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Problem AC - DC 24V / 8.5A

Posted by: sharley on

Hello everyone.

we are developing a source whose characteristics:
Input: 85 ~ 265 Vac
Output: 24Vdc - 8.5A

we execute the assembly exactly as the piExpert simulation
problems:

the output voltage does not stabilize at 24Vdc, in the circuit supply the output voltage reaches 52V causing problems in resistor R12.

could they give me a support to discover wharfs are the causes of this happening?
attached files for analysis

Thank you in advance for your support!

Files

Attachment Size
teste3.uds 904.5 KB
24V_-_8.5A.pdf 177.35 KB
24V_-_8.5A1.pdf 290.19 KB
24V_-_8.5A4.pdf 314.31 KB

Comments

Submitted by Easy Peasy on 02/19/2018

likely your opto is not high enough gain to raise the control pin at no load for zero switching

You could try a minimum load on the output

Or an opto with guaranteed higher gain

or the TL431 is fried...

Submitted by PI-Mallora on 02/22/2018

Hi Sharley,

Is it regulating at 52V even when you put some load? As what Easy Peasy mentioned, check your feedback with opto and TL431. Additionally, check if you have bias supply voltage across C8. Thank you.