Limitation circuit for highest output power of constant-current LED power supply and constant-current LED power supply circuit

Abstract

The invention relates to a limitation circuit for highest output power of a constant-current LED power supply and a constant-current LED power supply circuit. The limitation circuit comprises a voltage-stabilization source circuit and an output power limitation circuit, wherein the voltage-stabilization source circuit is used for setting a DC-DC output current, the voltage-stabilization source circuit for setting the DC-DC output current is connected with an output end of a monopole constant-voltage power supply circuit by adding the voltage-stabilization source circuit for setting the DC-DC output current and the output power limitation circuit to a traditional constant-current LED power supply circuit, the output power limitation circuit is connected with a constant-current output end ofa DC-DC constant-current output circuit, so that a voltage-stabilization input end of the voltage-stabilization source circuit is pulled down by a clamping effect between two diodes in the output power limitation circuit, the voltage of a control D end of the DC-DC constant-current output circuit is also reduced with same proportion, the DC-DC output current corresponding to the DC-DC constant-current output circuit is controlled to be substantially reduced by the control D end, and the output load power is limited.

Description

technical field [0001] The invention relates to an LED power supply, in particular to a circuit for limiting the maximum output power of a constant current LED power supply and a constant current LED power supply circuit. Background technique [0002] At present, the line structure of constant current LED power supply on the market mainly adopts the mode of single-stage constant voltage circuit + DC-DC step-down circuit in the front stage. The constant current LED power supply adopting this circuit structure has the characteristics of simple circuit, high cost performance and high efficiency, so this kind of LED power supply adopting this circuit structure is relatively common in the market. [0003] However, in this line architecture, the DC output ripple of the single-stage constant voltage power supply is relatively large, and the subsequent DC-DC step-down circuit itself also requires a certain voltage difference. Therefore, the DC-DC line input and output voltage diffe...

AI Technical Summary

Problems solved by technology

Since the input power of the constant current LED power supply during the overload test will greatly exceed the rated power, the temperature of the components in the constant current LED power supply will rise a lot, so that it exceeds the maximum temperature value required by the test standard for the components, resulting in the use of The constant current LED power supply of this line structure can not pass the overload test standard

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