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Method for controlling LED brightness

A brightness and state technology, applied in energy-saving control technology, lighting devices, light sources, etc., can solve the problems of changing brightness, complicated circuits, and large changes in brightness of light-emitting diodes, achieve smooth brightness changes, solve complex circuits, and achieve dream effects. Effect

Inactive Publication Date: 2007-01-24
HE SHAN LIDE ELECTRONICS ENTERPRISE CO LTD
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Problems solved by technology

In this method, each pixel needs a controllable current source, and its disadvantage is that the circuit is complicated and the cost is high; the other is PWM, that is, the pulse width modulation method, such as the Chinese patent number: 200510063068.5, and the name is: "A method using The method of controlling the brightness of light-emitting diodes by duty ratio", this technology is to control the proportion of the time that the light-emitting diodes are in the "bright" state in one cycle of the control signal in the cycle by CPU or software methods, and use Persistence of vision of the human eye to change the brightness
Although the present invention can provide multiple levels of brightness required for a single light-emitting diode, its shortcoming is: since the light-emitting diode is driven by a rectangular pulse, when a certain moment in a cycle of the control signal is added to make the light When the diode is turned on at a high level, the brightness of the light-emitting diode reaches the brightest in an instant; from the high level to the low level, the brightness changes from the brightest to off, and the brightness of the light-emitting diode varies greatly, so that the brightness of the light-emitting diode Poor effect, difficult to achieve desired dreamy effect

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Embodiment Construction

[0010] Below in conjunction with accompanying drawing, the present invention will be further described:

[0011] refer to figure 1 and figure 2 , the present invention is a method for controlling the brightness of an LED, which uses a silicon controlled rectifier 14 to control the "on" and "off" states of the LED through zero-crossing shutdown, and sends a trigger pulse level 24 through the CPU to drive the LED to be turned on. The CPU in this embodiment is a single-chip microcomputer chip EM78P153SN, wherein the thyristor makes the LED be in the "bright" state for part of the time in one cycle (0-t1) of the pulse power supply 23 or the AC power supply and in the "off" state for the rest of the time. In this embodiment, the pulse power supply is preferred, and the trigger pulse sent by the CPU in good time is used to control the turn-on time of the LED in the bright state. Since the pulse power supply is used to drive the LED to light up, the power signal changes relatively ...

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Abstract

This invention discloses a method for controlling brightness of LED, which utilizes a thyristor to control the 'on or off' state of the LED by zero-cross turning off and drives the turning-on of the LED by CPU emitting trigger pulses, in which, the thyristor makes the LED at the bright state for a part of time in a period of pulse supply or AC supply and dark state for the rest time and said CPU emits trigger pulses timely to control the turning-on time of the LED at the bright state. Advantage: simple structure and low cost.

Description

Technical field [0001] The invention relates to the field of lighting control circuits, in particular to a method for controlling the brightness of LEDs. Background technique [0002] At present, there are mainly methods for controlling the brightness of LEDs: one is the current control method, which changes the brightness by changing the current flowing through the LED. In this method, each pixel needs a controllable current source, and its disadvantage is that the circuit is complicated and the cost is high; the other is PWM, that is, the pulse width modulation method, such as the Chinese patent number: 200510063068.5, and the name is: "A method using The method of controlling the brightness of light-emitting diodes by duty ratio", this technology is to control the proportion of the time that the light-emitting diodes are in the "bright" state in one cycle of the control signal in the cycle by CPU or software methods, and use The persistence of vision of the human eye cha...

Claims

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Application Information

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IPC IPC(8): H05B37/02H05B37/00
CPCY02B20/42Y02B20/40
Inventor 樊邦弘
Owner HE SHAN LIDE ELECTRONICS ENTERPRISE CO LTD