Research On High Reliability DC-DC Power Supply With Low Voltage And High Current Output

After years of development, switching power supply has replaced the linearregulated power supply with its superior performance. Switching power supply is moreand more widely applied in almost all fields. In recent years, along with the technologyinnovation of computer and microelectronics industry, switching power supply with lowvoltage and high current output has became the hot topics in the study by scientificresearch personnel. As a key indicator which is a guarantee for electric devices to worka long time, the high reliability of power supply has become the target of switch powersupply technology especially in the field of aerospace. In this paper, the high reliabilityDC-DC power supply with low voltage and high current output is made in-depthresearch.Control technology is used to ensure the stability of switch power supply outputvoltage and current. At first, this paper analysis and studies the different feedbackcontrol methods, and then designs the amplitude modulation magnetic feedback circuitwith the voltage control mode, introduces its working principle, and carries on thesimulation. The simulation results show that the method can effectively guarantee thatthe power supply has a stable output voltage and a good dynamic characteristic. Thetransformer isolation method has a simple structure, can effectively realize the signalisolation between the input and output. It also has a long life and a good irradiationresistance. In order to analysis of the power supply loop effectively in theory, this paperbuilds the model of the active clamp forward, and then makes a small signal analysis ofthe amplitude modulation magnetic feedback. On this basis, the compensation circuithas been designed. The simulation results show that the loop has good amplitude andfrequency characteristics.In order to improve the reliability of power supply, redundant structure which isadopted widely in the field of communication power supply is used in this paper. First,this paper designs the dual machine redundant heat backup mode in parallel structure,and then studies output switch mode. Through the simulation process of main circuitswitching when a failure occurs, it can be got that the structure can switch to thestandby power supply in time after the main power failure, this structure can achieve ahigh reliability. Redundant structure used in this paper with a simple structure and smallpower consumption is beneficial to the improvement of the efficiency.Finally, this paper designs a DC-DC power supply prototype with5V/20Aoutput. Through analysis the experimental waveforms including output voltage andcurrent when load switching, voltage ripple, and tests the efficiency curve, the prototype can meet the requirements of the indicators. A good stability and dynamiccharacteristics can be achieved using the design of this paper, at the same time,achieving a high efficiency.