Thermal Shutdown TOP259EN-TOP261EN
I have designed 32V 7A SMPS.I designed using PIExpert. I wrapped the transformer as it was said in PIExpert.Output values are correct, i see 32 volts.
PROBLEM: Top259EN-Top261EN turns off after running for a few seconds. This shutdown is most likely caused by thermal shutdown.
QUESTION 1: What should I do for the circuit to work normally without going into thermal shutdown?
I installed a fairly large heatsink but it only increased the runtime by 1-2 minutes. As the load connected to the output increases, the closing time becomes shorter.
QUESTION 2: Vds voltage is 640-650V, sometimes even over 700V. It changes according to the load connected to the output. How can I lower the maximum vds voltage?
I tried making changes to the snubber circuit but top259EN-top261EN exploded. When I checked the circuit after it exploded, I saw that the tvszener diode (P6KE350A) was burned.
QUESTION 3: Is it 640-650V, 700-750V vds_max voltage high for circuit or normaly?
I attached the all needed documents. Real Schematic, Waveforms, Pıexpert project, transformer test results..
In the real schematic design, the values of some components were chosen different from the values that PIExpert said, since we do not have the same value component.
Transformer primary inductance: 250uH
Transformer leakage inductance: 5uH