Patent ID: 9716393
Date: 2017-07-25
CPC Classifications: G01R,H02J

Claim:
1. An apparatus for generating a signal indicative of a battery remaining time, comprising: a source of a mains supply voltage for energizing a first load circuit and a second load circuit, prior to an interruption in said mains supply voltage; a battery for providing battery backup operation to energize said second load circuit after said interruption in said mains supply voltage is detected; and a processor coupled to said first load circuit and is configured to initiate a current drain reduction in said first load circuit after detection of said interruption, and to access a stored battery current magnitude value for use in calculating a battery remaining time indicative signal, such that, during a transitional shutdown delay interval of the apparatus that follows the detection of said interruption, said battery remaining time indicative signal is based on said stored battery current magnitude value that is unaffected by real time variations and transient loading of said battery current magnitude during said transitional shutdown delay interval and is instead based on a current magnitude in a steady state of said battery backup operation.