| 摘要 |
PURPOSE: A safety circuit is provided to improve the response speed and to reduce the production cost. CONSTITUTION: A safety circuit(60) contains a power switching unit(X1) to control power toward a solenoid coil(L) and a switching unit to switch the power switching unit. In the switching unit, an initial driving switching unit(TR1) is serially connected with a second switching unit(TR3) between a first node(node1) and a ground. The initial driving switching unit is switched by a drive signal and contacted between the first node and the ground. The second switching unit is switched by a disable signal. A monitoring unit(61) is arranged between a second node(node2) and the first switching unit. The monitoring unit contains a resistor(R6) to be connected with the second node and a base of the first switching unit and a capacitor(C) to be connected between the base and the ground. Thereby, a boosting operation is unnecessary.
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