Method and apparatus for providing detection of excessive negative offset of a sensor
AssigneeTexas Instruments Incorporated
InventorsThomas R. Maher, David L. Corkum
Life of this patent
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Abstract
Detection of excessive negative offset of a condition responsive sensor such as a pressure responsive full Wheatstone bridge element (10) and circuitry associated therewith is obtained by taking the sensor's output signal, preferably after the signal has been compensated for both gain and offset and comparing (Q1) the signal (Vx) with a reference voltage (VREF1) selected to reflect an unobtainable stimulus input condition and driving the compensated signal to a fault level when the compensated signal exceeds the reference voltage.
Claims7
Apparatus for detection of excessive negative offset of a sensor comprising a sense element having a conditioning circuit with positive and negative power supply connections, an output node and connections to a sense element and capable of providing offset signal compensation comprising:
- a first comparator having a positive and a negative input and an output,
- a signal compensated by the offset and gain compensation circuits connected to the positive input of the comparator and a first reference voltage connected to the negative input of the comparator, the compensated signal also connected to a resistor which in turn is connected to the negative input of a second comparator,
- a controllable switch having an input connected to the output of the second comparator,
- the positive input of the second comparator connected to a second reference voltage and a feedback resistor connected between the output of the second comparator and the negative output thereof.
A method for providing detection of excessive negative offset of a condition responsive sensor signal of a sensor comprising the steps of
- compensating the signal for gain and offset,
- comparing the compensative sensor signal with a reference voltage selected to reflect an unobtainable condition when the sensor is properly functioning;
- and
- driving the compensated signal to a selected fault level when the compensated voltage rejects said unobtainable condition.
Dependencies are inferred from the claim text.