High-efficiency ac/dc power supply circuit and its control method and power supply method

Abstract

The inventing provides a high-efficiency AC / DC power supply circuit, and a control method and power supply method thereof. The AC / DC power supply circuit is characterized in that when a voltage amplitude of an alternating-current power supply is higher than a sum of an intermediate energy storage circuit voltage and a load voltage, the alternating-current power supply charges the intermediate energy storage circuit and provides energy for the load; when the voltage amplitude of the alternating-current power supply is lower than the sum of the intermediate energy storage circuit voltage and the load voltage and is higher than a difference between the load voltage and intermediate energy storage circuit voltage, the alternating-current power supply and the intermediate energy storage circuit provides energy for the load jointly and the intermediate energy storage circuit carries out discharging. The constant-current outputting can be realized by controlling the amplitude or discharging time of the discharging current of the intermediate energy storage circuit. According to the invention, the power device loss is extremely low; the conversion efficiency is extremely high; and the power application range of the drive power supply is extended. With the conduction angle of the rectifier bridge, the power factor of the power supply circuit is higher than that of the traditional rectification circuit; and the output voltage and the current ripple are small and the lightning-surge-resistant capability is high.

Description

technical field [0001] The invention relates to a high-efficiency AC / DC power supply circuit and its control method and power supply method, and relates to the field of AC / DC power supply, and more specifically, to the field of non-isolated LED driving power supply. Background technique [0002] Light emitting diodes (LEDs) are replacing traditional lighting sources in more and more lighting devices because of their smaller size, low power consumption, fast lighting operation, and long lighting lifetime. LEDs cannot be directly connected to AC power, and need to be configured with a corresponding current-limiting drive power supply. The current LED drive solution is mainly a traditional high-frequency switching power supply. The circuit is complex and the cost is high, making many manufacturers switch to linear power supply solutions. [0003] Traditional linear power supply circuits such as figure 1 As shown: the AC power is rectified by the rectifier bridge to charge the ...

AI Technical Summary

Problems solved by technology

[0005] First, when the mains voltage is high, the power consumption of the current-limiting power device M1 is very large, and the temperature rise of the current-limiting power device M1 is high, which limits the application power range of the linear drive power supply

[0006] 2. If there is no energy storage capacitor C1 or the capacity of C1 is very small: when the instantaneous value of the input voltage is lower than the voltage at both ends of the energy storage capacitor C2, the energy storage capacitor C1 cannot maintain the voltage at both ends of the capacitor C1 is always greater than the voltage at both ends of the load, resulting in load R_load In the late discharge stage of the energy storage capacitor C2, no current flows, the ripple is relatively large, and the utilization rate of the load is low; when the effective value of the input voltage is relatively low, the current-limiting power device M1 cannot achieve the purpose of constant current, making the linear adjustment rate low

[0007] 3. If there is a large energy storage capacitor C1, because the conduction angle of the rectifier bridge is relatively small, the power factor of the linear power supply circuit is low

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