Half-bridge converter power supply circuit diagram composed of two capacitors and high voltage transistors

Published:2011/3/29 1:26:00 Author:Nicole | Keyword: half-bridge converter, power supply, capacitor, transistor | From:SeekIC

In the high voltage switching power supply, the high Power Output always use half-bridge converter circuit. The figure as below, it is composed of two capacitors and two high voltage transistors. When two transistors cut off, if the capacity of two capacitors are equal and circuit symmetrical, then the voltage of point A is half of the input voltage. When VTl turns on, capacitor C01 will discharge through VTl, transformer primary winding N1; at the same time, capacitor C02 will charge through input power, VTl and primary winding N1 of T1. The potential of mid-point A will be decreased exponentially during the charge and discharge process. When VTl turns off, the potential of point A is (1 / 2) Ui-ΔUi, and the two transistors are all off. Collector to emitter voltage of two capacitors and two transistors is equal essentially, are all close to half of the input supply voltage. On the contrary, VT2 turns on, C02 discharges, C0l charges, the potential of point A will increase to (1 / 2) Ui + ΔUi, namely the potential of point A will be in the (1 / 2) Ui and index changed with the amplitude of ± △ U. Thus, in the half bridge circuit, the transformer primary winding always has current flowing in the whole cycle, the core is fully utilized.



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