Circuit and method for generating self-adapting silicon-controlled light regulating signal

Abstract

The invention discloses a circuit and method for generating a self-adapting silicon-controlled light regulating signal. The circuit comprises a phase angle detection module, an inverter, a filter and a comparer. The circuit can generate a corresponding light regulating signal according to a conducting phase angle signal of an input signal. The circuit and the method disclosed by the invention have the advantages that: by the improvement of traditional silicon-controlled light regulating signal, the width of the light regulating signal corresponding to controlled silicon in the minimum conduction angle is reduced, thus the output current of a light-emitting diode (LED) and the brightness of the LED are reduced; and the influence on the width of the light regulating signal when the silicon controlled conduction angle is larger is less, thus the light regulating range is increased.

Description

technical field [0001] The invention belongs to the technical field of switching power supplies, and relates to a thyristor dimming signal generating circuit and method. Background technique [0002] LED is a new type of energy-saving lighting equipment. It requires much less power than incandescent lamps to produce the same light. Compared with energy-saving lamps and incandescent lamps, LEDs have the advantages of small size and less damage. The brightness of the LED is directly related to the current flowing through it. In lighting applications, a driver is needed to convert the mains power into a constant current output or a constant voltage output to drive the LED. In some applications, the function of adjusting the brightness of the LED is required, that is, the dimming function. At present, a traditional method is to directly replace traditional lighting fixtures, such as incandescent lamps, with LEDs. Therefore, the dimming of LEDs often directly uses the original t...

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Problems solved by technology

[0003] There is a minimum conduction angle in the traditional thyristor dimmer, that is, before the dimming angle of the thyristor dimmer is adjusted to the maximum and it is completely turned off, the AC input waveform cannot be completely phase-cut to zero.

When the SCR is at the minimum conduction angle, there is still input power, which causes the output current of the LED to not be completely adjusted to zero, and the LED cannot be dimmed in a full range, and the higher the input voltage, the greater the input power, and the minimum output current of the LED bigger

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