Input voltage feedforward circuit and input voltage feedforward control method and device

Abstract

The invention provides an input voltage feedforward circuit and an input voltage feedforward control method. A ramp voltage generation circuit is used for generating a ramp voltage in direct proportion to an input voltage, the duty ratio is adjusted by using a control algorithm of a digital controller and an analog comparator in the digital controller to terminate the work period of a DPWM module,no matter how fast the input voltage changes, the product of the input voltage and the primary turn-on time is almost a constant value, and the feedforward control of the input voltage is realized. According to the invention, for line voltage input transient, output voltage can provide very fast response, and the compensation voltage can be stabilized when the input voltage changes, so that the output voltage is directly stabilized under the condition that a feedback loop does not act, a better loop response is obtained, and the stability and reliability of the system are improved.

Description

technical field [0001] The present application relates to the technical field of electronic circuits, in particular to an input voltage feedforward circuit based on a digital controller, an input voltage feedforward control method and a device. Background technique [0002] Under normal circumstances, the switching power supply is a regulated output. However, when the input voltage jumps rapidly, for example: when the input voltage rises rapidly, the output voltage overshoot is generally relatively high due to the feedback circuit alone. It is easy to cause the malfunction of the output overvoltage protection circuit; and when the input voltage drops rapidly, the output voltage drop will be relatively large only by the function of the feedback circuit, and it is easy to cause the reset of the load circuit. In order to avoid malfunction or reset of the load circuit, it is necessary to increase the input voltage feedforward circuit, so that the duty cycle of the drive signal c...

AI Technical Summary

Problems solved by technology

[0002] Under normal circumstances, the switching power supply is a regulated output. However, when the input voltage jumps rapidly, for example: when the input voltage rises rapidly, the output voltage overshoot is generally relatively high due to the feedback circuit alone. It is easy to cause the malfunction of the output overvoltage protection circuit; when the input voltage drops rapidly, the output voltage drop will be relatively large only by the function of the feedback circuit, and it is easy to cause the reset of the load circuit.

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