Tool/software:
Originally, the 9V input could only reach 12V/120W, but now it can reach 12V/170W, and the goal is 12V/200W.
R21: 4.99 k→3.3 k
R21: 120 k→150 k
R22: 80.6 k→56 k
Is there any room for improvement? What turns ratio can the transformer be replaced with?
Attachments include Qmain waveform & current transformer specification
This figure shows Qmain.Gate & Qmain.Drain waveform, 9Vin, Load: 13A
This figure shows the transformer specifications currently in use
Hi,
Based on your test data, from 12V/120W to 12V/170W, secondary-side voltage increase from turns ratio and Dmax is increased about 2V to get 120W to 170W so about 50W increase which Dmax is already over 83.5%, and fsw already reduced 20kHz. I would suggest you change Np:Ns from 3:7 to 3:8 to help another 2V increase on the secondary side to allow design margin.
Hi Hong Huang
Thank you for your support
The power conversion circuit alone can reach 9Vin and output 12V/200W. After 3 minutes, the main switch MOS VGS short-circuited and burned. The initial judgment was that it was caused by thermal wear due to excessive temperature. Q12 also burned in the previous test, which should also be thermal wear. The attachment is the waveform of Q19 and Q12 when it is unloaded and full, as well as the SPEC of the two materials. Please help review where the problem is. If you want to change the material, what parameters should you pay attention to? Or is it recommended to put two?
