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US 6,724,202 B2Granted
Physical quantity detection device with temperature compensation
AssigneeDenso Corporation
InventorYukihiko Tanizawa
Life of this patent
Estimating the term…
Abstract
First and second resistors (sensing elements) are connected in series between first and second potentials. The junction point voltage between the first and second resistor is supplied to an inverting input of a first operational amplifier. The non-inverting input is supplied with a reference voltage Vref generated by third and fourth resistors. A feedback resistor is connected between output and inverting input of the operational amplifier OP1. The difference between a temperature coefficient of resistance TCR of the sensing elements and a temperature coefficient of sensitivity TCS is equalized to a temperature coefficient of resistance of the feedback resistor. Further, the reference voltage is unchanged in accordance with the detected physical quantity or temperature variation.
Claims22
A physical quantity detection device comprising:
- an operational amplifier;
- a first resistor connected between an inverting input of said operational amplifier and a first reference potential;
- a second resistor connected between said inverting input of said operational amplifier and a second reference potential, said first and second resistors having a first temperature coefficient of resistance;
- a feedback resistor being connected between said inverting input of said operational amplifier and an output of said operational amplifier and having a second temperature coefficient of resistance;
- and
- a reference voltage generation circuit generating a reference voltage supplied to a non-inverting input of said operational amplifier, at least one of said first and second resistors comprising a sensing element of which resistance varies on the basis of a physical quantity with a temperature coefficient of sensitivity, wherein a difference between said first temperature coefficient of resistance and said temperature coefficient of sensitivity is substantially equal to said second temperature coefficient of resistance, and wherein said reference voltage generation circuit sets said reference voltage to a middle potential between said first potential and said second reference potential.
3 more elements
A physical quantity detection device comprising:
- an operational amplifier;
- a first resistor connected between an inverting input of said operational amplifier and a first reference potential;
- a second resistor connected between said inverting input of said operational amplifier and a second reference potential, said first and second resistors having a first temperature coefficient of resistance;
- a first feedback resistor being connected between said inverting input of said operational amplifier and an output of said operational amplifier and having a second temperature coefficient of resistance;
- a second feedback resistor having a trimming structure connected in parallel with said first feedback resistor;
- and
- a reference voltage generation circuit generating a reference voltage supplied to a non-inverting input of said operational amplifier, at least one of said first and second resistors comprising a sensing element of which resistance varies on the basis of a physical quantity with a temperature coefficient of sensitivity, wherein a difference between said first temperature coefficient of resistance and said temperature coefficient of sensitivity is substantially equal to said second temperature coefficient of resistance, and wherein said reference voltage generation circuit sets said reference voltage to a middle potential between said first potential and said second reference potential.
4 more elements
A physical quantity detection device comprising:
- an operational amplifier;
- a first resistor connected between an inverting input of said operational amplifier and a first reference potential;
- a second resistor connected between said inverting input of said operational amplifier and a second reference potential, said first and second resistors having a first temperature coefficient of resistance;
- a feedback resistor being connected between said inverting input of said operational amplifier and an output of said operational amplifier and having a second temperature coefficient of resistance;
- a reference voltage generation circuit generating a reference voltage supplied to a non-inverting input of said operational amplifier;
- a third resistor;
- another operational amplifier having an inverting input supplied with an output of said operational amplifier through said third resistor, a non-inverting input of said another operational amplifier being supplied with said reference voltage;
- and
- a fourth resistor disposed between an output terminal and inverting input of said another operational amplifier, at least one of said first and second resistors comprising a sensing element of which resistance varies on the basis of a physical quantity with a temperature coefficient of sensitivity, wherein a difference between said first temperature coefficient of resistance and said temperature coefficient of sensitivity is substantially equal to said second temperature coefficient of resistance, and wherein said reference voltage generation circuit includes first and second voltage dividing resistors connected in series between said first and second reference potentials to generate a divided voltage as said reference voltage.
6 more elements
A physical quantity detection device comprising:
- an operational amplifier;
- a first resistor connected between an inverting input of said operational amplifier and a first reference potential;
- a second resistor connected between said inverting input of said operational amplifier and a second reference potential, said first and second resistors having a first temperature coefficient of resistance;
- a feedback resistor being connected between said inverting input of said operational amplifier and an output of said operational amplifier and having a second temperature coefficient of resistance;
- and
- a reference voltage generation circuit generating a reference voltage supplied to a non-inverting input of said operational amplifier, at least one of said first and second resistors comprising a sensing element of which resistance varies on the basis of a physical quantity with a temperature coefficient of sensitivity, wherein a difference between said first temperature coefficient of resistance and said temperature coefficient of sensitivity is substantially equal to said second temperature coefficient of resistance, wherein if it is assumed that a sensitivity of said sensing element at a reference temperature is S0, a resistance of said sensing element at said reference temperature is R0, and a resistance of said feedback resistor at said reference temperature is Rts0, then, it is represented that said sensitivity of said sensing element at a temperature t which is different from said reference temperature by T is S(T), said resistance of said sensing element at t is R(T), and said resistance of said feedback resistor at t is Rts(T), and S(T), R(T), and Rts(T) are further represented by:
- S(T)=S0·(1+β1·T+β2·T2), R(T)=R0·(1+α1·T+α2·T2), and Rts(T)=Rts0·(1+A1·T+A2·T2), where said α1, α2, β1, β2, A1 and A2 are temperature coefficients, and wherein said α1, α2, β1, β2, A1 and A2 are determined so as to establish both A1=α1−β1 and A2=α2−β2−β1·(α1−β1).
4 more elements
A physical quantity detection device comprising:
- an operational amplifier;
- a first resistor connected between an inverting input of said operational amplifier and a first reference potential;
- a second resistor connected between said inverting input of said operational amplifier and a second reference potential, said first and second resistors having a first temperature coefficient of resistance;
- a feedback resistor being connected between said inverting input of said operational amplifier and an output of said operational amplifier and having a second temperature coefficient of resistance;
- and
- a reference voltage generation circuit generating a reference voltage supplied to a non-inverting input of said operational amplifier, at least one of said first and second resistors comprising a sensing element of which resistance varies on the basis of a physical quantity with a temperature coefficient of sensitivity, wherein said reference voltage generation circuit sets said reference voltage to a middle potential between said first potential and said second reference potential.
3 more elements
A physical quantity detection device comprising:
- an operational amplifier;
- a first resistor connected between an inverting input of said operational amplifier and a first reference potential;
- a second resistor connected between said inverting input of said operational amplifier and a second reference potential, said first and second resistors having a first temperature coefficient of resistance;
- a feedback resistor being connected between said inverting input of said operational amplifier and an output of said operational amplifier and having a second temperature coefficient of resistor;
- a reference voltage generation circuit generating a reference voltage supplied to a non-inverting input of said operational amplifier, at least one of said first and second resistors comprising a sensing element of which resistance varying on the basis of a physical quantity with a temperature coefficient of sensitivity,
- a third resistor;
- another operational amplifier, an inverting input of said another operational amplifier being supplied with an output of said operational amplifier through said third resistor, a non-inverting input of said another operational amplifier being supplied with said reference voltage;
- and
- a fourth resistor disposed between an output terminal and inverting input of said another operational amplifer.
6 more elements
A physical quantity detection device comprising:
- an operational amplifier;
- a first resistor connected between an inverting input of said operational amplifier and a first reference potential;
- a second resistor connected between said inverting input of said operational amplifier and a second reference potential, said first and second resistors having a first temperature coefficient of resistance;
- a feedback resistor being connected between said inverting input of said operational amplifier and an output of said operational amplifier and having a second temperature coefficient of resistance;
- and
- a reference voltage generation circuit connected between said first and second reference potentials for generating a reference voltage directly supplied to a non-inverting input of said operational amplifier, at least one of said first and second resistors comprising a sensing element of which resistance varies on the basis of a physical quantity with a temperature coefficient of sensitivity, wherein a difference between said first temperature coefficient of resistance and said temperature coefficient of sensitivity is substantially equal to said second temperature coefficient of resistance, and wherein said reference voltage generation circuit sets said reference voltage to a middle potential between said first potential and said second reference potential.
3 more elements
A physical quantity detection device comprising:
- an operational amplifier;
- a first resistor connected between an inverting input of said operational amplifier and a first reference potential;
- a second resistor connected between said inverting input of said operational amplifier and a second reference potential, said first and second resistors having a first temperature coefficient of resistance;
- feedback resistor means for providing feedback of said operational amplifier, wherein said feedback resistor means is connected between said inverting input of said operational amplifier and an output of said operational amplifier and includes a plurality of resistor elements to have a feedback resistance and a second temperature coefficient of resistance;
- and
- a reference voltage generation circuit generating a reference voltage supplied to a non-inverting input of said operational amplifier, at least one of said first and second resistors comprising a sensing element of which resistance varies on the basis of a physical quantity with a temperature coefficient of sensitivity, wherein a difference between said first temperature coefficient of resistance and said temperature coefficient of sensitivity is substantially equal to said second temperature coefficient of resistance, and wherein said reference voltage generation circuit sets said reference voltage to a middle potential between said first potential and said second reference potential.
3 more elements
Dependencies are inferred from the claim text.