LED dimming circuit and LED drive circuit
A dimming circuit and circuit technology, which is applied in the field of LED dimming, can solve problems such as high requirements for input dimming signals and stroboscopic LED drive circuits, and achieve the effects of eliminating LED stroboscopic, increasing operating frequency, and maintaining high linearity
Pending Publication Date: 2017-08-08
厦门奇力微电子有限公司
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Problems solved by technology
[0004] The invention provides an LED dimming circuit and an LED driving circuit to solve the technical problems of stroboscopic flickering and high requirements for input dimming signals in the existing LED driving circuit
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[0024] The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
[0025] see image 3 , and combined with Figure 4 As shown, an LED dimming circuit of the present invention includes a digital signal generator, a low-pass filter, a comparator and a sawtooth generator.
[0026] Among them, the digital signal generator is used to generate the pulse digital modulated signal, and is connected with the low-pass filter, which is converted into an analog signal through the low-pass filter, and the output terminal of the low-pass filter is connected to the first comparator input terminal;
[0027] The sawtooth generator is used to generate a sawtooth wave signal and is connected to the second input terminal of the comparator.
[0028] When w...
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The invention discloses a LED dimming circuit which includes a digital signal generator, a low-pass filter, a comparator and a sawtooth generator. According to the invention, in a LED dimming circuit, a digital signal is generated by using the digital signal generator, the digital signal is converted to a low-frequency simulation control signal through the low-pas filter, then the low-frequency simulation control signal and a signal which is output by the sawtooth generator are compared through the comparator so as to obtain the digital signal which has a variable duty ratio and a fixed frequency, and the digital signal is intended for controlling the on / off of a transistor to realize dimming of a LED lighting set. According to theinvention, since the digital signal generated by the digital signal generator is used, the LED dimming circuit can be regulated and controlled in spite of the influence from the LED drive circuit; also the low-pass filter is used to convert the digital signal to a simulation signal, such that the simulation signal and the duty ratio of the digital signal which is generated by the digital signal generator changes in proportion. In this way, the LED dimming circuit regulates the proportional changes between the digital signal and the dimming of the LEDs, thus eliminating the flickering of the LEDs.
Description
technical field [0001] The present invention relates to the technical field of LED dimming, and more specifically, to an LED dimming circuit and an LED driving circuit. Background technique [0002] For the current LED (Light Emitting Diode, Light Emitting Diode) lighting field, because customers have higher and higher requirements for dimming, there is not only the requirement for dimming accuracy, but also the requirement for even low flicker coefficient or even no flicker. Therefore, new LED dimming circuits need to be developed urgently. [0003] Such as figure 1 Shown is the structure diagram of a common LED step-down drive circuit, where VIN is the DC input power supply, and the sense resistor R SNS In series with the LED, the SNS module passes through the detection resistor R SNS The voltage drop to monitor the current flowing through the LED, the output of the SNS module is connected to the positive input terminal of the hysteresis comparator, the negative input t...
Claims
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Login to View More IPC IPC(8): H05B33/08H05B44/00
CPCH05B45/37Y02B20/30
Inventor 卢世勇丁西伦刘岩连光涛
Owner 厦门奇力微电子有限公司