Stability improvement of distributed power system by using full-regulated bus converter

The bus architecture, consisting of bus converter and POLs (point of load), has become very popular since POL can respond to some demands of multi power supply voltage, low driving voltage and series sequence/tracking of LSI with more flexibility than isolated DC-DC solution. However, the customer suffers the system instability issue caused by impedance overlap between the bus converter and POL. Bus converter has three types i) un-regulated, ii) semi-regulated, iii) full-regulated, and each type has different output characteristic. This makes matter more complex to understand and difficult to resolve the instability phenomena. This paper presents, the availability of full-regulated bus converter for system stability as compared with un-regulated and semi-regulated case, and is examined analytically and experimentally. As a result, it has been found that in the case of full-regulated bus converter, the bandwidth is extended in the presence of feedback loop due to damping of output impedance peak, and achieved higher stability.