Hi,
1. Double check the resistance of R1~R4
2. Remove P6KE300A and short R1~R4, check the VDD voltage, and power up UCCC28740. UCC28740 HV pin ABS voltage is 700V, make sure the voltage after rectification is lower than 700V when do this testing.
3. Place…
Part Number: OPA454
I connect 2 pins to 10K resistor to GND, 6 pins to 100K resistor feedback to 2 pins, 3 pins for reserved input, input resistance is 10K, 4 pins to -12V, 7 pins to 12V, 8 pins to 30PF to GND, 5 pins to 1M to 7 pins, there is no connection…
Part Number: OPA454
I connect 2 pins to 10K resistor to GND, 6 pins to 100K resistor feedback to 2 pins, 3 pins for reserved input, input resistance is 10K, 4 pins to -12V, 7 pins to 12V, 8 pins to 30PF to GND, 5 pins to 1M to 7 pins, there is no connection…