Patent ID: 7821760
Filing Date: 2010-10-26
Classification: H02H

Abstract:
1. A counter electromotive force prevention unit in a circuit arrangement which is configured so as to supply power from a direct-current supply source via a circuit element or a circuit unit that conducts a switching operation and outputs noise cause by an inductive load at the time of the switching operation, the counter electromotive force prevention unit comprising: a diode whose cathode is connected to a positive terminal of the direct-current supply source and whose anode is connected to a negative terminal of the direct-current supply source, wherein at least one of the anode and cathode connection is made via a fuse element; and a capacitor which is connected in parallel to the diode, wherein the diode absorbs counter electromotive force generated by an inductive load and the terminal of the fuse element connected to the diode and capacitor has no other connections, and the capacitor temporarily drops a voltage of the cathode of the diode to a prescribed level when the supply source is switched to an on state, temporarily raises a voltage of the cathode of the diode to a prescribed level when the supply source is switched to an off state, and reduces harmonic components generated by the counter electromotive force.