Battery depletion monitor

• US 4,313,079 A
• Filed: 01/16/1980
• Issued: 01/26/1982
• Est. Priority Date: 01/16/1980
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Lee, Yan S.
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US06/112,592
• Time in Patent Office: 741 Days
• Field of Search: 320/43, 320/48, 340/636, 307/304, 307/303, 324/433
• US Class Current: 340/636.15
• CPC Class Codes: A61N 1/3708 for power depletion
• CPC Class Codes: G01R 15/04 Voltage dividers
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• CPC Class Codes: Y10S 320/21 State of charge of battery

Abstract

A CMOS inverter is used to compare pacemaker battery voltage to a referenced voltage. When the reference voltage exceeds the measured battery voltage, the inverter changes state to indicate battery depletion.

Claims

1. A battery voltage monitor for sensing and indicating battery depletion in a pacemaker comprising at least one CMOS inverter having drain, source, input gate and output connections;

said source connection connected to ground potential;

said drain connection connected to a reference voltage;

said reference voltage source producing a reference voltage lower than the undepleted battery voltage;

a voltage divider connected to said battery for providing a measured voltage indicative of battery depletion to said input gate, such that said measured voltage level exceeds said reference voltage level in the undepleted battery condition; and

wherein

the voltage at said output connection changes from a low state to a high state to indicate the attainment of a preset depletion level when said measured voltage reaches a level substantially equal to one-half of said reference voltage.

2. A battery voltage monitor for sensing and indicating battery depletion in a pacemaker comprising:

a plurality of CMOS inverters having drain and source connections connected in parallel, respectively, a plurality of independent input gates and output connections;

said source connections connected to ground potential;

a reference voltage source producing a reference voltage level below the undepleted battery voltage level, connection to drain connections;

a voltage network having a plurality of taps respectively connected to said input gates for delivery to said gates measured voltages indicative of the level of battery depletion; and

a plurality of output connections whose output state changes to indicate when the respective input gate voltages are substantially equal to one-half of said reference voltage.

3. The monitor of claim 2 further including strobe means for periodically connecting said source connections to ground potential.