Opto feedback with UC2825 Full bridge controller?

cupoftea · Oct 10, 2023

Hi,
How would you best do opto feedback with UC2825?

1....opto in common emitter then pull down error amp output, with (EA inv pin) grounded?

2...Set up as "normal" then put opto in CC and dribble currnt into the grounded feedback resistor

3....Set up EA as buffer.....pull noninv up to 5v ref....then opto in CE to the pullup

UC2825

https://www.ti.com/lit/ds/symlink/uc2825.pdf?ts=1696962562904&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FUC2825

cupoftea · Oct 11, 2023

Looks like best way as per pg 2 of this..

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwir1JacjO6BAxVIXUEAHRKqC8cQFnoECDAQAQ&url=https%3A%2F%2Fnexgenpowersystems.com%2Fwp-content%2Fuploads%2F2020%2F03%2F800V-14V_Buck_convertor_1MHz_v1.0.pdf&usg=AOvVaw06MRbm4-XuOqUjvHZ2L9X-&opi=89978449

.....set up as inverting amplifier, and dribble current into grounded "lower divider resistor". Ref into NI input

Part 1 of original post looks bad, since EAout is said to be ABS MAX'd at 5mA....if it was a potential pull down for feedback opto, then they wouldnt say that?

Opto feedback with UC2825 Full bridge controller?

cupoftea

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cupoftea

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Opto feedback with UC2825 Full bridge controller?

cupoftea

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