LED lighting dimming system

Abstract

The invention discloses an LED lighting dimming system which comprises a single chip microcomputer, a controller, an LED lamp, a power supply and an LED driving circuit. The controller, the single chip microcomputer, the LED driving circuit and the LED lamp are connected in sequence. The single chip microcomputer is connected with a displayer. The LED lighting dimming system is further provided with a bright adjuster which is connected with the LED driving circuit. The power supply is connected with an LED. The single chip microcomputer is connected with the LED driving circuit in a pulse width modulation (PWM) mode. Any LED chromatography migration cannot happen in dimming due to the fact that the LED always works between full-range current and 0. High dimming accuracy is achieved, and impulse waveforms can be completely controlled to high accuracy, so that the accuracy of 10<-4> can be achieved easily. Even dimming is carried out in a large range, the phenomena of blinking can be avoided. The working condition (the step-up ratio or the step-down ratio) of a constant current source cannot be changed, and problems such as overheating can be avoided.

Description

technical field [0001] The invention relates to the technical field of lighting, in particular to an LED lighting dimming system. Background technique [0002] Ordinary incandescent and halogen lamps usually use thyristors for dimming. Because incandescent lamps and halogen lamps are purely resistive devices, it does not require the input voltage to be a sine wave, because its current waveform is always the same as the voltage waveform, so no matter how the voltage waveform deviates from the sine wave, as long as the effective value of the input voltage is changed, It can be dimmed. [0003] However, the adjustment of the thyristor dimming to the LED light source will produce unexpected problems, that is, the LC filter at the input end will cause the thyristor to oscillate, this oscillation is indifferent to the incandescent lamp, because the thermal inertia of the incandescent lamp makes This oscillation is not visible to the human eye at all, but it produces audible nois...

AI Technical Summary

Problems solved by technology

[0003] However, the adjustment of the thyristor dimming to the LED light source will produce unexpected problems, that is, the LC filter at the input end will cause the thyristor to oscillate, this oscillation is indifferent to the incandescent lamp, because the thermal inertia of the incandescent lamp makes The human eye cannot see this oscillation at all, but for the driving power of the LED, it will produce audio noise and flicker

In addition, the thyristor dimming will destroy the waveform of the sine wave, thereby reducing its power factor value (usually lower than 0.5), so the thyristor dimming greatly reduces the system efficiency of the LED

Moreover, the waveform of the thyristor dimming increases the harmonic coefficient, and the non-sinusoidal waveform will generate serious interference signals (EMI) on the line and pollute the power grid, which will seriously paralyze the power grid.

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