Adjustable High-Power Light Emitting Diode Driving Circuit and Its Lighting Application in Sports Venues

Abstract

High-power LED not only has the characteristics of energy saving, environmental protection, long service life, and high reliability, but also has the advantages of high light efficiency and large conduction current. According to the characteristics of high-power LED, an adjustable high-power LED driving circuit is designed in this study. The chip adopts the Boost circuit structure driven by constant current, and the output current on a single channel is converted into voltage by using the sampling resistor on the LED path and fed back to the circuit. After passing a mirror current independent of temperature through a resistor, the reference voltage source is obtained by voltage division. When designing the LDO circuit of voltage regulator, modules such as front-end voltage conversion circuit and input under voltage protection circuit are added. When designing the soft start circuit, the output voltage of the soft start replaces the output of the error amplifier and is connected to one end of the PWM comparator. In the design of dimming circuit, PWM dimming technology is adopted, and the DIM pin is connected to low level when there is no PWM signal. In the experiment, the lowest level of soft start is 0.78 V, the highest bit is 1.35 V, and the period is 374.6 us. When VIN = 8 V, the output voltage can be adjusted to 40 V in one period based on soft start, which meets the starting requirements of the driving circuit. When the DIM pin is connected with a PWM dimming signal with a duty ratio of 90% and a frequency of 10 kHz, the output current of the LED light is in a relatively stable state. Applying the designed LED driving circuit to the lighting of sports venues can meet the requirements of daily events and training, and has advantages in energy saving and environmental protection.