| 摘要 |
PROBLEM TO BE SOLVED: To provide an overcurrent detection device that reduces a loss without compromising detection accuracy.SOLUTION: An overcurrent detection device 1 includes: short-circuiting means (RY) capable of short-circuiting an overcurrent detecting resistor R2; a sign detecting resistor R1 interposed in a power line 6 to cause a voltage drop proportional to a current Io; and a short circuit control section (OP1, ZD1) for controlling the short-circuiting means (RY) on the basis of the voltage drop by the sign detecting resistor R1. A resistance value of the sign detecting resistor R1 is smaller than a resistance value of the overcurrent detecting resistor R2. The short circuit control section (OP1, ZD1) short-circuits the overcurrent detecting resistor R2 to prevent the current Io from flowing to the overcurrent detecting resistor R2 as long as the voltage drop by the sign detecting resistor R1 is equal to or lower than a predetermined threshold. |
