UCC25800EVM-1: May I modify the parameter from 18V,-5V to +12,-12V on the EVM?

Jimmy WANG

Genius 4115 points

Part Number: UCC25800EVM-1
Other Parts Discussed in Thread: TL431

Hi team,

May I modify the parameter from 18V,-5V to +12,-12V on the EVM?

I try to modify it. but when no-load condition that output voltage is stable.

I try to adjust output load up each channel and can not regulation normally.

Could you give me a suggeation? thx

over 3 years ago

0 Jerry Xu over 3 years ago

TI__Expert 3160 points

Hi Jimmy,

Can you provide your calculated corresponding resistor R5,R6,R7,R8,R9,R10?

Jerry Xu

0 Jimmy WANG over 3 years ago in reply to Jerry Xu

Genius 4115 points

Hi Jerry,

R5=R8= 510R

R7=R10=1K

R6=R9=5.6K

0 Jerry Xu over 3 years ago in reply to Jimmy WANG

TI__Expert 3160 points

Hi Jimmy,

Have you adjust the clamp voltage of D1?

Jerry Xu

0 Jerry Xu over 3 years ago in reply to Jimmy WANG

TI__Expert 3160 points

Hi Jimmy,

Have you adjust the clamp voltage of D1?

Jerry Xu

0 Jimmy WANG over 3 years ago in reply to Jerry Xu

Genius 4115 points

Hi Jerry,

D1 is DNP.

0 Jerry Xu over 3 years ago in reply to Jimmy WANG

TI__Expert 3160 points

Hi Jimmy,

I think you need to replace D1 with 12V Zener diode or select a proper resistor R2 to make the split regulator work normally such as below.

0 Jimmy WANG over 3 years ago in reply to Jerry Xu

Genius 4115 points

Hi Jerry,

thanks, but when +-12V different load. Does the circuit can regulator work normally? thx

ex 12V=0.03A

-12V=0.01A

0 Jerry Xu over 3 years ago in reply to Jimmy WANG

TI__Expert 3160 points

If you want to increase the output current for low side TL431, you can configure it as high side TL431.

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UCC25800EVM-1: May I modify the parameter from 18V,-5V to +12,-12V on the EVM?