Light emitting diode (LED) dimming color temperature adjusting circuit

Abstract

The invention discloses a Light emitting diode (LED) dimming color temperature adjusting circuit, which is used for dimming and color temperature adjusting of an LED lamp string comprising at least one warm light lamp string and at least one cold light lamp string. The LED dimming color temperature adjusting circuit comprises a master controller, a pulse-width modulation (PWM) control unit and a color temperature adjusting unit. The master controller is used for generating a path of dimming PWM signal and a path of color temperature adjusting PWM signal. The PWM control unit is connected with the master controller. The color temperature adjusting unit is connected with the master controller. The input side of the PWM control unit is connected with the input end of an alternating current (AC) through a rectification filter unit. The output side of the PWM control unit is connected with the LED lamp string through a power control unit. As the master controller controls the PWM control unit and the color temperature adjusting unit separately, and two paths of signal are independent, brightness adjustment of the LED lamp string does not cause change of the color and temperature, similarly, adjustment of the color and temperature does not cause change of brightness. When the master controller is an N-bit microprogrammed control unit (MCU), the grade of dimming color temperature adjustment can reach the grade of 2N*2N=22N, so that the brightness and color temperature of the light source can be adjusted precisely.

Description

technical field [0001] The invention relates to the lighting field, in particular to an LED dimming, coloring and temperature circuit. Background technique [0002] In the field of LED lighting, dimming and color temperature have always been the focus of attention. The so-called dimming is to adjust the brightness of the light source; the so-called color temperature is generally considered to be the adjustment of the color of the light source. The color temperature is the temperature of the black body when the color of the light emitted by the light source is the same as that of the black body at a certain temperature. In black body radiation, The color of light varies with temperature. The difference between color temperature and brightness often gives people different feelings. For example, under the illumination of high color temperature light source, low brightness will give people a cold atmosphere; under low color temperature light source, excessive brightness will gi...

AI Technical Summary

Problems solved by technology

[0005] The main disadvantage of the existing scheme is: assuming that a general-purpose N-bit MUC is used to generate two PWMs, each dimming color temperature combination is at most 2 N Level, the combination of two light sources is up to 2 N +2 N = 2 N+1 Level, this combination mode is not enough to adjust the level

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