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US 7,126,802 B2Granted
Drive circuit for switching device
AssigneeHitachi, Ltd.
InventorsKatsumi Ishikawa, Masataka Sasaki, Koichi Suda
Life of this patent
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Abstract
A drive circuit 21 that controls a switching device 23 ON/OFF and a soft cutoff command circuit that gradually decreases the gate terminal voltage of the switching device 23 when short circuit of the switching device 23 is detected. Additionally, an ON-pulse retention command circuit 11 retains the output of the drive circuit 21 ON when the gate terminal voltage is judged to have exceeded a specified value by a gate voltage judgment comparator 16 that detects the gate terminal voltage of the switching device 23.
Claims3
A drive circuit for controlling a switching device ON/OFF, comprising
- a short circuit detection means that detects short circuit of the switching device,
- a soft cutoff means that gradually decreases the gate terminal voltage of the switching device when short circuit is detected by the short circuit detection means,
- a gate voltage detection means that detects the gate terminal voltage of the switching device,
- an ON-pulse retention means that retains the drive circuit output ON when the gate terminal voltage detected by the gate voltage detection means exceeds a specified value, and
- a gate voltage clamp means that clamps the gate voltage of the switching device, wherein
- the gate voltage clamp means is operated by an output signal of the ON-pulse retention means.
3 more elements
Dependencies are inferred from the claim text.