Patent ID: 9467062
Filing Date: 2016-10-11
CPC Classification: H02M

Claim Text:
1. A capacitor input type smoothing circuit, comprising: a pulsating circuit that supplies a pulsating voltage to a load when a capacitor is not discharged; and a control circuit that controls discharging of the capacitor, wherein the control circuit includes a smoothing circuit, which is connected in parallel to the pulsating circuit, and a voltage detection circuit for detecting a voltage, the voltage detection circuit determines a voltage range to discharge the capacitor, and includes a first switch that is turned off by detecting that the pulsating voltage is in the voltage range, a second switch that is connected to the first switch and is turned on when the first switch is turned off, and a third switch that is connected to the second switch and is turned on when the second switch is turned on, when the pulsating voltage is not in a discharge voltage range of the capacitor, the first switch is turned on and the second and third switches are turned off so that capacitor power is not supplied to the load, and a discharge voltage of the capacitor is set within a range that is higher than a lower limit of a voltage that the load requires and is not equal to or greater than the voltage.