Magnetron power supply
AssigneeCeravision Limited
InventorKjell Lidstrom
Life of this patent
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Abstract
A power supply for a magnetron has a high voltage converter, a microprocessor and a resistor. The high voltage converter comprises an integrated circuit oscillator, switching transistors, an inductance L1, a transformer and a rectifier. A voltage source supplies an augmented DC voltage to the converter. An operational amplifier, arranged as an error signal magnifier with an integrating capacitor and a resistor, compares a control signal from the microprocessor and the resistor and supplies an output signal to the oscillator. The oscillator controls the switching transistors, the output of which is connected to the inductance and the primary winding of the transformer. The secondary winding of the transformer is connected to half bridge diodes and capacitors, which provide DC current from the transformer to the magnetron.
Claims17
A power supply for a magnetron comprising:
- a DC Voltage source;
- a converter for raising the output voltage of the DC voltage source, the converter having:
- a capacitative-inductive resonant circuit,
- a switching circuit adapted to drive the resonant circuit at a variable frequency controlled by a control signal input to provide an alternating voltage,
- a transformer connected to the resonant circuit for raising the alternating voltage,
- a rectifier for rectifying raised alternating voltage to a raised DC voltage for application to the magnetron;
- means for measuring the current from the DC voltage source passing through the converter;
- a microprocessor programmed to produce a control signal indicative of a desired output power of the magnetron;
- and
- an integrated circuit adapted to apply a control signal to the converter switching circuit, characterized in that:
- the variable frequency at which the switching circuit is adapted to drive the resonant circuit is above the resonant frequency of the resonant circuit;
- and
- the integrated circuit is arranged in a feedback loop to apply a control signal to the converter switching circuit in accordance with a comparison of a signal from the current measuring means with the signal from the microprocessor for controlling the power of the magnetron to the desired power;
- wherein
- the integrated circuit can react to a change in the measured power consumption of the magnetron independently of a change in the control signal from the microprocessor.
Dependencies are inferred from the claim text.