Dear engineers,
I would like to ask you for suggestions about what could be wrong with my negative buck converter design. I tried to measure only HI and LO outputs without MOSFETs, but there is no "PWM" signal on these outputs. I also checked SYNCOUT output, and there was a PWM signal with f=156 kHz, which was very close to the desired 146 MHz. I also checked UVLO pin - there was voltage more than 1,2 V (approx 1,6 V). Next thing which I checked was FB voltage - I connected desired -30V to output and checked reference voltage which was close to 1,2 V. Voltage on VIN pin was also OK (about 55 V).
You can find my design here.zaporna cast v4.pdf
I will appreciate any ideas.
Many thanks for your help.
