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Temperature independent voltage monitor for use in a battery operated electronic device

  • US 5,057,779 A
  • Filed: 04/05/1990
  • Issued: 10/15/1991
  • Est. Priority Date: 04/05/1990
  • Status: Expired due to Term
First Claim
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1. A battery-operated electronic device operational over an ambient temperature range and including a battery derived source of power for generating a voltage potential suitable for energizing at least a controlling circuit portion of said electronic device which is sensitive to the voltage potential for valid operation, said electronic device comprising:

  • means for monitoring said voltage potential, said monitoring means for setting a voltage potential threshold substantially independent of ambient temperature variation including;

    first circuit means for generating a first current proportional to the voltage potential being monitored;

    second circuit means coupled to the first circuit means and responsive to said first current for generating a second current in the second circuit means, said voltage potential threshold being set at a level where said first and second currents are substantially equal; and

    means responsive to said first and second currents for generating an undervoltage signal when the monitored voltage potential falls below the set voltage potential threshold, said undervoltage signal being coupled to said controlling circuit portion or suspending the operation thereof.

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