Patent attributes
An overcurrent detecting device for detecting an overcurrent in a load circuit, includes a DC power supply, a load, a semiconductor switch that controls ON/OFF of the load, a driver circuit that outputs a driving signal to the semiconductor switch, a reference voltage generating circuit that generates a reference voltage from the DC power supply, a voltage drop generating circuit that includes a resistor for generating a voltage drop and generates a voltage drop in the resistor for generating a voltage drop, a decision voltage generating circuit that generates, as a decision voltage, a voltage corresponding to a voltage obtained by adding a voltage drop generated when the semiconductor switch is turned ON and a voltage drop generated in the resistor for generating a voltage drop, and a comparing circuit that compares the decision voltage with the reference voltage and outputs a disconnecting command signal of the semiconductor switch to the driver circuit when the decision voltage is greater than the reference voltage.
