Research On Key Characterization Technology Of Radiation-proof Ability Of DC/DC Converter

The radiation-proof ability has become an important content of the Quality Assurance System of DC/DC Converters as they are widely used in the environment of space. The traditional characterization methods always damage devices badly or cost too much. Therefore, this paper expects to find a new characterization method which can avoid these disadvantages.Based on the radiation damage mechanism and the characteristics of low-frequency noise in DC-DC converter and PWM, which is one of the most vulnerable units in converter, ionization irradiation experiments were done. After analyzing the degradation of parameters, the most sensitive, faithful and measurable ones were selected. Then the models that used to characterize the radiation-proof ability of DC/DC converter and PWM were presented respectively. Some key technologies of a new characterization method named Small Dose Radiation-Anneal Method were also presented.Based on these works above, the main results of this paper are as follows:1. The results of the ionization irradiation experiments show: the output voltage of DC/DC converter can reflect more sensitively the degradation of converter than other electrical parameters; the degradation trend of noise parameters is consistent with the output voltage, but their degradation range is greater by two magnitudes. Some related results of experiment on PWM show: the voltage and noise parameters of Pin COMP can characterize the degradation of PWM well, and noise parameter is better.2. The degradation of the output voltage of DC/DC converter is caused by the decline of the CTR as well as the increase of the voltage reference. The degradation of voltage of Pin COMP is caused by the gain decline of the transistor in the input stage of the error amplifier.3. Both theory deduction and data fitting prove: the value change of the dot frequency characterizes the change of output voltage well, which could be applied to characterize the radiation-proof ability of DC/DC converter. The noise characterization model of PWM shows the correlation between the degradation of voltage of Pin COMP and the noise characteristics before irradiation as well as the density of positive charges seized during irradiation.4. Small Dose Radiation-Anneal Method has advantages of lower-damaged, accurate, universal and lower-cost. This method can be applied to characterize the radiation-proof ability of DC/DC converter.