AL1665 HIGH PERFORMANCE DIMMABLE LED CONTROLLER Description Pin Assignments NEW PRODUCT The AL1665 is a high performance single stage flyback and buckboost controller, targeting dimmable LED lighting application. It is a Primary Side Regulation (PSR) controller which can provide accurate Constant Current (CC) regulation without opto-coupler and secondary control circuitry. It can be operated at BCM mode which results in low EMI and high efficiency, and keeps high Power Factor (PF) and low Total Harmonic Distortion (THD) under universal input voltage. (Top View) The AL1665 can support analog/PWM dimming modes. When a 50mV to 2.5V DC signal is applied on ADIM pin, the device will be operated in analog dimming mode. The analog dimming range is 5% to 100%. When a PWM signal is applied to NTC/PWM pin, the device will be operated at PWM dimming mode. The PWM dimming range is 0.5% to 100% (1k PWM dimming frequency). The AL1665 features low operation current. It integrates multiple protections including over voltage, short circuit, over current and over temperature. The AL1665 is available in SO-8 (Standard) package. ADIM 1 8 FB NTC/PWM 2 7 VCC COMP 3 6 OUT CS 4 5 GND SO-8 (Standard) Applications General LED Lighting Driver with Dimming Function General Purpose Constant Current Source LED Backlighting Driver Smart LED Lighting Features Primary Side Regulation without Opto-Coupler Valley Switching for Low Switching Loss Low Start-Up Current Support Analog and PWM Dimming Analog Dimming Range: 5% to 100% PWM Dimming Range: 0.5% to 100% (1k PWM Frequency) Internal Protections Under Voltage Lock Out (UVLO) Output Over Voltage Protection (OVP) Output Short Protection (OSP) Over Current Protection (OCP) CS Short Protection Winding Short Circuit Protection Secondary Diode Short Protection Shorted Current Sense Protection User Programmable NTC Based Thermal Foldback Internal Thermal Fold-Back Protection (TFP) Over Temperature Protection (OTP) Low System Cost High PF>0.9 and Low THD<20% High Efficiency Tight LED Current Variation Range LED Current Line Regulation: 2% LED Current Load Regulation: 2% Full Load to Half Load Tight Output Open Voltage Variation Range Package: SO-8 (Standard) Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. "Green" Device (Note 3) Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS), 2011/65/EU (RoHS 2) & 2015/863/EU (RoHS 3) compliant. 2. See https://www.diodes.com/quality/lead-free/ for more information about Diodes Incorporated's definitions of Halogen- and Antimony-free, "Green" and Lead-free. 3. Halogen- and Antimony-free "Green" products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds. AL1665 Document number: DS41772 Rev. 1 - 2 1 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Typical Applications Circuit R14 C7 L1 T1 F1 AC Input D3 C5 R10 RTH C2 C1 R11 + C6 OUT C6 OUT D2 VR1 Aux R4 D1 DB1 CVCC NEW PRODUCT R5 D4 ADIM VCC FB AL1665 Q1 OUT R9 COMP R6 NTC/PWM GND CS RCOMP U1 CCOMP RCS Flyback Application Circuit L1 T1 RTH R11 + C2 C1 F1 D3 AC Input VR1 Aux R4 D1 DB1 R5 CVCC ADIM VCC FB AL1665 COMP R6 RCOMP D4 Q1 OUT R9 NTC/PWM GND CS CCOMP RCS Buck-Boost Application Circuit Pin Descriptions Pin Number Pin Name 1 ADIM 2 NTC/PWM 3 COMP 4 CS 5 GND Ground 6 OUT Gate Driver Output 7 VCC Supply Voltage of Gate Driver and Control Circuits of the IC 8 FB The Feedback Voltage Sensing from the Auxiliary Winding AL1665 Document number: DS41772 Rev. 1 - 2 Function Analog Dimming Input Pin NTC Input Pin for Thermal Foldback/PWM Dimming Input Pin Loop Compensation Pin Current Sense Pin, Connect This Pin to the Source of the Primary Switch 2 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Functional Block Diagram ADIM Thermal Foldback & PWM Dim NTC/ 2 PWM VCC 1 7 Analog Dim Control VREF UVLO &Bias VREF TFP NEW PRODUCT OVP FB 6 Driver Logical Control Valley Detector 8 OUT OTP 1.2V + CS 4 VREF + OCP OTP Internal Temperature Sense Gm 5 3 COMP GND Absolute Maximum Ratings (@TA = +25C, unless otherwise specified.) (Note 4) Symbol Parameter Rating Unit VCC Power Supply Voltage -0.3 to 30 V VCS Voltage at CS to GND -0.3 to 7 V VFB FB Input Voltage -0.3 to 7 V Voltage at Loop Compensation Pin -0.3 to 7 V Driver Output Voltage -0.3 to 20 V Voltage at NTC/PWM to GND -0.3 to 7 V Voltage at ADIM to GND -0.3 to 7 V Operating Junction Temperature -40 to +150 C TSTG Storage Temperature -65 to +150 C TLEAD Lead Temperature (Soldering, 10s) +300 C PD Power Dissipation at TA = +50C 0.65 W JA Thermal Resistance (Junction to Ambient) 136 C /W JC Thermal Resistance (Junction to Case) 30 C/W ESD (Human Body Model) 2000 V ESD (Charged-Device Model) 1000 V VCOMP VOUT VNTC/PWM VADIM TJ - Note: 4. Stresses greater than those listed under Absolute Maximum Ratings can 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 can affect device reliability. All voltages unless otherwise stated are measured with respect to GND. AL1665 Document number: DS41772 Rev. 1 - 2 3 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Recommended Operating Conditions (@TA = +25C, unless otherwise specified.) Symbol Parameter TA VCC Notes: Min Max Unit Ambient Temperature (Note 5) -40 +105 C Operating VCC Voltage (Note 6) 8.5 VCC_OVP (Min) V 5. The device may operate normally at +125C ambient temperature under the condition not triggers temperature protection. NEW PRODUCT 6. ICC should be limited less than 5mA. Electrical Characteristics Symbol (@TA = +25C, unless otherwise specified.) Parameter Conditions Min Typ Max Unit UVLO Section VCC_TH Startup Threshold Voltage - 15.8 18.5 19.5 V VOPR_MIN Minimal Operating Voltage After Turn On 5.8 7.8 9 V VCC_OVP VCC OVP Voltage - 21.8 25 29.5 V - 120 300 A - 2 4 mA 3.1 - - mA Standby Current Section IST Startup Current ICC Operating Current VCC = VCC_TH -0.5V, Before Start Up FB, CS Connect to GND, CGATE = 100pF Shunt Current in OVP Mode VCC > VCC_OVP tR Output Voltage Rise Time (Note 7) CL = 1nF - 100 - ns tF Output Voltage Fall Time (Note 7) CL = 1nF - 100 - ns Output Clamp Voltage VCC = 20V 9.8 12 15.5 V tON_MIN Minimum On Time (Note 7) - - 1000 2010 ns tON_MAX Maximum On Time - - 20 31 s tOFF_MAX Maximum Off Time - - 290 405 s Maximum Frequency - - 150 - kHz Internal Reference Voltage - 0.394 0.4 0.406 V Primary Current Clamp Voltage - 1.8 2 2.5 V Primary Over Current Voltage - - 3 - V Trans-Conductance - - 27 - A/V Amplifier Source Current - - 7.2 - A FB CV Threshold - 2.5 3.0 3.5 V - Analog Dimming Range on ADIM - 0.05 - 2.5 V - Analog Dimming High Level - 2.45 2.5 2.55 V - Analog Dimming Range Ratio - 5% - 100% - ICC_OVP Drive Output Section VOUT_CLAMP fMAX Internal CS Reference VREF VCS_CLAMP VCS_OCP Error Amplifier Gm ISOURCE Feedback Input Section VFB_CV ADIM Section Note: 7. These parameters, although guaranteed by design, are not 100% tested in production. AL1665 Document number: DS41772 Rev. 1 - 2 4 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Electrical Characteristics (@TA = +25C, unless otherwise specified.) (continued) Symbol Parameter Conditions Min Typ Max Unit - 2.5 - V 70.5 85 91 A NTC/PWM Section NEW PRODUCT VNTC/PWM(PULL-UP) Pull-Up Voltage when NTC/PWM Open NTC/PWM Pin Open IOTP(REF) Reference Current for Direct Connection of NTC/PWM (Note 9) - VOTP(OFF) Fault Detection Level for OTP (Note 8) VNTC/PWM Falling - 0.50 - V VNTC/PWM Rising - 0.70 - V - 250 - 370 s - 0.94 1.00 1.06 V - 0.64 0.69 0.74 V - 40 50 60 % Overheating Temperature Regulation (Note 7) - - +150 - C - +180 - C VOTP(ON) tOTP(START) VTF(START) VTF(STOP) VREF(50) NTC/PWM Pin Level for Operation Recovery after an OTP Detection OTP Blanking Time when Circuit Starts Operating (Note 9) NTC/PWM Pin Voltage at which Thermal Fold-Back Starts (VREF is Decreased) NTC/PWM Pin Voltage at which Thermal Fold-Back Stops (VREF is Clamped to VREF50) VREF @ VNTC/PWM = 600mV (Percent of VREF) Thermal Fold-Back Section TREG Over Temperature Protection Section - Notes: Shutdown Temperature (Notes 7, 8) - 7. These parameters, although guaranteed by design, are not 100% tested in production. 8. The device will latch when OTP happens and won't be operated constantly at this temperature. 9. At startup, when VCC reaches VCC(ON), the controller blanks OTP for more than 250s to avoid detecting an OTP fault by allowing the NTC/PWM pin voltage to reach its nominal value if a filtering capacitor is connected to the NTC/PWM pin. AL1665 Document number: DS41772 Rev. 1 - 2 5 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Performance Characteristics (Note 10) Startup Threshold Voltage vs. Ambient Temperature Minimum Operating Voltage vs. Ambient Temperature 19.0 8.0 7.8 18.5 7.6 7.4 VOPR_MIN (V) VCC_TH (V) 17.5 17.0 7.2 7.0 6.8 6.6 6.4 16.5 6.2 16.0 -40 -20 0 20 40 60 80 100 6.0 -40 120 o -20 0 Ambient Temperature ( C) 40 60 80 100 120 o VCC OVP Voltage vs. Ambient Temperature Startup Current vs. Ambient Temperature 250 230 29 210 28 190 ICC_ST (mA) 27 VCC_OVP (V) 20 Ambient Temperature ( C) 30 26 25 24 170 150 130 110 23 90 22 70 21 20 -40 50 -40 -20 0 20 40 60 80 100 -20 0 20 40 60 80 100 120 o 120 Ambient Temperature ( C) o Ambient Temperature ( C) Operating Current vs. Ambient Temperature CS Reference Voltage vs. Ambient Temperature 0.410 1.00 0.95 0.405 0.90 0.400 0.85 VCS_REF (V) ICC_OPR (mA) NEW PRODUCT 18.0 0.80 0.75 0.395 0.390 0.70 0.385 0.65 0.60 -40 -20 0 20 40 60 80 o 100 120 0.380 -40 Ambient Temperature ( C) Note: -20 0 20 40 60 80 100 120 o Ambient Temperature ( C) 10. These electrical characteristics are tested under DC condition. The ambient temperature is equal to the junction temperature of the device. AL1665 Document number: DS41772 Rev. 1 - 2 6 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Performance Characteristics (continued) CS Clamp Reference Voltage vs. Ambient Temperature FB CV Threshold vs. Ambient Temperature 2.20 3.3 2.15 3.2 VFB_CV (V) VCS_CLAMP (V) 3.1 2.05 2.00 1.95 3.0 2.9 2.8 1.90 2.7 1.85 1.80 -40 -20 0 20 40 60 80 100 2.6 -40 120 -20 0 3.4 0.405 3.2 0.400 3.0 0.390 2.6 0.385 13 15 17 19 21 0.380 7 23 9 11 13 PWM Dimming Curve 90 90 80 80 Dimming Percentage (%) 100 70 60 50 40 30 20 PWM Frequency=1kHz 10 20 30 40 50 60 Document number: DS41772 Rev. 1 - 2 15 17 19 21 23 70 80 70 60 50 40 30 20 10 90 100 0 0.0 PWM Duty (%) AL1665 120 Analog Dimming Curve 100 0 0 100 VCC Voltage (V) VCC Voltage (V) 10 80 0.395 2.8 11 60 CS Reference Voltage vs. VCC Voltage 0.410 VCS_REF (V) VFB_CV (V) FB CV Threshold vs. VCC Voltage 3.6 9 40 o Ambient Temperature ( C) 2.4 7 20 Ambient Temperature ( C) o Dimming percentage (%) NEW PRODUCT 2.10 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 VADIM (V) 7 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Application Information The AL1665 is a constant current high PF flyback and buck-boost controller with Primary Side Regulation (PSR), targeting LED lighting applications. The device eliminates the opto-couplers or the secondary feedback circuits, which is helpful to cost down the whole system. High power factor is achieved by constant on-time operation. In order to reduce the switching losses and improve EMI performance, quasi-resonant switching mode is applied. The AL1665 integrates multiple protections including UVLO protection, V CC over voltage protection, output open voltage protection, over current protection, thermal fold-back protection and over temperature protection. The AL1665 can support analog and PWM dimming modes. R14 C7 NEW PRODUCT L1 T1 F1 AC Input D3 C5 R10 RTH C2 C1 R11 + C6 OUT C6 OUT D2 VR1 Aux R4 D1 DB1 CVCC R5 AL1665 COMP NTC/ PWM R6 RCOMP D4 ADIM VCC FB Q1 OUT R9 GND CS U1 CCOMP RCS Figure 1. Flyback Application Circuit L1 T1 RTH R11 + C2 C1 F1 D3 AC Input VR1 Aux R4 D1 DB1 R5 CVCC ADIM VCC FB R6 RCOMP AL1665 COMP NTC/ PWM D4 Q1 OUT R9 GND CS CCOMP RCS Figure 2. Buck-Boost Application Circuit Start-Up After AC supply is powered on, the capacitor CVCC across VCC and GND pin will be charged up by BUS voltage through a start-up resistor RTH. Once VCC reaches VCC_TH, the internal blocks start to work. VCC will be supplied by VBUS until the auxiliary winding of flyback transformer could supply enough energy to maintain VCC above VOPR_MIN. If VCC voltage is lower than VOPR_MIN, switch will be turned off. After VCC exceeds VCC_TH, the drive blocks won't start to switch on/off signals until VCOMP is higher than the initial voltage VCOMP_ST, which can be programmed by RCOMP. The formula is shown as below. Such design can program startup on time to reduce the startup time or the output overshoot current. VCOMP _ ST 1.4V 700A RCOMP Where VCOMP_ST is the pre-charged voltage of COMP pin. RCOMP is shown as Figure 1. Generally, a big capacitance of CCOMP is necessary to achieve high power factor and stabilize the system loop (1F to 2F is recommended). The pre-charged voltage in start-up procedure can be programmed by RCOMP. AL1665 Document number: DS41772 Rev. 1 - 2 8 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Application Information (continued) Protections 1. Output Open Protection (OVP) NEW PRODUCT The output voltage is reflected by the voltage on transformer's auxiliary winding. Both the FB pin and the VCC pin of IC have the over voltage protection function. When there is a rapid line and load transient, the output voltage may exceed the regulated value. If V CC exceeds VCC_OVP, the VCC over voltage protection will be triggered, the switch will be turned off and the VCC will be discharged. Once VCC is lower than VOPR_MIN, the IC will shut down and be powered on again by BUS voltage through start up resistor. If VFB exceeds VFB_CV, the FB over voltage protection will be triggered, switch will be turned off and VCC will be latched for 16s, then VCC will be discharged. Once VCC is below VOPR_MIN. the IC will shut down and be powered on again by BUS voltage through start up resistor. Power dissipation is low when FB over voltage protection happens. Thus, output over voltage depends on the minimum voltage between both OVP protections' limitation. It can be gotten by below formula. N N R5 R 6 VOVP Min S VCC _ OVP , S VFB _ CV N N R 6 AUX AUX Where VOVP is the output over voltage setting; R5 and R6 shown in Figure 1 are divider resistors connected from the auxiliary winding. NAUX is the turns of auxiliary wind; NS is turns of the secondary wind. VCC_OVP is the OVP Voltage of VCC. 2. Output Short Protection (OSP) When the output is shorted, the output voltage would drop down to zero. The output voltage of the auxiliary winding, which is proportional to the output winding, will drop down too. If the VFB drops below 0.4V, the output short protection will be triggered, switch will be turned off and VCC will be latched for 16s, then VCC will be discharged. Once VCC is below the VOPR_MIN, the IC will be shut down and powered on again by the BUS voltage through the startup resistor. Power dissipation is low when output short protection happens. 3. Over Current Protection (OCP) The AL1665 has a built-in cycle by cycle over current protection of primary inductor current. When CS pin voltage reaches the voltage V CS_CLAMP, the switch will be turned off until next switch period. The maximum peak current (I PEAK (MAX)) of the inductor can be calculated as below: Where VCS_CLAMP means primary current clamp voltage that is 2V. RCS is current sense resister which is shown as Figure 1. 4. CS Short Protection When CS pin is shorted to GND, CS voltage is latched to zero. If CS is detected lower than 0.3V for 7 pulses, the CS short protection will be triggered, switch will be turned off and VCC will be latched for 16s, then VCC will be discharged. Once VCC is below VOPR_MIN, the IC will be shut down and powered on again by the BUS voltage through the startup resistor. High rush current appears when CS is shorted to GND, and it may damage the components. 5. Secondary Diodes/Primary Windings/Secondary Windings Short Protection The CS voltage will be high when secondary diodes/primary windings/secondary windings are shorted. If the CS voltage is higher than VCS_OCP, the protection will be triggered, switch will be turned off and VCC will be latched for 16s, then VCC will be discharged. Once VCC is below VOPR_MIN, the IC will be shut down and powered on again by the BUS voltage through the startup resistor. Power dissipation is low when output short protection happens. 6. Thermal Fold-back Protection (TFP) Connect a NTC between the NTC/PWM pin and ground to detect an over temperature condition. In response to a high temperature (detected if VNTC/PWM drops below VTF(START)), the circuit gradually reduces the LED current down 50% of its nominal value when VNTC/PWM reaches VTF(STOP), in accordance with the characteristic of Figure 3. If this thermal fold-back cannot prevent the temperature from rising (testified by VNTC/PWM droping below VOTP), the circuit would be latched off or enter the auto-recovery mode, and cannot be re-operated until VNTC/PWM exceeds VOTP(ON) to provide some temperature hysteresis (around +10C typically). The OTP thresholds nearly correspond to the following resistances of the NTC: Thermal fold-back starts when RNTC <=RTF(START)(11.7k typically); Thermal fold-back stops when RNTC <=RTF(STOP) (8.0k typically); OTP triggers when RNTC <= ROTP(OFF) (5.9k typically); OTP is removed when RNTC >= ROTP(ON) (8.0k typically). At startup, when VCC reaches VCC(ON), the OTP comparator is blanked for at least 250s in order to allow the NTC/PWM pin voltage to reach its nominal value if a filtering capacitor is connected to the NTC/PWM pin. This would avoid flickering of the LED light during turn-on. AL1665 Document number: DS41772 Rev. 1 - 2 9 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Application Information (continued) IOUT Temperature Increases Temperature Decreases 50%IOUT(NOM) Shutdown NEW PRODUCT IOUT(NOM) VOTP(OFF) VTF(STOP) VOTP(ON) VTF(START) VNTC/PWM Figure 3. Output Current Reduction versus NTC/PWM Pin Voltage 7. Over Temperature Protection (OTP) The AL1665 has built-in Over Temperature Protection (OTP) function. When the temperature goes up to +165C, the over temperature protection will be triggered, which leads to a latch mode protection. When OTP happens, the system needs to be powered off and restart. Output Constant Current Control According to the definition of mean output current, the mean output current can be obtained as below: I O _ MEAN t 1 I SP ONS dt 02 t SW 1 Where IO_MEAN is the mean output current; ISP is the secondary peak current of transformer; tONS is the discharge time of secondary side of transformer; tSW is the switch period. According to the principle of AL1665 closed loop control, the voltage of RCS will be sampled when switch is turned off and the value will be held until discharge time tONS is over. It can be described by following formula: Where IP is the primary peak current of transformer; RCS is the current sense resister which is shown as Figure 1. tONS is the discharge time of secondary side of transformer; tSW is the switch period. VREF is internal reference voltage that is equal to 0.4V. The peak current at secondary side has the following relationship with primary side peak current, if the effect of the leakage inductor is neglected. I SP N PS I P Where NPS is the turns' ratio of flyback transformer (NPS=1 for buck-boost); IP is the primary peak current of the transformer. According to these above formulas, the mean output current can be induced finally by the expression below: I O _ MEAN N PS VREF 2 RCS Where IO_MEAN is the mean output current; RCS is the current sense resister which is shown as Figure 1 and Figure 2; VREF is the internal reference voltage that is equal to 0.4V; NPS is the turns' ratio of flyback transformer (NPS=1 for buck-boost); Therefore, the constant output current control can be realized with appropriate parameter design. AL1665 Document number: DS41772 Rev. 1 - 2 10 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Application Information (continued) PF and THD Compensation Circuit In typical application, AL1665 can provide PF>0.9 and THD <40%. It can improve PF>0.95 and THD<20% by adding the compensation circuit as below. The VBUS is connected to bus line which is after the rectifier bridge. The COMP pin voltage will increase an offset that is almost followed NEW PRODUCT with bus line voltage in the circuit. Due to the COMP voltage controls the switch-on time, the phase difference between input voltage and input current will be reduced, which can optimize the PF and THD. In the circuit, the range of resister value R12 is from 800k to 1.5M, and the range of resistor value R13 is from 500 to 5.1k. The Range of capacitance C11 is 1F to 2F. The PF and THD circuit can be improved by fine-tuning these components. VBUS R12 C11 CCOMP R13 COMP RCOMP Figure 4. PF and THD Compensation Circuit Line Regulation Compensation Function The AL1665 can achieve good line regulation by adjusting FB pull-up resistor RFB1 and CS external horizontal resistor RCS1. The circuit is shown as Figure 5. IFB3 is the current that flows from GND to the internal FB pull-down resistor. IFB3 will be detected during tONP time, and flows into CS to compensate VREF. VREF is the internal reference voltage that is equal to 0.4V; K is conversion coefficient of IFB3 that is equal to 4; VIN is the input Voltage; NAP is the turns' ratio of auxiliary winding and primary winding; RFB2 is the external FB pull-down resistor; RFB3 is the internal FB pull-down resistor that is connected to the system during tONP time, and equals to 207; RCS2 is the internal horizontal resistor that is 6k. As RFB1 and RFB2 are far larger than RFB3, the output current can be calculated approximately as following: - ) - AL1665 Q1 VREF CS RCS1 K RCS2 FB tONP IFB3 RFB1 RFB2 RFB3 RCS Figure 5. Line Regulation Compensation Circuit AL1665 Document number: DS41772 Rev. 1 - 2 11 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Application Information (continued) Dimming Mode The AL1665 can support two dimming modes: analog dimming and PWM dimming. 1. Analog Dimming Mode In analog dimming mode, the dimming signal is added to ADIM pin directly to realize dimming function. The setting circuit is shown as Figure 6. When VAPWM is higher than 2.5V, the driver will output 100% of rated current; when the voltage V ADIM is in the range from 50mV to 2.5V, the output current will be changed linearly with the voltage VAPWM. The dimming curve is shown as Figure 7 and the dimming range is from 2% to NEW PRODUCT 100%. 100% 50mv~2.5V Dimming Signal ADIM CAPWM AL1665 5% 0 50mV Figure 6. Analog Dimming Setting Circuit 2.5V Figure 7. Analog Dimming Curve 2. PWM Dimming Mode In PWM dimming mode, dimming signal will be added to NTC/PWM pin .The setting circuit is shown as Figure 8. The output current is chopped by the dimming signal directly. The logic high level of the dimming signal needs to be higher than 1V while the logic low level is lower than 0.5V. The switch is turned off at logic low level. The dimming curve is shown as Figure 9. The dimming range can be 100% to 0.5% with 1kHz frequency of PWM signal. PWM Dimming Signal AL1665 Output Current Percentage (%) 100 NTC /PWM 80 60 40 20 PWM Frequency=1kHz 0 0 20 40 60 80 100 PWM Duty (%) Figure 8. PWM Dimming Setting Circuit AL1665 Document number: DS41772 Rev. 1 - 2 Figure 9. PWM Dimming Curve 12 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Application Information (continued) Operation Parameters Design 1. Setting the Current Sense Resistor RCS The current sense resistance can be calculated as following: NEW PRODUCT RCS N PS VREF 2 I O _ MEAN Where IO_MEAN is the mean output current; RCS is the current sense resister which is shown as Figure 1; VREF is the internal reference voltage that is equal to 0.4V; NPS is the turns' ratio of flyback transformer (NPS=1 for buck-boost). 2. Setting Transformer Selection (T1) NPS is limited by the electrical stress of the switch MOSFET, can be calculated by below formula. N PS VMOS _( BR ) DS 90% 2 VIN _ MAX VS VO VD _ F Where VMOS_(BR)DS is the breakdown voltage of the switch MOSFET. VIN_MAX is the max rated input voltage. VS is the overshoot voltage clamped by RCD snobbier during OFF time. VO is the output voltage. VD_F is the forward voltage of secondary diode. NPS is the turns' ratio of flyback transformer (NPS=1 for buck-boost); For boundary conduction mode and constant on time method, the peak current of primary inductance can be calculated as below. 2 I O _ MEAN IP N PS sin( ) 0 2 VIN _ RMS sin( ) 2 VIN _ RMS sin( ) N PS Vo d Where VIN_RMS is the rate input voltage; IP is the primary inductance current. NPS is the turns' ratio of flyback transformer (NPS=1 for buck-boost); IO_MEAN is the mean output current; VO is the output voltage. The switching frequency is not constant for AL1665 due to boundary conduction mode. To set the minimum switching frequency fMIN at the crest of the minimum AC input, primary inductance can be obtained by below formula. LP 2 VIN _ RMS N PS VO I P ( 2VIN _ RMS N PSVO ) f MIN Where VIN_RMS is the rate input voltage; IP is the primary inductance current. NPS is the turns' ratio of flyback transformer (NPS=1 for buck-boost); VO is the output voltage; fMIN is the minimum switching frequency at the crest of the minimum AC input. According to the Faraday's Law, the winding number of the inductance can be calculated by: NP LP I P Ae Bm NS NP N PS Where, Ae is the core effective area. Bm is the maximum magnetic flux density. AL1665 Document number: DS41772 Rev. 1 - 2 13 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Ordering Information AL1665 X - X Package Packing S : SO-8 (Standard) 13 : 13" Tape & Reel NEW PRODUCT Product Name 13" Tape and Reel Part Number Package Code AL1665S-13 S Package SO-8 (Standard) Quantity Part Number Suffix 4000/Tape & Reel -13 Marking Information (Top View) 8 7 6 5 Logo YY : Year : 19, 20, 21~ WW : Week : 01~52; 52 represents 52 and 53 week X X : Internal Code AL1665 Marking ID YY WW X X 1 AL1665 Document number: DS41772 Rev. 1 - 2 2 3 4 14 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 Package Outline Dimensions (All dimensions in mm.) Please see http://www.diodes.com/package-outlines.html for the latest version. (1) Package Type: SO-8 (Standard) E1 h A3 NEW PRODUCT 4 5 E A2 A 1 O L A1 e D b OPTION A (TOP VIEW) c Gauge Plane Seating Plane SO-8 (Standard) Dim Min Max Typ A --1.75 A1 -0.10 0.25 A2 -1.25 1.65 A3 -0.50 0.70 b -0.30 0.51 c -0.15 0.25 D -4.80 5.00 E 5.80 6.20 6.00 E1 -3.80 4.00 e 1.27 --h -0.25 0.50 L -0.45 0.82 O -0 8 All Dimensions in mm OPTION B (TOP VIEW) Suggested Pad Layout Please see http://www.diodes.com/package-outlines.html for the latest version. (1) Package Type: SO-8 (Standard) X1 Dimensions Value (in mm) C 1.27 X 0.802 X1 4.612 Y 1.505 Y1 6.50 Y1 Y C AL1665 Document number: DS41772 Rev. 1 - 2 X 15 of 16 www.diodes.com March 2019 (c) Diodes Incorporated AL1665 IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). NEW PRODUCT Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes Incorporated website, harmless against all damages. Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel. Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application. Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings noted herein may also be covered by one or more United States, international or foreign trademarks. This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the final and determinative format released by Diodes Incorporated. LIFE SUPPORT Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein: A. Life support devices or systems are devices or systems which: 1. are intended to implant into the body, or 2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in significant injury to the user. B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems. Copyright (c) 2019, Diodes Incorporated www.diodes.com AL1665 Document number: DS41772 Rev. 1 - 2 16 of 16 www.diodes.com March 2019 (c) Diodes Incorporated