Apparatus and method for monitoring operation of an insulated gate bipolar transistor
AssigneeFreescale Semiconductor, Inc.
InventorsRANDALL C. GRAY, IBRAHIM S. KANDAH, PHILIPE J. PERRUCHOUD, JOHN M. PIGOTT, THIERRY SICARD
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Abstract
Operation of an insulated gate bipolar transistor (IGBT) is monitored by an apparatus that has a capacitor connected between a collector of the IGBT and an input node. A processing circuit, coupled to the input node, responds to current flowing through the capacitor by providing an indication whether a voltage level at the collector is changing and the rate of that change. The processing circuit also employs the capacitor current to provide an output voltage that indicates the voltage at the IGBT collector.
Claims20
An apparatus for monitoring operation of a transistor that has an emitter, a collector and a gate, wherein a potential applied to the gate controls a conduction path between the emitter and the collector, said apparatus comprising:
- a capacitor connected between the collector and an input node of the apparatus;
- a processing circuit coupled to the input node, configured to respond to current flowing through the capacitor by providing a first indication whether voltage level at the collector is changing.
An apparatus for monitoring operation of a transistor that has an emitter, a collector and a gate, wherein a potential applied to the gate controls a conduction path between the emitter and the collector, said apparatus comprising:
- a capacitor connected to the collector;
- a rectifier that produces a first signal indicating an amount of current flowing from the capacitor into the rectifier and a second signal indicating an amount of current flowing from the rectifier to the capacitor;
- and
- a voltage change detector that receives the first and second signals and responds thereto by producing an output signal indicating whether a voltage level at the collector is changing.
A method for monitoring operation of a transistor that has an emitter, a collector and a gate, wherein a potential applied to the gate controls a conduction path between the emitter and the collector, said apparatus comprising:
- providing a capacitor connected to the collector and to a monitor circuit;
- detecting flow of current through the capacitor;
- and
- in response to detecting flow of current, providing a first indication whether a voltage level at the collector is changing.
Dependencies are inferred from the claim text.