Patent ID: 9341680
Filing Date: 2016-05-17
CPC Classification: A61N,G01R,H02J

Claim Text:
1. An implantable cardiac device having a hermetic container including a battery coupled to operational circuitry for providing functionality to the implantable medical device, the operational circuitry including a battery monitoring circuit comprising the following: a voltage divider to generate a scaled voltage related to a battery voltage; a resistor, Rdiff, having first and second nodes; an amplifier having an output current and taking the scaled voltage and applying the scaled voltage to the first node of the Rdiff resistor; a level shifting reference voltage input coupled to the second node of the Rdiff resistor, such that the current through the Rdiff resistor is related to the difference between the scaled voltage and the level shifting reference voltage at the level shifting reference voltage input; a current mirror coupled to the output of the amplifier driving an output resistance, coupled such that the current mirror uses the current through Rdiff as a reference; and an output generating a battery voltage indicator coupled to the current mirror.