LM3481: EVM circuit

Jerry Hsueh

Expert 2730 points

Part Number: LM3481

I want to ask about the circuit of LM3481 EVM.

What are the functions of the following yellow area circuits?

Should they be added to output high voltage applications?

Thank you

Jerry

over 6 years ago

0 kai klaas69 over 6 years ago

Guru 140200 points

Hi Jerry,

D3 is to lower down the 120V output voltage to a more suited supply voltage for the opto-LED. D4 and D5 help during power-up and power-down.

Kai

0 Jasper Li over 6 years ago

TI__Mastermind 46905 points

Hi Jerry,
I agree with Kai about the function of these circuit. to be detail, the D5 is used to clamp the output of the U3 during startup to achieve softstart of the output voltage.

Power management

Power management forum

LM3481: EVM circuit