switching speed of LM317

Takahiro Nishizawa

Genius 5575 points

Other Parts Discussed in Thread: LM317

I have question about LM317.

We design the following circuit.

- Constant current circuit by using LM317

- Switching circuit by using transistor and FET.

The switching speed is 2Mbps.

Are there problems with switching speed of 2Mbps?

And please tell me optimum switching speed if there are problems about 2Mbps.

Best regards,

Takahiro Nishizawa

over 8 years ago

0 Michael Hartshorne over 8 years ago

TI__Genius 13325 points

Hello,

Are you using LM317 as a LED driver? In that case it will be difficult to use at 2 MHz, the LM317 startup time can be around ~ 1 ms. Because of this, the device cannot turn off/on again in less than 1 ms, so, 2 MHz would be too fast. You would need to switch at a much lower frequency.

Regards,

Mike

0 Takahiro Nishizawa over 8 years ago in reply to Michael Hartshorne

Genius 5575 points

Thank you for your help!

We think that the customer use this IC for LED.
Do you know optimum switching speed(~bps) under this condition?

Best regards,

Takahiro Nishizawa

Power management

Power management forum

switching speed of LM317