Toyota Jidosha Kabushiki Kaisha

Hajime Kosugi

Ken Asakura

Hideo Yamawaki

A switching control circuit includes voltage application means that applies a first voltage to a gate of a power device in a first period and applies a second voltage to the gate of the power device in a second period, wherein the first period starts when the power device is turned on; current detection means that detects whether a current flowing through the power device exceeds a threshold; and voltage decrease means that decreases the voltage with a first speed if the current detection means detects that the current exceeds the threshold in a second detection period, decreases the gate voltage with a second speed, lower than the first speed, if the current detection means detects that the current exceeds the threshold in a third detection period, and does not decrease the gate voltage if the current detection means detects that the current exceeds the threshold in the first period.

Switching control circuit and control method thereof

A substrate unit includes a conductive case, an insulating case arranged in the conductive case, a first screw member having conductivity, arranged in the conductive case and fixing the insulating case to an inner wall surface of the conductive case, a circuit substrate provided opposite to the inner wall surface with respect to the insulating case and fixed to the insulating case, and a second screw member having conductivity and fixing the circuit substrate to the insulating case. The first screw member and the second screw member are screwed in toward the inner wall surface. The first screw member and the second screw member are spaced from each other. The first screw member and the second screw member are connected to each other with a connecting member having conductivity.

Substrate unit

A switching element driving device has a first transistor that decreases the gate voltage of a power element at a faster rate than during a normal turn-off, and a second transistor that decreases the gate voltage of the power element at a slower rate than during a normal turn-off. If the gate voltage detected by the gate voltage monitoring means when an overcurrent in the power element is detected by overcurrent detection means is greater than a predetermined value, the gate voltage is decreased by the first transistor, and then, while the power element remains on, the gate voltage is decreased by the second transistor. If the gate voltage detected by the gate voltage monitoring means when an overcurrent in the power element is detected by overcurrent detection means is less than or equal to the predetermined value, the gate voltage is decreased only by the second transistor.

Growing community of inventors

Okazaki, Japan

Hajime Kosugi