APPARATUS AND METHOD FOR A TEMPERATURE COMPENSATION OF A CATHETER TIP PRESSURE TRANSDUCER

A compensation circuit for a resistance bridge corrects errors in the response of signal outputs thereof and has a voltage controlled current source across a power input and a ground reference providing a bridge excitation output current proportional to a fixed circuit reference voltage. A buffer amplifier at the power input generates a buffer output voltage proportional thereto. An instrumentation amplifier at the signal outputs generates an initial output proportional to the response therefrom. A programmable gain amplifier at the initial output provides a compensated output independent of the bridge pressure response. A gain correction part of a compensation network compensates for variations in the bridge response and an offset correction part generates an initial offset current in response to the buffer output voltage. An offset correction amplifier generates a correction signal. The buffer output voltage and the initial offset current vary with temperature providing a temperature dependent part of the correction signal. A reference input of the instrumentation amplifier uses the correction signal and modifies the initial output to counteract fixed and temperature dependent parts of offset errors in the signal outputs response. The offset correction part adjusts the fixed part independently of the temperature dependent part. A single resistor adjusts positive or negative values of the fixed part. Another resistor adjusts positive or negative slope of the temperature dependent part. A method compensates the offset errors with steps of energizing the bridge and measuring the output and resistance at two temperatures and at two pressures. The measurements are used to find correction resistances for variations in bridge offset, temperature and pressure response.