When I start to increase loading, I am getting a phenomenon where the controller will completely skip PWM cycles and eventually transition to half the switching frequency (starts at 100kHz, transitions to 50kHz and then overcurrent protects). Any ideas why this is happening?
20V Input, 19 → 18 Ohm transition
- CH1 = Vin (diff)
- CH2 = VCS at pin
- CH3 = I-inductor
- CH4 = Vout (passive)
Nominal 100kHz before skipped cycle
Moment of skipped cycle
Eventually transitions to half frequency (50kHz) causing overcurrent and eventual protection
