Research On Radiation Property Of DC-DC Switch Mode Power Supply

Recently years, with the development of technology, the subject of studying the effects of ionizing radiation for semiconductor devices and integrated circuits, and how to improve their anti-radiation property become increasingly important in micro-electronics field. While DC-DC converter is the core part of equipment, and its property determined stability of the whole system. Therefore, it is significant to research the radiation property of DC-DC converter, and improve its anti-radiation level.This paper discusses the radiation property of DC-DC converter, simulating the change of electrical property of several circuits. A method is proposed to maintain the stability of circuit under radiation environment. Based on the previous theory and research on detailed process of Boost DC-DC converter, a new circuit is designed as required, the simulation is carried out in Pspice with 6V input and 15V output. Analyze the basic radiation effects in semiconductor materials; give a detailed analysis of the main influenceβin BJT and threshold voltage in MOS devices. Then the method of first-order approximation is employed to analyze the circuits and research on the change of electrical property before and after radiation, including operational amplifier, reference voltage source. The parameter of operational amplifier is varied when the dose of radiation changed, a detailed analyzes of open loop gain and input offset voltage is given in this paper. The change of reference voltage after radiation is different from it, under low dose of radiation, there is nearly no influence, when the total dose is bigger than 90krad, there is a significant increase of output voltage. Research the property of the basic topology under radiation. When the total dose is bigger than 45krad, there is a decrease in output voltage and an increase in input current. The useless power of transistor is increasing rapid, which is not good for the transistor and circuit's stability. A method using an auxiliary circuit is proposed to compensate the change of threshold voltage after analyzing the main factor to reduce power consumption and improve circuit's stability. The improved circuit reduces 3/4 power by the current as a half of the origin circuit, improve the circuit's radiation property. Due to low dropout linear voltage circuit's uniqueness, analysis of its radiation property is performed in this paper after a circuit is designed to reach the property of MSK5275-5.0H.