A kind of pfc voltage follow output voltage fine-tuning circuit

Abstract

The invention discloses a circuit for fine-tuning the PFC voltage following the output voltage, which includes a voltage regulation signal processing circuit and a voltage regulation signal isolation drive circuit. After receiving an external voltage regulation command, the voltage regulation signal processing circuit processes the external signal, processes After that, it is divided into two signals, one signal is sent to the output voltage feedback circuit to make the output voltage reach the preset value; the other signal is sent to the voltage regulation signal isolation drive circuit, through which the secondary voltage regulation signal is transmitted to the primary PFC voltage control circuit, Realize fine-tuning of PFC voltage following output voltage. The present invention can make the output voltage of the power supply adjustable and applicable, and improves the problem of power supply performance degradation when the output voltage range is adjusted to deviate from the optimal operating point. Because the performance is improved, it can reduce the problem of increasing heat dissipation measures and using high-performance devices. The cost increase brought about by etc. saves the cost of materials, makes it easier to achieve the required performance indicators, reduces the difficulty of debugging, and shortens the development cycle of the power supply.

Description

technical field [0001] The invention relates to a circuit for fine-tuning the PFC voltage of a switching power supply following the output voltage. Background technique [0002] At present, in many cases, it is required that the output voltage of the power supply can be adjusted in a wide range, and various performance indicators are required to be guaranteed within the output voltage adjustment range. [0003] Generally, the PFC voltage of a switching power supply is fixed. Due to the limitation of the transformer turn ratio, a transformer can only be used in a small output voltage range. If it exceeds this range, the performance of the power supply will decline significantly. The more obvious the performance decline is, such as the reduction of efficiency, the increase of device temperature, the increase of output ripple, etc., in order to solve these problems, it is often necessary to increase the heat dissipation design, increase the filter circuit, use high-performance ...

AI Technical Summary

Problems solved by technology

[0003] Generally, the PFC voltage of a switching power supply is fixed. Due to the limitation of the transformer turn ratio, a transformer can only be used in a small output voltage range. If it exceeds this range, the performance of the power supply will decline significantly. The more obvious the performance decline is, such as the reduction of efficiency, the increase of device temperature, the increase of output ripple, etc., in order to solve these problems, it is often necessary to increase the heat dissipation design, increase the filter circuit, use high-performance devices and other measures, resulting in the increase of device cost and power debugging. Difficulty and long development cycle, the actual adjustable range of the power supply is limited, such as figure 1 , figure 2 shown

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