An interleaved parallel flyback led drive power supply and its pfm control circuit

Abstract

The invention discloses a staggered parallel flyback LED driving power supply and a PFM (pulse width modulation) control circuit thereof. A main circuit of the driving power supply is formed by staggering and parallel connection of two flyback converters, and comprises an alternating-current input end, an EMI (electromagnetic interference) filter, a bridge rectifier, the two parallel flyback converters, an output rectifier and an LED load. By the aid of the staggered parallel main circuit structure, current stress of switching tubes is reduced, input and output current ripple is reduced, the EMI filter design is simplified, power level of the driving power supply is increased, and the like. A PFM control method is adopted in the control circuit of the driving power supply; compared with a common PWM control method, the PFM control method has the advantages that by the aid of the PFM control circuit, the driving power supply can change in switching tube turning-on time and switching frequency simultaneously when the load changes, working loss during light load of the driving power supply is reduced, and power supply efficiency is improved. The driving power supply is suitable for applications of an LED driving power supply with an automatic dimming function.

Description

technical field [0001] The invention belongs to the technical field of power electronics applications, and in particular relates to an interleaved parallel flyback LED drive power supply and a PFM control circuit thereof, which are suitable for switching power supplies, especially in the application field of LED drive power supplies. Background technique [0002] Switching power supply is an indispensable power electronic device in modern social life, and it has a very wide range of applications in the fields of electronics, communications, electricity, energy, lighting, aerospace, military and home appliances. With the further development of power electronics technology, the society has further increased the requirements for the volume, reliability, cost, energy saving and environmental protection of switching power supply. In recent years, with the maturity of LED lighting technology, LED driving power supply has become a research hotspot. More and more countries and organ...

AI Technical Summary

Problems solved by technology

[0004] The present invention aims at the deficiencies existing in the actual use of the existing LED drive power supply, such as large switch stress, large power supply EMI, large current ripple, short power supply life, etc., and proposes an interleaved parallel flyback LED drive power supply and its The PFM control circuit makes the performance of the driving power supply greatly optimized

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