| 摘要 |
PURPOSE:To prevent a negative voltage from being charged and held in a capacitor in a power-OFF state as to the driving device which is equipped with the capacitor for removing a radio noise generated by the constant-current driving of the inductance load and is provided additionally with a reverse contacting protecting function. CONSTITUTION:This device is a device which drives a solenoid 2 with a constant current through the switching of a transistor(TR) 1, and equipped with a path cutoff TR 2, the capacitor C1 for radio noise removal, and a diode D2 for prevention against C1 deterioration due to the ripple of a battery voltage in a fly-back current path and also equipped with a Zener diode ZD which absorbs a fly-back voltage by turning ON the TR 1 when the TR 2 is OFF and the diode D4 for reverse contacting protection; and a resistor RA is connected to the capacitor C1 in parallel. Consequently, even if the capacitor C1 is temporarily charged to a negative voltage owing to a negative surge of the solenoid 2 which is caused in the power-OFF state, the capacitor can be discharged thereafter. |
