US 2013/0094114 A1 · CONTROL APPARATUS FOR SWITCHING DEVICE

Abstract

A control apparatus for a switching device which suppresses surge voltages at the time of current shutoff of a switching device to protect from overcurrents although the switching device is not in an overcurrent state, including a current sensor, a comparator, a timer latch, a control circuit, and a transistor. The current sensor detects the current of a switching device and outputs a detected voltage. The comparator outputs a signal when the detected voltage is equal to or greater than a reference voltage. When the time duration of the output signal is equal to or greater than a setting time, the timer latch outputs a surge suppression detection signal, based on which the control circuit outputs to the transistor a driving signal to turn off the switching device. The reference voltage is smaller than a reference voltage used when detecting an overcurrent flowing in the switching device.

Claims17

Dependent claims

A control apparatus which controls conduction and shutoff of a switching device having an overcurrent threshold, the control apparatus comprising:

a current sensor which detects a current flowing in the switching device and generates a detected current signal representative of the current;
a first comparison circuit which compares the detected current signal with a predetermined first reference value, and when the detected current signal is equal to or greater than the first reference value, outputs a surge suppression signal;
and
a first shutoff circuit which shuts off the switching device in response to output of the surge suppression signal from the first comparison circuit,
wherein the first reference value is smaller than a predetermined second reference value, the second reference value representing a value of the detected current signal corresponding to the overcurrent threshold.

2 more elements

A control apparatus for a switching device, which controls conduction and shutoff of the switching device, comprising:

a current sensor which detects a current flowing in the switching device and generates a detected current signal representative of the current;
a comparison circuit which compares the detected current signal with a predetermined reference, and when the detected current signal is equal to or greater than the reference value, outputs a detection signal;
a first signal generation circuit which outputs a surge suppression signal when a time duration of the detection signal output from the comparison circuit is equal to or greater than a predetermined first setting time;
and
a first shutoff circuit which shuts off the switching device in response output of the surge suppression signal from the first signal generation circuit,
wherein the first setting time is set to be shorter than a predetermined second setting time that is a time threshold indicating an overcurrent flowing in the switching device.

3 more elements

Dependencies are inferred from the claim text.

Control apparatus for switching device

Life of this patent

Control apparatus for switching device

Life of this patent

Abstract

Claims17