The dimming technology and future development of led floodlight manufacturers :
1. The main dimming technology of led floodlight manufacturers
(1). The method is to realize the dimming of the LED floodlight by adjusting the driving current of the LED, because the brightness of the LED chip and the LED driving current have a fixed ratio.
(2) The dimming is generally referred to as analog dimming mode or linear dimming. The advantage of this dimming is that when the driving current is linearly increased or decreased, the LED chip is relatively lowered, and the immunity of the control circuit is strong against the overshoot of the driving current. The disadvantage is that the change in drive current will have a certain effect on the color temperature of the led chip.
The third mode of dimming is the pulsed light modulator (PWM) mode. This method is achieved by a certain control to make the driving current square, the variable pulse width, the duration of the change by the pulse width adjustment, and also the output power can be changed, thereby achieving the purpose of energy saving. The frequency conversion speed regulation is generally in the range of 200 Hz to 10 kHz, because the human eye is visually retained, and the process of light movement of the flickering light is not felt. The advantage of this method is that the advantage of moving light is that it can improve the heat dissipation of the LED. The disadvantage is that the overshoot of the drive current has a certain effect on the life of the led chip.
The above three dimmer methods are classified according to the output control of the LED drive current. The control circuit can also be divided into analog control and PWM control, and the control circuit is usually completed by a microcontroller.
2. Dimming system and future development
Perfect intelligent control should have manual control, intelligent control, light control, time control and fault alarm function. When the sun goes down, the sky will gradually light up and the light will be automatically halved at 12 o'clock; after dawn, the light can be automatically extinguished; in special cases, people can control it manually; when the control fails, the control system can automatically Call the police.
The intelligent dimming system includes a server, the central controller, a single-chip controller and a signal detection circuit.
Server: Host and computer software, mainly composed of monitoring and alarm functions. The connection of the web server to the streetlight management control center and the central controller can be achived by power line carrier, network or wireless.
Central controller: responsible for receiving signals from the server and sending them to the controller, control and signal detection, and sending the results to the decoding unit of the server.
Signal detection circuit detects ambient brightness, drives power supply voltage, and current. And the signal to be detected is sent to the unit controller or the central controller.
Unit controller: Each led light is equipped with a unit controller, by receiving a command, the central controller to control the light or to turn the LED on and off, while the LED is driven by the voltage, the current signal is detected by the central controller of the circuit. When there is a led floodlighting fault, the fault signal is sent to the central controller.
At present, in the field of road lighting, the application of led floodlights is spreading rapidly. Long life and reliability are still one thing to consider, but as technology develops, life and reliability issues are solved, to a certain extent. On, the LED lighting application will inevitably move towards the pace of intelligent dimming systems.