Soft switching circuit without absorption loss

The invention modifies circuit structure with no absorption loss in existed soft switching as follows. In BOOST boosted circuit, a branch circuit composed of cascaded diode D2, D3 and D4 is connected to two ends of freewheeling diode D1 in BOOST circuit in parallel. One end of resonance branch circuit composed of capacitance C2 and inductance L2 is connected to positive end of diode D1, and the other end of the resonance branch circuit is connected to between diode D3 and D4. One end of capacitance C3 is connected between diode D2 and D3, and the other end is connected to end of cathode of switching tube. If needed, circuit with no absorption loss of positive/negative excited convertor can be added to modified circuit. 本发明涉及一种一种对现有软开关无损耗吸收电路结构的改良。它主要是在BOOST升压电路中，由二极管D#-[2]、二极管D#-[3]和二极管D#-[4]同向串联而成的支路，同向并接在所述的BOOST电路中的续流二极管D#-[1]的两端；而由电容C#-[2]和电感L#-[2]串联的谐振支路一端接于二极管D#-[1]的正极，另一端接于二极管D#-[3]与二极管D#-[4]之间；且在二极管D#-[2]与二极管D#-[3]之间接有电容C#-[3]的一端，电容C#-[3]另一端接于开关管的阴极端。需要时，还可在其电路上增设正、反激变换器的无损耗吸收电路。