Output correction circuit for three-axis accelerometer
First Claim
1. A sensor unit with a temperature compensation circuit for connection to an accelerometer in which the accelerometer detects a plurality of acceleration values respectively for a plurality of axis directions, wherein the plurality of acceleration values have a temperature dependency, the sensor unit comprising:
- an input capacitor, connected to the accelerometer, for sequentially holding the plurality of acceleration values;
a correction value generation circuit that sequentially generates a plurality of correction values for respectively correcting the plurality of acceleration values, wherein each of the plurality of correction values is a temperature coefficient value for correcting the temperature dependency; and
a correction circuit connected to the correction value generation circuit, wherein the correction circuit receives the plurality of correction values from the correction value generation circuit and sequentially corrects the plurality of acceleration values with the plurality of correction values to generate a plurality of corrected acceleration values, and wherein the correction circuit includes;
a plurality of switched capacitor circuits, connected to the input capacitor and the correction value generation circuit, for respectively holding the plurality of correction values; and
a plurality of operational amplifiers connected to the plurality of switched capacitor circuits respectively, wherein the operational amplifiers each receive one of the plurality of acceleration values from the input capacitor via a corresponding one of the plurality of switched capacitor circuits to correct the received acceleration value with the correction value held by the corresponding switched capacitor circuit.
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Accused Products
Abstract
A sensor unit for a three-axis accelerometer enabling reduction in chip size. The sensor unit is connected to an accelerometer that detects a plurality of acceleration values for a plurality of axis directions. The sensor unit includes a correction value generation circuit that sequentially generates a plurality of correction values for correcting the plurality of acceleration values. A correction circuit is connected to the correction value generation circuit to sequentially correct the plurality of acceleration values with a plurality of correction values and generate a plurality of corrected acceleration values.
23 Citations
8 Claims
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1. A sensor unit with a temperature compensation circuit for connection to an accelerometer in which the accelerometer detects a plurality of acceleration values respectively for a plurality of axis directions, wherein the plurality of acceleration values have a temperature dependency, the sensor unit comprising:
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an input capacitor, connected to the accelerometer, for sequentially holding the plurality of acceleration values; a correction value generation circuit that sequentially generates a plurality of correction values for respectively correcting the plurality of acceleration values, wherein each of the plurality of correction values is a temperature coefficient value for correcting the temperature dependency; and a correction circuit connected to the correction value generation circuit, wherein the correction circuit receives the plurality of correction values from the correction value generation circuit and sequentially corrects the plurality of acceleration values with the plurality of correction values to generate a plurality of corrected acceleration values, and wherein the correction circuit includes; a plurality of switched capacitor circuits, connected to the input capacitor and the correction value generation circuit, for respectively holding the plurality of correction values; and a plurality of operational amplifiers connected to the plurality of switched capacitor circuits respectively, wherein the operational amplifiers each receive one of the plurality of acceleration values from the input capacitor via a corresponding one of the plurality of switched capacitor circuits to correct the received acceleration value with the correction value held by the corresponding switched capacitor circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A sensor unit with a temperature compensation circuit for connection to an accelerometer in which the accelerometer detects a plurality of acceleration values respectively for a plurality of axis directions, wherein the plurality of acceleration values have a temperature dependency, the sensor unit comprising:
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a temperature coefficient offset (TCO) circuit for generating temperature coefficient values used to adjust the acceleration values in order to compensate said temperature dependency; a C-V conversion circuit connected to the accelerometer and receiving capacitance values indicative of the acceleration values, and converting the capacitance values to corresponding voltage values; an output circuit connected to the TCO circuit and the C-V circuit, the output circuit including, an input capacitor connected to the C-V circuit for sequentially holding the plurality of acceleration values; a plurality of switched capacitor circuits, connected to the input capacitor TOC circuit for respectively holding the plurality of temperature coefficient values; and a plurality of operational amplifiers connected to the plurality of switched capacitor circuits respectively, wherein the operational amplifiers each receive one of the plurality of acceleration values from the input capacitor via a corresponding one of the plurality of switched capacitor circuits and combine the received acceleration value with the temperature coefficient value held by the corresponding switched capacitor circuit.
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Specification