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US 8,402,823 B2Granted
Low power metering using pulse counting
AssigneeSilicon Laboratories Inc.
InventorsMarty Lynn Pflum, Michael L. Duffy, Douglas S. Piasecki, Michael Keith Odland
Life of this patent
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Abstract
A metering system can include a pull up circuit to be selectively coupled between a voltage node and a metering line that communicates a signal indicative of status of a flow line through which a metered substance flows. An impedance of the pull up circuit is set to reduce power consumption based on a calibration, and the pull up circuit can be disabled between sampling of the signal to reduce power consumption.
Claims22
An apparatus comprising:
- a pull up circuit to be selectively coupled between a voltage node and a metering line, the metering line to communicate a signal to a metering circuit indicative of status of a flow line through which a metered substance flows, wherein an impedance of the pull up circuit is controlled to reduce power consumption based on a calibration, and the pull up circuit can be disabled between samplings of the signal to reduce power consumption of the apparatus.
A system comprising:
- a comparator having a first input coupled to receive a sampled value from a metering line that provides information regarding a flow rate along a metered line and a second input coupled to receive a programmable threshold value and to compare the sampled value to the programmable threshold value;
- and
- a reference generator to generate the programmable threshold value, wherein the reference generator is to be powered on to update the programmable threshold value when a change in the programmable threshold value occurs and further to refresh the programmable threshold value at a periodic rate, and otherwise the reference generator is to be powered off.
A method comprising:
- switching a selected pullup resistance of a pullup circuit coupled between a voltage node and a metering line to the metering line to charge the metering line;
- sampling the metering line using a comparator of a pulse counting circuit coupled to the metering line to determine if a voltage on the metering line exceeds a first threshold;
- updating at least one counter based on the determination if the voltage exceeds the first threshold;
- and
- thereafter switching the selected pullup resistance off the metering line and allowing the metering line to tri-state.
2 more elements
Dependencies are inferred from the claim text.