| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect electric current with a simple structure. SOLUTION: When a circuit is driven, bases of transistors Q1, Q2 constituting a first current mirror circuit 7 are grounded via a switch means 10 so that an electric current flows forcedly in the bases thereof. Accordingly, the circuit operation can be ensured when started. Part of a load current is also accurately shunted via the first current mirror circuit 7, a second current mirror circuit 8 and a resistor R1 having a first resistance that is a predetermined multiplying factor of a resistance of a shunt resistor Rs, and an output terminal for the shunted current is grounded via a resistor R2 having a second resistance, so that an output voltage VOUT proportional to load current IL can be accurately obtained from the resistor R2, and the load current IL can be accurately found from the output voltage VOUT.
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