你的反饋太弱了.加大反饋的電流.個人意見的. 因為我也是初學(xué)的.
就是幫你定.你試試吧.

取樣電流電阻太大

同上

這個問題可多了,先檢查一下有沒有聯(lián)錯,比如連焊之類的.還有變壓器有沒有問題,整流管有沒有倒,再就是反饋!!!

can you show your schematic?
It can be one of the following reasons:

1. The PWM driving circuit is not able to drive the transformer when on load.
2. output was connected with chips which was somewhere short.
3. Feedback control, the resistance value must be correct.