Current limiting method, current limiting-constant current combined power circuit and control method thereof

Abstract

The invention discloses a current limiting method, a current limiting-constant current combined power circuit and a control method thereof. The current limiting method comprises the steps of when an input voltage is higher than a set voltage, limiting an AC component of current output by a rectifier bridge by a capacitance value of a current limiting capacitor; and when the input voltage is lower than the voltage of the current limiting capacitor, supplying power to a load by the current limiting capacitor. The power circuit comprises an AC power supply, a rectifier bridge, a current limiting-constant current circuit and a load, wherein the AC power supply is a sine wave AC power supply, the rectifier bridge comprises two input ends and positive and negative electrode output ends, and the two input ends are connected with the AC power supply; the current limiting-constant current circuit comprises four ends, wherein the first end is connected with the positive electrode output end of the rectifier bridge, the second end is connected with the negative electrode output end of the rectifier bridge, the third end is connected with one end of the load, and the fourth end is connected with the other end of the load. The method is combined with the circuit for limiting the current and reducing the power consumption of the power circuit at the same time.

Description

technical field [0001] The invention belongs to the field of linear power supply circuits, more specifically a current limiting method, a current limiting-constant current combined power supply circuit and a control method thereof, and is especially used in the field of LED driving power supplies. 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] At present, there are many similar power supply circuits and current-limiting methods, such as applic...

AI Technical Summary

Problems solved by technology

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 based on 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] At present, there are many similar power supply circuits and current-limiting methods, such as application number 201310202695, the title of the invention is "a multi-circuit current-limiting power supply circuit and its control method and current-limiting power supply method", which have been described in the background technology of this patent out of existing power circuits such as figure 1 , figure 2 Defects in the power supply circuit; at the same time, the improved method of the patent is as image 3 and Figure 4 As shown, the current limiting method adopted in this patent is to control the load current through the current limiter, and the energy storage capacitor 405 only plays the role of storing charge; thus causing the current limiter to carry too high power consumption, and the temperature of the current limiter is biased. High, which limits the application range of this linear drive power supply

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