The IC active abnormal when surge happens.
The main issues are:
- Comparing with former DCBUS voltage, the Vsense voltage should be higher than OVP point all the time. But from the waveform, the vsense voltage have fluctuation to drop down to 5.1V
- When the vsense voltage>5.1V, there still be big duty cycle here.
About first issue , I think we need to increase the vsense capacitor. But I am worrying about whether bigger capacitor would significantly reduce the control response time to output voltage deviations.Now the capacitor is 1n
About second issue, Is there any inference that would cause the OVP disable, please?
Channel 1: MOV voltage
Channel 2: Vsense voltage
Channel 3: Drive waveform(Gate voltage)
Channel 4: Vds of Mosfer
Add a output voltage waveform:
Channel 1: MOV voltage
Channel 2: Voltage between Bridge Rectifier pin 1 and pin 4
Channel 3: Bulk capacitor voltage
Channel 4: Vds of PFC Mosfet