High frequency cathode heater supply for a microwave source

摘要

A high frequency cathode heater supply for a microwave source includes a SMPS inverter and an isolation transformer having a primary winding arranged to be powered by the SMPS inverter, a monitor winding passing through primary core assemblies of the primary winding and a secondary winding arranged for connection to the cathode heater. A current monitor is arranged to monitor a current in the primary windings. Signal processing modules are arranged to receive a first input signal from the monitor winding indicative of a voltage across the cathode heater and a second input signal from the current monitor indicative of a current through the cathode heater. The signal processing modules are arranged to output a control signal to the SMPS inverter to control power supplied to the cathode heater dependent on a monitored resistance of, or monitored power supplied to, the cathode heater as determined from the first input signal and the second input signal.

主权项

1. A cathode heater supply for a microwave source comprising:
a switched mode power supply (SMPS) inverter; an isolation transformer comprising:
a primary winding arranged to be powered by the SMPS inverter;a monitor winding passing through primary core assemblies of the primary winding; anda secondary winding arranged for connection to the cathode heater; a current monitor arranged to monitor a current in the primary windings; and a signal processor arranged to receive a first input signal from the monitor winding indicative of a voltage across the cathode heater and a second input signal from the current monitor indicative of a current through the cathode heater, the signal processor being arranged to output a control signal to the SMPS inverter to control power supplied to the cathode heater dependent on the first input signal and the second input signal.