Power supply system and image forming apparatus

摘要

A power supply system includes: a switching power supply; and a control device, wherein the switching power supply includes: a transformer; a semiconductor switching element; a switch control unit; and a rectifying/smoothing circuit, the switch control unit is supplied with power from the main power supply, starts to control the switching of the semiconductor switching element, and oscillates a primary side of the transformer to induce a voltage on the secondary side of the transformer, the control device outputs a control pulse signal to the switch control unit to stop the oscillation of the transformer, thereby changing the mode of the switching power supply to an output stop mode, in an output mode in which the switching power supply smoothes the voltage induced on the secondary side and outputs the smoothed voltage.

主权项

1. A power supply system comprising:
a power supply device including a switching power supply that converts an input voltage applied from a main power supply and outputs the converted voltage; and a control device that is a different device from the power supply device and is supplied with power from the switching power supply of the power supply device, wherein the switching power supply of the power supply device includes:
a transformer;a semiconductor switching element that is connected to a primary coil of the transformer;a switch control unit that controls the switching of the semiconductor switching element; anda rectifying/smoothing circuit that is provided on a secondary side of the transformer, the switch control unit starts up in response to being supplied with power from the main power supply and starts to control the switching of the semiconductor switching element, thereby oscillating a primary side of the transformer to induce a voltage on the secondary side of the transformer, the control device outputs a control pulse signal to the switch control unit to stop the oscillation of the transformer, thereby changing the mode of the switching power supply to an output stop mode, in an output mode in which the switching power supply smoothes the voltage induced on the secondary side and outputs the smoothed voltage, and the control device includes either of: a first electric storage unit that is charged by the output of the switching power supply and serves as a power supply for the control device in the output stop mode; and a photoelectric cell that converts optical energy into power and serves as a power supply for the control device in the output stop mode.