LED lighting dimming technology and market potential for future development

There are mainly three types of dimming technology for LED lamps. These three types of dimming technologies are classified according to the control of the LED drive current output terminal. The control circuit can also be divided into analog control and PWM control. The control circuit is usually implemented by a microcontroller.

The first kind: The dimming method is to achieve the dimming of the LED lamp by adjusting the LED driving current, because the brightness of the LED chip is proportional to the LED driving current.

Second: The dimming mode is usually called analog dimming mode or linear dimming mode. The advantage of this kind of dimming method is that when the driving current increases or decreases linearly, the influence of the driving current overshoot on the LED chip is relatively reduced, and the control circuit has strong anti-interference. The disadvantage is that the size of the drive current changes, which will have a certain influence on the color temperature of the LED chip.

The third kind: The dimming method is the pulse modulation (PWM) method. In this method, the drive current is square wave shaped through a certain control, the pulse width thereof is variable, the time for the continuous lighting of the LED lamp is changed by the adjustment of the pulse width, and the output power is also changed at the same time, thereby achieving the purpose of energy saving. The frequency is generally controlled at 200Hz to 10KHz. Due to the persistence of human eyes, the flickering of the light source during the dimming process is not felt. The advantage of this dimming method is that it can improve the heat dissipation of the LED. The disadvantage is that the overshoot of the driving current has a certain influence on the lifetime of the LED chip.

Technology composition and future development

The intelligent dimming system is mainly composed of a server, a central controller, a single-chip controller and a signal detection circuit.

Server: It is composed of upper computer and upper computer software. It mainly realizes monitoring operation and alarm function. The server is located in a control center such as a street lamp management, and the connection between the server and the central controller may be power carrier, network, or wireless.

The central controller is responsible for receiving the signals sent by the server and sending the signals to the unit controller after decoding. The control is realized and the result of the signal detection is transmitted to the server.

Signal detection circuit: Detects environmental brightness, driving power supply voltage, and current. The detected signal is sent to the unit controller or the central controller.

Unit controller: Each LED lamp is equipped with a unit controller. By receiving the instruction of the central controller, the LED is dimmed or turned on and off, and the LED lamp driving voltage and current are sent to the signal detection circuit. Central controller. When the LED lamp fails, the fault signal is transmitted to the central controller.

Currently, in the field of road lighting, the application of LEDs is rapidly gaining popularity. Long life and reliability are still the first factors currently considered. However, with the development of technology, when the problems of life and reliability have been solved to some extent, LED Lighting applications are bound to make great strides towards intelligent dimming systems. Perfect intelligent control should have manual control, intelligent control, light control, time control and fault alarm control functions. When the sun goes down, it will automatically light up, and the illumination of the lamp will be halved automatically after 12 o'clock in the morning. After daylight, the light will automatically go out; in special circumstances, the person can control it manually; when the light fails, the control system Automatic alarm.

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