A method and circuit for solving dimmer flickering of led by silicon controlled rectifier
A silicon dimming and control circuit technology, which is applied in the electronic field, can solve problems such as asymmetry of wave cutting of thyristor dimmers, reduction of compatibility of thyristor dimmers, and different dimming effects of dimmers.
Active Publication Date: 2021-01-29
MAXIC TECHNOLOGY CORPORATION
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[0003] However, when the traditional linear LED drive circuit is used with a thyristor dimmer, when the conduction angle of the thyristor is small (or the wave cutting angle is large), there will be a flickering problem. The reason for this problem is When the input peak voltage is close to the output LED voltage after wave-cutting rectification of the silicon controlled rectifier, serious asymmetry will appear in the wave-cutting of the wave-cutting of the silicon-controlled dimmer, so that the peak voltage input after the wave-cutting rectification of the silicon controlled rectifier is aperiodically greater than or less than the output LED voltage (as figure 2 As shown, two peak voltages Vin_pkA and peak voltage Vin_pkB are correspondingly obtained after wave cutting, and Vin_pkA>V LED >Vin_pkB), causing the current on the LED to change drastically aperiodically, and the frequency of the current change at this time is less than the recognition frequency of the human eye, resulting in the phenomenon of flicker visible to the human eye, and due to the dimming effect of different dimmers vary, thus greatly reducing compatibility with TRIAC dimmers
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[0026] The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.
[0027] In the AC-powered linear LED-driven thyristor dimming circuit, when the difference between the input peak voltage and the LED voltage (or output voltage) is less than △V (△V>0), it can There will be serious asymmetry in silicon-controlled wave cutting, resulting in flashing lights. Among them, △V is the difference voltage between the input peak voltage and the LED voltage. For the same LED drive circuit, when different thyristor dimmers have severe asymmetry, the difference voltage △V between the input peak voltage and the LED voltage is The values are different. When the difference between the input peak voltage and the LED voltage after SCR wave cutting is not less than △V, there will be no asymmetry during the SCR wave cutting process, that is, there will be no light flicker. Therefore, if the difference ...
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Disclosed is a method for solving the dimming and flickering of LEDs by silicon controlled rectifiers. The method may include: detecting a wave cutting angle of the thyristor, and outputting a wave cutting angle signal. Detect whether the wave cutting angle signal is a threshold signal, when the wave cutting angle signal is a threshold signal, start to output a compensation signal, and control the current value on the LED according to the compensation signal. The method is to detect the cutting wave angle information of the thyristor dimmer, compensate the output current according to the cutting wave angle information, and reduce the LED current to zero before the cutting wave of the thyristor dimmer does not appear seriously asymmetrical, thereby Solve the flashing light problem.
Description
technical field [0001] The present application relates to the field of electronic technology, and in particular to a method and circuit for solving the flickering of LED dimming by silicon controlled rectifiers. Background technique [0002] The LED drive circuit adopts the connection mode of linear drive, such as figure 1 shown. This connection method has the advantages of simple structure, low Electro Magnetic Interference (EMI), compatibility with most thyristor dimmers to realize dimming, and the like. [0003] However, when the traditional linear LED drive circuit is used with a thyristor dimmer, when the conduction angle of the thyristor is small (or the wave cutting angle is large), there will be a flickering problem. The reason for this problem is When the input peak voltage is close to the output LED voltage after wave-cutting rectification by silicon controlled rectifier, serious asymmetry will appear in the wave-cutting of silicon controlled rectifier dimmer, so...
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IPC IPC(8): H05B45/10H05B45/37H05B44/00
CPCH05B45/37
Inventor 张攀牟在鑫刘柳胜程宝洪
Owner MAXIC TECHNOLOGY CORPORATION