High-side sensing of zero inductor current for step down DC-DC converter

摘要

A DC to DC converter circuit includes circuitry for generating a PWM waveform signal at a phase node of a DC to DC converter responsive to an input voltage and a monitor output voltage. The circuitry further includes a high side switching transistor connected between the input voltage and a phase node and a low side switching transistor connected between the phase node and ground. An output filter is connected to the circuitry for generating the PWM waveform signal. The output filter includes an inductor having a first side connected to the phase node and a second side connected to an output voltage node. Detection circuitry detects zero current crossings in the inductor responsive to a voltage across the high side switching transistor and a voltage across the low side switching transistor.