preliminary PT6910 1.2a led driver with integrated switch tel: 886-66296288 ? fax: 886-29174598 ? http://www.princeton.com.tw ? 2f, 233-1, baociao road, si ndian, taipei 23145, taiwan description the PT6910 is a continuous mode inductive step-down converter, designed for driving single or multiple series white leds efficiently from a voltage source higher than the output led voltage. the ic operates from an input supply between 6v and 36v and provides an externally adjustable output current of up to 1.2amp. the PT6910 includes the internal switch and a high-side output current sensing circuit, which uses an external resister to set the average out put current. also the output current can be adjusted below the set value by using the external adj pin. the adj pin will accept either a dc voltage or a pwm waveform. depending upon the control pwm frequency, the ic will provide either a continuous or a gated output current with the internal pwm filter circuit. the PT6910 provides a soft-start feature. and the soft-start time can be increased by using an external capacitor from the adj pin to ground if you need a longer soft-start time. anyway if you apply a voltage of 0.2v or lower the output switch will be off and the ic go into a low current standby state. features ? high efficiency (up to 95%) ? soft-start (adjustable) ? maximum 1.2a output current ? low/high frequency pwm dimming with internal pwm filter ? wide input voltage: 6v ~ 36v ? internal open-circuit led protection ? typical 5% output current accuracy ? sot-89-5l applications ? dc/dc led driver ? low voltage industrial led lighting ? low voltage halogen replacement leds ? decorative led lighting ? led table lighting block diagram
PT6910 pre1.0 2 april 2010 typical application
PT6910 pre1.0 3 april 2010 order information valid part number package type top code PT6910 sot-89-5l PT6910 pin configuration pin description pin names description pin no. lx drain of the internal nmos switch 1 gnd signal ground 2 adj ? multi-function on/off and brightness control pin ? leave floating for normal operation. ? drive to voltage below 0.2v to turn off output current. ? drive with dc voltage (0.3v to 1.3v) to adjust output current from 25% to 110% of iout. ? drive with pwm signal from open-collector or open-drain transistor , to adjust output curr ent from 25% to 100% of iout for f>10khz and from 1% to 100% for f<500hz. ? connect a capacitor from th is pin to ground to increase soft-start time. 3 isns output current sense pin 4 vin input supply pin. must be locally bypassed. 5 exposed pad power ground
PT6910 pre1.0 4 april 2010 important notice princeton technology corporation (ptc ) reserves the right to make co rrections, modifications, enhancements, improvements, and other changes to its products and to discontinue any product without notice at any time. ptc cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a ptc product. no circuit patent licenses are implied. princeton technology corp. 2f, 233-1, baociao road, sindian, taipei 23145, taiwan tel: 886-2-66296288 fax: 886-2-29174598 http://www.princeton.com.tw
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