Supply circuit for CMOS memory circuits - has capacitive stage to maintain supply for period following main supply drop=out

摘要

The CMOS memory circuit includes a capacitive stage to provide a power supply condition for a specified period in the event of main supply failure. The main supply (1) feeds a voltage regulator (3) that is coupled to the control stage (4.1) of the memory circuit (4). Typically the memory circuit is a bidirectionalcounter. A comparator (5) monitors the difference in relation to a reference value (Vref 1) to control switching stages (6,7). The circuit responds to a theshold value to maintain a supply provided by a capacitor (8) and diode (9) stage.