A Selective Supervision Device for Paralleling Operating AC/DC and DC/DC Converters

This paper describes a device suitable to control the output of several converters, each voltage regulated and parallel operating with forced load sharing, so that, when failure occurs, it becomes possible to identify and shut-down the failed unit without affecting to other parallel connected units. Undervoltage and overvoltage supervision is garanted by the device to avoid output voltage changes dangerous for the supplied equipment. The supervision device has been designed by taking in to account the use of last power transistor on the power circuit. Beacause of that, the device includes a pulse by pulse control of power transistor integrity to cut-off as possible the failed unit. Besides, the device is able to control the transistor peak collector current to shut-down the power transistor, with an automatic reset function, during output short-circuits or overloads. The device described has been utilized in the transistorized buck/boost converters and rectifiers for low power system for telecommunication plants [3].