Capacitance-to-voltage conversion method and apparatus

A technology of voltage converter and capacitance, which is applied in the direction of capacitance measurement, measurement device, and fluid pressure measurement using capacitance change, etc., which can solve the problems of reducing ESD protection performance, leakage current generation, and increased cost of integrated readout circuits, etc.

Active Publication Date: 2008-06-11
TEXAS INSTR INC
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  • Summary
  • Abstract
  • Description
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Problems solved by technology

Therefore, it is necessary to use a special ESD protection circuit, but this will increase the cost of the integrated readout circuit and reduce the ESD protection performance
In addition, due to dust or moisture on the printed circuit board or due to assembly problems, and due to the resistive elements inside the chip, without relying on the ESD protection circuit, leakage current will also occur

Method used

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  • Capacitance-to-voltage conversion method and apparatus
  • Capacitance-to-voltage conversion method and apparatus
  • Capacitance-to-voltage conversion method and apparatus

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Embodiment Construction

[0019] [019] FIG. 1 schematically shows the inventive capacitance-to-voltage converter 14 and its connected sensing capacitor C at input 16. P . The capacitance-to-voltage converter 14 is implemented on an integrated readout circuit. Sensing Capacitor C P and capacitance-to-voltage converter 14 are usually co-mounted on a circuit board. The integrated readout circuit includes two ESD protection circuits 18 connected between the input terminal 16 and ground, a sampling capacitor C S , reference capacitor C R and a further readout circuit 20 . The resistance R shown connected between one of the inputs 16 and ground is a parasitic resistance which may be formed, for example, by dust or moisture on the circuit board. The readout circuit 20 includes a sampling amplifier and a reference voltage source, which are not shown in FIG. 1 . Two ESD protection circuits 18 protect the readout circuit 20 from electrostatic discharge. One of the input terminals 16 is directly connected ...

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Abstract

A method of capacitance-to-voltage conversion using an external sensing capacitor (CP) and a capacitance-to-voltage converter (14) implemented on an integrated readout circuit comprising a reference capacitor (CR), a sampling capacitor ( Cs) and a sampling amplifier (22), with its input (16) connected to the sensing capacitor (CP). The method comprises the following steps: a) Applying a reference voltage (Vref) to a sensing capacitor (CP) and a reference capacitor (CR) connected in series, and charging a sampling capacitor (Cs) to the sensing capacitor (CP) and reference capacitor (CR ) between the potential at the interconnection node (A); b) connecting the sampling capacitor (Cs) to the input of the sampling amplifier. The method further comprises the following steps: c) applying a reference voltage (Vref) with a polarity opposite to that in step a) to the sensing capacitor (CP) and reference capacitor (Cs) connected in series, and charging the sampling capacitor (Cs) to the potential at the interconnection node (A) between the sensing capacitor (CP) and the reference capacitor (CR), and d) connecting the sampling capacitor (Cs) to the sampling amplifier in the opposite polarity to that in step b) of these inputs.

Description

technical field [0001] [001] The present invention relates to a method of capacitance-to-voltage conversion using an external sensor capacitor and a capacitance-to-voltage converter implemented on an integrated readout circuit comprising a reference capacitor, a sampling capacitor and a sampling amplifier, and the integrated readout circuit has an input connected to the sensing capacitor. The invention further relates to a capacitance-to-voltage converter implemented on an integrated readout circuit for sensing an external sensing capacitor and comprising a reference capacitor, a sampling capacitor and a sampling amplifier, the sensing capacitor being connected to Input to the Capacitor-to-Voltage Converter. The invention further relates to a tire pressure monitoring automotive system comprising, for each tire to be monitored, a pressure sensor comprising a sensing capacitor and a capacitance-to-voltage converter. Background technique [0002] [002] Capacitance-to-voltage ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R27/26G01D5/24G01L9/12
CPCG01L9/12G01D5/24G01R27/2605H03M1/001G01R31/001
Inventor O·尼赫里格R·甘兹
Owner TEXAS INSTR INC
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