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Low battery voltage detector

  • US 4,119,904 A
  • Filed: 04/11/1977
  • Issued: 10/10/1978
  • Est. Priority Date: 04/11/1977
  • Status: Expired due to Term
First Claim
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1. Apparatus for detecting a low voltage condition in a battery comprising:

  • a MOSFET having a gate, a source and a drain;

    an inverter having an input and an output;

    first means for connecting the gate of the MOSFET to one terminal of the battery;

    second means for connecting the source of the MOSFET to the other terminal of the battery;

    third means for connecting the drain of the MOSFET to the one terminal of the battery and to the input of the inverter; and

    feedback means for connecting the output of the inverter to the gate of the MOSFET;

    a predetermined low voltage condition in the battery causing a decrease in voltage at the gate of the MOSFET, when this voltage becomes below the threshold voltage of the MOSFET, the MOSFET starts to turn off thus producing an increased voltage at the input of the inverter and a decreased voltage at the output of the inverter which is fed back to further decrease the voltage and cause rapid shut off of the MOSFET and producing an indication of the low voltage condition in the battery.

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