How do dimmable LED drivers work?

2020-07-06

At present, the most commonly used LED dimmable LED drivers includes: triac dimming led driver, 0 / 1-10V dimmable LED drivers and PWM dimmable LED drivers. Other dimming working principle is to achieve LED dimming function by controlling the output of current, voltage and frequency. Please see the detailed principle of various dimming methods below.

1. Triac dimmable LED drivers
Triac dimming has been used in incandescent lamps and energy-saving lamps for a long time, and it is also the most widely used dimming mode in LED dimming. Triac dimming led driver working principle is to generate a tangent output voltage waveform after passing the input voltage waveform through the conduction angle shear wave. Applying the tangent principle, the effective value of output voltage can be reduced, so as to reduce the power of common load (resistance load). The advantages of SCR dimming are high efficiency and stable performance. .

2. 0 / 1-10V dimmable LED drivers
The LED driver is designed with a control chip. When the 0-10V dimmer is connected, the output current of the LED driver is changed and the light is reduced by changing the 0-10V voltage. For example, when the 0-10v dimmable led driver is modulated to 0V, the current is reduced to 0, and the light brightness is in the off state (with a switch function). When the 0-10V dimmer is adjusted to the maximum 10V, the output current will reach 100% of the power output, and the brightness will also reach 100%.
The voltage is constant 1-10V dimming principle: When the resistance dimming device is adjusted to the minimum 1V, the output current is also changed by 10%. When it is adjusted to 10V (adjusted to the maximum), the output current will also reach 100% of the power output, and the brightness will also be 100%. (the output voltage is unchanged).

3. PWM dimmable LED drivers
Digital dimming, also known as PWM dimming. Led pwm driver changes the on-time of the forward current by turning on and off the led by PWM wave, so as to achieve the effect of brightness adjustment. The method is based on the fact that the human eye is not sensitive to the brightness flicker, which makes the load led light and dark. If the frequency of light and dark exceeds 100Hz, what the human eye sees is the average brightness, rather than the LED flashing. PWM can adjust the brightness by adjusting the time proportion of light and dark. In a PWM cycle, because the human eye blinks the light within 100Hz, the perceived brightness is a cumulative process, that is, the larger the proportion of light time in the whole cycle, the brighter the human eye feels.

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