JPS6423765A - Power supply unit - Google Patents

Abstract

PURPOSE:To prevent switching elements from being destroyed, by connecting two transformers to a space between the opposite sides of a bridge so that the induced voltage of the same voltage and reversed polarity may be applied to the respective opposite sides of the bridge. CONSTITUTION:A power circuit in converter system is composed of two pairs of switching elements S1-S4 connected in a bridge shape and turned conductive alternately and converting DC input voltage to square-wave alternating-voltage, and two transformers T1-T2 connected to a space between the opposite sides of a bridge and contrived to apply the induced voltage of the same voltage and reversed polarity to the respective opposite sides of the bridge when the respective pairs of the switching elements S1-S4 are in a conductive state, and current is fed to a load or the like from a main transformer T via a stabili zation section R. When the switching elemente S1 and S3 (S2 and S4) are turned conductive together by error action and short-circuit current is forced to flow to, then by the two transformers T1-T2, a high impedance is shown, and great current is suppressed to flow, and the switching elements S1 and S3 (S2 and S4)can be prevented from being destroyed.