A switching power supply

Abstract

The invention provides a switching power supply. The switching power supply includes an inductor and a main switch which is controlled for conduction or turn-off so as to enable the switching power supply to output the output voltage. The switching power supply also includes a first branch circuit which is in parallel connection with the inductor, a detection module, and a logic module, wherein the first branch circuit includes a first switch and a ringing inhibition resistor which are connected in series; the connection node between the inductor and the main switch is marked as a switching node; an input terminal of the detection module is directly or indirectly coupled with the switching node, and the detection module is suitable for detecting whether the reduction amplitude of the voltage of the switching node in the preset time exceeds the threshold-voltage, and an output terminal of the detection module outputs the detection result; and a first input terminal of the logic module is coupled with the output terminal of the detection module, and a second input terminal of the logic module is coupled with a control terminal of the main switch, so that when the main switch is controlled to be turned off and the detection result indicates that the reduction amplitude of the voltage of the switching node in the preset time exceeds the threshold-voltage, the logic module controls the first switch to be conducted until the main switch is controlled to be conducted, or the logic module controls the first switch to be turned off. The switching power supply can inhibit ringing, and is low in cost and high in stability.

Description

technical field [0001] The invention relates to the field of power supply design, 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. A switching power converter generally consists of a pulse width modulation (Pulse Width Modulation, PWM for short) control circuit, an energy storage element (such as an inductor) and a switch tube. A large number of switching power supply converters are used in mobile terminals, for various internal modules such as a central processing unit (Central Processing Unit, referred to as CPU), a subscriber identification module (Subscriber Identification Module, referred to as SIM) card, a radio frequency power amplifier, etc., Provide stable power. [0003] figure 1 A switched DC boost switching power supply 100 is shown, and the switching power s...

AI Technical Summary

Problems solved by technology

[0004] A method of suppressing ringing in the prior art is to insert a magnetic bead L2 between the input terminal of the switching power supply 100 and the inductor L1, but this will increase the system cost; in addition, when the parameters of the magnetic bead L2 are not set When appropriate, it may cause abnormalities such as howling of system components, that is, oscillations that fall into the audio frequency range (20Hz-20kHz)

Images