Charging system and dual mode power conversion circuit thereof

Abstract

A power conversion circuit for performing conversion between a first and a second power sources, includes: an N-level Pulse Width Modulation (PWM) power converter, configured to switch electrical connections of an inductor and a capacitor in an N-level PWM mode; and a capacitor switching power converter, configured to switch electrical connections of the capacitor in a capacitor conversion mode. During a mode transition process between the N-level PWM mode and the capacitor conversion mode, the power conversion circuit is configured to perform a soft-transition operation: during a soft-transition period, in a conduction state when a first switch is periodically switched, a voltage at a control terminal of the first switch is controlled to a bias voltage to limit a first switch current flowing through the first switch. The first switch corresponds to one of the switches in the N-level PWM power converter and the capacitor switching power converter.

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