Design consideration of full-regulated bus converter for system stability of on-board distributed power system

The bus architecture consisting of bus converter and point of load (POL) is generally used as distributed power supply system for IT infrastructure equipments. The most important factor is the system stability in bus architecture design. The overlap between the output impedance of bus converter and input impedance of POL causes system instability, and it has been an actual problem. Increasing the bus capacitor, system stability can be reduced easily. However, due to the limited space on the system board, increasing of bus capacitors is impractical. The urgent solution of the issue is desired strongly. This paper presents the stability design for on-board distributed power system consisting of full-regulated bus converter and POLs. The output impedance of the bus converter and the input impedance of the POL are analyzed, and it is conformed by experimentally for stability criterion. As a result, the standard of the discrimination of stability on a frequency response of input and output impedance is clarified. Furthermore, the design process for system stability is proposed