微型X射线管灯丝电源的研制

根据微型X射线管的特点,设计了基于推挽电路和闭环反馈电路的灯丝驱动电源。采用了UCC3808脉宽调制(Pulse Width Modulation,PWM)控制芯片产生两路相位相反的PWM信号,并经由UCC37324金属氧化物半导体(Metal-Oxide-Semiconductor,MOS)管大电流驱动器提高驱动效率,实现推挽结构的后端驱动电路。闭环反馈电路的设计采用精密电阻将管电流的信号转换为等比例的电压信号引入到反馈环节,通过系统自身的闭环控制实现管电流的恒定,并保持高效率和低功耗。实验首先通过外接1.5?的功率电阻测量系统功率,测得输入功率为11 W,效率超过80%,符合灯丝电源的功耗指标要求;然后连接实际的X光管灯丝,经测试可正常工作,管流稳定度为0.227%。

Development of the filament power supply of micro X-ray tube

Background: X-ray is widely used in various industries whilst the filament power supply is an important core component of X-ray tube. Traditional technology that applies 220-V AC input power frequency, power factor correction, the step-down transformer heating filament works fine for medium and large X-ray tube filament power supply, but is unsuitable for the micro X-ray tube. Purpose: This study aims to develop a novel filament power supply for practical micro X-ray tube.Methods: According to the characteristics of the micro X-ray tube, the push-pull circuit and a closed-loop feedback circuit were employed for the filament drive power supply. UCC3808 pulse width modulation (PWM) control chip was used to generate two opposite phase PWM signals, and the driving efficiency was improved through the UCC37324 metal-oxide-semiconductor (MOS) tube high current drive, so as to achieve the back-end of push-pull driving circuit. The tube current signal was converted into isometric voltage signal through the precision resistor, and then be introduced into the feedback loop through closed-loop control of the system to achieve a constant tube current, and maintain high efficiency and low power consumption.Results: The input power is measured to be 11W, and efficiency to be more than 80% when firstly connected to a 1.5-W power resistance, which meets the power consumption requirements of the filament power supply. Then an actual X light tube filament was connected for practical test, results show it is in working order with tube flow stability of 0.227%. Conclusions: The filament power supply proposed in this paper meets the requirements of practical micro X-ray tube, its stability is mainly induced by the ripple of high voltage power on the filament, and the unoptimized parameters of tube flow closed-loop feedback loop. These will be improved in the future work.