Analysis of a ringing choke converter

The ringing choke converter is widely used as an electronic power supply with a small capacity. A number of works have been published on the feedback systems for adjustment of output voltage. No sufficient analysis, however, has been undertaken on the static and dynamic characteristics. In this paper, a nonlinear differential equation describing the basic operation is first derived. Next, from a small signal model obtained from this differential equation, a loop transfer function of the converter is derived. Further, the transfer function for an input variation and a load variation under regulation have been derived. As a result, the characteristic equation becomes linear and it is shown that the converter is extremely stable. The dynamic characteristic parameters of the ringing choke converter are found different from those of the conventional reactor current discontinuity mode converter. Both the gain bandwidth product of the loop transfer function and that of the transfer function of the output voltage fluctuations for the input voltage fluctuations under regulation are smaller in the ringing choke converter than in the reactor current discontinuous mode converter. It is found that the ringing choke converter is less susceptible to the input voltage fluctuations and operates with a greater stability than the reactor current discontinuous mode converter.