I'm currently designing a 150W Half Bridge SMPS with the UC28025 (with multiple outputs).I need a reference design for the Half Bridge SMPS either based on UC1825-series (1825, 2825 or 3825) or UC28025.
I'm having trouble designing the FB/EA-circuit around the IC from the opto coupler (voltage levels etc.).
Attached is a paper on the half bridge topology using a UC2825 and current mode control.
In addition i noticed a couple of things that are probably impacting the circuit performance. The first is that there is a sneek path in the feedback loop that will result in a higher gain than designed and probably some instability as a result. this is explained in a paper you can find at the link:
Because of the integrating nature of the feedback loop on the secondary side you might find that you run into Turn on Overshoot" which is discussed in the following paper:
And lastly the current mode controlled half bridge has a tendancy to go into oscillation due to imbalances and this and the solution is discussed in the following paper:
Hope these comments help
Thank you very much for your help! I will read this during the weekend and make the adjustments as soon as possible!
I'll get back to you if I have any questions!
"Because of the integrating nature of the feedback loop on the secondary side you might find that you run into Turn on Overshoot" which is discussed in the following paper:
Your link doesn't work..?
Try copying it directly into your browser
Thank you. Very interesting reading. It works by copying it to the browser address bar.
Have a nice weekend.
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