Temperature independent voltage monitor for use in a battery operated electronic device
First Claim
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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Accused Products
Abstract
A voltage potential monitoring circuit is operative to set a voltage potential threshold substantially independent of ambient temperature variation. The monitoring circuit includes a first circuit for generating a first current proportional to the voltage potential being monitored, and a second circuit responsive to the first circuit for generating a second current. The voltage potential threshold is set substantially as a function of the first and second currents. The monitoring circuit further includes a circuit responsive to the first and second currents for generating an undervoltage signal when the monitored voltage potential falls below the set voltage potential threshold. The voltage potential monitoring circuit has application in an electronic device which is operational over an ambient temperature range and includes a source of power for generating a voltage potential suitable for energizing the electronic device.
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Citations
15 Claims
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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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A voltage potential monitoring circuit for use in an electronic device operational over an ambient temperature range and including a source of power for generating a voltage potential suitable for energizing the electronic device, said monitoring circuit comprising:
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means for monitoring said voltage potential, said monitoring means for setting a voltage potential threshold substantially independent of ambient temperature variation and 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. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification