LED current sampling circuit, LED driving power supply and current control method

Abstract

The invention discloses an LED current sampling circuit, an LED driving power supply and a current control method. The current sampling circuit comprises a sampling resistor used for converting a current signal flowing through an LED into a voltage signal, an amplifying circuit used for amplifying an end voltage of the sampling resistor, and an integral circuit used for integrating an output voltage of the amplifying circuit; the sampling resistor is connected with the input end of the amplifying circuit; and the output end of the amplifying circuit is connected with the input end of the integrating circuit. According to the LED current sampling circuit, the function of sampling an LED current is realized through the sampling resistor; the amplifying circuit amplifies the end voltage of the sampling resistor, and under the condition of ensuring that voltage signals fed back in the current sampling process are the same, the resistance of the sampling resistor can be reduced, so that theloss of the sampling resistor is reduced; and the integral circuit is used for performing integral operation on the output voltage of the amplifying circuit, so that the effect of filtering fluctuation and high-frequency interference is achieved.

Description

technical field [0001] The invention relates to the technical field of electronic circuits, and more specifically relates to an LED current sampling circuit, an LED driving power supply for its application, and an LED current control method. Background technique [0002] Due to the volt-ampere characteristics of LEDs (light-emitting diodes) (the current flowing through the LEDs changes exponentially with the terminal voltage) and temperature characteristics, the LED driving power in the prior art generally adopts a constant current driving power. [0003] Those skilled in the art know that the deviation or fluctuation of the current flowing through the LED not only affects the working life of the LED, its luminous flux or brightness, but also affects the spectral distribution of its light emission. In some occasions that require high brightness and spectrum, such as LED light sources used for photoelectric system calibration, or LED solar simulators, etc., there are more str...

AI Technical Summary

Problems solved by technology

This current sampling circuit has the following defects: 1. Although the structure of the current sampling circuit is simple, only one sampling resistor is needed, but the loss is high, and the larger the resistance value of the sampling resistor, the higher the loss; 2. The sampling accuracy of the current is not good. The high current control accuracy of the drive power supply is not high

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