Current supply for switch-off critical systems, has first timer started at mains drop-out, reset if mains restored in support period, otherwise second timer starts, generates interrupt signal

摘要

The supply has a basic current supply (BSV) supplied from a mains system (SNE) and an accumulator-supplied bridging supply (UBS) controlled by control logic (STL) for supplying a switch-off critical system (AKS) without interruption for a defined period in the event of a mains supply drop-out. The control logic has first and second timers (TM1, TM2). The first timer starts with a mains drop-out and is reset if the mains is restored within a defined support period, otherwise the second timer starts at the end of the first period and generates an interrupt signal to causes the system to be taken down. The bridging supply is switched off after expiry of a buffer period specified by the second timer.