| 摘要 |
PROBLEM TO BE SOLVED: To provide a power source which has a simple structure contriving a power saving and can be commonly used among different types of equipment. SOLUTION: In a standby state, as a current to be supplied to IPS (information processing system) and the like is so small and a voltage drop at a detective resistance 40 is small, a transistor 38 does not turn on and a phototransistor 36B does not turn on. Therefore an ON/OFF terminal of control circuit 52 is input by a voltage at a high level so that a control signal to be output to a MOS-FET50 is turned off, and a power supply to a motor and the like is interrupted. When a FAX directive signal or the like is detected, an energy consumption increases as a IPS or the like is actuated for forming an image and a voltage drop at a detective 40 becomes large. The transistor 38 is turned on as the voltage drop on the detective resistance 40 becomes large. With this the phototransistor 36B is turned on and the ON/OFF terminal of the control circuit 52 is input by a voltage at a low level, the control signal output to the MOS-FET50 is started and the power supply is resumed. |
