Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 General Description Features The AP3029 is an inductor-based DC/DC converter designed to drive up to six white LEDs in series or 2 rows of LEDs with 5 for each in parallel for backlight. Only one feedback resistor is needed to control the LED current and obtain required brightness. · · · · · A constant frequency 1.2MHz PWM control scheme is employed in this IC, which means tiny external components can be used. In fact, 1mm tall inductor and 0.22µF output capacitor for a typical application is sufficient. Additionally, the schottky diode in boost circuit is integrated on this chip. AP3029 also provides a disable pin to ease its use for different systems. · · · Inherently Uniform LED Current High Efficiency up to 83.5% No Need for External Schottky Diode Over Output Voltage Protection Drives 2 to 6 LEDs in Series or 2 Rows of LEDs with 5 for Each in Parallel Fast 1.2MHz Switching Frequency Uses Tiny 1mm Tall Inductor Requires Only 0.22µF Output Capacitor Applications The over output voltage protection is equipped in AP3029. When any LED is broken or in other abnormal conditions, the output voltage will be clamped to 27V. · · · · · The AP3029 is available in standard SOT-23-6 and TSOT-23-6 packages. Cellular Phones Digital Cameras LCD modules GPS Receivers PDAs, Handheld Computers TSOT-23-6 SOT-23-6 Figure 1. Package Type of AP3029 Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 1 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Pin Configuration K/KT Package (SOT-23-6/TSOT-23-6) Pin 1 Dot by Marking SW 1 6 VIN GND 2 5 VOUT FB 3 4 CTRL Figure 2. Pin Configuration of AP3029 (Top View) Pin Description Pin Number Pin Name Function 1 SW 2 GND 3 FB 4 CTRL Shutdown and Dimming Pin. Connect to 1.8V or higher to enable device; Connect to 50mV or less to disable device; Connect to a voltage between 1.8V and 50mV to achieve linear dimming 5 VOUT Output Pin. Connected to the cathode of internal schottky diode 6 VIN Switch Pin. Connect external inductor Ground Pin Voltage Feedback. Reference voltage is 200mV Input Supply Pin. Must be locally bypassed Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 2 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Functional Block Diagram FB SW 3 1 5 SOFT START VIN 6 200 mV VREF 1.25 V OVP DRIVER A1 Q R A2 VOUT Q1 S COMPARATOR Σ CTRL 2 4 GND RAMP GENERATOR 1.2 MHz OSCILLATOR Figure 3. Functional Block Diagram of AP3029 Ordering Information AP3029 - Circuit Type E1: Lead Free G1: Green Package TR: Tape and Reel K: SOT-23-6 KT: TSOT-23-6 Package Temperature Range SOT-23-6 -40 to 85oC TSOT-23-6 o -40 to 85 C Part Number Lead Free Marking ID Green Lead Free Green Packing Type AP3029KTR-E1 AP3029KTR-G1 E8S G8S Tape & Reel AP3029KTTR-E1 AP3029KTTR-G1 S9F L9F Tape & Reel BCD Semiconductor's Pb-free products, as designated with "E1" suffix in the part number, are RoHS compliant. Products with "G1" suffix are available in green packages. Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 3 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Absolute Maximum Ratings (Note 1) Parameter Symbol Value Unit VIN 20 V SW Voltage 27 V FB Voltage 20 V CTRL Voltage 20 V 265 oC/W 150 oC Input Voltage Thermal Resistance (Junction to Atmosphere, no Heat sink) RθJA Operating Junction Temperature Storage Temperature Range TSTG -65 to 150 o TLEAD 260 o ESD (Machine Model) 250 V ESD (Human Body Model) 2000 V Lead Temperature (Soldering, 10sec) C C 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 Operating Temperature Range TOP -40 85 o Input Voltage VIN 2.5 16 V CTRL Voltage VCTRL 16 V Aug. 2008 Rev. 1. 2 Unit C BCD Semiconductor Manufacturing Limited 4 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Electrical Characteristics (VIN=3V, VCTRL =3V, TA=25oC, unless otherwise specified.) Parameter Symbol Minimum Operating Voltage VIN(min) Maximum Operating Voltage VIN(max) Conditions Min Typ Max Unit 2.5 V 16 IOUT=20mA, 4 LEDs, Feedback Voltage VFB FB Pin Bias Current IFB Supply Current ICC VFB=VIN, No Switching Shutdown Quiescent Current IQ VCTRL=0V TA=-40oC to 85oC 188 200 212 mV 35 100 nA 1.5 2.5 3.2 mA 2.0 3.2 5.0 µA 1.5 MHz Switching Frequency f 0.9 1.2 Maximum Duty Cycle DMAX 90 93 Switch Current Limit (Note 2) ILIMIT Switch VCE Saturation Voltage VCESAT Switch Leakage Current CTRL Pin Voltage VCTRL TA=25oC, D=40% 550 TA=25oC, D=80% 550 ISW=250mA 360 VSW=5V 0.01 High Schottky Forward Drop VDROP Schottky Leakage Current 5 µA V 55 TA=85oC 50 TA=-40oC 75 ID=150mA 0.7 Reverse Voltage VR=23V 0.1 Reverse Voltage VR=27V Soft Start Time mV 0.05 40 ICTRL mA 1.8 Low CTRL Pin Bias Current % t 72 µA V 4 µA 150 300 µS Note 2: The Switch Current Limit is related to Duty Cycle. Please refer to Figure 16 for detail. Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 5 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Typical Performance Characteristics 85 85 84 84 83 83 82 82 Efficiency (%) Efficiency (%) (VF of WLED is 3.45V @ IF=20mA, unless otherwise noted ) 81 80 VIN=3.6V, IOUT=20mA, 4 LEDs CIN=1µF, COUT=0.22µF, L=22µH 79 80 O IOUT=20mA, 4 LEDs, TA=25 C CIN=1µF, COUT=0.22µF, L=22µH 79 78 77 -50 81 78 -25 0 25 50 75 77 2.5 100 3.0 3.5 4.0 4.5 5.0 o Junction Temperature ( C) Input Voltage (V) Figure 4. Efficiency vs. Junction Temperature Figure 5. Efficiency vs. Input Voltage 350 84 300 Schottky Forward Current (mA) 85 Efficiency (%) 83 82 81 80 O VIN=3.6V, IOUT=20mA, TA=25 C CIN=1µF, COUT=0.22µF, L=22µH 79 250 200 150 100 50 78 0 77 2 3 4 5 0 6 200 400 600 800 1000 Schottky Forward Drop (mV) LEDs (PCS) Figure 6. Efficiency vs. LED's Number Figure 7. Schottky Forward Current vs. Schottky Forward Drop Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 6 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Typical Performance Characteristics (Continued) 30 3.0 25 2.5 Supply Current (mA) Quiescent Current (µA) (VF of WLED is 3.45V @ IF=20mA, unless otherwise noted ) 20 15 10 2.0 1.5 1.0 O -50 C O 25 C O 100 C 5 0.5 0 2 4 6 8 10 12 14 16 0.0 0 Input Voltage (V) 2 4 6 8 10 12 14 16 Input Voltage (V) Figure 8. Shutdown Quiescent Current vs. Input Voltage Figure 9. Supply Current vs. Input Voltage 29.0 4.0 3.8 3.6 28.0 3.4 Input Current (mA) Output Clamp Voltage (V) 28.5 27.5 27.0 26.5 26.0 3.2 3.0 2.8 2.6 2.4 25.5 2.2 2.0 2.5 25.0 2 4 6 8 10 12 14 16 3.0 3.5 4.0 4.5 5.0 Input Voltage (V) Input Voltage (V) Figure 10. Output Clamp Voltage vs. Input Voltage Figure 11. Input Current in Output Open Circuit vs. Input Voltage Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 7 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Typical Performance Characteristics (Continued) (VF of WLED is 3.45V @ IF=20mA, unless otherwise noted ) 210 1.35 208 1.30 206 Feedback Voltage (mV) 1.40 Frequency (MHz) 1.25 1.20 1.15 1.10 1.05 204 202 200 198 196 1.00 194 0.95 192 0.90 -50 -25 0 25 50 75 190 -50 100 -25 Figure 12. Switching Frequency 50 75 100 Figure 13. Feedback Voltage vs. Junction Temperature vs. Junction Temperature 0.80 0.50 0.78 0.45 0.76 0.40 Schottky Leakage Current (µA) Schottky Forward Drop (V) 25 Junction Temperature ( C) Junction Temperature ( C) 0.74 0.72 0.70 0.68 0.66 0.64 0.62 0.60 -50 0 o o -25 0 25 50 75 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 -50 100 o Junction Temperature ( C) VR=10V VR=16V VR=23V -25 0 25 50 75 100 o Junction Temperature ( C) Figure 14. Schottky Forward Drop vs. Junction Temperature Figure 15. Schottky Leakage Current vs. Junction Temperature Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 8 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Typical Performance Characteristics (Continued) (VF of WLED is 3.45V @ IF=20mA, unless otherwise noted ) 700 450 400 Saturation Voltage (mV) Current Limit (mA) 600 500 400 300 O -50 C O 25 C O 100 C 200 100 30 350 300 250 200 150 100 50 50 40 50 60 70 80 90 100 150 200 250 300 Switch Current (mA) Duty Cycle (%) Figure 17. Switch Saturation Voltage Figure 16. Switch Current Limit vs. Duty Cycle vs. Switch Current Feedback Voltage VFB (mV) 250 200 150 100 50 0 0.0 0.5 1.0 1.5 2.0 2.5 CTRL Voltage (V) Figure 18. Feedback Voltage vs. CTRL Pin Voltage Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 9 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Application Information R1 = Operation 200mV I LED The AP3029 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 3. Over Voltage Protection At the start of each oscillator cycle, the SR latch is set and 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 SR latch is reset and the switch is turned off. Soft Start The AP3029 has an internal open-circuit protection circuit. When the LEDs are disconnected from circuit or fail open, the output voltage is clamped at 27V. The AP3029 will switch at a low frequency, and minimize input current. The AP3029 has an internal soft start circuit to limit the inrush current during startup. The time of startup is controlled by internal soft start capacitor. Please refer to Figure 20. 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. VIN ≥ 3V IIN 100mA/div VOUT 5V/div VFB 100mV/div L1 VCTRL 2V/div Time 100µs/div VIN Control Signal SW VOUT CTRL C1 GND Figure 20. Soft Start Waveform VIN=3.6V, 5 LEDs, ILED=20mA C2 AP3029 FB R1 Dimming Control 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. Figure 19. Typical Application circuit to Decide R1 LED Current Control Refer to Figure 19, the LED current is controlled by the feedback resistor R1. 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 R1 is in inverse proportion to the LED current since the feedback reference is fixed at 200mV. The relation for R1 and LED current can be expressed as below: (1). Adding a Control Signal to CTRL Pin There are three methods to control CTRL pin signal First, adding a PWM Signal to CTRL pin directly. The AP3029 is turned on or off by the PWN signal when it is applied on the CTRL pin. The typical frequency of Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 10 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Application Information (Continued) 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 Figure 24. this PWM signal can be up to 2KHz. Please refer to Figure 21. AP3029 CTRL up to 2kHz Figure 21. Dimming Control Using a PWM Signal in CTRL Pin AP3029 Secondly, adding a constant DC voltage through a resistor divider to CTRL pin can control the dimming. The FB voltage is indirectly adjusted when the CTRL pin voltage is between 50mV to 1.8V, which can be used as dimming control. Please refer Figure 22. VDC VDC R3 90K R1 10Ω R2 5K Effective Feedback Voltage Figure 24. Dimming Control Using DC Voltage AP3029 R1 10k 0.1 to 3.6 V FB Second, using a filtered PWM signal can do it. The filtered PWM signal can be considered as a varying and adjustable DC voltage. CTRL R2 10k Figure 22. Dimming Control Using a DC Voltage in CTRL Pin AP3029 Thirdly, using a filtered PWM signal adding to CTRL pin can achieve dimming control. The filtered PWM signal can be considered as an adjustable DC voltage. It will change the FB voltage indirectly and achieve dimming control. The circuit is shown in Figure 23. PWM Signal FB PWM C R3 90K 0.1µF R2 5K R1 10Ω Figure 25. Dimming Control Using a Filtered PWM Voltage AP3029 R1 5k R4 10K Effective Feedback Voltage CTRL Third, using a logic signal to change the feedback voltage. For example, the FB pin is connected to the GND through a mosFET and a resistor. And this mosFET is controlled a logic signal. The luminous intensity of LEDs will be changed when the mosFET turns on or off. C1 100nF Figure 23. Dimming Control Using a Filtered PWM Signal Voltage in CTRL Pin (2). Changing the Effective Feedback Voltage There are three methods to change the effective feedback voltage. Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 11 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Application Information (Continued) AP3029 FB Logic Signal Effective Feedback Voltage R2 2N7002 R1 Figure 26. Dimming Control Using Logic Signal Typical Application VIN ≥ 3V 10µΗ VIN Control Signal SW VOUT AP3029 CTRL GND 0.22µF FB 1µF 10Ω C: X5R or X7R Dielectric L: SUMIDA CDRH5D28R-100NC or Equivalent This circuit can work in full temperature A. Four White LEDs Driver Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 12 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Typical Application (Continued) VIN ≥ 3V 22µΗ SW VIN Control Signal VOUT AP3029 CTRL 0.22µF FB GND 1µF 10Ω C: X5R or X7R Dielectric L: SUMIDA CDRH5D28R-220NC or Equivalent This circuit can work in full temperature B. Six White LEDs Driver VIN ≥ 3V 22µΗ SW VIN Control Signal VOUT AP3029 CTRL 0.22µF FB GND 1µF 10Ω 10Ω C: X5R or X7R Dielectric L: SUMIDA CDRH5D28R-220NC or Equivalent Two transistors are recommended to use Dual Matched transistor pairs This circuit can work in full temperature C. Ten White LEDs Driver Figure 27. Typical Application of LED Drivers Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 13 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 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 0.300(0.012) 0.600(0.024) 4 1.500(0.059) 1.700(0.067) 2.650(0.104) 2.950(0.116) 6 0.200(0.008) Pin 1 Dot by Marking 1 2 3 0.700(0.028)REF 0.950(0.037)TYP 0.000(0.000) 0.100(0.004) 1.800(0.071) 2.000(0.079) 0.100(0.004) 0.200(0.008) 1.050(0.041) 1.050(0.041) 1.150(0.045) 1.250(0.049) Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 14 Preliminary Datasheet WHITE LED STEP-UP CONVERTER AP3029 Mechanical Dimensions TSOT-23-6 2.800(0.110) 3.000(0.118) 1.500(0.059) 1.700(0.067) Unit: mm(inch) R0.100(0.004) MIN 0° 8° 2.600(0.102) 3.000(0.118) Pin 1 Dot by Marking 0.370(0.015) MIN 0.950(0.037) BSC 0.100(0.004) 0.250(0.010) 1.900(0.075) BSC 0.250(0.010) BSC GAUGE PLANE 0.700(0.028) 0.800(0.031) 0.700(0.030) 0.900(0.035) 0.000(0.000) 0.100(0.004) 0.350(0.014) 0.510(0.020) Aug. 2008 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 15 BCD Semiconductor Manufacturing Limited http://www.bcdsemi.com IMPORTANT NOTICE BCD Semiconductor Manufacturing Limited reserves the right to make changes without further notice to any products or specifications herein. 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