emi suppression circuit, switching power supply, DC power supply and household appliances

Abstract

The embodiment of the invention provides an EMI (Electro-Magnetic Interference) applied to a DC power supply, a switching power supply, a DC power supply and a household electrical appliance, and belongs to the field of electromagnetic interference suppression. The switching power supply is used for converting alternating current from an AC power supply into direct current to output. The EMI suppression circuit comprises a filtering capacitor, a first capacitor and a second capacitor, wherein a first end of the filtering capacitor is connected to a grounding terminal, and a second end of the filtering capacitor is connected to an output end of the switching power supply; a first end of the first capacitor is connected to a part between the first end of the filtering capacitor and the grounding terminal, and a second end of the first capacitor is connected to a DC negative output end of a rectification module; and a first end of the second capacitor is connected to a live line of the ACpower supply, and a second end of the second capacitor is connected to the second end of the filtering capacitor. Therefore, the invention can provide a scheme capable of effectively controlling EMIgrounding, and an EMI problem of the switching power supply can be effectively eliminated.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to an EMI suppression circuit for a DC power supply, a switching power supply, a DC power supply and household appliances. Background technique [0002] Due to the defect of low conversion efficiency of linear power supply, switching power supply with higher conversion efficiency has been favored and popularized by many household appliance manufacturers. [0003] The working principle of the switching power supply is: the switching power supply directly converts the AC current into a DC current at the input end, and under the action of the high-frequency oscillating circuit, uses the switching tube to control the on-off of the current to form a high-frequency pulse current, and then inductance With the help of the device, a stable low-voltage DC power supply is output. Commonly used switching tubes include transistors, thyristors, magnetic switches, etc. When the switch tube w...

AI Technical Summary

Problems solved by technology

[0006] First, the common mode suppression device is relatively large and needs to occupy a large space on the circuit board, which is not conducive to the design and layout of the circuit board;

[0007] Second, the cost of common mode suppression devices is relatively high;

[0008] Third, the common mode suppression device generates a lot of heat, which leads to a decrease in the thermal conversion efficiency of the whole machine

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