Switching power supply

Abstract

The invention brings forward a switching power supply which comprises a switching power supply module, a detection module which is connected with an output end of the switching power supply module and is used for detecting output current of the switching power supply module so as to generate a detection signal, a reference voltage providing module used for providing a reference voltage, a comparison module which is respectively connected with the detection module and the reference voltage providing module and is used for comparing the detection signal and the reference voltage so as to generate a comparison signal, a drive module which is connected with the comparison module and is used for generating a drive signal according to the comparison signal, and a control module which is connected with the drive module and the switching power supply module and is used for adjusting operating frequency of the switching power supply module according to the drive signal. By the adoption of the switching power supply, switching frequency can be changed; a switching device can operate in the most efficient state; service life of the switching device is prolonged; and EMC problem of the switching power supply is improved.

Description

technical field [0001] The invention relates to the technical field of electronic power, in particular to a switching power supply. Background technique [0002] Switching power supply is a kind of power supply that uses modern power electronic technology to control the time ratio of switching on and off to maintain a stable output voltage. Switching power supply is generally controlled by PWM (Pulse WidthModulation, pulse width modulation) IC (Integrated Circuit, integrated circuit) and switching devices such as MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor, Metal-Oxide-Semiconductor Field-Effect Transistor), BJT (Bipolar Junction Transistor, bipolar junction transistor) and other components. [0003] Such as figure 1 Shown is a schematic structural diagram of an existing switching power supply circuit. The alternating current is input through the AVIN terminal, and then rectified and filtered through the rectification and filtering circuit composed of diode ...

AI Technical Summary

Problems solved by technology

[0019] To sum up, the disadvantages of the existing technology are: the switching frequency of the switching power supply is fixed during the whole process of changing the output of the switching power supply from small power to the rated power, so as the output power of the switching power supply decreases, its output efficiency is lowered

When the output power of the switching power supply is significantly lower than the rated power, the efficiency of the switching power supply is reduced when the output power is small, the energy loss of the switching power supply device is increased, the life of the device is reduced, and the EMC of the switching power supply is further aggravated. (Electro Magnetic Compatibility, electromagnetic compatibility) problem

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