Magnetron with full wave bridge inverter

摘要

An arrangement for providing power to a cooking magnetron uses a full wave bridge inverter circuit. Four semiconductor switches, pairs of which are switched on and off by a pulse width modulation control circuit provide power to a primary winding of a power transformer. A secondary winding of the power transformer supplies the power to the magnetron. The control circuit switches two of the four transistors on and off by way of an isolated drive circuit such that the control terminals of the semiconductor switches float with respect to the other two semiconductor switches. The control circuit includes pulse width modulation circuitry which provides a control pulse having a width proportional to an input provided across a transconductance amplifier. A signal dependent upon magnetron current is used as part of a feedback loop such that a magnetron current is stabilized against variations due to line voltage changes.