Delta Electronics (shanghai) Co., Ltd

Yuhua Hu

Jinfa Zhang

Kai Dong

Yichao Wang

In the present disclosure, the multi-level AC/DC conversion circuit and the multi-level DC/DC conversion circuit calculate the duty ratio of synchronous rectification switch according to the input voltage, the output voltage, the interval time of turning on the main switch, the switching cycle and the duty ratio of main switch, thereby eliminating the need for additional zero-current detecting function or zero-crossing detection circuit in conventional AC/DC conversion circuits. Accordingly, for the multi-level AC/DC conversion circuit and the multi-level DC/DC conversion circuit of the present disclosure, the cost is reduced, and the reliability is enhanced.

Multi-level AC/DC conversion circuit, multi-level DC/DC conversion circuit and control methods thereof

A multi-level conversion circuit and a control method for flying capacitor voltage thereof are provided. In the multi-level conversion circuit, each flying capacitor is connected between a common connection node of the lower switches connected therewith and a common connection node of the upper switches connected therewith. When the conversion circuit works in a DCM, the control method includes steps of: (a) determining the main switch and synchronous rectification switch of the lower and upper switches; (b) acquiring an adjustment value corresponding to each flying capacitor; and (c) adjusting a duty ratio of the main switch according to the adjustment value corresponding to the flying capacitor connected therewith, wherein the adjustment trend of the duty ratio under D<(N−2)/(N−1) is opposite to that under (N−2)/(N−1)<D≤1, and D is the duty ratio before the adjustment.

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Shanghai, China

Yuhua Hu