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

Abstract

The invention relates to a silicon-controlled light dimming circuit, which is used for receiving an external alternating-current power supply and generating a light dimming signal so as to adjust the brightness of a following LED lamp load. The silicon-controlled light dimming circuit comprises a silicon-controlled rectifying circuit, a rectifying bridge, a conducting phase-angle signal generating circuit and a light dimming signal generating circuit, wherein the silicon-controlled rectifying circuit is used for receiving the alternating-current power supply and outputting a default-phase alternating-current voltage signal; the rectifying bridge is used for receiving the default-phase alternating-current voltage signal and converting the default-phase alternating-current voltage signal into a default-phase direct-current voltage signal; the conducting phase-angle signal generating circuit is connected with the rectifying bridge and is used for receiving the default-phase direct-current voltage signal and generating a control signal for representing the conducting phase-angle range of the silicon-controlled rectifying element; the light dimming signal generating circuit is providedwith a phase-angle light dimming range determined by a preset starting phase angle and a stopping phase angle; and the light dimming signal generating circuit is connected with the conducting phase-angle signal generating circuit, and is used for receiving the control signal and a reference slope signal and comparing the control signal and the reference slope signal, and the output result is usedas the light dimming 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 driving circuit 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 sch...

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