Microwave output stabilizing apparatus of a microwave oven and a method thereof

A microwave output stabilizing apparatus for a microwave oven, comprising:

• a rectifier circuit for rectifying power from an AC power supply into a constant DC voltage;
• an inverter circuit for generating a high frequency power signal by controlling said DC voltage at an intermittent output state;
• a high voltage transformer for stepping up said high frequency power signal;
• a magnetron drive circuit including a magnetron for rectifying the stepped up high frequency power signal and causing a magnetron to oscillate;
• an inverter control circuit for detecting a current flowing into a primary winding of said high voltage transformer, converting said detected current into a corresponding first voltage, comparing said corresponding first voltage with a reference voltage and controlling said inverter circuit according to a result of said comparing;
• an anode current detecting circuit for detecting an anode current of said magnetron and converting said detected anode current into a voltage corresponding to a second voltage;
• and
• a reference voltage adjusting circuit for controlling said reference voltage of said inverter control circuit in accordance with said voltage corresponding to said detected anode current, said reference voltage adjusting circuit including
• a plurality of resistors selectably connectable to control a voltage to be presented to said inverter control circuit, and
• a microprocessor including an A/D input and a plurality of output ports, said A/D input being connected to said anode current detecting circuit to receive said second voltage, said microprocessor determining whether the anode current is within a predetermined range on the basis of said second voltage and producing an output collectively at said plurality of output ports based on said determination, said output controlling connection of said plurality of resistors.