Kazuhiko Itakura

New switching control for synchronous rectifications in low-voltage paralleled converter system without voltage and current fluctuations

Synchronous rectifiers (SRs) used in paralleled converter system cause several problems such as surge voltage, inhalation current and return current. Normally, to avoid the problems, SR operation is stopped in light load. However, at the same time, voltage fluctuation occurs, which causes serious errors in semiconductor devices such as CPU and LSI operating with very low voltage. Moreover, unstable current fluctuation occurs due to the voltage fluctuation in the paralleled system with current-sharing control. This paper proposes new switching control methods for rectifiers to reduce the voltage and current fluctuations. Experimental results are shown to confirm the effectiveness of the proposed methods.

Abnormal Phenomenon of Output-Voltage Increase and Its Solution in a Parallel-Redundant DC-DC Converter System with Current Sharing Control

Abnormal phenomenon of output voltage is observed in a paralleled N+1 redundant DC-DC converter (DDC) system. The phenomenon is caused by a current sharing control under the condition of periodic load change, resulting in output-voltage increase. The mechanism of the phenomenon is analyzed with a circuit simulator and confirmed by experiment. A new type of current sharing circuit is proposed to solve the problem