Constant-current dimming device for LED lamp

Abstract

The invention discloses a constant-current dimming device for an LED lamp. The device comprises a signal generator and a power converter, the input end of the signal generator is externally connectedwith dimming equipment; the output end of the signal generator is connected with the power converter, the input end of the power converter is connected with input voltage, the output end of the powerconverter is connected with the positive electrode end and the negative electrode end of the LED lamp, and the signal generator is used for receiving dimming signals of dimming equipment and then sending frequency conversion pulse signals to the power converter. The dimming range is wide, the dimming depth can reach 0.1% of rated voltage or rated current, flickering can be avoided in the dimming process and after dimming is stable, output ripples are small in the dimming process, and the power converter can use low switching frequency to achieve high conversion efficiency and output power.

Description

technical field [0001] The invention relates to the field of LED lighting, in particular to a constant-current dimming device for LED lamps to achieve deep dimming. Background technique [0002] At present, the dimming scheme applied to the LED driving power supply mainly adopts the following methods: The first method is analog dimming, that is, the output current or voltage changes continuously with the analog dimming signal. The advantages of this method are the dimming process and dimming. There is no flicker after stabilization, but this dimming method is easily disturbed during dimming, and the dimming range is narrow, generally in the range of 5%-100%, and flicker is easy to occur when it is lower than 5%; the second method, PWM pulse width Modulation dimming, that is, using a pulse width modulated pulse signal to control the power conversion module, so that the output current or voltage changes with the PWM signal, although it has strong anti-interference ability and ...

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Problems solved by technology

[0002] At present, the dimming scheme applied to LED drive power supply mainly adopts the following methods: The first method is analog dimming, that is, the output current or voltage changes continuously with the analog dimming signal. The advantage of this method is that the dimming process and dimming There is no flicker after stabilization, but this dimming method is susceptible to interference during dimming, and the dimming range is narrow, generally within the range of 5%-100%, and flicker is prone to occur when it is lower than 5%; the second method, PWM pulse width Modulation dimming, that is, the use of pulse width modulated pulse signals to control the power conversion module, so that the output current or voltage changes with the PWM signal. Although it has strong anti-interference ability and wide dimming range, this dimming method occupies When the duty cycle is small, the number of pulses output by the DC / DC controller within the enabling time of the dimming signal is small, and the output current changes in steps with the number of pulses during the dimming process, resulting in a dimming process. Flickering, if the operating frequency of the power conversion module is increased, the device loss will be too large; the third method, PWM+analog hybrid dimming, that is, PWM+analog dimming is used when the brightness is small, and analog dimming is used when the brightness is high. Dimming, the dimming depth is wide, generally can achieve a dimming range of 1%-100%, but at a very small dimming depth, the dimming process will still flicker

[0003] Therefore, none of the above dimming schemes can achieve a very low dimming depth, especially when using a lower operating frequency in some high power demand situations, the disadvantages are more obvious

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