Data Sheet WHITE LED STEP-UP CONVERTER AP3032 General Description Features The AP3032 is an inductor-based DC/DC boost converter designed to drive up to 4 rows of LEDs with 7 series for each in parallel for backlight. * * * * * * * * * * * * A constant frequency 1MHz PWM control scheme is employed in this IC, which means tiny external components can be used. Specifically, 1mm tall 6.8H inductor and 1F aluminum output capacitor for the typical application is sufficient. The over output voltage protection is equipped in AP3032, which protects the IC under open load condition. The AP3032 includes UVLO, soft-start, stand-by mode, current limiting and OTSD to protect the circuit under over load condition Efficiency Up to 81%VIN=5V, IOUT=80mA Drives up to 4 Rows of WLEDs with 7 Series for Each in Parallel (VIN=5V) Fast 1 MHz Switching Frequency Wide Input Voltage Range: 2.7V to 9V Low Feedback Voltage: 200mV Output Over Voltage Protection Cycle-by-cycle Current Limit: 1.4A Built in Soft-start Built in Standby-mode to Achieve High Frequency PWM Dimming Built in Thermal Shutdown Function Under Voltage Lockout Applications The AP3032 is available in SOT-23-6 package. * * * 7' to 10' LCD Panels Digital Photo Frame GPS Receiver SOT-23-6 Figure 1. Package Type of AP3032 Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 1 Data Sheet WHITE LED STEP-UP CONVERTER AP3032 Pin Configuration K Package (SOT-23-6) Pin 1 Mark SW 1 6 VIN GND 2 5 OV FB 3 4 CTRL Figure 2. Pin Configuration of AP3032 (Top View) Pin Description Pin Number Pin Name 1 SW 2 GND 3 FB Dec. 2012 4 CTRL 5 OV 6 VIN Function Switch pin. Connect external inductor and Schottky Ground Voltage feedback. Reference voltage is 200mV Enable and dimming control pin. Connect to a high input to enable the IC or a low input to disable the IC. Connect to a PWM input to achieve dimming control If logic low time is less than about 0.7 ms, AP3032 is hold on standby mode, at which it shut down the power switch but shield the soft-start function, to achieve high frequency dimming Over voltage protection input. Connect to the output directly. On OVP condition, the output voltage will clamp Input supply pin. Must be locally bypassed Rev. 1. 2 BCD Semiconductor Manufacturing Limited 2 Data Sheet WHITE LED STEP-UP CONVERTER AP3032 Functional Block Diagram FB SW 3 1 SOFT START 5 OVP VIN 6 VREF A1 1.25V CONTROL LOGIC A2 COMPARATOR Q1 OVER TEMPERATURE DETECTOR 2 CTRL OV DRIVER 200mV GND 4 RAMP GENERATOR STAND BY 1.2MHz OSCILLATOR Figure 3. Functional Block Diagram of AP3032 Ordering Information AP3032 - Circuit Type G1: Green TR: Tape & Reel Package K: SOT-23-6 Package Temperature Range SOT-23-6 -40 to 85C Part Number AP3032KTR-G1 Marking ID GJL Packing Type Tape & Reel BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS compliant and green. Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 3 Data Sheet WHITE LED STEP-UP CONVERTER AP3032 Absolute Maximum Ratings (Note 1) Parameter Symbol Value Unit Input Voltage VIN 20 V SW Pin Voltage VSW 38 V FB Pin Voltage VFB 20 V OV Voltage VOV 35 V VCTRL 20 V JA 265 C/W TJ 150 C Storage Temperature Range TSTG -65 to 150 C Lead Temperature (Soldering, 10sec) TLEAD 260 C ESD (Machine Model) 200 V ESD (Human Body Model) 2000 V CTRL Pin Voltage Thermal Resistance (Junction Ambient, No Heat Sink) Operating Junction Temperature to Note 1: Stresses greater than those listed under "Absolute Maximum Ratings" 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 under "Recommended Operating Conditions" is not implied. Exposure to "Absolute Maximum Ratings" for extended periods may affect device reliability. Recommended Operating Conditions Parameter Symbol Min Max Unit Operating Temperature Range TOP -40 85 C Input Voltage VIN 2.7 9 V 9 V CTRL Pin Voltage Dec. 2012 VCTRL Rev. 1. 2 BCD Semiconductor Manufacturing Limited 4 Data Sheet WHITE LED STEP-UP CONVERTER AP3032 Electrical Characteristics VIN=VCTRL=5.0V, unless otherwise specified. Specification with standard typeface are for TA= 25C, and those in boldface type apply over the full operating temperature rang (TA=-40C to 85C). Parameters Symbol Conditions Min Typ Max Unit 9 V 5.0 mA SUPPLY VOLTAGE (VIN PIN) Input Voltage VIN Quiescent Current Shutdown Supply Current IQ ISHDN 2.7 VFB=VIN, Not Switching 3.0 VCTRL=0V 4.0 50 A ENABLE (EN PIN) CTRL Pin Voltage VCTRL 1.2 V CTRL Pin Bias Current ICTRL 60 A VOVP 27 V OUTPUT VOLTAGE OVP Voltage VOLTAGE REFERENCE (FB PIN) Feedback Voltage VFB Feedback Bias Current IFB 188 200 212 mV 35 100 A 1.3 MHz SWITCHING REGULATOR Switching Frequency f 0.75 1 Maximum Duty Cycle DMAX 90 93 % Switch Current Limit ILIMIT D=60% 1.2 1.4 A VCE_SAT ISW=1A 300 mV VSW=9V 0.01 Switch VCE Saturation Voltage Switch Leakage Current 5 A THERMAL SHUTDOWN Thermal Shutdown TOTSD 160 C Thermal Shutdown Hysteresis THYS 20 C Soft-start Time tSS 300 s Standby Time tSTANDBY 0.7 ms SOFT START Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 5 Data Sheet WHITE LED STEP-UP CONVERTER AP3032 Typical Performance Characteristics The WLED forward voltage (VF) is 3.2V at ILED=20mA, unless otherwise noted. 100 1.8 90 1.7 80 1.6 Current Limit (A) Efficiency (%) 70 60 50 40 30 O 1.4 1.3 1.2 TA=25 C LED:7S4P,20mA Per Channel 20 1.5 o TA=25 C 1.1 10 0 1.0 3 4 5 6 7 8 9 0 10 20 30 Figure 4. Efficiency vs. Input Voltage 50 60 70 80 90 Figure 5. Switch Current Limit vs. Duty Cycle 2.70 4.7 2.65 4.6 TA= -40 C 4.5 TA= 25 C Quiescent Current (mA) Minimum Operating Voltage (V) 40 Duty Cycle (%) Input Voltage (V) 2.60 2.55 2.50 2.45 2.40 2.35 o 4.3 4.2 4.1 4.0 3.9 2.25 3.8 3.7 -40 -20 0 20 40 60 80 100 120 2 140 3 4 5 6 7 8 9 Input Voltage (V) o Temperature ( C) Figure 6. Minimum Operating Voltage vs. Temperature Dec. 2012 TA= 85 C 4.4 2.30 2.20 -60 o o Rev. 1. 2 Figure 7. Quiescent Current vs. Input Voltage BCD Semiconductor Manufacturing Limited 6 Data Sheet WHITE LED STEP-UP CONVERTER AP3032 Typical Performance Characteristics (Continued) The WLED forward voltage (VF) is 3.2V at ILED=20mA, unless otherwise noted. 2.0 80 o 1.8 TA= -40 C o 75 TA= 25 C CTRL Pin Voltage (V) Shutdown Quiescent Current (A) 85 o TA= 85 C 70 65 60 55 1.6 1.4 1.2 1.0 50 0.8 45 0.6 40 2 3 4 5 6 7 8 0.4 -60 9 -40 -20 0 40 60 80 100 120 140 Temperature ( C) Figure 8. Shutdown Quiescent Current vs. Input Voltage Figure 9. CTRL Pin Voltage vs. Temperature 220 212 200 210 208 180 Feedback Voltage (mV) CTRL Pin Current (A) 20 o Input Voltage (V) 160 140 120 100 80 60 206 204 202 200 198 196 194 192 40 IOUT= 20mA 190 188 -60 20 2 3 4 5 6 7 8 9 -40 -20 0 20 40 60 80 100 120 140 o Temperature ( C) CTRL Pin Voltage (V) Figure 10. CTRL Pin Current vs. CTRL Pin Voltage Dec. 2012 Figure 11. Feedback Voltage vs. Temperature Rev. 1. 2 BCD Semiconductor Manufacturing Limited 7 Data Sheet WHITE LED STEP-UP CONVERTER AP3032 Typical Performance Characteristics (Continued) The WLED forward voltage (VF) is 3.2V at ILED=20mA, unless otherwise noted. 30 1.4 1.3 28 OVP Voltage (V) Frequency (MHz) 1.2 1.1 1.0 0.9 26 24 0.8 22 0.7 0.6 -60 20 -40 -20 0 20 40 60 80 100 120 140 -60 o -40 -20 0 20 40 60 80 100 120 140 o Temperature ( C) Temperature ( C) Figure 12. Frequency vs. Temperature Figure 13. OVP Voltage vs. Temperature 100 90 o Case Temperature ( C) 80 70 60 50 40 o TA=25 C 7S4P,20mA Per Channel 30 20 3 4 5 6 7 8 9 Input Voltage (V) Figure 14. Case Temperature vs. Input voltage Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 8 Data Sheet WHITE LED STEP-UP CONVERTER AP3032 Application Information th 1. Operation the inrush current during startup. If logic low time on CTRL pin is more than about 0.7ms and then enable the IC, the AP3032 will start smoothly to protect system departments. The time of startup is controlled by internal soft start capacitor. Details please refer to Figure 15. The AP3032 is a boost DC-DC converter which uses a constant frequency, current mode control scheme to provide excellent line and load regulation. Operation can be best understood by referring to the Figure 21. At the start of each oscillator cycle, switch Q1 turns on. The switch current will increase linearly. The voltage on sense resistor is proportional to the switch current. The output of the current sense amplifier is added to a stabilizing ramp and the result is fed into the non-inversion input of the PWM comparator A2. When this voltage exceeds the output voltage level of the error amplifier A1, the switch is turned off. It is clear that the voltage level at inversion input of A2 sets the peak current level to keep the output in regulation. This voltage level is the output signal of error amplifier A1, and is the amplified signal of the voltage difference between feedback voltage and reference voltage of 200mV. So, a constant output current can be provided by this operation mode. Figure 15. Soft Start Waveform 2. LED Current Control Refer to Figure 21, the LED current is controlled by the feedback resistor RISET. LEDs' current accuracy is determined by the regulator's feedback threshold accuracy and is independent of the LED's forward voltage variation. So the precise resistors are preferred. The resistance of RISET is in inverse proportion to the LED current since the feedback reference is fixed at 200mV. The relation for RISET and LED current (ILED) can be expressed as below: RISET = 5. Standby and Dimming To avoid audio noise and achieve high frequency dimming, AP3032 setup a standby function. If logic low time on CTRL pin is less than about 0.7ms and then enable the IC, AP3032 will hold on standby mode and start directly to achieve high frequency dimming. Details please refer to Figure 16. 200mV I LED 3. Over Voltage Protection The AP3032 has an internal open-load protection circuit. When the LEDs are disconnected from circuit or fail open, the output voltage is clamped at 27V. The AP3032 will switch at a low frequency, and minimize current to avoid input voltage drop. Figure 16. Standby Waveform 4. Soft Start The AP3032 has an internal soft start circuit to limit Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 9 Data Sheet WHITE LED STEP-UP CONVERTER AP3032 Application Information (Continued) Two typical types of dimming control circuit are present as below. First, controlling CTRL Pin voltage to change operation state is a good choice. Second, changing the feedback voltage to get appropriate duty and luminous intensity is also useful. 5.2 Changing the Effective Feedback Voltage There are two popular methods to change the effective feedback voltage. First, adding a constant DC voltage through a resistor divider to FB pin can control the dimming. Changing the DC voltage or resistor between the FB Pin and the DC voltage can get appropriate luminous intensity. Comparing with all kinds of PWM signal control, this method features a stable output voltage and LEDs current. Please refer to Figure 19. 5.1 Adding a Control Signal to CTRL Pin Adding a PWM signal to CTRL pin directly, the AP3032 is turned on and off by this signal. When the PWM frequency is lower than 2.5kHz (Typ), the IC works in the soft-start mode to dimming the light. But we intense suggest set the PWM signal frequency higher than 25kHz to avoid audio noise. In this situation, IC works in the standby mode and start directly to achieve dimming the light. More details please refer to Figure 17 and Figure 18. AP3032 CTRL up to 25kHz Figure 17. Dimming Control Using a PWM Signal on CTRL Pin Figure 19. Dimming Control Using DC Voltage Second, using a filtered PWM signal can do it. The filtered PWM signal can be considered as a varying and adjustable DC voltage. Please refer to Figure 20. Figure 18. High Frequency (25kHz) Dimming Waveform Figure 20. Dimming Control Using Filtered PWM Voltage Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 10 Data Sheet WHITE LED STEP-UP CONVERTER AP3032 Typical Application Figure 21. Typical Application of AP3032 (7S4P) Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 11 Data Sheet WHITE LED STEP-UP CONVERTER AP3032 Mechanical Dimensions SOT-23-6 Unit: mm(inch) 0 2.820(0.111) 8 3.020(0.119) 0.300(0.012) 0.400(0.016) 5 4 2 3 0.300(0.012) 0.600(0.024) 1.500(0.059) 1.700(0.067) 2.650(0.104) 2.950(0.116) 6 0.200(0.008) Pin 1 Mark 1 0.700(0.028)REF 0.950(0.037)TYP 0.000(0.000) 0.150(0.006) 1.800(0.071) 2.000(0.079) 0.100(0.004) 0.200(0.008) 0.900(0.035) 1.450(0.057) MAX 1.300(0.051) Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 12 BCD Semiconductor Manufacturing Limited http://www.bcdsemi.com IMPORTANT NOTICE IMPORTANT NOTICE BCD Semiconductor BCD Semiconductor Manufacturing Manufacturing Limited Limited reserves reserves the the right right to to make make changes changes without without further further notice notice to to any any products products or or specifispecifications herein. cations herein. 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