Abstract: An overcurrent detection circuit for detecting an overcurrent condition in an output transistor connected in series with an electrical load includes a pair of transistors having input terminals connected together. The pair of transistors is interposed between a current mirror circuit and a resistor and between the current mirror circuit and a detection transistor capable of being turned on at the same time as the output transistor. When a voltage is applied to the input terminals of the pair of the transistors, output terminals of the current mirror circuit are fixed at the same potential. Thus, even when an early effect occurs in the current mirror circuit, an electric current flowing through the resistor becomes equal to that flowing through the detection transistor. The overcurrent detection circuit can accurately detect the overcurrent condition based on a voltage drop across the resistor.

Abstract: An overcurrent detection circuit for detecting an overcurrent condition in an output transistor connected in series with an electrical load includes a pair of transistors having input terminals connected together. The pair of transistors is interposed between a current mirror circuit and a resistor and between the current mirror circuit and a detection transistor capable of being turned on at the same time as the output transistor. When a voltage is applied to the input terminals of the pair of the transistors, output terminals of the current mirror circuit are fixed at the same potential. Thus, even when an early effect occurs in the current mirror circuit, an electric current flowing through the resistor becomes equal to that flowing through the detection transistor. The overcurrent detection circuit can accurately detect the overcurrent condition based on a voltage drop across the resistor.