Patent ID: 6909616

Claim:
A power supply for an electronic equipment, comprising: a power key which outputs a key-off signal in response to a manipulation of a user; a power switch; a first rectifying part which rectifies an alternating voltage and outputs a first DC voltage; a transformer having a first winding having a first end connected to the first DC voltage, and a second winding magnetically coupled with the first winding; a first switching part connected to a second end of the first winding and which switches on/off a current supply to the first winding; a second rectifying part which rectifies a voltage induced in the second winding and outputs a second DC voltage; a pulse width modulation part which controls an on/off state of the first switching part; and a power supply control device, comprising: a key-off device which: detects whether the key-off signal is output for a predetermined time, and outputs a power-off signal to control the pulse width modulation part to switch off the first switching part in response to detecting that the key off signal is output for the predetermined time, and a power supply control part which outputs a power-on signal to control the pulse width modulation part to switch on/off the first switching part in response to one of an externally supplied power-on signal and an on/off operation of the power switch.