Siemens Medical Systems, Inc.

Michael J Marziale

Roger Nelson Hitchcock

Lance W Thompson

Robert J Froelich

Circuits and methods are described for providing gate drive to a gate terminal of a first switching device. The circuit includes a transformer having a core, a primary winding, and at least one secondary winding. The primary winding of the transformer is for coupling to a power source. The at least one secondary winding is for coupling to the gate terminal of the first switching device. A second switching device is connected in series with the primary winding of the transformer. The second switching device controls conduction of current in the primary winding which causes energy to be stored in the core of the transformer. The second switching device is operable to stop the current from flowing in the primary winding thereby causing a current pulse to be generated in the at least one secondary winding from the energy stored in the core. The current pulse is used for driving the gate terminal of the first switching device.

Current sourced gate driver for fast thyristors

A line type modulator for modulating an RF power device in a medical linear accelerator is described. The modulator employs a low voltage DC power source and a flyback transformer. Current sensing circuitry senses current in the primary winding of the flyback transformer and generates a current sense signal indicative thereof. A solid-state switching stage is coupled between the DC power source and the flyback transformer which electrically connects and disconnects the DC power source and the primary winding in response to a control signal. Control circuitry coupled to the current sensing circuitry and the switching stage generates the control signal in response to the current sense signal. The anode of a charge diode assembly is coupled to the secondary winding of the flyback transformer. A delay element is coupled to the cathode of the charge diode assembly. A pulse forming network is coupled to the delay element and generates an energy pulse. A solid-state switch assembly is also coupled to the cathode of the charge diode assembly and discharges energy stored in the pulse forming network via the delay element in response to a trigger signal. A pulse transformer coupled to the pulse forming network delivers the energy pulse to the RF power device.

Compact solid state klystron power supply

A high voltage pulse generating circuit for powering klystrons, and the like. The circuit includes a source of D.C. power having positive and negative terminals, a flyback transformer having a primary winding and a secondary winding, the primary winding having first and second terminals for connection to the source of D.C. power, a sensor for generating a signal indicating the amplitude of the current in the primary winding, and a solid state switching circuit for coupling the source of D.C. power to the primary winding of the flyback transformer. The primary winding is coupled to the power source in response to a control signal, and decoupled from the power source when a predetermined level of current is detected in the primary winding.

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El Sobrante, CA, United States of America

Michael J Marziale