OVERCURRENT DETECTION CIRCUIT AND OVERCURRENT DETECTION 1 PROTECTION CIRCUIT

Japanese Patent JP3589392

B2

PROBLEM TO BE SOLVED: To provide an overcurrent detection circuit that accurately detects overcurrent even if it is a period where a rush current flows and an overcurrent detection 1 protection circuit that accurately interrupts the overcurrent without repeating supply/interruption even if it is a period when the rush current flows.
SOLUTION: A reference circuit, connected in parallel with a series circuit consisting of a load L and a power MOSFET QA in this overcurrent detection circuit, consists of a series circuit consisting of a reference resistor means 2b equivalent to the load L and the power MOSFET QB and a reference MOSFET QB. A detection means CP detects an overcurrent flowing to the power MOSFET, whose value varies with the presence of the over-current on the basis of a drain-source voltage of the reference MOSFET QB. A resistance value control means 2c controls the resistance of the reference resistor means 2b to be high so as to decrease the drain-source voltage of the reference MOSFET more than the reduction in the drain-source voltage of the power MOSFET QA due to a rush current for a prescribed period immediately after the power MOSFET QA is conductive.

Yoshikazu Nagashima

JP5180299A

November 17, 2004

February 26, 1999

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Yazaki Corporation

H03K17/08; H03K17/687; (IPC1-7): H03K17/08; H03K17/687

JP61184331U
JP7095033A
JP5304450A
JP10107605A
JP2000509933A
JP62043914A

Hideo Takino
Hiroshi Ochi
Sadao Matsumura
Isamu Kakiuchi

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