Voltage detector for battery operated device
First Claim
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1. A battery operated device including a voltage detector comprising:
- a first terminal of a voltage detector connected to a first battery terminal and a second terminal of said voltage detector connected to a second battery terminal;
a voltage reference source in said voltage detector comprising a first node and a second node, said voltage reference source including one or more components for generating a signal with a negative temperature coefficient applied to said first node and one or more components for generating a signal with a positive temperature coefficient applied to said second node for offsetting said negative temperature coefficient, said voltage reference source further including a comparator,said comparator having a third terminal coupled to said first node and a fourth terminal coupled to said second node; and
a voltage divider network connected between said first terminal and said second terminal for creating a divided battery voltage, a signal corresponding to said divided battery voltage being applied to said one or more components for generating a signal with a negative temperature coefficient and being applied to said one or more components for generating a signal with a positive temperature coefficient, an output of said comparator indicating when said divided battery voltage is below a threshold voltage.
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Abstract
A voltage detector is described herein which eliminates an entire operational amplifier or comparator from conventional voltage detectors. In one embodiment of such a voltage detector, a band gap reference generator is connected so as not to incorporate any feedback mechanism and where an off balance in the band gap reference generator is used to detect whether an input voltage falls below a threshold voltage. By eliminating the feedback path in the band gap reference generator, a comparator is eliminated. Other types of voltage detectors which provide a highly stable operation over a wide range of temperatures are described.
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Citations
11 Claims
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1. A battery operated device including a voltage detector comprising:
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a first terminal of a voltage detector connected to a first battery terminal and a second terminal of said voltage detector connected to a second battery terminal; a voltage reference source in said voltage detector comprising a first node and a second node, said voltage reference source including one or more components for generating a signal with a negative temperature coefficient applied to said first node and one or more components for generating a signal with a positive temperature coefficient applied to said second node for offsetting said negative temperature coefficient, said voltage reference source further including a comparator, said comparator having a third terminal coupled to said first node and a fourth terminal coupled to said second node; and a voltage divider network connected between said first terminal and said second terminal for creating a divided battery voltage, a signal corresponding to said divided battery voltage being applied to said one or more components for generating a signal with a negative temperature coefficient and being applied to said one or more components for generating a signal with a positive temperature coefficient, an output of said comparator indicating when said divided battery voltage is below a threshold voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification