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| Preliminary Datasheet WHITE LED STEP-UP CONVERTER General Description The AP3019 is an inductor-based DC/DC converter designed to drive up to five white LEDs in series for backlight. Only one feedback resistor is needed to control the LED current and obtain satisfied brightness. A constant frequency 1.0MHz PWM control scheme is employed in this IC, which means the tiny external components can be used. In fact, 1mm tall inductor and 0.22F output capacitor for the typical application is very appropriate. Additionally, the schottky diode in boost circuit is integrated in this chip. AP3019 also provides a disable port to ease its use for different systems. The over output voltage protection is equipped in AP3019. When any LED is broken or in other abnormal conditions, the output voltage will be clamped to 27V. The AP3019 is available in standard SOT-23-6 package. AP3019 Features * * * * * * * * Inherently Uniform LED Current High Efficiency up to 84% No Need for Extra Schottky Diode Over Output Voltage Protection Drives 2 to 5 LEDs Fast 1.0MHz Switching Frequency Uses Tiny 1mm Tall Inductor Requires Only 0.22F Output Capacitor Applications * * * * * Cellular Phones Digital Cameras LCD modules GPS Receivers PDAs, Handheld Computers SOT-23-6 Figure 1. Package Type of AP3019 Apr. 2007 Rev. 1. 1 1 BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Pin Configuration K Package (SOT-23-6) AP3019 VOUT GND FB 1 2 3 6 5 4 SW VIN CTRL Figure 2. Pin Configuration of AP3019 (Top View) Pin Description Pin Number 1 2 3 4 5 6 Pin Name SW GND FB CTRL VOUT VIN Switch Pin. Connect external inductor Ground Pin Voltage Feedback. Reference voltage is 200mV 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 Output Pin. Connected to the cathode of internal schottky diode Input Supply Pin. Must be locally bypassed Function Apr. 2007 Rev. 1. 1 2 BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Functional Block Diagram FB 3 SOFT START AP3019 SW 1 5 VOUT DRIVER OVP Q1 VIN 6 VREF 1.25 V 200 mV A1 A2 COMPARATOR R S Q 2 CTRL 4 RAMP GENERATOR GND 1.0 MHz OSCILLATOR Figure 3. Functional Block Diagram of AP3019 Ordering Information AP3019 Circuit Type Package K: SOT-23-6 E1: Lead Free TR: Tape and Reel Package SOT-23-6 Temperature Range -40 to 85 C o Part Number AP3019KTR-E1 Marking ID E9S Packing Type Tape & Reel BCD Semiconductor's Pb-free products, as designated with "E1" suffix in the part number, are RoHS compliant. Apr. 2007 Rev. 1. 1 3 BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Absolute Maximum Ratings (Note 1) Parameter Input Voltage SW Voltage FB Voltage CTRL Voltage Thermal Resistance (Junction to Atmosphere, no Heat sink) Operating Junction Temperature Storage Temperature Range Lead Temperature (Soldering, 10sec) ESD (Machine Model) ESD (Human Body Model) TSTG TLEAD RJA Symbol VIN Value 20 27 20 20 265 150 -65 to 150 260 250 2000 Unit V V V V oC/W oC oC oC AP3019 V V 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 Operating Temperature Range Input Voltage CTRL Voltage Symbol TOP VIN VCTRL Min -40 2.5 Max 85 16 16 Unit oC V V Apr. 2007 Rev. 1. 1 4 BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Electrical Characteristics (VIN=3V, VCTRL =3V, TA=25oC, unless otherwise specified.) Parameter Minimum Operating Voltage Maximum Operating Voltage Feedback Voltage FB Pin Bias Current Supply Current Supply Current Switching Frequency Maximum Duty Cycle Switch Current Limit (Note 2) Switch VCE Saturation Voltage Switch Leakage Current CTRL Pin Voltage VCTRL Symbol VIN(min) VIN(max) VFB IFB ICC IQ f DMAX ILIMIT VCESAT TA=25oC, D=40% TA=25oC, D=80% ISW=250mA VSW=5V High Low 40 CTRL Pin Bias Current ICTRL TA=85oC TA=-40oC Schottky Forward Drop Schottky Leakage Current Soft Start Time t VDROP ID=150mA VR=23V VR=27V 300 55 50 75 0.7 0.1 4 150 S V A 1.8 0.05 72 A VFB=VIN, Not Switching VCTRL=0V 1.3 2.0 0.7 90 IOUT=20mA, 4 LEDs, TA=-40oC to 85oC 188 200 35 2.0 3.2 1.0 93 500 350 360 0.01 5 mV A V Conditions Min 2.5 V 16 212 100 2.7 5.0 1.3 mV nA mA A MHz % mA Typ Max Unit AP3019 Note 2: The Switch Current Limit is related to Duty Cycle. Please refer to Figure 16 for detail. Apr. 2007 Rev. 1. 1 5 BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Typical Performance Characteristics (VF of WLED is 3.45V @ IF=20mA, unless otherwise noted ) AP3019 85 85 84 84 Efficiency (%) 83 Efficiency (%) 83 82 82 81 VIN=3.6V, IOUT=20mA, 4LEDS CIN=1F, COUT=0.22F, L=22H 81 IOUT=20mA, 4LEDS, TA=25 C CIN=1F, COUT=0.22F, L=22H O 80 -50 -25 0 25 50 o 75 100 80 2.5 3.0 3.5 4.0 4.5 5.0 Junction Temperature ( C) Input Voltage (V) Figure 4. Efficiency vs. Junction Temperature Figure 5. Efficiency vs. Input Voltage 85 350 300 Schottky Forward Current (mA) 84 250 Efficiency (%) 83 200 82 150 100 81 VIN=3.6V, IOUT=20mA, TA=25 C CIN=1F, COUT=0.22F, L=22H O 50 80 2 3 4 5 0 0 200 400 600 800 1000 LEDS (PCS) Schottky Forward Drop (mV) Figure 6. Efficiency vs. LED's Number Figure 7. Schottky Forward Current vs. Schottky Forward Drop Apr. 2007 Rev. 1. 1 6 BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Typical Performance Characteristics (Continued) (VF of WLED is 3.45V @ IF=20mA, unless otherwise noted ) AP3019 30 3.0 25 2.5 Quiescent Current (A) 20 Supply Current (mA) 2.0 15 1.5 10 1.0 5 0.5 0 2 4 6 8 10 12 14 16 0.0 0 2 4 6 8 10 12 -50 C O 25 C O 100 C 14 16 O Input Voltage (V) Input Voltage (V) Figure 8. Shutdown Quiescent Current vs. Input Voltage Figure 9. Supply Current vs. Input Voltage 29.0 4.0 28.5 3.8 3.6 3.4 Output Clamp Voltage (V) 28.0 27.5 27.0 26.5 26.0 25.5 Input Current (mA) 2 4 6 8 10 12 14 16 3.2 3.0 2.8 2.6 2.4 2.2 25.0 2.0 2.5 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 Apr. 2007 Rev. 1. 1 7 BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Typical Performance Characteristics (Continued) (VF of WLED is 3.45V @ IF=20mA, unless otherwise noted ) AP3019 1.20 1.15 1.10 1.05 210 208 206 Feedback Voltage (V) 204 202 200 198 196 194 192 190 -50 Frequency (MHz) 1.00 0.95 0.90 0.85 0.80 0.75 0.70 -50 -25 0 25 50 o 75 100 -25 0 25 50 o 75 100 Junction Temperature ( C) Junction Temperature ( C) Figure 12. Switching Frequency vs. Junction Temperature Figure 13. Feedback Voltage vs. Junction Temperature 0.80 0.78 0.50 0.45 Schottky Leakage Current (A) 0.76 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 -50 Schottky Forward Drop (V) VR=10V VR=16V VR=23V 0.74 0.72 0.70 0.68 0.66 0.64 0.62 0.60 -50 -25 0 25 50 o 75 100 -25 0 25 50 o 75 100 Junction Temperature ( C) Junction Temperature ( C) Figure 14. Schottky Forward Drop vs. Junction Temperature Figure 15. Schottky Leakage Current vs. Junction Temperature Apr. 2007 Rev. 1. 1 8 BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Typical Performance Characteristics (Continued) (VF of WLED is 3.45V @ IF=20mA, unless otherwise noted ) AP3019 700 500 600 500 Saturation Voltage (mV) -50 C O 25 C O 100 C O 450 400 350 300 250 200 150 100 50 Current Limit (mA) 400 300 200 100 30 40 50 60 70 80 90 100 150 200 250 300 Duty Cycle (%) Switch Current (mA) Figure 16. Switch Current Limit vs. Duty Cycle Figure 17. Switch Saturation Voltage vs. Switch Current 250 200 Feedback Voltage (mV) 150 100 50 0 0.0 0.5 1.0 1.5 2.0 CTRL Voltage (V) Figure 18. Feedback Voltage vs. CTRL Pin Voltage Apr. 2007 Rev. 1. 1 9 BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Application Information Operation The AP3019 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. 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. It is clear that the voltage level at non-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 L1 AP3019 R1 = 200mV I LED Over Voltage Protection The AP3019 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 AP3019 will switch at a low frequency, and minimize input current. Soft Start The AP3019 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. IIN 100mA/div VOUT 10V/div VCTRL 2V/div VIN Control Signal C1 CTRL SW VOUT C2 FB R1 Time 100s/div AP3019 GND Figure 20. Soft Start Waveform VIN=3.6V, 4LEDS, ILED=20mA Dimming Control 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: Apr. 2007 Rev. 1. 1 10 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. (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 AP3019 is turned on or off by the PWN signal when it is applied on the CTRL pin. The typical frequency of BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Application Information (Continued) this PWM signal is 500Hz to 1KHz. Please refer to Figure 21. AP3019 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. AP3019 CTRL 500Hz to 1KHz Figure 21. Dimming Control Using a PWM Signal in CTRL Pin AP3019 FB VDC R3 90K R2 5K R1 10 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. R1 10K R2 10K Effective Feedback Voltage AP3019 CTRL Figure 24. Dimming Control Using DC Voltage VDC 0.1 to 3.6V Second, using a filtered PWM signal can do it. The filtered PWM signal can be considered as a varying and adjustable DC voltage. Figure 22. Dimming Control Using a DC Voltage in CTRL Pin AP3019 FB PWM R4 10K C R3 0.1F 90K R2 5K R1 10 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. Effective Feedback Voltage PWM R 5K C 100nF AP3019 CTRL Figure 25. Dimming Control Using a Filtered PWM Voltage Figure 23. Dimming Control Using a Filtered PWM Signal Voltage in CTRL Pin 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. (2). Changing the Effective Feedback Voltage There are three methods to change the effective feedback voltage. Apr. 2007 Rev. 1. 1 11 BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Application Information (Continued) AP3019 FB Logic Signal R2 2N7002 R1 Effective Feedback Voltage AP3019 Figure 26. Dimming Control Using Logic Signal Apr. 2007 Rev. 1. 1 12 BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Typical Application VIN 3V 10 AP3019 VIN Control Signal 1F CTRL SW VOUT 0.22F FB 10 AP3019 GND C: X5R or X7R Dielectric L: SUMIDA CDRH5D28R-100NC or Equivalent This circuit can work in full temperature A. Four White LEDs Driver VIN 3V 22 Control Signal 1F VIN CTRL SW VOUT 0.22F FB 10 AP3019 GND C: X5R or X7R Dielectric L: SUMIDA CDRH5D28R-220NC or Equivalent This circuit can work in full temperature B. Five White LEDs Driver Figure 27. Typical White LED Drivers Apr. 2007 Rev. 1. 1 13 BCD Semiconductor Manufacturing Limited Preliminary Datasheet WHITE LED STEP-UP CONVERTER Mechanical Dimensions SOT-23-6 Unit: mm(inch) AP3019 2.820(0.111) 3.020(0.119) 0.300(0.012) 0.400(0.016) 0.300(0.012) 0.600(0.024) 0 8 0.200(0.008) 6 2.650(0.104) 2.950(0.116) 5 4 Pin 1 Dot by Marking 1 2 3 0.700(0.028)REF 0.950(0.037)TYP 1.800(0.071) 2.000(0.079) 0.000(0.000) 0.100(0.004) 0.100(0.004) 0.200(0.008) 1.050(0.041) 1.050(0.041) 1.150(0.045) 1.250(0.049) Apr. 2007 Rev. 1. 1 14 1.500(0.059) 1.700(0.067) 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. BCD Semiconductor Manufacturing Limited does not assume any responsibility for use of any its products for any particular purpose, nor does BCD Semiconductor Manufacturing Limited assume any liability arising out of the application or use of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or other rights nor the rights of others. MAIN SITE BCD Semiconductor Manufacturing Limited - Wafer Fab Shanghai SIM-BCD Semiconductor Manufacturing Limited 800, Yi Shan Road, Shanghai 200233, China Tel: +86-21-6485 1491, Fax: +86-21-5450 0008 BCD Semiconductor Manufacturing Limited - IC Design Group Advanced Analog Circuits (Shanghai) Corporation 8F, Zone B, 900, Yi Shan Road, Shanghai 200233, China Tel: +86-21-6495 9539, Fax: +86-21-6485 9673 REGIONAL SALES OFFICE Shenzhen Office Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd. Shenzhen Office Advanced Analog Circuits (Shanghai) Corporation Shenzhen Office Room E, 5F, Noble Center, No.1006, 3rd Fuzhong Road, Futian District, Shenzhen 518026, China Tel: +86-755-8826 7951 Fax: +86-755-8826 7865 Taiwan Office BCD Semiconductor (Taiwan) Company Limited 4F, 298-1, Rui Guang Road, Nei-Hu District, Taipei, Taiwan Tel: +886-2-2656 2808 Fax: +886-2-2656 2806 USA Office BCD Semiconductor Corporation 30920 Huntwood Ave. Hayward, CA 94544, U.S.A Tel : +1-510-324-2988 Fax: +1-510-324-2788 |
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