Apple Inc.
Peak Voltage Overshoot Control for Switch Mode Power Converters

Abstract:

A switching power converter circuit may include output voltage overshoot mitigation circuitry that can modify operation of the converter responsive to an overvoltage condition by switching from a pulse width modulation (PWM) mode to a pulse frequency modulation (PFM) mode. A clamp may be provided to clamp a control voltage or a compensating capacitor voltage of the main output voltage control loop (e.g., a PWM control loop) to a control voltage of the PFM loop. An output pull down circuit may be provided to temporarily apply a load to the converter output.