Switching power source and switching power source control method

Abstract

The invention discloses a switching power source and a switching power source control method, belonging to the field of the switching power source. The method is characterized in that a primary circuit comprises N bridge arms; a control circuit sends N pairs of first control signals for controlling the N bridge arms and N second control signals for controlling rectification switches; and in each pair of first control signals, the high level width of one control signal is a first fixed value; the low level width of the control signal can be adjusted, the low level width of the other control signal is a second fixed value and the high level width of the other control signal can be adjusted. According to the switching power source and the switching power source control method, no matter how the input voltage changes, each bridge arm and each rectification switch can work in a zero current on-off state or in a zero voltage on-off state; and therefore, the power density is improved, the output ripple is lowered, the output voltage is stabilized, and the reliability of a power supply is guaranteed.

Description

technical field [0001] The invention relates to the field of switching power supplies, in particular to a switching power supply and a method for controlling the switching power supply. Background technique [0002] With the development of communication technology, more and more information is produced. In order to transmit and process these information quickly, the processing speed of digital computer CPU must be improved. With the improvement of CPU processing speed, the performance requirements for power supplies are getting higher and higher. Traditional hard switching can no longer meet the requirements of high operating frequency and high conversion efficiency of power supplies. Various soft switching technologies have emerged as the times require. [0003] An asymmetrical half-bridge switching power supply is provided in the prior art, such as figure 1 As shown, Q1 and Q2 form a half-bridge, Q3 is a synchronous rectification switch, and the switching states of Q1, Q2...

AI Technical Summary

Problems solved by technology

[0004] Since the existing control circuit is controlled by the traditional PWM (Pulse Width Modulation, pulse width modulation), the characteristics of the traditional PWM are: the frequency is constant, the on-time and off-time change at the same time, when the input voltage is 48V The synchronous rectifier tube Q3 realizes zero-current switching, but when the input voltage rises to 60v, the current becomes a relatively large negative value at the time of switching, and zero-current switching cannot be realized, resulting in increased loss on the power supply and reducing the reliability of the switching power supply

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