Compiler: I want to find a 3W single LED driver of high speed

user4502281

Other Parts Discussed in Thread: LM3414, TPS54200, TPS92515

Tool/software: TI C/C++ Compiler

Hi,

I want to find a single LED driver of high speed to drive a 3W 3V LED.The most concerned parameters are rise time of the LED current and peak-to-peak LED current ripple.The parameter requirements are as follows.

Vin(min):3.3V

Iout (Max) : 1A

rise time of the LED current :less than 50us(The smaller is the better)

peak-to-peak LED current ripple:less than 1%

Thank you for the reply.

Regards,

Zhou

over 8 years ago

0 Summer SU over 8 years ago

TI__Expert 4445 points

Hi Zhou,

If you need the very small LED peak to peak, there is larger cap in the output, this will impact the current slew rate. May I know the slew rate in the start up or PWM dimming?

Thanks!

Summer

0 user4502281 over 8 years ago in reply to Summer SU

Prodigy 20 points

Hi Summer,
Thanks for your reply.I know the current slew rate and the peak-to-peak LED current ripple are contradictory.I have used LM3414 to control it.To get the very small LED peak to peak,I used a very large inductor caculated by the formula.So the result was that the slew rate in the start up got much longer.
because I need to use the 3W lED in two differentconditions,I think I can take the requist apart into two devices.The first one should have small peak-to-peak LED current ripple and it's rise time should be short than 1ms.The other one should have short rise time less than 50us and the current ripple is OK.
I appreciate if you can share any thoughts you may have .
Thanks
Zhou