To work long hours at low brightness may make the step-down constant current source efficiency to reduce the temperature rise increased unable to work. Most people may think that just down to reduce the output power of constant-current source, so it can not cause the power consumption of high intensity uv led of the step-down constant current source to increase the temperature rise increased. Little do they know when the forward voltage drop caused by the lower forward current make buck than the lower. The efficiency of the step-down constant current source and high intensity uv led, buck ratio, the lower the efficiency the greater the wear and tear on the chip’s power consumption.
Adjust the forward current cannot be precise dimming. Because the forward current and light output is not completely proportional relationship between the different high intensity uv leds have different forward current and light output curve. So adjust the forward current is difficult to achieve precise light output control.
The led high bay is a diode, it can achieve fast switching. The switching speed can be up to the microsecond above. Is unmatched by any light-emitting devices. Therefore, as long as the power source into a pulsed constant current source, the method of changing the pulse width can change its brightness. This method is called pulse width modulation (PWM) dimming method. If the pulse cycle tpwm, pulse width of the ton, the D (or called porosity) ton / tpwm. Work to change the pulse of constant current source can change the brightness of the high intensity uv led.