LED light modulation device

Abstract

The invention relates to an LED light modulation device, wherein the LED light modulation device comprises a light modulation signal generation module, a frequency modulation module and an LED driving module. An output end of the light modulation signal generation module is connected with an input end of the frequency modulation module. An output end of the frequency modulation module is connected with an input end of the LED driving module. The frequency modulation module comprises a first current source (U1), a first switch (S1), a second current source (U2), a second switch (S2), a capacitor (C) and a comparator (COMP). The light modulation signal generation module is an adjustable resistor (R). By adjusting the resistance of the adjustable resistor, the working frequency of the circuit is modulated, the duty ratio of a switch tube in the LED driving module is changed, and LED light modulation is finally realized; in addition, the circuit structure is simple, the working frequency is not increased by the reduced peak current, the loss of the switch tube in the LED driving module is lowered, the working is stable, and the cost is low.

Description

technical field [0001] The present invention relates to the field of electronic technology, in particular to circuit design, and in particular to an LED dimming device. Background technique [0002] Energy saving is one of the most prominent advantages of LED. In general lighting, if dimming technology is introduced, the energy saving advantages of LED lighting can be brought into full play. At present, the commonly used dimming technologies include linear dimming, PWM dimming and thyristor dimming, among which the linear dimming circuit is relatively simple, which changes the peak current of the inductor by changing the voltage or resistance to change the LED drive current. The disadvantage is The smaller peak current will increase the operating frequency of the drive circuit and increase the switching loss, while reducing the LED current will cause the white light to shift to the yellow spectrum. Moreover, the cost of SCR dimming and MCU-controlled dimming in the existing...

AI Technical Summary

Problems solved by technology

At present, the commonly used dimming technologies include linear dimming, PWM dimming and thyristor dimming, among which the linear dimming circuit is relatively simple, which changes the peak current of the inductor by changing the voltage or resistance to change the LED drive current. The disadvantage is The smaller peak current will increase the operating frequency of the drive circuit, increase the switching loss, and reduce the LED current while causing the white light to shift to the yellow spectrum

Moreover, in the existing dimming technology, the cost of thyristor dimming and MCU-controlled dimming is relatively high. It is relatively simple to change the peak current of the inductor by changing the voltage or resistance to change the LED drive current.

[0003] see figure 1 As shown, the non-isolated LED drive working waveform, the switch tube is turned on, the inductor current rises from zero, the switch tube is turned off, the inductor current starts to drop from the peak value, and a working cycle time T=T ON +T OFF ∝ I PK , the operating frequency of the circuit increases exponentially with the decrease of the peak current, reducing the LED current will cause the white light to shift to the yellow spectrum

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