Control circuit for semiconductor device having overheating protection function

Abstract

A control circuit includes a drive circuit which applies a drive voltage to a semiconductor device having an overheating protection function according to an externally supplied signal; and a current detecting circuit which outputs a detection signal when a drive current flowing through the semiconductor device exceeds a predetermined threshold current. The semiconductor device incorporates a semiconductor element, a temperature detecting circuit for detecting temperature increase of a chip, and an interrupting circuit for interrupting an input to the semiconductor element according to a detection output of the temperature detecting circuit. The drive circuit turns off the semiconductor element and changes the drive voltage to a predetermined voltage so that the drive current exceeds the threshold current when the interrupting circuit interrupts an input to the semiconductor element, and keeps the drive voltage at the predetermined voltage while the detection signal is output from the current detecting circuit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and advantages of the present invention will become more apparent by describing in detail preferred exemplary embodiments thereof with reference to the accompanying drawings, wherein:

FIG. 1 is a block diagram showing the configuration of a control circuit for a semiconductor device having an overheating protection function according to a first embodiment of the present invention;

FIG. 2 is a specific circuit diagram showing the configuration of the control circuit for the semiconductor device having an overheating protection function shown in FIG. 1;

FIG. 3 is a waveform diagram showing the operation of the control circuit for the semiconductor device having an overheating protection function shown in FIG. 2;

FIG. 4 is a circuit diagram showing the configuration of a control circuit for a semiconductor device having an overheating protection function according to a second embodiment of the invention;

FIG. 5 is a circuit diagram showing the configuration of a control circuit for a semiconductor device having an overheating protection function according to a third embodiment of the invention; and

FIG. 6 is a block diagram showing the configuration of a control circuit for a semiconductor device having an automatic-recovery-type overheating protection function.

Claims

1. A control circuit for controlling a semiconductor device having an overheating protection function, the semiconductor device which incorporates, in one chip, a semiconductor element, a temperature detecting circuit for detecting temperature increase of the chip, and an interrupting circuit for interrupting an input to the semiconductor element according to a detection output of the temperature detecting circuit, the control circuit comprising: a drive circuit which applies a drive voltage to the semiconductor device according to an externally supplied signal; anda current detecting circuit which outputs a detection signal when a drive current flowing through the semiconductor device exceeds a predetermined threshold current,wherein the drive circuit turns off the semiconductor element and changes the drive voltage to a predetermined voltage so that the drive current exceeds the threshold current when the interrupting circuit interrupts an input to the semiconductor element, and keeps the drive voltage at the predetermined voltage while the detection signal is output from the current detecting circuit.

2. The control circuit according to claim 1, wherein the drive circuit stops applying the drive voltage to the semiconductor device when supply of power from a power source is shut off or a reset signal is externally supplied to the drive circuit.

3. The control circuit according to claim 1, wherein the current detecting circuit is configured so as to be able to output the detection signal to the outside.