Design And Implementation Of High Precision Intelligent Deuterium Lamp Power Supply

Deuterium lamp is a kind of ultraviolet light source with many advantages,such as high radiation intensity,good stability and long life.So that it is regarded as one of the standard lamps of ultraviolet radiation.It is widely used in the field of UV detection,such as spectral instruments and chromatographic instruments.Such analytical instruments require stable light source whose stability is directly related to the power supply.At the same time,the intelligence and lower power consumption of analytical instruments are also the future development direction.In this paper,a high precision intelligent deuterium lamp power supply was designed,which greatly improved the stability and intelligence of the deuterium lamp.The whole deuterium lamp power supply system was based on the STM32 microcontroller controlling preheating,lighting and constant current modules.The main tasks completed include the following aspects:In order to provide constant supply voltage for deuterium lamp,a flyback switching power supply topology is applied to design constant current circuit.Output voltage is sampled by using the 12bits ADC converter embedded in the chip of STM32.After sampling,the voltage is digitized,and the PID algorithm is used to adjust the closed-loop feedback.In consequence,the precision output current is improved.The constant current module is divided into three gears.When the deuterium lamp is successfully illumined,the gears are automatically changed according to the deuterium lamp’s intensity sent by the host in order to control the intensity in a stable level.The preheating circuit module was composed of a wide output high frequency Synchronous Step-Down Controller TPS40057 as the main control chip,an N trench field effect transistor TPCA8050-H and other components.It could output the voltage and current of 2.5V/4A when the deuterium lamp was preheated with a preheating time of 20s.The voltage and current of 1V/0.8A was continuously supplied to the deuterium lamp after preheating.A single end flyback topology was applied in the high voltage trigger module,using a high frequency transformer and a field effect tube to convert the 30V DC voltage to the 550V AC voltage for charging the capacitor.After the charging finished,the relay was controlled by STM32 to switch the circuit for discharging the deuterium lamp anode by the high voltage capacitor to excite the deuterium molecule and realized the high pressure trigger process.Using the chip in STM32 to control all modules of the circuit,a high precision intelligent deuterium lamp is devised.From experimental results:the deuterium lamp power supply devised in this paper can provide stable power supply for deuterium lamp,the output current accuracy was 0.004%,the current drift was ± 0.06%/h,and the trigger voltage is close to 400V.Automatically adjust the lamp’s gear can let new lamp use low gear in order to reduce the waste,and let old lamp use high gear.That can extend life and improve performance,which meet the development concept of intelligent and energy saving power supply.