PWM Drive And Its Application Of The LED Light Source

With the continuous development of LED technology,LED light source has been widely used in lighting,display,medical treatment and other fields due to its high luminous efficiency,long life,energy saving and environmental protection.At present,the driving method of applying LED is mainly DC-type constant current driving,that is,the current through the LED is kept constant.The drive is important for LED lighting,and control technology is more important.The application of dimming technology can make LED lamps last longer and save energy.The three commonly used dimming methods are analog dimming,thyristor dimming,and PWM dimming.This paper mainly studies the PWM drive and its application of LED light source module.Firstly,this paper uses STM32 microcomputer as the control core to design a solar energy and commercial power intelligent complementary power supply system based on the principle of dual-input Buck converter and PWM switching power supply,and verify its simulation.Keep Vout=Vsolar+Vgrid without the storage equipment such as battery.,avoid the power supply system from being subject to weather changes,and avoid energy loss caused by charging and discharging of energy storage equipment such as batteries,thereby further improving energy efficiency.Secondly,since the ultraviolet LED with a wavelength of about 365 nm is driven by direct current,the radiation efficiency is as high as 40%,and the electric energy can be efficiently converted into ultraviolet light energy.The solar power and the electric power intelligent complementary power supply system is used to drive the LED photocatalyst through the RT8480 driving chip.Direct power supply can effectively ensure the radiation efficiency of the UV LED and improve the efficiency of degrading the sewage.At the same time,according to the length of sunshine,the power consumption can be greatly saved.Through experiments,the LED photocatalyst can work stably in the three power supply system modes of solar supply power alone,grid power supply alone,and photovoltaic/grid hybrid power.This system greatly improves the energy utilization rate,and at the same time,it also eliminates the cost brought by the battery and the pollution to the environment,achieving the purpose of energy saving and environmental protection.Finally,according to the nature of the peak wavelength of the monochromatic LED,the peak wavelength of the LED will shift with the change of the injection current.The spectrum of the LED with the peak wavelength of 460 nm will be blueshifted and red-shifted with the change of the current.In this paper,the efficiency of degrading bilirubin is improved by independently adjusting the monochromatic LED currents of various peak wavelengths to improve the matching of the actual spectrum of the LED light source with the target spectrum.This paper proposes a pulse width modulation LED driver circuit composed of MAX16823 driver chip and NE555 timer as the core components.The driver circuit is simulated and verified by Multisim10,and then the LED light source of the neonatal jaundice phototherapy instrument is driven by the board,55 cm away from the center of the light source.The illuminance and spectral changes at different duty cycles are measured.The experimental results show that the illumination range of the monochromatic LEDs with four different peak wavelengths is 0~35lux,0~61lux,0~215lux,0~337lux.The peak wavelength varies by about 20 nm,and the half-height width varies by about 50 nm when the four LEDs with different peak wavelengths emit light at the same time.The driving circuit has good dimming effect,basically meets the purpose of adjustable illumination and adjustable spectrum.And On the basis of ensuring the uniform spectrum of the receiving surface of the light source,improving the matching degree between the actual spectrum of the LED light source of the neonatal jaundice phototherapy instrument with the target spectrum.Thus enhances the jaundice phototherapy apparatus to the newborn jaundice disease treatment effect.