Sensor apparatus including compensating circuit for temperature effects
First Claim
1. A sensor apparatus comprising a sensor device (H), said sensor device (H) having an input(E), a control-side output (A), a control current (IH) which flows through said sensor device and a temperature dependent internal resistance as well as a sensitivity and a temperature dependence of the control current (IH) characterized by a temperature coefficient;
- and an electrical circuit connected to said sensor device (H) including a temperature compensating means for compensating temperature changes adversely effecting the sensitivity of the sensor device;
wherein said temperature compensating means includes a differential amplifier (OV1) having a noninverting input(+), an inverting input(-) and an output (O'"'"'), the noninverting input (+) of the differential amplifier (OV1) being connected with the control-side output (A) of the sensor device (H);
a feedback circuit branch comprising a feedback resistor (LR) connected between the input (E) of the sensor device(H) and the inverting input (-) of the differential amplifier (OV1);
means for supplying a biasing voltage connected electrically to the inverting input (-) of the differential amplifier (OVl);
a current sensing resistor (F) connected between the output (A) of the sensor device (H) and ground (G) and a current controlling means (T) for controlling the control current (IH) connected electrically with the output (O'"'"') of the differential amplifier (OV1).
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Accused Products
Abstract
The sensor apparatus includes a sensor device having a control current (IH) flowing through it, a sensitivity and a temperature dependence of the control current characterized by a temperature coefficient, and a temperature compensating circuit for compensating temperature changes adversely effecting the sensitivity of the sensor device. The temperature compensating circuit includes a circuit portion which sets or adjusts the temperature coefficient of the control current(IH) according to changes in the temperature dependent internal resistance of the sensor device so that changes in negative temperature coefficients of other physical quantities determining the sensor sensitivity are compensated.
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Citations
7 Claims
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1. A sensor apparatus comprising a sensor device (H), said sensor device (H) having an input(E), a control-side output (A), a control current (IH) which flows through said sensor device and a temperature dependent internal resistance as well as a sensitivity and a temperature dependence of the control current (IH) characterized by a temperature coefficient;
- and an electrical circuit connected to said sensor device (H) including a temperature compensating means for compensating temperature changes adversely effecting the sensitivity of the sensor device;
wherein said temperature compensating means includes a differential amplifier (OV1) having a noninverting input(+), an inverting input(-) and an output (O'"'"'), the noninverting input (+) of the differential amplifier (OV1) being connected with the control-side output (A) of the sensor device (H);
a feedback circuit branch comprising a feedback resistor (LR) connected between the input (E) of the sensor device(H) and the inverting input (-) of the differential amplifier (OV1);
means for supplying a biasing voltage connected electrically to the inverting input (-) of the differential amplifier (OVl);
a current sensing resistor (F) connected between the output (A) of the sensor device (H) and ground (G) and a current controlling means (T) for controlling the control current (IH) connected electrically with the output (O'"'"') of the differential amplifier (OV1). - View Dependent Claims (2, 3, 4)
- and an electrical circuit connected to said sensor device (H) including a temperature compensating means for compensating temperature changes adversely effecting the sensitivity of the sensor device;
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5. A sensor apparatus comprising a sensor device (H), said sensor device (H) having an input (E), a control-side output (A), a control current (IH) which flows through said sensor device and a temperature dependent internal resistance as well as a sensitivity and a temperature dependence of the control current (IH) characterized by a temperature coefficient;
- and an electrical circuit connected to said sensor device (H) including a temperature compensating means for compensating temperature changes adversely effecting the sensitivity of the sensor device;
wherein said temperature compensating means includes a differential amplifier (OV1) having a noninverting input(+), an inverting input (-) and an output (O'"'"'), the inverting input (-) of the differential amplifier (OV1) being connected with the control-side output (A) of the sensor device (H);
a feedback circuit branch comprising a feedback resistor (LR) connected between the input (E) of the sensor device (H) and the noninverting input (+) of the differential amplifier (OV1);
means for supplying a biasing voltage connected electrically to the noninverting input (+) of the differential amplifier (OVI) and a current sensing resistor (F) connected between the output (A) of the sensor device (H) and ground (G). - View Dependent Claims (6, 7)
- and an electrical circuit connected to said sensor device (H) including a temperature compensating means for compensating temperature changes adversely effecting the sensitivity of the sensor device;
Specification