: The diagnostic flash is initiated by the processor. After this diagnostic flash, the determined maximum flash current can be read back through the 2 I C interface from register led_current_min (see page 30) and used for the setting for the main flash. Therefore the current in the main-flash is constant and additionally the camera system can use this current for picture quality adjustments - the waveforms for this concept are shown in Figure 20: Figure 20. Low Voltage Current Reduction Waveform with Diagnostic-Flash and Main-Flash Phase " " &' ( " " ! # " " ! " # $" % % %" Short Diagnostic Pulse. If the diagnostic flash should be short (e.g. 4ms) it is recommended to operate this diagnostic flash at a different vcompl_adj (see page 27) and higher vin_low_v (see page 24) settings compared to the main flash as shown in Figure 21: Figure 21. Low Voltage Current Reduction Waveform with Short Diagnostic-Flash and Main-Flash Phase !" " "" " "# $ "# "% "& ' (!")" "# $*+ " "#"% """""" " ,!")"%%-"" "& '"" ." " " " "/-" " "# $ 0!"" "/ "% #" "% "#"% www.ams.com/AS3649 1.0-2 16 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n The AS3649 efficiency reduction during main flash can be compensated during a short diagnostic flash by adjusting vcompl_adj as shown in Figure 21. Reducing vin_low_v during main flash additionally takes into account a longer time constant of the battery for high loads and allows a very short diagnostic pulse (only 4ms). Using the ams AG linux software driver it is possible to calculate the maximum flash duration for a given operating condition (additionally using TJUNCTION measured through the AS3649 ADC). 8.5.2 Load Balancing To improve the efficiency of the AS3649 for LEDs with unmatched forward voltage and reduce the internal power dissipation of the AS3649, set the bit load_balance_on=1. This bit can change the currents through the LEDs by up to +/-15% to match the forward voltage of the LED better as shown in Figure 22: Figure 22. Load Balancing !" !" ! # ! # 8.6 Flash Strobe Timings The flash timing are defined as follows: 2 1. Flash duration defined by register flash_timeout and flash is started immediately when this mode is selected by the I C command (see Figure 23): set strobe_on = 0, start the flash by setting mode_setting = 11b 2. Flash duration defined by register flash_timeout and flash started with a rising edge on pin STROBE (see Figure 24): set strobe_on = 1 and strobe_type = 0 3. Flash start and timing defined by the pin STROBE; the flash duration is limited by the timeout timer defined by flash_timeout (see Figure 25 and Figure 26): set strobe_on = 1 and strobe_type = 1 Figure 23. AS3649 Flash Duration Defined by flash_timeout Without Using STROBE Input %!& ! "# $$ www.ams.com/AS3649 1.0-2 17 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Figure 24. AS3649 Flash Duration Defined by flash_timeout, Starting Flash with STROBE Rising Edge % ! &# '( "#$ Figure 25. AS3649 Flash Duration and Start Defined by STROBE, Limited by flash_timeout; Timer Not Expired & !" % !" ' ( !"" #$ Figure 26. AS3649 Flash Duration and Start Defined by STROBE, Limited by flash_timeout; Timer Expired $ "# % &' ! www.ams.com/AS3649 1.0-2 18 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n 8.7 ADC The internal ADC is used to monitor LED temperature and DIE temperature. To operate the ADC, set the adc_channel (see page 27) and start the conversion by adc_convert. When adc_convert returns to `0' the result is available in register adc_result (see page 30) (Bits 9...7)and adc_result_lsbs (Bits 1...0). The DIE junction temperature measurement returns the value according to Table 6: Table 6. Junction Temperature Measurement ADC result Junction Temperature - C ADC Return Value (10bit) -30 352 -20 343 -10 334 0 325 10 316 20 306 30 297 40 287 50 278 60 268 70 259 80 249 90 239 100 229 110 219 120 209 130 199 140 189 150 179 8.8 I2C Serial Data Bus 2 The AS3649 supports the I C bus protocol. A device that sends data onto the bus is defined as a transmitter and a device receiving data as a receiver. The device that controls the message is called a master. The devices that are controlled by the master are referred to as slaves. A master device that generates the serial clock (SCL), controls the bus access, and generates the START and STOP conditions must control the 2 bus. The AS3649 operates as a slave on the I C bus. Within the bus specifications a standard mode (100kHz maximum clock rate) and a fast mode (400kHz maximum clock rate) are defined. The AS3649 works in both modes. Connections to the bus are made through the open-drain I/ O lines SDA and SCL. The following bus protocol has been defined (Figure 27): Data transfer may be initiated only when the bus is not busy. During data transfer, the data line must remain stable whenever the clock line is HIGH. Changes in the data line while the clock line is HIGH are interpreted as control signals. Accordingly, the following bus conditions have been defined: Bus Not Busy. Both data and clock lines remain HIGH. Start Data Transfer. A change in the state of the data line, from HIGH to LOW, while the clock is HIGH, defines a START condition. Stop Data Transfer. A change in the state of the data line, from LOW to HIGH, while the clock line is HIGH, defines the STOP condition. www.ams.com/AS3649 1.0-2 19 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Data Valid. The state of the data line represents valid data when, after a START condition, the data line is stable for the duration of the HIGH period of the clock signal. The data on the line must be changed during the LOW period of the clock signal. There is one clock pulse per bit of data. Each data transfer is initiated with a START condition and terminated with a STOP condition. The number of data bytes transferred between START and STOP conditions are not limited, and are determined by the master device. The information is transferred byte-wise and each receiver acknowledges with a ninth bit. Acknowledge. Each receiving device, when addressed, is obliged to generate an acknowledge after the reception of each byte. The master device must generate an extra clock pulse that is associated with this acknowledge bit. A device that acknowledges must pull down the SDA line during the acknowledge clock pulse in such a way that the SDA line is stable LOW during the HIGH period of the acknowledge-related clock pulse. Of course, setup and hold times must be taken into account. A master must signal an end of data to the slave by not generating an acknowledge bit on the last byte that has been clocked out of the slave. In this case, the slave must leave the data line HIGH to enable the master to generate the STOP condition. 2 Figure 27. Data Transfer on I C Serial Bus SDA MSB SLAVE ADDRESS R/W DIRECTION BIT ACKNOWLEDGEMENT SIGNAL FROM RECEIVER ACKNOWLEDGEMENT SIGNAL FROM RECEIVER SCL 1 2 6 7 8 9 1 2 3-7 8 9 ACK START CONDITION REPEATED IF MORE BYTES ARE TRANSFERRED STOP CONDITION OR REPEATED START CONDITION Depending upon the state of the R/W bit, two types of data transfer are possible: 1. Data transfer from a master transmitter to a slave receiver. The first byte transmitted by the master is the slave address. Next follows a number of data bytes. The slave returns an acknowledge bit after each received byte. Data is transferred with the most significant bit (MSB) first. 2. Data transfer from a slave transmitter to a master receiver. The master transmits the first byte (the slave address). The slave then returns an acknowledge bit, followed by the slave transmitting a number of data bytes. The master returns an acknowledge bit after all received bytes other than the last byte. At the end of the last received byte, a "not acknowledge" is returned. The master device generates all of the serial clock pulses and the START and STOP conditions. A transfer is ended with a STOP condition or with a repeated START condition. Since a repeated START condition is also the beginning of the next serial transfer, the bus is not released. Data is transferred with the most significant bit (MSB) first. The AS3649 can operate in the following two modes: 1. Slave Receiver Mode (Write Mode): Serial data and clock are received through SDA and SCL. After each byte is received an acknowledge bit is transmitted. START and STOP conditions are recognized as the beginning and end of a serial transfer. Address recognition is performed by hardware after reception of the slave address and direction bit (see Figure 28). The slave address byte is the first byte received after the master generates the START condition. The slave address byte contains the 7-bit AS3649 address, 13 which is 0110000, followed by the direction bit (R/W), which, for a write, is 0. After receiving and decoding the slave address byte the device outputs an acknowledge on the SDA line. After the AS3649 acknowledges the slave address + write bit, the master transmits a www.ams.com/AS3649 1.0-2 20 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n register address to the AS3649. This sets the register pointer on the AS3649. The master may then transmit zero or more bytes of data, with the AS3649 acknowledging each byte received. The address pointer will increment after each data byte is transferred. The master generates a STOP condition to terminate the data write. 2. Slave Transmitter Mode (Read Mode): The first byte is received and handled as in the slave receiver mode. However, in this mode, the direction bit indicates that the transfer direction is reversed. Serial data is transmitted on SDA by the AS3649 while the serial clock is input on SCL. START and STOP conditions are recognized as the beginning and end of a serial transfer (Figure 29 and Figure 30). The slave address byte is the first byte received after the master generates a START condition. The slave address byte contains the 714 bit AS3649 address, which is 0110000, followed by the direction bit (R/W), which, for a read, is 1. After receiving and decoding the slave address byte the device outputs an acknowledge on the SDA line. The AS3649 then begins to transmit data starting with the register address pointed to by the register pointer. If the register pointer is not written to before the initiation of a read mode the first address that is read is the last one stored in the register pointer. The AS3649 must receive a "not acknowledge" to end a read. <Slave Address> S 0110000 <RW> Figure 28. Data Write - Slave Receiver Mode 0 <Word Address (n)> A XXXXXXXX A XXXXXXXX S - Start A - Acknowledge (ACK) P - Stop <Data(n+X)> <Data(n+1)> <Data(n)> A XXXXXXXX A XXXXXXXX A P NA P Data Transferred (X + 1 Bytes + Acknowledge) <Slave Address> S 0110000 <RW> Figure 29. Data Read (from Current Pointer Location) - Slave Transmitter Mode 1 <Data(n+1)> <Data(n)> A S - Start A - Acknowledge (ACK) P - Stop NA - Not Acknowledge (NACK) XXXXXXXX A XXXXXXXX <Data(n+X)> <Data(n+2)> A XXXXXXXX A XXXXXXXX Data Transferred (X + 1 Bytes + Acknowledge) Note: Last data byte is followed by a NACK 13.The address for writing to the AS3649 is 60h = 01100000b 14.The address for read mode from the AS3649 is 61h = 01100001b www.ams.com/AS3649 1.0-2 21 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n S 0110000 0 A XXXXXXXX A XXXXXXXX <Slave Address> Sr A 0110000 A XXXXXXXX S - Start Sr - Repeated Start A - Acknowledge (ACK) P - Stop NA - Not Acknowledge (NACK) 1 A <Data(n+X)> <Data(n+2)> <Data(n+1)> <Data(n)> XXXXXXXX <Word Address (n)> <RW> <RW> Figure 30. Data Read (Write Pointer, Then Read) - Slave Receive and Transmit A NA XXXXXXXX P Data Transferred (X + 1 Bytes + Acknowledge) Note: Last data byte is followed by a NACK 8.9 Register Description Table 7. ChipID Register ChipID Register Addr: 0 This register has a fixed ID Bit Bit Name Default Access Description 2:0 version Xh R AS3649 chip version number 7:3 fixed_id 11000b R This is a fixed identification (e.g. to verify the I C communication) 2 Table 8. Current Set LED1 Register Current Set LED1 Register Addr: 1 Bit Bit Name This register defines design versions Default Access Description Define the current on pin LED_OUT1; torch mode uses bits 5:0 of this current setting (max. 1/4 of full current setting) indicator or low current pwm mode uses only 5:0 of this current setting (max. 1/4 of full current setting) Note: Always keep led_current1 >= led_current2 7:0 led_current1 9Ch R/W 0h 0mA 1h 7.8mA 2h 11.7mA ... ... 3Fh 250mA (maximum current for torch light mode, indicator or low current pwm mode, mode_setting=01 or 10) ... ... 7Fh 500mA ... ... 9Ch 613.3mA - default setting ... ... FEh 996mA (1245mA if current_boost=1) FFh 1000mA (1250mA if current_boost=1) 1 1 1. Only use current_boost=1 for currents > 1000mA(code >= CCh) www.ams.com/AS3649 1.0-2 22 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 9. Current Set LED2 Register Current Set LED2 Register Addr: 2 Bit Bit Name This register defines design versions Default Access Description Define the current on pin LED_OUT2; torch mode uses bits 5:0 of this current setting (max. 1/4 of full current setting) indicator or low current pwm mode uses only 5:0 of this current setting (max. 1/4 of full current setting) Note: Always keep led_current1 >= led_current2 led_current2 7:0 9Ch R/W 0h 0mA 1h 7.8mA 2h 11.7mA ... ... 3Fh 250mA (maximum current for torch light mode, indicator or low current pwm mode, mode_setting=01 or 10) ... ... 7Fh 500mA ... ... 9Ch 613.3mA - default setting ... ... FEh 996mA (1245mA if current_boost=1) FFh 1000mA (1250mA if current_boost=1) 1 1 1. Only use current_boost=1 for currents > 1000mA(code >= CCh) Table 10. TXMask Register TXMask Register Addr: 3 Bit Bit Name This register defines the TXMask settings and coil peak current Default Access Description Defines operating mode for input pin TXMASK/TORCH 1:0 txmask_torch_mode 00 00 pin has no effect 01 txmask-mode; during flash if TXMASK/TORCH=1, the LED current is set to flash_txmask_current - (see TXMASK on page 15) 10 external torch mode: if TXMASK/TORCH=1 and mode_setting=00, the AS3649is set into external torch mode 1 (LED current is defined by the 6LSB bits of led_current1 and led_current2) 11 don't use R/W Defines the maximum coil current (parameter ILIMIT) 3:2 www.ams.com/AS3649 coil_peak 10 R/W 00 ILIMIT = 2.5A 01 ILIMIT = 2.9A 10 ILIMIT = 3.3A 11 ILIMIT = 3.7A 1.0-2 23 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 10. TXMask Register (Continued) TXMask Register Addr: 3 Bit This register defines the TXMask settings and coil peak current Bit Name Default Access Description Define the current on pin LED_OUT1 and LED_OUT2 (each current source) in flash mode if txmask_torch_mode=01 and TXMASK/ TORCH=1 7:4 flash_txmask_current 2 6h R/W 0h 0mA 1h 31mA (39mA if current_boost=1) 2h 63mA (78mA if current_boost=1) 3h 94mA (118mA if current_boost=1) 4h 125mA (157mA if current_boost=1) 5h 157mA (196mA if current_boost=1) 6h 188mA (235mA if current_boost=1) - default 7h 220mA (275mA if current_boost=1) 8h 251mA (314mA if current_boost=1) 9h 282mA (353mA if current_boost=1) Ah 314mA (392mA if current_boost=1) Bh 345mA (431mA if current_boost=1) Ch 376mA (471mA if current_boost=1) Dh 408mA (510mA if current_boost=1) Eh 439mA (549mA if current_boost=1) Fh 471mA (588mA if current_boost=1) 1. The MSB bit of this register not used to protect the LED; therefore the maximum current = 1/4 the maximum flash current 2. If current_boost=1, the LED current is increased by 25%. Table 11. Low Voltage / NTC Register Low Voltage / NTC Register Addr: 4 Bit Bit Name This register defines the operating mode with low battery voltages Default Access Description Voltage level on VIN where current reduction triggers during operation (see Current Reduction by VIN Measurements in Flash Mode and Diagnostic Pulse on page 15) - only in flash mode; if VIN drops below this voltage during current ramp up, the current ramp up is stopped; during operation the current is decreased until the voltage on VIN rises above this threshold - status_uvlo is set 2:0 www.ams.com/AS3649 vin_low_v 4h R/W 0h function is disabled 1h 3.0V 2h 3.07V 3h 3.14V 4h 3.22V - default 5h 3.3V 6h 3.38V 7h 3.47V 1.0-2 24 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 11. Low Voltage / NTC Register (Continued) Low Voltage / NTC Register Addr: 4 Bit Bit Name This register defines the operating mode with low battery voltages Default Access Description Enable overtemperature protection on pin NTC (internal comparator comparing NTC to VNTC_TH) 3 ntc_on 0 R/W 0 disabled 1 enabled Current through the NTC (INTC); it is enabled once the LED current source (LED_OUT1/2) is operating and ntc_on=1 or the ADC measures the LED temperature (see NTC - Flash LED Overtemperature Protection on page 14) 7:4 www.ams.com/AS3649 ntc_current 8h R/W 0h off; can be used to use an external current to bias the NTC 1h 40A 2h 80A 3h 120A 4h 160A 5h 200A 6h 240A 7h 280A 8h 320A - default 9h 360A Ah 400A Bh 440A Ch 480A Dh 520A Eh 560A Fh 600A 1.0-2 25 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 12. Flash Timer Register Flash Timer Register Addr: 5 Bit This register identifies the flash timer and timeout settings Bit Name Default Access Description Define the duration of the flash timer and timeout timer 5:0 flash_timeout 1 26h R/W 00h ... 4ms 01h ... 8ms 02h ... 12ms 03h ... 16ms 04h ... 20ms 05h ... 24ms 06h ... 28ms 07h ... 32ms 08h ... 36ms 09h ... 40ms 0Ah ... 44ms 0Bh ... 48ms 0Ch ... 52ms 0Dh ... 56ms 0Eh ... 60ms 0Fh ... 64ms 10h ... 68ms 11h ... 72ms 12h ... 76ms 13h ... 80ms 14h ... 84ms 15h ... 88ms 2Bh ... 484ms 2Ch ... 516ms 2Dh ... 548ms 2Eh ... 580ms 2Fh ... 612ms 30h ... 644ms 31h ... 676ms 32h ... 708ms 33h ... 740ms 34h ... 772ms 35h ... 804ms 36h ... 836ms 37h ... 868ms 38h ... 900ms 39h ... 932ms 3Ah ... 964ms 3Bh ... 996ms 3Ch ... 1028ms 3Dh ... 1060ms 3Eh ... 1092ms 3Fh ... 1124ms 16h ... 92ms 17h ... 96ms 18h ... 100ms 19h ... 104ms 1Ah ... 108ms 1Bh ... 112ms 1Ch ... 116ms 1Dh ... 120ms 1Eh ... 124ms 1Fh ... 128ms 20h ... 132ms 21h ... 164ms 22h ... 196ms 23h ... 228ms 24h ... 260ms 25h ... 292ms 26h ... 324ms 27h ... 356ms 28h ... 388ms 29h ... 420ms 2Ah ... 452ms 1. Internal calculation for codes above 20h: flash timeout [ms] = (flash_timeout-32) * 32 + 132 [ms] Table 13. Control Register Control Register Addr: 6 Bit Bit Name This register identifies the operating mode and includes an all on/off bit Default Access Description Define the AS3649 operating mode - see Table 5, "Operating Mode and Current Settings," on page 14 standby/shutdown or external torch mode if txmask_torch_mode (page 23)=10 00 indicator mode (or low current mode using PWM) 01 1:0 mode_setting 00 R/W 1 LED current is defined by the 6LSB bits of led_current1 and led_current2 pwm modulated defined by register inct_pwm (31.5kHz: 1/16...4/16, 7.9kHz: 1/64...3/64) torch light mode: 10 2 LED current is defined by the 6LSB bits of led_current1 and led_current2 flash mode: LED current is defined by led_current1 and led_current2 (mode_setting is automatically cleared after a flash pulse) 11 www.ams.com/AS3649 1.0-2 26 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 13. Control Register (Continued) Control Register Addr: 6 Bit Bit Name This register identifies the operating mode and includes an all on/off bit Default Access Description Increase min. on time of DCDC converter - use for diagnostic pulse, if freq_switch_on=1. If this register is not 00 and freq_switch_on=1, the DCDC converter will use 4MHz operation forced PWM mode or pass-through mode but will not switch to 1MHz operation 3:2 min_on_increase 00 R/W 00 100% - default min. on time 01 108% 10 131% 11 157% Force DCDC operation even in pass-through mode - use for diagnostic pulse, if freq_switch_on=1 4 force_dcdc_on 0 R/W 0 DCDC is only enabled when needed; default 1 DCDC is always enabled even when pass-though mode could be used Increase voltage compliance of current source for diagnostic pulses see Short Diagnostic Pulse on page 16 vcompl_adj 7:5 000b R/W 000 default - 0mV 001 14mV (26mV if current_boost=1) 010 29mV (51mV if current_boost=1) 011 43mV (77mV if current_boost=1) 100 57mV (103mV if current_boost=1) 101 71mV (129mV if current_boost=1) 110 85mV (154mV if current_boost=1) 111 100mV (180mV if current_boost=1) 1. The two MSB bits of this register are not used to protect the LED; therefore the maximum indicator (or low current mode using PWM) light current = 1/4 the maximum flash current multiplied by the duty cycle defined by inct_pwm 2. The two MSB bits of this register not used to protect the LED; therefore the maximum torch light current = 1/4 the maximum flash current Table 14. Strobe Signalling / ADC Register Strobe Signalling / ADC Register Addr: 7 Bit Bit Name This register defines the flash current reducing and mode for STROBE Default Access Description Select ADC channel for conversion 3:0 www.ams.com/AS3649 adc_channel 000b R/W 000 NTC 001 TJUNC 010 VIN 1.0-2 27 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 14. Strobe Signalling / ADC Register (Continued) Strobe Signalling / ADC Register Addr: 7 Bit Bit Name This register defines the flash current reducing and mode for STROBE Default Access Description Start ADC conversion adc_convert 4 0 R/W 0 ADC conversion finished 1 Start ADC conversion - once finished the register bit is automatically reset and the result is stored in adc_result Allow pulseskip operation of DCDC - see Table 4 on page 12 5 dcdc_skip_enable 1 R/W 0 Disabled - force 4MHz (1MHz) operation 1 Enabled - can use pulseskip 1 Defines if the STROBE input is edge or level sensitive; see also bit strobe_on (page 28) strobe_type 6 1 R/W 0 STROBE input is edge sensitive 1 STROBE input is level sensitive Enables the STROBE input strobe_on 7 1 R/W 0 STROBE input disabled 1 STROBE input enabled in flash mode 1. Exception depending on freq_switch_on (see page 29) - see Table 4 on page 12 Table 15. Fault Register Fault Register Addr: 8 Bit 0 1 2 3 Bit Name status_uvlo reserved fault_ntc fault_txmask This register identifies all the different fault conditions and provide information about the LED detection Default 0 0 0 0 Access R/sC 1 Description an undervoltage event has happened - see Current Reduction by VIN Measurements in Flash Mode and Diagnostic Pulse on page 15 0 No 1 Yes R R/sC R/sC reserved - don't use 1 1 LED overtemperature detection hit - see NTC - Flash LED Overtemperature Protection on page 14 0 No 1 Yes TXMASK/TORCH event triggered during flash - see TXMASK event occurred on page 13 0 No 1 Yes see Flash Timeout on page 14 4 www.ams.com/AS3649 fault_timeout 0 R/sC 1 0 No fault 1 Flash timeout exceeded 1.0-2 28 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 15. Fault Register (Continued) Fault Register Addr: 8 Bit This register identifies all the different fault conditions and provide information about the LED detection Bit Name Default Access Description see Overtemperature Protection on page 13 5 fault_overtemp 0 R/sC 1 0 No fault 1 Junction temperature limit has been exceeded see Short Circuit Protection on page 13 6 fault_led_short 0 R/sC 1 0 No fault 1 A shorted LED is detected (pin LED_OUT1/2) see Overvoltage Protection on page 13 fault_ovp 7 0 R/sC 1 0 No fault 1 An overvoltage condition is detected (pin VOUT) 1. R/sC = Read, self clear; after readout the register is automatically cleared Table 16. PWM and Indicator Register PWM and Indicator Register Addr: 9 Bit This register defines the PWM mode (e.g. for indicator) and 4/1MHz mode switching Bit Name Default Access Description Define the AS3649 PWM with 31.5kHz or 7.9kHz operation for indicator or low current mode (mode_setting=01) 1 2:0 inct_pwm 00 R/W 000 1/16 duty cycle / 31.5kHz 001 2/16 duty cycle / 31.5kHz 010 3/16 duty cycle / 31.5kHz 011 4/16 duty cycle / 31.5kHz 100 1/64 duty cycle / 7.9kHz; needs const_v_mode=1 (additional quiescent current) 101 2/64 duty cycle / 7.9kHz; needs const_v_mode=1 (additional quiescent current) 110 3/64 duty cycle / 7.9kHz; needs const_v_mode=1 (additional quiescent current) 111 (4/64 duty cycle / 7.9kHz) don't use; use 000 setting instead Exact frequency switching between 4MHz/1MHz for operation close to maximum pulsewidth - see Table 4 on page 12 3 freq_switch_on www.ams.com/AS3649 0 R/W 0 Pulseskip operation is allowed depending on dcdc_skip_enable (see page 28) 1 if led_current1>=40h or led_current2>=40h and current_boost=0, the DCDC is running at 4MHz or 1MHz and pulseskip is disabled results in improved noise performance 1.0-2 29 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 16. PWM and Indicator Register (Continued) PWM and Indicator Register Addr: 9 Bit 4 This register defines the PWM mode (e.g. for indicator) and 4/1MHz mode switching Bit Name Default load_balance_on 0 Access R/W Description Balance the current sources (up to +/-15% of set current) to improve application efficiency for unmatched LED forward voltages - see Load Balancing on page 17 0 disabled 1 enabled Enables Constant output voltage mode 5 const_v_mode 0 0 Normal operation defined by mode_setting 1 5V constant voltage mode on VOUT1/2; LED current can be controlled by registers mode_setting, led_current1 and led_current2 as in normal operating mode, but the ramping up/down of the current sources is disabled (instantaneous on/off of the LED current) R/W 1. Using 31.5kHz modulation avoids audible noise on the output capacitor CVOUT Table 17. ADC Result Register ADC Result Register Addr: Ah This register reports the actual set LED current Bit Bit Name Default Access Description 7:0 adc_result NA R Result of ADC conversion for channel adc_channel Table 18. ADC Result LSBs Register ADC Result LSBs Register Addr: Bh This register reports the actual set LED current Bit Bit Name Default Access Description 1:0 adc_result_lsbs NA R Result of ADC conversion for channel adc_channel Table 19. Minimum LED Current Register Minimum LED Current Register Addr: Eh Bit 7:0 This register reports the minimum LED current from the last operation cycle Bit Name led_current_min Default 123 00h Access Description R see Current Reduction by VIN Measurements in Flash Mode and Diagnostic Pulse (see page 15) and Figure 20 on page 16 1. Only the current through LED_OUT1 is reported. 2. As the internal change of this register is asynchronous to the readout, it is recommended to readout the register after the flash pulse. The register will store the minimum current through the LED after e.g. a previous flash. This current can be used for a subsequent flash pulse for a safe operating range. 3. This register is only set if an actual current reduction happens (status_uvlo (see page 28)=1) otherwise led_current_min=0. www.ams.com/AS3649 1.0-2 30 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 20. Actual LED Current Register Actual LED Current Register Addr: Fh Bit 7:0 This register reports the actual set LED current Bit Name led_current_actual 12 Default Access Description 00h R Actual set current through the current source (including all current reductions as described in Flash Current Reductions (see page 15) including LED current ramp up/down) 1. Only the current through LED_OUT1 is reported. 2. As the internal change of this register is asynchronous to the readout, it is recommended to readout the register twice and compare the results. Table 21. Unlock Register Register Unlock Register Register Addr: 80h Protection for register Current Boost Bit Bit Name Default Access Description 7:0 unlock NA W Write 55h into this register to enable access to register 81h Table 22. Current Boost Register Current Boost Register Addr: 81h Bit Increase output current by 25% Bit Name Default Access Description Boost all LED currents by 25% 0 current_boost 1 0 R/W 0 all LED current are as described in the tables 1 all LED current are increased by 25% 2 1. Write 55h into register unlock (0x80) to enable access to this register (unlocking is only valid for the next I C access) - required on any write access to this register www.ams.com/AS3649 1.0-2 31 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n 8.10 Register Map Table 23. Register Map Register Definition 1 Addr Default Name Content b7 b6 b5 b4 b3 ChipID 0 Cxh Current Set LED1 1 9Ch led_current1 Current Set LED2 2 9Ch led_current2 TXMask 3 68h flash_txmask_current Low Voltage / NTC 4 84h ntc_current Flash Timer 5 26h Control 6 00h Strobe Signalling / ADC 7 E0h dcdc_skip adc_conv strobe_on strobe_ty pe _enable ert Fault 8 00h fault_over fault_time fault_txm fault_ovp fault_led_ short temp out ask PWM and Indicator 9 00h const_v_ load_bala freq_switc mode nce_on h_on ADC Result Ah NA ADC Result LSBs Bh NA Minimum LED Current Eh 00h led_current_min Actual LED Current Fh 00h led_current_actual Unlock Register 80h 00h unlock Current Boost 81h 00h b2 fixed_id b1 b0 version coil_peak txmask_torch_mode ntc_on vin_low_v flash_timeout force_dcd c_on vcompl_adj min_on_increase mode_setting adc_channel fault_ntc reserved status_uvl o inct_pwm adc_result adc_result_lsbs current_b oost 1. Always write'0' to undefined register bits www.ams.com/AS3649 1.0-2 32 - 39 AS3649 Datasheet - A p p l i c a t i o n I n f o r m a t i o n 9 Application Information 9.1 External Components 9.1.1 Input Capacitor CVIN Low ESR input capacitors reduce input switching noise and reduce the peak current drawn from the battery. Ceramic capacitors are required for input decoupling and should be located as close to the device as is practical. Table 24. Recommended Input Capacitor Part Number C TC Code Rated Voltage Size Manufacturer GRM188R60J106ME47 10 >3F@4.5V >2F@5.25V X5R 6V3 0603 Murata www.murata.com LMK107BBJ106MA 10 >3F@4.5V X5R 6V3 0603 Taiyo Yuden www.t-yuden.com If a different input capacitor is chosen, ensure similar ESR value and at least 3F capacitance at the maximum input supply voltage. Larger capacitor values (C) may be used without limitations. Add a smaller capacitor in parallel to the input pin VIN (e.g. Murata GRM155R61C104, >50nF @ 3V, 0402 size). 9.1.2 Output Capacitor CVOUT Low ESR capacitors should be used to minimize VOUT ripple. Multi-layer ceramic capacitors are recommended since they have extremely low ESR and are available in small footprints. The capacitor should be located as close to the device as is practical. X5R dielectric material is recommended due to their ability to maintain capacitance over wide voltage and temperature range. Table 25. Recommended Output Capacitor Part Number C TC Code Rated Voltage Size GRM219R61A106ME47 10F +/-10% >4.2F@5V X5R 10V 0805 (2.0x1.25x0.85mm max 1mm height) 22F >4.2F@4.5V X5R 6.3V 0805 (2.0x1.25x1.25mm max. 1.4mm height) 10F +/-20% >4.2F@4V X5R 6.3V 0603 (1.6x0.8x0.85mm max. 0.95mm height) GRM21BR60J226M 1 GRM188R60J106ME84 2 Manufacturer Murata www.murata.com 1. Use only for VLED < 4.1V 2. Use only for VLED < 3.75V If a different output capacitor is chosen, ensure similar ESR values and at least 4.2F capacitance at 5V output voltage. www.ams.com/AS3649 1.0-2 33 - 39 AS3649 Datasheet - A p p l i c a t i o n I n f o r m a t i o n 9.1.3 Inductor LDCDC The fast switching frequency (4MHz) of the AS3649 allows for the use of small SMDs for the external inductor. The saturation current 15 ISATURATION should be chosen to be above the maximum value of ILIMIT . The inductor should have very low DC resistance (DCR) to reduce 2 the I R power losses - high DCR values will reduce efficiency. Table 26. Recommended Inductor Part Number L DCR ISATURATION Size Manufacturer LQM32PN1R0MG0 1.0H >0.6H @ 3.0A 60m 3.0A 3.2x2.5x0.9mm max 1.0mm height Murata www.murata.com SPM4012T-1R0M 1.0H +/-20% 38m 4.57A 4.4x4.1x1.2 mm height is max 2 3.2x3x1.2 mm height is max 4 3.2x2.5mm max 1.0mm height 4 3.2x2.5x0.9mm max 1.0mm height 3 2.4x2.4x1.2mm (height is max.) 4 2.5x2.0x1.2mm height is max 1 SPM3012T-1R0M 1.0H +/-20% 57m +/-10% 3.4A CIG32W1R0MNE 1.0H >0.7H @ 2.7A >0.6H @ 3.0A 60m +/-25% 3.0A CKP3225N1R0M 1.0H >0.6H @ 3.0A <60m 3.0A NRH2412T1R0N 1.0H >0.6H @ 2.5A 77m 2.5A MAMK2520T1R0M 1.0H >0.6H @ 2.75A 45m 3.1A TDK www.tdk.com Samsung Electro-Mechancs www.sem.samsung.co.kr Taiyo Yuden www.t-yuden.com 1. Flash pattern: 200ms/3A, 200ms pause, 200ms/3A, 2s then repeat again (no limit on the number of total cycles) Alternative pattern with 1000ms/1.6A, 200ms pause, 200ms/3A, 200ms pause, 200ms/3A, 2s then repeat again. (no limit on the number of total cycles). Use only up to coil_peak=2.9A setting 2. Inductance changes by -30%, use only up to coil_peak=3.3A setting 3. Use only for coil_peak=2.5A setting. 4. Use only up to coil_peak=2.9A setting. If a different inductor is chosen, ensure similar DCR values and at least0.6H inductance at ILIMIT. 9.1.4 Thermistor (NTC) The NTC is used to protect the LED against overheating (hardware protection inside the AS3649, which works without any software - see NTC Flash LED Overtemperature Protection on page 14). The thermistor has to be thermally coupled to the LED (and therefore as close as possible to the LED) and it shall not share the same ground connection as the LED return ground (if they share the same ground connection the high current through the LED will offset the measurement of the NTC). Table 27. Recommended Thermistors Part Number Resistance @ 25C B-constant 25/50C NCP03WL224E05RL 220k +/-3% 4485K +/-1% NCP03WL104E05RL 100k +/-3% 4485K +/-1% NCP15WF104F03RC 100k NCP15WL683J03RC 68k Size Manufacturer 0201 Murata www.murata.com 0402 It is recommended to use 220k resistance for a detection threshold of 125C, 100k for 110C and 68k for 80C LED temperature detection threshold. 15.Can be adjusted in I2C mode with register coil_peak (see page 23) www.ams.com/AS3649 1.0-2 34 - 39 AS3649 Datasheet - A p p l i c a t i o n I n f o r m a t i o n 9.2 PCB Layout Guideline The high speed operation requires proper layout for optimum performance. Route the power traces first and try to minimize the area and wire length of the two high frequency/high current loops: Loop1: CVIN/CVIN2 - LDCDC - pin SW1/2 - pin GND - CVIN/CVIN2 Loop2: CVIN/CVIN2 - LDCDC - pin SW1/2 - pin VOUT1/2 - CVOUT - pin GND - CVIN/CVIN2 At the pin GND a single via (or more vias, which are closely combined) connects to the common ground plane. This via(s) will isolate the DCDC high frequency currents from the common ground (as most high frequency current will flow between Loop1 and Loop2 and will not pass the ground plane) - see the `island' in Figure 31. Figure 31. Layout Recommendation "-. ** +,-./,-01 * '$ ) )$ ) "-.. ) !"# *4 ,-", $ 5 * 234 234, !"# $ % & $ $$ ) * /2+1 Note: If component placement rules allow, move all components close to the AS3649 to reduce the area and length of Loop1 and Loop2. It is recommended to use the main ground plane for the LED ground connections (improved thermal performance of the LEDs) - it is recommend to use a separate ground line as shown Figure 31 for the ground connection of the NTC (this avoids errors for the temperature measurement of the LEDs due to the high LED current in the main ground plane). Keep the LED path (from pin LED_OUT1/2 to the LED and the ground return path) below 10cm (represents an inductance of less than 100nH). An additional 100nF (e.g. Murata GRM155R61C104, >50nF @ 3V, 0402 size) capacitor CVIN2 in parallel to CVIN is recommended to filter high frequency noise for the power supply of AS3649. This capacitor should be as close as possible to the AGND/VIN pins of AS3649. www.ams.com/AS3649 1.0-2 35 - 39 AS3649 Datasheet - A p p l i c a t i o n I n f o r m a t i o n 9.3 5V Operating Mode The AS3649 can be used to power a 5V system (e.g. audio amplifier). The operating mode is selected by setting register bit const_v_mode (page 30)=1. Note: There is always a diode between VIN and VOUT1/2 due to the internal circuit. Therefore VOUT1/2 cannot be completely switched off Figure 32. 5V Operating Mode AS3649 www.ams.com/AS3649 1.0-2 36 - 39 AS3649 Datasheet - P a c k a g e D r a w i n g s a n d M a r k i n g s 10 Package Drawings and Markings Figure 33. WL-CSP16 Marking Note: Line 1: Line 2: Line 3: ams AG logo AS3649 <Code> Encoded Datecode (4 characters) Figure 34. WL-CSP16 Package Dimensions ! "#$ %#& * '' ' $ $' $* $* $' $ $ ' * * ' ( ( (' (* (* (' ( ( )' ) ) $ ) )' )* )* ) ' + ' The coplanarity of the balls is 40m. www.ams.com/AS3649 1.0-2 37 - 39 AS3649 Datasheet - O r d e r i n g I n f o r m a t i o n 11 Ordering Information The devices are available as the standard products shown in Table 28. Table 28. Ordering Information Ordering Code AS3649-ZWLT Description Delivery Form Package Tape & Reel 16-pin WL-CSP (2.06x2.02x0.6mm) 0.5mm pitch RoHS compliant / Pb-Free / Green 2500mA High Current LED Flash Driver Z Temperature Range: -30C - 85C WL Package: Wafer Level Chip Scale Package (WL-CSP) 2.06x2.02x0.6mm T Delivery Form: Tape & Reel Note: All products are RoHS compliant and ams green. Buy our products or get free samples online at www.ams.com/ICdirect Technical Support is available at www.ams.com/Technical-Support For further information and requests, email us at sales@ams.com (or) find your local distributor at www.ams.com/distributor www.ams.com/AS3649 1.0-2 38 - 39 AS3649 Datasheet - O r d e r i n g I n f o r m a t i o n Copyrights Copyright (c) 1997-2013, ams AG, Tobelbaderstrasse 30, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered (R). All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. All products and companies mentioned are trademarks or registered trademarks of their respective companies. Disclaimer Devices sold by ams AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. ams AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. ams AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with ams AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing by ams AG for each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location. The information furnished here by ams AG is believed to be correct and accurate. However, ams AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. 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