Dimming technology and future development of LED projection lamp

Datetime：2017-04-26   

Click amount：3846

Perfect LED projector light intelligent control should have manual control, intelligent control, light control, time control and fault alarm function. When the sun goes down and the sky is dark, the light can be automatically lit, and the lights at 12 midnight can be automatically halved. After daylight, the light can be turned off automatically.

The main LED light dimming technology

The first method is to adjust the light of the LED light to drive the current to achieve the dimming of the light, because the brightness of the LED chip and LED drive current has a fixed proportion.

The second dimming is usually referred to as an analog dimming mode or a linear dimming. The advantage of the dimming is that when the drive current is linearly increased or reduced, the effect of the LED chip, the immunity of the control circuit and the overshoot of the drive current is relatively reduced. Its drawback is that changes in the driving current will have a certain impact on the LED chip color temperature, and thus affect the color temperature of LED light.

The third mode of dimming is the pulse optical modulator (PWM) mode. This method is through certain control to drive the current square, variable pulse width, the duration of pulse width change, also can change the output power at the same time, so as to achieve the purpose of energy saving. Frequency conversion speed is generally in 200Hz to 10kHz, due to the visual retention of the human eye, so that people can not feel the light of the flashing light of the moving process. The advantage of this method is that it can improve the heat dissipation of LED. The drawback is that, in the drive current overshoot, a certain marketing of the LED chip life, shorten the life of the light projector.

The above three dimmer methods are classified according to the output control of the drive current of the LED. The control circuit can also be divided into analog control and PWM control, and the control circuit is completed by micro controller.

Dimming system and its future development

Perfect intelligent control should have manual control, intelligent control, light control, time control and fault alarm function. When the sun goes down a dark light automatically, 12 midnight lights can be automatically halved; after dawn, the light can be automatically extinguished; in special circumstances, people can control and manual control; when a fault occurs, the control system can automatically alarm.

The intelligent dimming system comprises a server, a central controller, a monolithic controller and a signal detection circuit 4 parts.

Server: mainframe and computer software, mainly to achieve monitoring and alarm functions. The site server is located in the street light management control center and the central controller's connection may through the power line carrier wave, the network or wireless way achived.

Central controller: a unit responsible for receiving signals from the server and sending them to the controller, control and signal detection, and sending the results to the server.

The signal detection circuit detects the environmental brightness, drives the power supply voltage, and the current. And 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 command, the central controller to control the light or open and close LED, and LED from the driving voltage, current signal detection circuit of the central controller. When the presence of the LED luminaire fails, the fault signal is given to the central controller.

At present in the field of road lighting, the application of LED is spreading rapidly, long service life and reliability is still the first thing to consider to do, but with the development of technology, the life and reliability of the problem, to a certain extent, LED lighting applications will inevitably lead to the pace of the intelligent light system.