| 摘要 |
PROBLEM TO BE SOLVED: To detect a power failure state at an early stage and reduce power consumption of a device in a stand-by state.SOLUTION: A power source includes: rectification means which performs full-wave rectification of an input AC voltage; a first converter which converts the rectified voltage; a second converter connected to the first converter in parallel; zero cross detection means which detects zero cross of the AC voltage; voltage detection means which detects the AC voltage; a first capacity element connected between a line and ground after the full-wave rectification; a first discharge resistor which discharges an electrical charge charged in the first capacity element; first switch means which blocks a current flowing in the first discharge resistor; and stop means which causes the voltage detection means to detect the AC voltage using the current flowing in the first discharge resistor and stops an operation of the second converter when the detected voltage is smaller than a threshold. The power source also includes a first state in which the first switch means is in a block state and a second state in which the first switch means is in an energization state. |
