DRIVE CIRCUIT FOR INVERTER MICROWAVE OVEN

PURPOSE:To make a microwave over small in size and light in weight by letting the primary winding of a step-up transformer and the group of switching elements form a closed loop, and connecting the connecting points of the group of the elements and the center tap of the primary winding of the transformer to a low voltage capacitor. CONSTITUTION:A DC power supply 1 is connected to the group of switching elements 8a and 8b via a choke coil 11 and a low voltage capacitor 12, and the other end of the power supply is connected to the primary winding center tap 3c of a step-up transformer 3. When the power MOSFET of the group of the elements 8a is turned on, current flows to the voltage double rectifier of the secondary circuit 4 of the transformer 3 and the closed loop of a magnetron 5, so that electric energy is supplied to the magnetron 5. And when the MOSFET of the group of the elements 8a is turned off, electric energy stored in the transformer 3 is regenerated to the power supply 1 while being supplied to the magnetron. And high frequency electric power is supplied to the magnetron 5 with the aforesaid action repeated. By this constitution, no DC/AC inverter is required, a drive circuit inexpensive and high in output can thereby be provided.