Silicon-controlled light-dimming circuit, light-dimming method and LED (light-emitting diode) driver applying the same

Abstract

The present invention relates to an SCR dimming circuit and method for regulating the luminance of an LED load. In one embodiment, an SCR dimming circuit can include: an SCR element that generates a lack-phase AC voltage based on a sinusoidal AC supply; a rectifier bridge that generates a lack-phase DC voltage based on the lack-phase AC voltage; a conduction angle generator that receives the lack-phase DC voltage, and generates a controlling signal representative of a conduction angle of the SCR element; and a dimming signal generator that generates a dimming signal to regulate luminance of the LED load, where the dimming signal generator receives the controlling signal, an adjustable signal, and a clamping voltage, an amplitude of a dimming phase angle range is selected by a fixed signal determined by the clamping voltage, and the dimming phase angle range may be shifted by regulating the adjustable signal.

Description

technical field [0001] The present invention relates to a dimming circuit applied to drive lamp loads, in particular to a thyristor dimming circuit, a thyristor dimming method and an LED driver using the same. Background technique [0002] For the field of lighting, since the thyristor phase control (chopper method) dimming method has the advantages of small size, reasonable price and wide range of dimming power, the thyristor phase control dimming method is currently the most widely used The dimming method is widely used in the fields of stage lighting and ambient lighting. By applying the SCR phase-controlled working principle, by controlling the conduction angle of the SCR rectifier element, a part of the sine wave voltage input by the AC power grid is cut off to reduce the average value of the output voltage, thereby controlling the power supply voltage of the lamp circuit and realizing Dimming function for lamp load. [0003] refer to Figure 1A , shows a schematic bl...

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Problems solved by technology

However, since the characteristic parameters of thyristor rectifier elements are different, the conduction phase angle ranges are different. For different thyristor rectifier elements, the parameters of the thyristor dimming circuit need to be adjusted differently, otherwise, it may be The dimming performance of the thyristor dimming circuit will be reduced, so the existing thyristor dimming circuit is not very versatile

For example, the adjustable phase angle range determined by the silicon controlled rectifier element is preferably 60°-120° phase angle; and when the initial conduction angle of another silicon controlled rectifier element is 75° phase angle, if the same SCR dimming circuit, the adjustable brightness range of the load is correspondingly reduced

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