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

Abstract

The invention provides an EMI inhibition circuit for a switching power supply, the switching power supply, a DC power supply and a household electrical appliance, and belongs to the field of EMI inhibition. The switching power supply converts AC from an AC power supply into DC output. The EMI inhibition circuit comprises a filtering capacitor, a first capacitor and a second capacitor; the first end of the filtering capacitor is connected to the grounding end, and the second end of the filtering capacitor is connected to the output end of the switching power supply; the first end of the first capacitor is connected to the first end of the filtering capacitor, and the second end of the first capacitor is connected to a live wire of the AC power supply; and the first end of the second capacitor is connected to a zero line, and the second end of the second capacitor is connected to the second end of the filtering capacitor. Thus, an effective EMI grounding control scheme can be provided, and an EMI problem of the switching power supply can be eliminated effectively.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to an EMI suppression circuit for a switching 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...

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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