Auto Adjust & Dimming LED driver IC. Auto Adjust Voltage DC-DC Converter & Current Controller

Transcription

1 Auto Adjust & Dimming LED driver IC Auto Adjust Voltage DC-DC Converter & Current Controller Features Use for high brightness LED lighting driving Supply voltage input range from 3V boost to 400V stepdown application 400K Hz frequency more than 90% efficiency Constant current control for LED driving Adjustable LED drive current by external resistor for dimming function Auto-detect and auto-adjust for optimum power efficiency Auto-detect LED serial number for optimum operating voltage Easy adjustable PWM duty cycle for step-down DC-DC control Auto step down and optimum for power efficiency and saving the power drop in IC when LED Vf drop down Parallel 3-channel(BL801) for independent adjustable LED current control Parallel 3-channel(BL801) connection available for 1A current loading in IC Maximum 10A driving current for for 1-channel (BL801S) application Built-in band-gap circuit for steady voltage reference Built-in regulator with external resistor for lower IC temperature Built temperature IC protecting to 120 C ESD protection up-to 4KV Application AC to DC LED driver application DC to DC LED driver application Hight brightness LED driver application LED lighting and dimming function LED string & R,G,B color driving application LED flash light & true color lighting Back lighting of flat panel displays Auto adjust voltage power driver, boost or switching power supply multi applications 1

2 Description BL801 is a LED driver ASIC for 3 channels output current sink. Every channel could sink up to 350mA for 1W-LED application. The 3 channels output current could be determined separately by 3 input resistors. Parallel connection of these 3 channels is available for driving more than 1A lighting applications. For the applications of serial connection, BL801 could automatically adjust necessary supply voltage for LED by step-down DC-DC approach, to achieve optimum power efficiency. Package BL801S (SOP- 8) BL801 (SOP- 14) Function Block 2

3 Pin Assignment & Description Pin Name Pin # Pin # I/O Description SOP-8 SOP-14 VDD 1 5 P Power input ISEN 2 6 IN Current sense for feedback control PWM 3 7 OUT PWM pulse output OUT1 4 8 OUT ch-1 current driver OUT2 4 9 OUT ch-2 current driver OUT OUT ch-3 current driver GND 5 11&12 P Power ground IN IN ch-3 drive current control IN IN ch-2 drive current control IN1 6 1 IN ch-1 drive current control OSC 7 3 IN Setup PWM frequency FB 8 4 IN Auto-detection and feedback for optimum LED power TEST - 2 IN Test Pin, No Connect Absolute Maximum Ratings Supply Voltage V to 9V Other I/O Pin Voltage V to (V DD +0.3V) OUT Current (1-CH) A Allowable Power Dissipation W Operating Temperature Range to +140 Storage Temperature Range to

4 Electrical Characteristics (Ta=25,VDD=5V) SUPPLY SECTION Regulated Voltage I REG = 20mA V DD V Input Leakage I LI 10 ua Output Leakage I LO 10 ua BL801S Operation Current w/o Regulator R IN =500 ohm I DD_1CH 4 6 ma R IN =5 kohm I DD_3CH ma R IN =50 kohm I DD_1CH ma BL801 Operation Current w/o Regulator R IN =500 ohm I DD_3CH ma R IN =5 kohm I DD_1CH 2 3 ma R IN =50 kohm I DD_3CH ma Regulator Sink Current V DD =5V I REG 35 ma OSCILLATOR SECTION OSC frequency OSC Input High Voltage V DD =5V, C=50PF F OSC khz V DD =5V V IH V OSC Input Low Voltage V DD =5V V IL V OUT SINK SECTION BL801S OUT Sink Current V OL=0.5V,R IN=500 ohm I SINK ma V OL=0.5V,R IN=5 kohm I SINK ma V OL=0.5V,R IN=50 kohm I SINK ma BL801 OUT1~3 Sink Current V OL=0.5V,R IN=500 ohm I SINK ma V OL=0.5V,R IN=5 kohm I SINK ma V OL=0.5V,R IN=50 kohm I SINK ma 4

5 PWM SECTION PWM Active High Duty OSC only connect to Capacitor, V DD =5V PWM_duty % PWM Source current V DD =5V, V OH =4.2V I PWM_OH ma PWM Sink current V DD =5V, V OL =0.8V I PWM_OL ma TEMPERATURE PROTECTION SECTION Thermal Shutdown Temperature Thermal Shutdown Hysteresis V DD =5V T SD 120 V DD =5V T HYST 20 CURRENT PROTECTION SECTION ISEN Voltage Threshold V DD =5V V ISEN V *Note: Reference to Application 5

6 Application Note Vin should be higher 1V than the driving voltage The supply power need more than the driving power. The OSC designed around 400KHz, it can be adjusted by R2,C2 to optimize the transfer efficiency of power. will optimize the suitable voltage and duty cycle for the driving power in the beginning. FB will detect the feedback voltage and auto adjust in the range 0.2~2.5V to stable the output voltage and current. The driving voltage can be setting by the R7,R8 for the feedback voltage. FB has 64 level to step up the driving voltage if the power is not enough for the driving voltage. Adjust the resister of Pin6 IN can control the current sink volume from 10mA to 1A. If the driving power is not enough, the LED driving will be unstable. The PIN7 ISEN is the ON/OFF control. The level is 0.25V, high is OFF. When using 3 channels, the driving voltage is the same. The output current is independently controlled each channel. Please note to adjust the load for voltage balance not over than 0.6V. 6

7 Typical Application: -- BL801S VIN>V_LED+1V -- BL801 step VIN>V_LED+1V 7

8 -- BL801S step >1A~10A -- BL801S step VIN<V_LED+1V 8

9 Package Dimension (SOP-8) 9

10 Package Dimension (SOP-14) 10