Push-pull output switch power supply

Abstract

The invention relates to a switch power supply technology and discloses a push-pull output switch power supply. The problem that a push-pull output switch power supply which works in a voltage-control mode is not balanced in magnetic flux is solved. The push-pull output switch power supply comprises a pulse width modulation control unit, a first error amplification unit, a second error amplification unit, a first switch part, a second switch part, a push-pull output transformer and a mean value difference solving unit. According to the push-pull output switch power supply, connecting time of the first switch part and the second switch part is controlled, connecting time of a primary half winding with the large voltage-second number is reduced, connecting time of a primary half winding with the small voltage-second number is increased, so that, the voltage-second numbers of the two primary half windings are equal, and control over magnetic flux balance is achieved. The switch power supply works in a voltage-control mode, slope compensation is of no need, extra power consumption is not introduced, and circuit working is stable. The two primary half windings of the push-pull output transformer are balanced in current, and the push-pull output transformer is balanced in magnetic flux.

Description

technical field [0001] The invention relates to switching power supply technology, in particular to push-pull output switching power supply in voltage control mode and magnetic flux balance control technology. Background technique [0002] The basic structure of a push-pull output switching power supply under pulse width modulation usually includes a pulse width modulation control unit, an error amplifier unit, a first switching device, a second switching device, a push-pull output transformer and its rectification and filtering circuit. The output terminal of the error amplification unit is connected to the pulse width modulation control unit, the input terminal is respectively connected to the output voltage division and the reference voltage, and an error voltage is output according to the difference between the output voltage division and the reference voltage. The pulse width modulation control unit generates two driving signals to respectively drive the first switching...

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the shortcomings of the above-mentioned traditional magnetic flux unbalance solution, the present invention proposes a push-pull output switching power supply, which uses a magnetic flux balance control circuit under voltage control mode to solve the problem of the push-pull output switch working under voltage control mode. Unbalanced power supply flux, no slope compensation is required, and no additional power consumption is introduced

Images