Environmental sensor
First Claim
1. An oscillator circuit, comprising:
- a plurality of timer circuits cascaded in series with each other, wherein each timer circuit is comprised of a plurality of transistors and operates to output two voltages with opposite polarities, such that the polarities of the two voltages oscillate periodically based on leakage current in the plurality of transistors;
wherein each timer circuit further includes one or more tuning transistors that operate to adjust a frequency at which the polarities of the two voltages oscillate; and
a complementary-to-absolute temperature (“
CTAT”
) voltage generator configured to receive a regulated voltage and supply a bias voltage to the one or more tuning transistors in each of the plurality of timer circuits, where the CTAT voltage generator adjusts the bias voltage linearly and inversely with changes in temperature.
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Accused Products
Abstract
An environmental sensor implementing a sleep mode timer with an oscillator circuit suitable for low power applications is presented. The oscillator circuit includes a plurality of timer stages cascaded in series with each other. Each timer circuit includes a plurality of transistors and operates to output two voltages with opposite polarities, such that the polarities of the two voltages oscillate periodically based on leakage current in the plurality of transistors. Each timer circuit further includes one or more tuning transistors that operate to adjust a frequency at which the polarities of the voltages oscillate. A complementary-to-absolute temperature (“CTAT”) voltage generator is configured to receive a regulated voltage and supply a bias voltage to the one or more tuning transistors in each of the plurality of timer circuits, where the CTAT voltage generator adjusts the bias voltage linearly and inversely with changes in temperature.
2 Citations
20 Claims
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1. An oscillator circuit, comprising:
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a plurality of timer circuits cascaded in series with each other, wherein each timer circuit is comprised of a plurality of transistors and operates to output two voltages with opposite polarities, such that the polarities of the two voltages oscillate periodically based on leakage current in the plurality of transistors; wherein each timer circuit further includes one or more tuning transistors that operate to adjust a frequency at which the polarities of the two voltages oscillate; and a complementary-to-absolute temperature (“
CTAT”
) voltage generator configured to receive a regulated voltage and supply a bias voltage to the one or more tuning transistors in each of the plurality of timer circuits, where the CTAT voltage generator adjusts the bias voltage linearly and inversely with changes in temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An oscillator circuit, comprising:
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a plurality of timer circuits cascaded in series with each other, wherein each timer circuit includes a pair of inverters cross-coupled to each other and two tuning transistors, such that a first one of the two tuning transistors is coupled to an output of a first inverter in the pair of inverters, and a second one of the two tuning transistors is coupled to an output of a second inverter in the pair of inverters; and a complementary-to-absolute temperature (“
CTAT”
) voltage generator configured to receive a regulated voltage and supply a bias voltage to each of the two tuning transistors in each of the plurality of timer circuits, where the CTAT voltage generator adjusts the bias voltage linearly and inversely with changes in temperature. - View Dependent Claims (9, 10, 11, 12, 13)
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14. An environmental sensor comprising:
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a sensor device configured to detect, during an active mode of operation, an existence or measure an amount of a physical parameter associated with an environment in which the environmental sensor has been deployed; and a sleep mode timer configured to wake up the sensor device from a sleep mode of operation to the active mode of operation, wherein the sleep mode timer comprises; a plurality of timer circuits cascaded in series with each other, wherein each timer circuit is comprised of a plurality of transistors and operates to output two voltages with opposite polarities, such that the polarities of the two voltages oscillate periodically based on leakage current in the plurality of transistors, wherein each timer circuit further includes one or more tuning transistors that operate to adjust a frequency at which the polarities of the two voltages oscillate; and a complementary-to-absolute temperature (“
CTAT”
) voltage generator configured to receive a regulated voltage and supply a bias voltage to the one or more tuning transistors in each of the plurality of timer circuits, where the CTAT voltage generator adjusts the bias voltage linearly and inversely with changes in temperature. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification