Thyristor dimming LED drive power supply and its dimming control method

Abstract

The invention discloses a thyristor dimming LED driving power supply and a dimming control method thereof which can improve the dimming depth of thyristor; the driving power comprises a dimming control circuit, a driving chip and an LED lamp string, and the dimming control circuit comprises Input the average voltage sampling module, the input end of the input average voltage sampling module is electrically connected to the input voltage end of the drive power supply, and the output end is electrically connected to the VLN pin of the drive chip; the input average voltage sampling module is used to sample the input average voltage of the drive power supply And send it to the driver chip to adjust the input current waveform of the driver power supply, thereby changing the dimming depth. By sampling the average input voltage to adjust the inductor current at small conduction angles, the dimming depth of the thyristor dimmable LED lamps is improved, and the output current is reduced without reducing the maintenance current; by changing the driver chip The power supply method avoids the possible flicker caused by the continuous restart of the chip.

Description

technical field [0001] The invention relates to the technical field of integrated circuit driving, in particular to a thyristor dimming LED drive power supply and a dimming control method thereof, which can improve the depth of dimming of thyristors, and are applied in the driving industry. Background technique [0002] Compared with traditional light sources, in addition to the advantages of green, energy saving, and environmental protection, LED lighting is also an important advantage of dimming. Common dimming methods include analog dimming, PWM dimming, wall switch dimming and thyristor dimming. Among them, thyristor dimming is the most widely used, especially in North America and Western European countries, almost more than 90% of lamps use thyristor dimming. Dimming depth is an important indicator of thyristor dimming lamps, which represents the minimum LED brightness without flicker when the conduction phase is small. The deeper the dimming depth, the better the end...

AI Technical Summary

Problems solved by technology

[0016] When the conduction angle is small, the input voltage Vin is very small, Istart is also very low, and the power supply of the chip is insufficient. When Vin drops to the undervoltage lockout voltage of the chip, the chip stops switching, and the continuous restart of the chip may cause flickering

[0017] 2. When the conduction angle is very small (such as Figure 2B As shown), since the input current Iac is the highest when the two shutdown modes are switched, the Iac presents as Figure 2B In the shape shown, in order to ensure sufficient holding current, the output current cannot be reduced, so that the dimming depth cannot be made very deep

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