JP2008281374A - Sensitivity temperature compensation circuit and compensation method for physical quantity sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensitivity temperature compensation circuit and compensation method for a physical quantity sensor capable of facilitating temperature compensation and selection of a component for performing the temperature compensation by performing the temperature compensation by amplifying a temperature detection voltage with a different amplification factor to the temperature detection voltage, and by making a current corresponding to the amplified voltage flow into a physical quantity sensor, concerning the circuit for compensating a temperature characteristic of sensitivity of the physical quantity sensor and the compensation method therefor. <P>SOLUTION: The sensitivity temperature compensation circuit for driving the physical quantity sensor based on a signal related to the temperature detection voltage includes a variable amplification part having each different amplification factor to the temperature detection voltage, and a driving part for making the current corresponding to an output voltage from the variable amplification part flow into a physical quantity sensor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a circuit for compensating a sensitivity temperature characteristic of a physical quantity sensor and a compensation method thereof, and relates to a physical quantity sensor sensitivity temperature compensation circuit for facilitating selection of components for performing temperature compensation and temperature compensation and a compensation method thereof. .

  The sensitivity of a pressure sensor composed of a semiconductor or the like has a temperature characteristic that has both a negative first-order and a second-order positive temperature fluctuation component. The temperature compensation circuit compensates for this temperature characteristic and will be described with reference to FIG. FIG. 4 compensates for the first-order temperature characteristic.

  The pressure sensor temperature compensation circuit 400 includes a pressure sensor 11 including resistors Rs1 to Rs4 having a bridge circuit configuration, a resistor Rt15 having a primary temperature characteristic (or temperature coefficient) opposite to the temperature characteristic of the sensitivity of the pressure sensor 11, and a resistor R151 to R156, operational amplifiers (so-called operational amplifiers) 151 to 153, and a differential amplifier circuit composed of a voltage follower 154, a temperature sensitive resistor Rt4 and a resistor R344 connected in series between the power source and the ground, and these The voltage at the connection point of the temperature-sensitive resistor Rt4 and the resistor R344 is applied to the differential amplifier circuit as a reference voltage Vof (t) to perform primary temperature compensation for the offset of the pressure sensor 11, and the temperature characteristics of the resistor Rt15 and Based on the amplification factor of the differential amplifier circuit, the first temperature compensation is performed for the sensitivity of the pressure sensor 11. You have me.

When the pressure sensor 11 is driven at the constant voltage Vcc, the sensitivity and offset of the pressure sensor 11 become lower when the temperature becomes higher. Therefore, in order to compensate for such temperature fluctuation, the reference voltage Vof (t) and the resistance Rt15 are set to 1 Next, by providing a positive temperature characteristic, it is possible to compensate the first-order temperature fluctuation component with respect to the sensitivity and offset of the pressure sensor, and to obtain a detection output that is substantially temperature compensated.

  A temperature compensation circuit that compensates for primary and secondary temperature characteristics will be described with reference to FIG.

The pressure sensor temperature compensation circuit 401 includes a sensitivity temperature correction circuit 23 and an offset temperature correction circuit 24 in addition to the pressure sensor 11, the voltage follower 12 and the differential amplifier circuit 15.

The sensitivity temperature correction circuit 23 generates an operational amplifier 231 whose output terminal is connected to the power supply terminal T1 of the pressure sensor 11 via the voltage follower 12, and a voltage Vbg1 (t) that has negative primary temperature characteristics. A band gap reference circuit 232 applied to the non-inverting input terminal of the operational amplifier 231, a temperature sensitive resistor Rt 23 having a positive primary temperature characteristic and connected between the inverting input terminal and the output terminal of the operational amplifier 231, The resistor R323 is connected between the inverting input terminal of the operational amplifier 231 and the ground.

The band gap reference circuit 232 includes resistors R231 and R232 and a transistor (diode) Q231 connected in series between the power supply and the ground, and a resistor R233 and transistor (diode) Q232 connected in series between the power supply and the ground. And an operational amplifier 233 having a non-inverting input terminal connected to the connection point between the resistors R231 and R232 and an inverting input terminal connected to the connection point between the resistor R233 and the transistor Q232.

The sensitivity temperature correction circuit 23 configured as described above generates an output voltage as the power supply voltage Vcc (t) between both output terminals T3 and T4 of the pressure sensor 11, and generates both primary negative and secondary positive temperatures. The sensitivity is set to have temperature characteristics having both positive and secondary temperature fluctuation components so as to cancel out the sensitivity temperature fluctuation component having fluctuation components.

Here, the conditions for making the output of the sensitivity temperature correction circuit 23 have temperature characteristics having both positive and negative temperature fluctuation components in the first order and the second order will be described. When the ambient temperature is t, the voltage Vbg1 (t) of the bandgap reference circuit 232 can be expressed by the following formula (1), and the temperature characteristic Rt23 (t) of the temperature sensitive resistor Rt23 is expressed by the following formula (2). Can be expressed as However, b2, c2, b3, and c3 are constants, and b2 <0 and b3> 0.

In this case, the voltage Vcc (t) applied to the power supply terminal T1 has a temperature characteristic represented by the following formula (3).

  A, B, and C can be expressed by the following formulas (4) to (6).

Accordingly, since A is negative, if the differential value of Rt23 (t) × Vbg1 (t) or B is set to be positive, the output of the sensitivity temperature correction circuit 23 is negative in the first order and negative in the second order. These temperature characteristics have both temperature fluctuation components.

A voltage Vcc (t) having a temperature characteristic having both first-order positive and second-order negative temperature fluctuation components from the sensitivity temperature correction circuit 23 to the power supply terminal T1 of the pressure sensor 11 via the voltage follower 12. ) Is applied. As a result, a detection voltage from which the sensitivity temperature fluctuation component is removed or reduced is output from the pressure sensor 11.

This detection voltage is amplified at a predetermined amplification factor in the differential amplifier circuit 15 and output as an output voltage Vout (t). Although the description of the offset temperature correction circuit 24 is omitted, the primary and secondary temperature fluctuation components can be compensated for the temperature characteristics of the offset and sensitivity of the pressure sensor 11 as described above.

JP 2001-91387 A

  The pressure sensor temperature compensation circuit 400 in FIG. 4 requires a resistor Rt15 having a characteristic opposite to the sensitivity temperature characteristic of the pressure sensor 11. However, the selection of the resistor Rt15 is not easy, and is more expensive than a general resistor (for example, a metal film resistor).

  In addition, since the sensitivity of the pressure sensor 11 has a second-order positive temperature characteristic, the sensitivity curve with respect to temperature is symmetric at or below a predetermined temperature. However, a sensitivity temperature compensation circuit that performs first-order temperature compensation using Rt15 for a pressure sensor having sensitivity curves with different curvatures (curvatures) without being symmetric, for example, insufficient temperature compensation in a portion with a large curvature. The detected voltage with a large error may be output.

  Further, the sensitivity temperature correction circuit 23 in FIG. 5 adds the Vcc (t) determined from the constants A, B, and C to the pressure sensor 11 as shown in the equation (3), thereby the temperature of the sensitivity of the pressure sensor 11. Compensate for characteristics. Here, the constants A, B, and C are determined from b2, c2, b3, c3, and R323 as shown by the equations (4) to (6). As shown in the equation (1), b2 and c2 represent the temperature characteristics of Vbg1 (t), and therefore are determined by the temperature characteristics of Vbe (the voltage between the base and the emitter) of the transistors Q231 and Q232. Further, as shown by the equation (2), b3 and c3 are determined by the temperature characteristic of the temperature sensitive resistor Rt23.

  Therefore, the transistors Q231 and Q232 and the temperature sensitive resistor Rt23 need to be selected so as to have constants A, B, and C that can compensate for the temperature characteristics of the sensitivity of the pressure sensor 11. However, as shown in equations (4) to (6), b2, c2, b3, c3, and R323 interfere with each other, so that transistors Q231 and Q232 and temperature sensitive resistor Rt23 can be easily selected. However, temperature compensation for sensitivity is not easy.

  An object of the present invention relates to a circuit for compensating sensitivity temperature characteristics of a physical quantity sensor and a compensation method thereof. The temperature detection voltage is amplified by a different amplification factor with respect to the temperature detection voltage, and a current corresponding to the amplified voltage is supplied to the physical quantity sensor. The temperature compensation and the compensation method of the physical quantity sensor that facilitates selection of the components for performing the temperature compensation and the temperature compensation are provided.

In order to achieve such an object, the invention of claim 1
In the physical quantity sensor sensitivity temperature compensation circuit that drives the physical quantity sensor based on the signal related to the temperature detection voltage,
A variable amplification unit having a different amplification factor with respect to the temperature detection voltage;
A drive unit that causes a current corresponding to the output voltage of the variable amplification unit to flow to the physical quantity sensor is provided.
It is characterized by that.

The invention of claim 2 is the invention of claim 1,
The variable amplification unit is different in a first amplification factor for the temperature detection voltage equal to or higher than a predetermined voltage and a second amplification factor for the temperature detection voltage lower than the predetermined voltage.
It is characterized by that.

The invention of claim 3 is the invention of claim 2,
The variable amplifying unit includes a front-stage and rear-stage operational amplifier biased by the predetermined voltage, and an input resistance and a feedback resistance of the rear-stage operational amplifier that determine the first gain and the second gain.
It is characterized by that.

The invention of claim 4 is the invention according to any one of claims 1 to 3,
The drive unit causes a current obtained by adding a current corresponding to the output voltage of the variable amplification unit and a predetermined current not related to the temperature detection voltage to flow to the physical quantity sensor.
It is characterized by that.

The invention of claim 5 is the invention according to any one of claims 1 to 4,
The physical quantity sensor is a pressure sensor.
It is characterized by that.

The invention of claim 6
In a physical quantity sensor sensitivity temperature compensation method for driving a physical quantity sensor based on a signal related to a temperature detection voltage,
Amplifying the temperature detection voltage with a different amplification factor;
Passing a current corresponding to the amplified output voltage to the physical quantity sensor,
It is characterized by that.

The present invention relates to a circuit for compensating the sensitivity temperature characteristic of a physical quantity sensor and a compensation method thereof, and amplifies the temperature detection voltage with a different amplification factor with respect to the temperature detection voltage, and supplies a current corresponding to the amplified voltage to the physical quantity sensor. It is possible to realize temperature compensation and selection of parts for performing temperature compensation by performing the temperature compensation in the flow.

[First embodiment]
A first embodiment will be described with reference to FIG. FIG. 1 is a physical quantity sensor sensitivity temperature compensation circuit diagram to which the present invention is applied. In this embodiment, the temperature compensation of the sensitivity of the pressure sensor having a predetermined temperature characteristic is performed by changing the amplification factor with respect to the temperature detection voltage.

  The physical quantity sensor sensitivity temperature compensation circuit 34 includes a temperature detection unit 30, a variable amplification unit 31, a drive unit 33, and the like. The pressure sensor 35 is driven by the drive unit 33, and the differential amplification unit 36 amplifies the output of the pressure sensor 35. As a result, voltages Vp and Vo corresponding to the pressure applied to the pressure sensor 35 and temperature compensated are obtained.

  The temperature detection unit 30 includes a resistor R1 and a diode D1. The internal power supply voltage VC for supplying power to each part such as the variable amplifier 31 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to each part. Connected to the common potential L1.

  The temperature detection voltage Vt output from the connection point between the resistor R1 and the diode D1 is a forward voltage (a voltage between the anode and the cathode) of the diode D1. Since Vt changes corresponding to the ambient temperature of the diode D1, the ambient temperature is detected.

  The variable amplifying unit 31 includes a resistor R21, a diode D21, operational amplifiers OP2 and OP3, a DC voltage unit 32, and the like.

  Vt, which is the output of the temperature detection unit 30, is connected to one end of the resistor R21 and one end of the resistor R24. The other end of the resistor R21 is connected to the inverting input terminal of the pre-stage operational amplifier OP2, the cathode of the diode D21, and one end of the resistor R22. The non-inverting input terminal of the front-stage operational amplifier OP2 is connected to the positive voltage side of the DC voltage unit 32, and the negative voltage side of the DC voltage unit 32 is connected to the common potential L1. The non-inverting input terminal of the front operational amplifier OP2 is biased by a predetermined voltage Vref that is the voltage of the DC voltage unit 32. The output terminal of the pre-stage operational amplifier OP2 is connected to the anode of the diode D21 and the cathode of the diode D22. The anode of the diode D22 is connected to the other end of the resistor R22 and one end of the resistor R23.

  The other end of the resistor R23 is connected to the inverting input terminal of the post-stage operational amplifier OP3, the other end of the resistor R24, and one end of the resistor R25. The output terminal of the post-stage operational amplifier OP3 is connected to the other end of the resistor R25, and the non-inverting input terminal of the post-stage operational amplifier OP3 is connected to the positive voltage side of the DC voltage unit 32 and is biased by the predetermined voltage Vref. Here, the resistor R23 is an input resistor of the post-stage operational amplifier OP3, and the resistor R25 is a feedback resistor of the post-stage operational amplifier OP3. Vts is an output of the post-stage operational amplifier OP3, and is a voltage obtained by amplifying the temperature detection voltage Vt.

  The drive unit 33 includes a resistor R2, an operational amplifier OP1, a transistor Q1, and the like.

  Vts which is the output of the variable amplifying unit 31 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the inverting input terminal of the operational amplifier OP1, one end of the resistors R2 and R4, and the other end of the resistor R2 is , Connected to VC. The non-inverting input terminal of the operational amplifier OP1 is connected to the positive voltage side of the DC voltage unit 32 and is biased by the predetermined voltage Vref. The output terminal of the operational amplifier OP1 is connected to the base terminal of the transistor Q1. The emitter terminal of the transistor Q1 is connected to the other end of the resistor 4 and one end of the resistor R5, and the other end of the resistor R5 is connected to the common potential L1. The collector terminal of the transistor Q1 is connected to the pressure sensor 35.

  The pressure sensor 35 includes resistors Rp1 to Rp4, and these resistors constitute a bridge. The connection point between the resistors Rp1 and Rp2 is connected to VC, and the connection point between the resistors Rp3 and Rp4 is connected to the collector terminal of the transistor Q1. A connection point between the resistors Rp1 and Rp4 and a connection point between the resistors Rp2 and Rp3 are connected to the differential amplifier 36, respectively.

  In order to drive the pressure sensor 35, the drive unit 33 causes a current Ip corresponding to Vts to flow from VC to the common potential L1 via the pressure sensor 35, the transistor Q1, and the resistor R5. For example, in the case of a semiconductor pressure sensor, the resistors Rp1 to Rp4 are formed on a semiconductor (for example, silicon) to which pressure is applied, and these resistance values change corresponding to the pressure. The voltage Vp between the connection point of the resistors Rp1 and Rp4 and the connection point of the resistors Rp2 and Rp3 is a voltage corresponding to the pressure. The differential amplifier 36 amplifies Vp and outputs a voltage Vo corresponding to the pressure.

  Here, the sensitivity of the pressure sensor 35 is a change in Vp corresponding to the change in pressure when a predetermined pressure is applied to the pressure sensor 35 and changed. For example, when the pressure changes from 0 kPa to 10 kPa, the change in Vp corresponding to the change in pressure is the sensitivity of the pressure sensor 35.

  Next, the sensitivity temperature compensation operation of the pressure sensor 35 will be described with reference to FIG. Here, the sensitivity voltage Vs of the pressure sensor 35 represents a change in Vp corresponding to the pressure change. FIG. 2D shows the relationship between Vs (vertical axis) and temperature (horizontal axis) when a constant current Ip flows through the pressure sensor 35, and Vs has a predetermined temperature characteristic. Regarding the gradient of Vs, the gradient in the case of exceeding the predetermined temperature Tref is different from the gradient in the case of the predetermined temperature Tref or less. These gradients are approximately represented by straight lines (broken lines). At Tref, Vs becomes Vsref. An operation for compensating this temperature characteristic will be described.

  FIG. 2A shows the relationship between the temperature detection voltage Vt (vertical axis) and the temperature (horizontal axis). FIG. 2B shows the relationship between Vts (vertical axis) and temperature (horizontal axis). FIG. 2C shows the relationship between Ip (vertical axis) and temperature (horizontal axis). FIG. 2E shows the relationship between Vs (vertical axis) obtained by temperature compensation of Vs in FIG. 2D and temperature (horizontal axis).

  In FIG. 2A, the forward voltage Vt of the diode D1 is a straight line having a negative gradient with respect to the temperature (for example, the gradient is −2 mV per + 1 ° C.). At a predetermined temperature Tref (for example, 25 ° C.), Vt becomes Vref.

  In order to describe FIG. 2B, the operation of the variable amplification unit 31 will be described. The amplification factor of the variable amplification unit 31 with respect to Vt varies depending on the voltage value of Vt. When Vt is equal to or higher than the predetermined voltage Vref, Vts is expressed by the following formula (7), and when Vt is lower than the predetermined voltage Vref, Vts is expressed by the following formula (8).

  Therefore, when Vt is equal to or higher than the predetermined voltage Vref, the amplification factor G1 (first amplification factor) of the variable amplification unit 31 is the following equation (9). When Vt is less than the predetermined voltage Vref, the amplification factor of the variable amplification unit 31 G2 (second amplification factor) is expressed by the following formula (10).

  Here, if the reverse polarity value of the broken line gradient below the predetermined temperature Tref in FIG. 2D matches G1, and the reverse polarity value of the broken line gradient exceeds the predetermined temperature Tref matches G2. Vs can be compensated for temperature. Details will be described later.

  When Vt is equal to or lower than Tref, Vts is expressed by equation (7). When Vt exceeds Tref, Vts can be expressed by equation (8). At Tref, Vt is Vref, so Vts is Vref. From the above, Vts is represented in FIG. 2B and is folded at Vref.

  In order to describe FIG. 2C, the operation of the drive unit 33 will be described. The drive unit 33 causes the pressure sensor 35 to pass an addition current of a current I1 corresponding to Vts flowing via R3 and a current I2 corresponding to VC flowing via R2. The drive unit 33 detects the current Ip flowing through the pressure sensor 35 with the resistor R5, feeds back the detected voltage to the operational amplifier OP1 via the resistor R4, and causes the added current to flow through the pressure sensor 35. Here, Ip is represented by the following formula (11).

  Here, the first term and the second term of Ip correspond to I2 and become a predetermined current value Iref not related to temperature (temperature detection voltage Vt). The third term of Ip corresponds to I1 and performs temperature compensation in relation to the output voltage Vts of the variable amplifying unit 31. At Tref, since Vts is Vref, Ip is Iref (for example, 0.6 mA). From the above, Ip is represented in FIG. 2C and is folded back at Iref.

  Then, when Ip becomes the reverse polarity of the gradient of the broken line in FIG. 2D, Vs becomes a solid line shown in FIG. 2E, and temperature compensation of the sensitivity of the pressure sensor 35 can be performed. The broken line in FIG. 2 (e) is a temperature-compensated version of the broken line in FIG. 2 (d).

  Next, in order to compensate for the temperature as shown in FIG. 2E, the reverse polarity value of the gradient of the broken line below the predetermined temperature Tref in FIG. 2D coincides with G1 and exceeds the predetermined temperature Tref. A description will be given of selecting a component so that the reverse polarity value of the slope of the broken line coincides with G2.

  As the sensitivity temperature characteristics of the pressure sensor 35, the slope of the broken line below the predetermined temperature Tref in FIG. 2D is −A (V) per + 1 ° C., and the slope of the broken line when exceeding the predetermined temperature Tref is + B per + 1 ° C. The case of (V) will be described. A and B are positive values. Here, a part is selected as represented by the following formula (12).

  By substituting Equation (12) into Equation (9) and Equation (10), the ratio between G1 and G2 is expressed by Equation (13) below.

  In order to compensate the sensitivity temperature characteristic of the pressure sensor 35, G1 is set to + A and G2 is set to −B as shown in the following formula (14).

  If the resistance values of the resistors R23 and R25 are selected as shown in the equation (14), the temperature compensation of Vs can be performed as shown in FIG. Thus, the first amplification factor G1 and the second amplification factor G2 are determined based on the ratio of the input resistance R23 and the feedback resistance R25 of the post-stage operational amplifier OP3, and can compensate the temperature of Vs. Since the resistance values of the resistors R23 and R25 only need to be selected, the selection of components is facilitated and temperature compensation is facilitated. As the resistors R23 and R25, an inexpensive resistor (for example, a metal film resistor) can be selected. Further, as shown in FIG. 2 (d), temperature compensation can be performed even if the curvature (bending) of Vs in the case where the predetermined temperature Tref is exceeded and in the following cases are different.

The present embodiment relates to a circuit for compensating the temperature characteristic of the sensitivity of a physical quantity sensor and a compensation method thereof, amplifying the temperature detection voltage with a different amplification factor with respect to the temperature detection voltage, and supplying a current corresponding to the amplified voltage to the physical quantity sensor. It is possible to realize temperature compensation and selection of parts for performing temperature compensation by performing the temperature compensation in the flow.

[Second Embodiment]
A second embodiment will be described with reference to FIG. In the present embodiment, even if the temperature detection voltage Vt is a curve with respect to the temperature, temperature compensation is performed for the sensitivity of the pressure sensor having a predetermined temperature characteristic.

FIG. 3A shows the relationship between the temperature detection voltage Vt (vertical axis) and the temperature (horizontal axis). FIG. 3B shows the relationship between Vts (vertical axis) and temperature (horizontal axis). FIG. 3C shows the relationship between Ip (vertical axis) and temperature (horizontal axis). FIG. 3D shows the relationship between Vs (vertical axis) and temperature (horizontal axis) when a constant current Ip flows through the pressure sensor 35. FIG. 3E shows the relationship between Vs (vertical axis) obtained by temperature compensation of Vs in FIG. 3D and temperature (horizontal axis). Here, FIG. 3 (d) is the same as FIG. 2 (d).

  In FIG. 3A, Vt is a curve having a negative gradient with respect to temperature. Here, the broken line represents a straight line approximated to this curve. Vt becomes slightly smaller than the broken line as it exceeds or becomes less than Tref. As Tref is exceeded, the difference between Vt and Vref becomes larger than the difference between the broken line and Vref. Further, as Tref or less, the difference between Vt and Vref becomes smaller than the difference between the broken line and Vref.

  For this reason, from Expression (8), in FIG. 3B, Vts becomes larger than the broken line as it exceeds Tref. On the other hand, Vts becomes smaller than the broken line as it becomes equal to or lower than Tref according to the equation (7).

  Similarly, from equation (11), in FIG. 3C, Ip becomes smaller than the broken line as it exceeds Tref. Moreover, Ip becomes larger than a broken line as it becomes below Tref.

  Then, due to the temperature compensation of FIGS. 3 (a) to 3 (d), when Tref is exceeded in FIG. 3 (e), Vs becomes almost flat, and Vs becomes slightly larger than the broken line as Tref becomes lower than Tref. Compensation is performed. In addition, each broken line of Fig.3 (a) to (e) respond | corresponds to operation | movement of each part.

  Thus, for example, even if a thermistor whose resistance value decreases as the temperature rises is used instead of the diode D1, temperature compensation can be performed. For example, when a resistance temperature detector whose resistance value increases as the temperature rises is used instead of the diode D1, Vt has a positive gradient with respect to the temperature. Therefore, temperature compensation can be performed by inserting an inverting amplification unit between the variable amplification unit 31 and the drive unit 33.

According to this embodiment, even if the temperature detection voltage is a curve with respect to the temperature, temperature compensation similar to that of the first embodiment can be realized.

When Vt is Vref, Vts in Expression (7) and Expression (8) is Vref. Therefore, “above Vref” described above can be expressed as “beyond Vref” and “below Vref” can be expressed as “below Vref”. Similarly, “exceeding Tref” can be expressed as “greater than or equal to Tref”, and “below Tref” can be expressed as “less than Tref”.

Further, temperature compensation can also be performed when a physical quantity sensor that detects a flow rate, acceleration, vibration, and the like in addition to pressure as a physical quantity has the same temperature characteristics as in FIG. In addition, for a physical quantity sensor having a reverse temperature characteristic (convex upward) as shown in FIG. 2D, temperature compensation can be performed by inserting an inverting amplification unit between the variable amplification unit 31 and the drive unit 33. it can.

In addition, this invention is not limited to the above-mentioned Example, In the range which does not deviate from the essence, many changes and deformation | transformation are included.

It is a physical quantity sensor sensitivity temperature compensation circuit diagram to which the present invention is applied. It is operation | movement explanatory drawing of each part of the physical quantity sensor sensitivity temperature compensation circuit to which this invention is applied. It is other operation | movement explanatory drawing of each part of the physical quantity sensor sensitivity temperature compensation circuit to which this invention is applied. It is a temperature compensation circuit diagram of a conventional pressure sensor. It is a temperature compensation circuit diagram of another conventional pressure sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 30 Temperature detection part 31 Variable amplification part 32 DC voltage part 33 Drive part 34 Physical quantity sensor sensitivity temperature compensation circuit 35 Pressure sensor 36 Differential amplification part

Claims (6)

In the physical quantity sensor sensitivity temperature compensation circuit that drives the physical quantity sensor based on the signal related to the temperature detection voltage,
A variable amplification unit having a different amplification factor with respect to the temperature detection voltage;
A drive unit that causes a current corresponding to the output voltage of the variable amplification unit to flow to the physical quantity sensor is provided.
A physical quantity sensor sensitivity temperature compensation circuit. The variable amplification unit is different in a first amplification factor for the temperature detection voltage equal to or higher than a predetermined voltage and a second amplification factor for the temperature detection voltage lower than the predetermined voltage.
The physical quantity sensor sensitivity temperature compensation circuit according to claim 1. The variable amplification section includes a front stage and a rear stage operational amplifier biased by the predetermined voltage, and an input resistance and a feedback resistance of the rear stage operational amplifier that determine the first amplification factor and the second amplification factor,
The physical quantity sensor sensitivity temperature compensation circuit according to claim 2. The drive unit causes a current obtained by adding a current corresponding to the output voltage of the variable amplification unit and a predetermined current not related to the temperature detection voltage to flow to the physical quantity sensor.
The physical quantity sensor sensitivity temperature compensation circuit according to claim 1, wherein The physical quantity sensor is a pressure sensor.
The physical quantity sensor sensitivity temperature compensation circuit according to claim 1, wherein the physical quantity sensor sensitivity temperature compensation circuit is according to claim 1. In a physical quantity sensor sensitivity temperature compensation method for driving a physical quantity sensor based on a signal related to a temperature detection voltage,
Amplifying the temperature detection voltage with a different amplification factor;
Passing a current corresponding to the amplified output voltage to the physical quantity sensor,
A physical quantity sensor sensitivity temperature compensation method.

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