Instantaneous junction temperature detection
First Claim
1. A circuit for detecting a junction temperature of an insulated gate bipolar transistor (IGBT), the IGBT being alternately biased on and off in response to a gate signal to control an amount of output current, the circuit comprising:
- a differentiator circuit operable to receive a collector to emitter voltage of the IGBT and produce an output voltage proportional to a rate at which the collector to emitter voltage changes; and
a feedback circuit operable to receive the output voltage and alter the gate signal when the output voltage indicates that the rate at which the collector to emitter voltage changes is outside a predetermined limit.
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Accused Products
Abstract
A circuit, for detecting a junction temperature of an insulated gate bipolar transistor (IGBT) which is alternately biased on and off in response to a gate signal, includes a differentiator circuit operable to receive a collector to emitter voltage of the IGBT and produce an output voltage proportional to a rate at which the collector to emitter voltage changes; and a feedback circuit operable to receive the output voltage and alter the gate signal when the output voltage indicates that the rate at which the collector to emitter voltage changes is outside a predetermined limit.
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Citations
19 Claims
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1. A circuit for detecting a junction temperature of an insulated gate bipolar transistor (IGBT), the IGBT being alternately biased on and off in response to a gate signal to control an amount of output current, the circuit comprising:
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a differentiator circuit operable to receive a collector to emitter voltage of the IGBT and produce an output voltage proportional to a rate at which the collector to emitter voltage changes; and a feedback circuit operable to receive the output voltage and alter the gate signal when the output voltage indicates that the rate at which the collector to emitter voltage changes is outside a predetermined limit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A circuit for detecting junction temperatures of at least first and second insulated gate bipolar transistors (IGBTs) of at least one half bridge circuit, the IGBTs being alternately biased on and off in response to first and second gate signals, respectively, to produce an output current, the circuit comprising:
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a differentiator circuit operable to receive an input voltage from a node connecting an emitter of the first IGBT and a collector of the second IGBT, the differentiator circuit producing an output voltage proportional to a rate at which the input voltage changes; and a feedback circuit operable to receive the output voltage and alter the first and second gate signals when the output voltage indicates that the rate at which the input voltage changes is outside predetermined limits. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification