A buck converter circuit with soft switching and its timing control method

Abstract

The invention discloses a Buck converter circuit with a soft switch and a timing control method thereof. The circuit includes a soft switch branch and an auxiliary inductance L r ; The soft switching branch is connected in parallel between the first branch and the second branch; the auxiliary inductance L r The power MOSFET tube Q connected in series on the second branch 1 with power MOSFET Q 2 between. The method starts freewheeling at the peak point of the main inductor current through the soft switching branch, and the auxiliary capacitor stores energy; the soft switching branch in the circuit is connected, and the energy stored in the auxiliary capacitor is partially fed back to the power supply, and the power is realized in the process. MOSFET Q 1 , Q 2 and Q r soft switch. The invention effectively and reliably reduces switching loss, saves a lot of heat loss, improves the operation stability of switching devices, the conversion efficiency of circuits and the safety of equipment using the circuits.

Description

technical field [0001] The invention relates to the technical field of Buck converter control, in particular to a Buck converter circuit provided with a soft switch and a timing control method thereof. Background technique [0002] With the development of power supply technology, converters with high efficiency and high power density have become a trend. The switching loss of the hard switching technology is large during high-frequency switching, which reduces the efficiency of the converter. At the same time, the electromagnetic interference is relatively serious. Therefore, the soft switching technology is proposed, which can effectively reduce the switching loss and improve the efficiency of the converter. In the switching power supply, Buck circuit is one of the frequently used DC / DC topologies. [0003] The traditional Buck circuit such as figure 1 As shown, but the switching loss and inductor current loss during the working process constitute the majority of the circ...

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Problems solved by technology

[0003] The traditional Buck circuit such as figure 1 As shown, but the switching loss and inductor current loss in the working process constitute the majority of the circuit loss, and at the same time generate a large amount of heat loss, which is not conducive to the stable operation of the switching device, the conversion efficiency of the circuit and the safe operation of the system

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