Apparatus and method for discharging capacitor of input filter of power supply, and power supply including the apparatus
AssigneeFairchild Korea Semiconductor Ltd.
InventorsSang Cheol Moon, Hyun Min Kim, Sung-Won Yun, Min-Woo Lee
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Abstract
A power supply includes an input filter and a discharging device. The input filter includes a capacitor to which an AC power source is provided. The discharging device rectifies and samples the AC power source. The discharging device generates a reference voltage according to a peak voltage of a generated sampling signal, generates an AC power source cutoff detection signal according to a comparison signal generated by comparing the sampling signal and a reference voltage, and discharges the capacitor through a discharging resistor according to the AC power source cutoff detection signal.
Claims14
A device for discharging a first capacitor of an input filter of a power supply, comprising:
- a rectifier for rectifying an AC power source to generate a rectified AC signal;
- a sampler for sampling the rectified AC signal to generate a sampling signal;
- a reference voltage generator for generating a reference voltage according to a peak voltage of the sampling signal;
- a first comparator for comparing the sampling signal and the reference voltage to generate a comparison signal;
- a power source cutoff detector for generating a cutoff detection signal of the AC power source according to the comparison signal;
- and
- a first discharging resistor for discharging the first capacitor according to the cutoff detection signal.
A method for discharging a capacitor an input filter of a power supply, comprising:
- rectifying an AC power source to generate a rectified AC signal;
- sampling the rectified AC signal according to a clock signal to generate a sampling signal;
- generating a reference voltage that varies according to a peak voltage of the sampling signal;
- comparing the sampling signal with the reference voltage to generate the comparison signal;
- generating a cutoff detection signal of the AC power source according to the comparison signal;
- and
- discharging the capacitor through a discharging resistor according to the cutoff detection signal.
A power supply, comprising:
- an input filter having a capacitor provided with an AC power source;
- and
- a discharging device for generating a reference voltage according to a peak voltage of a sampling signal generated by rectifying and sampling the AC power source, generating a cutoff detection signal of the AC power source according to a comparison signal generated by comparing the sampling signal with the reference voltage, and discharging the capacitor through a discharging resistor according to the cutoff detection signal.
Dependencies are inferred from the claim text.