Primary edge control type switch power supply with high-precision constant-voltage/constant-current output and high-pulse-frequency (PF) value

Abstract

The invention discloses a primary edge control type switch power supply with high-precision constant-voltage/constant-current output and a high-pulse-frequency (PF) value. The primary edge control type switch power supply comprises an electromagnetic interference and filtering circuit, a rectifying filtering circuit, a transformer, a voltage stabilizing buffer circuit, a filtering shaping output circuit, a metal oxide semiconductor (MOS) tube, a sampling resistor and a constant-voltage and constant-current pulse frequency control (PFC) driving module, wherein the voltage stabilizing buffer circuit, the filtering shaping output circuit, the MOS tube, the sampling resistor and the constant-voltage and constant-current PFC driving module are connected in parallel with the transformer. The primary edge control type switch power supply has the advantages that the transformer primary edge is detected and is fed back to a PFC control chip, and a pulse frequency modulation (PFM) mode is adopted, so high-precision current and voltage can be output. Compared with the traditional driving circuit, the primary edge control type switch power supply has the advantages that peripheral devices such as optical couplers and the like are omitted, so a peripheral circuit is simpler, the PF value and the electric work efficiency of the whole power supply are obviously improved, and the primary edge control type switch power supply has the obvious characteristics that the periphery circuit is simple, the cost is low, and the performance is high. The large-scale popularization and application can be easily realized.

Description

technical field [0001] The invention belongs to the field of switching power supplies, and relates to a switching power supply with high precision, constant voltage / constant current output, and high PF value primary side control technology. Background technique [0002] In traditional switching power supplies, in order to ensure that the output voltage and current achieve a higher accuracy, the switching power supply generally uses an optocoupler at the output end, and the output voltage is fed back to the input end through the optocoupler, and the input end is based on the feedback signal. Adjusting the output voltage, such a circuit makes the structure of the circuit more complicated, requires a large number of components, the accuracy of the output voltage and current is poor, and the optocoupler has aging problems, which affects the stability and life of the circuit to a certain extent , This approach also makes the production cost higher, and the PF value and electric p...

AI Technical Summary

Problems solved by technology

[0002] In traditional switching power supplies, in order to ensure that the output voltage and current achieve a higher accuracy, the switching power supply generally uses an optocoupler at the output end, and the output voltage is fed back to the input end through the optocoupler, and the input end is based on the feedback signal. Adjusting the output voltage, such a circu

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