Design And Realization Of The Radiation Hardened Boost DC/DC Converter

Because of the nearly timeless working of aerospace equipments in the bad space radiation environment, the damage made by the radiation in electronic systems becomes an important inducement that makes the whole aerospace equipments out of order, and even finally causes a disaster result of satellite or aerospace machine. Then the DC/DC converter working as the important power supply in aerospace equipments is subjected to radiation influence firstly, as a result its credibility especially its anti-radiation performance receives a lot of attention.The Boost DC/DC converter’s basic topology is introduced firstly here, and through the PSpiCE software’s simulation, the circuit work principle is analyzed in detail, and the PWM voltage mode, current mode and then the unsteady of the current mode are described in detail. Then the space radiation environment, single event effect and total dose effect are introduced, followed by detailed explanation to the mechanism of the two kinds of effects. By a great deal of experiment data and chart gathered in the paper, we discovered that in the DC/DC converter, power MOS transistor is easily subjected to a total dose effect radiation damage and cause threshold voltage decrease and finally may make the converter fail to work, the PWM controller is also easily subjected to the total dose effect’s and single event effect’s radiation hurt and result in missing output pulses, reference voltage drift deteriorate phenomenon etc.Then the radiation sensitive parts of the Boost DC/DC converter is analyzed, including the power VDMOS switch, PWM integrated control module and the Schottky diode. After that the technology of the DC/DC converter’s radiation hardness assurance is discussed, including hardening method based the sensitive parts’screening and based the optical coupler feedback. Subsequently, by PSpiCE simulation, the technology of the radiation hardness assurance based on circuit design is analyzed in detail. For the power MOS switch transistor’s threshold voltage dropping case, a corresponding circuit raising source voltage is designed to offset the threshold voltage’s descend, then the circuit is simulated, validated by PSpiCE.A kind of Boost DC/DC converter based on the PWM integrated controller UC2843is designed. Then a new Boost DC/DC converter structure with transformer insulation is introduced, so the anti-radiation performance is improved because of adding transformer insulation. The two DC/DC converters are designed and simulated by the software SIMetrix, the results accord with the design request. Also the real object electric circuits are made, its function satisfy the design request by testing. Finally, a radiation hardness assurance is carried out in the DC/DC converter with transformer insulation, the simulation results indicate its correction and rationality.