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Apparatus and method for a temperature compensation of a catheter tip pressure transducer

  • US 5,146,788 A
  • Filed: 10/25/1990
  • Issued: 09/15/1992
  • Est. Priority Date: 10/25/1990
  • Status: Expired due to Term
First Claim
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1. A compensation circuit for a resistance bridge with a pair of arms, wherein each arm includes a pair of resistors, one of which increases with strain, and another of which decreases with strain comprising:

  • a) a power input, a ground reference, a positive signal output and a negative signal output of the resistance bridge providing a response across the signal outputs as a function of pressure applied to the resistance bridge and an electrical signal applied to the power input;

    b) an offset reference generator to receive a fixed circuit reference voltage for generating a reference offset voltage;

    c) a voltage controlled current source connected across the power input and the ground reference, the voltage controlled current source having a bridge excitation output current directly proportional to the fixed circuit reference voltage;

    d) a buffer amplifier having a buffer input connected to the power input, the buffer amplifier configured as a voltage follower generating a buffer output voltage proportional to the power input voltage;

    e) an instrumentation amplifier with a positive terminal and a negative terminal connected to the positive signal output and negative signal output respectively to generate an initial output proportional to the response of the signal outputs;

    f) a compensation network having an offset correction part to receive the buffer output voltage and the ground reference, for generating an initial offset current wherein the buffer output voltage varies proportionately to temperature change of the resistance bridge providing a temperature dependent part of the initial offset current;

    g) an offset correction amplifier for receiving the initial offset current, the buffered output voltage, and the fixed circuit reference voltage, for generating a correction signal to counteract an offset error in the response of the signal outputs wherein the buffer output voltage and the initial offset current both vary proportionately to temperature change in the resistance bridge and thereby provide a temperature dependent part of the correction signal; and

    h) a reference input of the instrumentation amplifier connected for receiving the correction signal to modify the initial output in response to the correction signal.

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