| 摘要 |
PURPOSE:To save number of terminals supplied to an output section and to miniaturize the titled switch by comparing a control input terminal voltage of an output switching element with a reference voltage and stopping the output of a detection switch section based on the compared output. CONSTITUTION:When a switch circuit 1 detects an object and produces an output, a constant current circuit 10 is driven, an output transistor (Tr)4 is driven by a constant current and a load current is applied to a load L. When the load current is within a prescribed range, a terminal voltage across a short-circuit detection resistor R5 is low and lower than a reference voltage Vr of a comparator circuit 11 comprising a constant current circuit 12, a diode 13 and a resistor R14, then the circuit 11 gives an output to a delay circuit 15. When Trs 16, 18 are conducted, the current of the circuit 10 flows to the Tr 16, 18 and the resistor 19 to limit the short-circuit current to a prescribed value. When a prescribed time is elapsed, a short-circuit signal is given from the circuit 15 to an output terminal of the circuit 1 to stop the output of the circuit 1. |
