Leds for lighting are characterized by directional light emission, as almost all power leds are equipped with reflectors, and the efficiency of this reflector is significantly higher than that of lamps. In addition, the efficiency of its own reflector is included in the light effect detection of LED. For the landscape lights using LED, the directional luminescence characteristics of LED should be taken advantage of as far as possible, so that each LED in the street lamp can be directly illuminated to each area of the illuminated road surface, and then the auxiliary light distribution of the lamp reflector is used to achieve a very reasonable comprehensive light distribution of the street lamp.
It is suggested that led landscape lights and street lamps should meet the standard illuminance and illuminance uniformity requirements, and lamps should include three light distribution functions for better implementation. LED with reflector and reasonable beam output Angle has good main light distribution function. In the lamp, the installation position and luminous direction of each LED can be designed according to the height of the road lamp and the width of the road, so as to achieve a good secondary light distribution function.
The reflector in this lamp is used only as an aid to tertiary light distribution to ensure uniformity of road lighting. In order for the LED driver circuit to display constant current characteristics, the internal impedance of the output of the led landscape lamp must be very high when looking inward from the output end of the driver circuit. When operating, the load current will also pass through the internal impedance of this output. If the drive circuit consists of step-down, rectifier and filter plus DC constant current source circuit or general switching power supply plus resistance circuit, a large amount of active power must also be consumed. Therefore, under the premise of basically satisfying the constant current output, the efficiency of these two driving circuits cannot be very high. The correct design solution is to use an active electronic switching circuit or high frequency current to drive the LED landscape lights. Using the above two schemes, the drive circuit can still have high conversion efficiency under the premise of maintaining good constant-current output characteristics
