| 摘要 |
<p>A high frequency cathode heater supply for a microwave source includes a switched mode power supply (SMPS) inverter 13 and an isolation transformer 12 having a primary winding 122 arranged to be powered by the SMPS inverter, a monitor winding 123 passing through primary core assemblies of the primary winding, and a secondary winding 121 arranged for connection to the cathode heater 11. A current monitor 141 is arranged to monitor a current in the primary windings. Signal processing modules 14, 131, 132 are arranged to receive a first input signal from the monitor winding 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 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.</p> |
