阅读说明：本技术 一种温度传感器线性模拟输出的截距修调方法 (Intercept trimming method for linear analog output of temperature sensor ) 是由 白玮 于翔 谢程益 于 2020-03-31 设计创作，主要内容包括：一种温度传感器线性模拟输出的截距修调方法,所述截距是指线性模拟输出表达式中的截距,通过在所述截距部分设置第一修调电阻R1和在所述线性模拟输出表达式中的斜率部分设置第二修调电阻R2,使所述第二修调电阻R2的修调变化△R-2反向于所述第一修调电阻R1的变化△R-1,从而能够在截距得到修调的同时保持斜率不变。(An intercept trimming method for linear analog output of a temperature sensor, wherein the intercept is the intercept in a linear analog output expression, and the trimming change DeltaR of a second trimming resistor R2 is realized by arranging a first trimming resistor R1 at the intercept part and arranging a second trimming resistor R2 at the slope part in the linear analog output expression 2 Variation Δ R opposite to the first trimming resistance R1 1 Thereby, the slope can be kept unchanged while the intercept is modified.)

1. A method for adjusting the intercept of the linear analog output of a temperature sensor is characterized in that an operational amplifier with an output end as a linear analog output voltage end Vout determines a first adjusting resistor R1 and a second adjusting resistor R2 which are respectively connected with the negative input end of the operational amplifier, the negative input end of the operational amplifier is connected with a zero-temperature-coefficient band-gap reference voltage end VBG in a band-gap reference voltage circuit through the first adjusting resistor R1, the negative input end of the operational amplifier is connected with the ground end through the second adjusting resistor R2, the positive input end of the operational amplifier is connected with a positive temperature coefficient voltage end Vptat in the band-gap reference voltage circuit, the linear analog output voltage end Vout is connected with the negative input end of the operational amplifier through a third resistor R3, when the intercept in the linear analog output Vout expression is adjusted, firstly changing R1 to satisfy the intercept trimming, and then changing the trimming of the second trimming resistor R2 by delta R ₂Variation Δ R opposite to the first trimming resistance R1₁。

2. The method of claim 1, wherein the modification variation is performed according to the following relationship: delta R₂*R₁＝-△R₁*R₂。

3. The method of claim 1, wherein the linear analog output Vout expression is as follows:

wherein Vptat is included to determine the slope value, VBG is included to determine the intercept value, and R is changed₁The intercept value is changed, and the simultaneous change R is obtained by setting the following calculation to be vertical₂Then makeKeeping the same:

the following equation is obtained:

4. the method of claim 1, wherein the band-gap reference voltage circuit comprises a first NPN transistor and a second NPN transistor having bases interconnected, a ratio of a number of transistors in the first NPN transistor to a number of transistors in the second NPN transistor is n:1, n is a natural number greater than 1, a base of the second NPN transistor is connected to the zero-temperature-coefficient band-gap reference voltage terminal VBG, and an emitter of the first NPN transistor is connected to the positive temperature coefficient voltage terminal V through a fourth resistor R4 _ptatThe emitter of the second NPN triode is connected with the positive temperature coefficient voltage end V_ptatThe positive temperature coefficient voltage terminal V_ptatThe linear analog output voltage end Vout is connected with the grounding end through a load capacitor.

Technical Field

The invention relates to the intercept technology of a temperature sensor, in particular to an intercept trimming method of linear analog output of the temperature sensor, wherein the intercept refers to the intercept in a linear analog output expression, and the trimming change delta R of a second trimming resistor R2 is realized by arranging a first trimming resistor R1 at the intercept part and arranging a second trimming resistor R2 at the slope part in the linear analog output expression₂Variation Δ R opposite to the first trimming resistance R1₁Thereby, the slope can be kept unchanged while the intercept is modified.

Background

When designing a linear temperature sensor for analog output, the actual temperature sensor chip is always affected by process parameters, packaging stress and the like, so that the output result and circuit simulation have certain deviation. To obtain the desired accuracy, trimming (Trim) of the chip is required) For example Trim temperature sensor intercept techniques. However, how to perform simple and effective Trim is an urgent problem to be solved. The inventor realizes that the linear analog output expression of the temperature sensor chip relates to the slope and the intercept, and the slope and the intercept relate to the shared trimming resistance, so that the slope is changed when the intercept is changed, and the Trim work which only needs the intercept trimming cannot be carried out. The inventors considered that if the trimming change Δ R of the second trimming resistance R2 is made by providing the first trimming resistance R1 in the intercept part and the second trimming resistance R2 in the slope part in the linear analog output expression₂Variation Δ R opposite to the first trimming resistance R1₁Thereby, the slope can be kept unchanged while the intercept is modified. In view of the above, the present inventors have completed the present invention.

Disclosure of Invention

Aiming at the defects or shortcomings in the prior art, the invention provides an intercept trimming method of linear analog output of a temperature sensor, wherein the intercept refers to the intercept in a linear analog output expression, and the trimming change delta R of a second trimming resistor R2 is realized by arranging a first trimming resistor R1 at the intercept part and arranging a second trimming resistor R2 at the slope part in the linear analog output expression₂Variation Δ R opposite to the first trimming resistance R1₁Thereby, the slope can be kept unchanged while the intercept is modified.

The technical scheme of the invention is as follows:

the intercept trimming method for the linear analog output of the temperature sensor is characterized in that an operational amplifier with an output end as a linear analog output voltage end Vout determines a first trimming resistor R1 and a second trimming resistor R2 which are respectively connected with a negative input end of the operational amplifier, the negative input end of the operational amplifier is connected with a zero temperature coefficient band gap reference voltage end VBG in a band gap reference voltage circuit through the first trimming resistor R1, the negative input end of the operational amplifier is connected with a ground end through the second trimming resistor R2, and the positive input end of the operational amplifier The positive temperature coefficient voltage end Vptat in the band gap reference voltage circuit is connected, the linear analog output voltage end Vout is connected with the negative input end of the operational amplifier through a third resistor R3, when the intercept in the linear analog output Vout expression is modified, R1 is firstly changed to meet the intercept modification, and then the modification change delta R of the second modification resistor R2 is changed₂Variation Δ R opposite to the first trimming resistance R1₁。

The trimming change is performed according to the following relation: delta R₂*R₁＝-△R₁*R₂。

The linear analog output Vout expression is as follows:

wherein Vptat is included to determine the slope value, VBG is included to determine the intercept value, and R is changed₁The intercept value is changed, and the simultaneous change R is obtained by setting the following calculation to be vertical₂Then makeKeeping the same:

the following equation is obtained:

the band-gap reference voltage circuit comprises a first NPN triode and a second NPN triode which are interconnected through bases, the ratio of the number of the triodes in the first NPN triode to the number of the triodes in the second NPN triode is n:1, n is a natural number larger than 1, the base of the second NPN triode is connected with the zero-temperature-coefficient band-gap reference voltage end VBG, and the emitting electrode in the first NPN triode is connected with the positive temperature coefficient through a fourth resistor R4 Voltage terminal V_ptatThe emitter of the second NPN triode is connected with the positive temperature coefficient voltage end V_ptatThe positive temperature coefficient voltage terminal V_ptatThe linear analog output voltage end Vout is connected with the grounding end through a load capacitor.

The invention has the following technical effects: the invention relates to an intercept trimming method of linear analog output of a temperature sensor, which is implemented by carrying out trimming on a resistor R₁And a resistance R₂The reverse resistance value is modified to ensure that the slope is unchanged while the intercept Trim is carried out, and the reverse resistance value is modified by the resistor R₁And a resistance R₂The opposite is true, i.e., one increases and the other decreases.

Drawings

Fig. 1 is a schematic diagram of a circuit structure applied to implement the method for adjusting the intercept of the linear analog output of the temperature sensor according to the present invention.

Fig. 2 is a schematic diagram of the Bandgap reference voltage circuit Bandgap in fig. 1.

The reference numbers are listed below: a Bandgap-Bandgap reference voltage circuit; VDD-supply voltage terminal; an OPA-operational amplifier; VBG-zero temperature coefficient band gap reference voltage end (zero temperature coefficient band gap reference voltage V) _BG，V_BGIs a negative temperature coefficient voltage V_BE2And the sum of the positive temperature coefficient voltage Vptat, V_BE2Is BQ2 base-emitter voltage); vptat-positive temperature coefficient voltage terminal; vout-linear analog output voltage terminal; CL-load capacitance; GND-ground; mp 1-first PMOS transistor; mp 2-second PMOS transistor; BQ 1-a first NPN transistor; BQ 2-second NPN triode; n is 1-the number ratio or the area ratio of the triodes of BQ1 and BQ 2; r1 — first trimming resistor; r2 — second trimming resistor; R3-R5-third to fifth resistors.

Detailed Description

The invention is described below with reference to the accompanying drawings (fig. 1-2).

Fig. 1 is a schematic diagram of a circuit structure applied to implement the method for adjusting the intercept of the linear analog output of the temperature sensor according to the present invention. Fig. 2 is a schematic diagram of the Bandgap reference voltage circuit Bandgap in fig. 1. Referring to fig. 1 to 2, in a method for adjusting an intercept of a linear analog output of a temperature sensor, an operational amplifier OPA having an output terminal as a linear analog output voltage terminal Vout determines a first adjustment resistor R1 and a second adjustment resistor R2 connected to a negative input terminal (-) of the operational amplifier OPA, respectively, the negative input terminal (-) of the operational amplifier OPA is connected to a zero temperature coefficient Bandgap reference voltage terminal VBG of a Bandgap reference voltage circuit Bandgap through the first adjustment resistor R1, the negative input terminal of the operational amplifier OPA is connected to a ground terminal GND through the second adjustment resistor R2, a positive input terminal (+) of the operational amplifier OPA is connected to a positive temperature coefficient voltage terminal Vptat of the Bandgap reference voltage circuit Bandgap, and the linear analog output voltage terminal Vout is connected to the negative input terminal (,negative input terminal) of the operational amplifier OPA through a third resistor R3, when the intercept in the linear analog output Vout expression is modified, R1 is firstly changed to meet the intercept modification, and then the modification of the second modification resistor R2 is changed by DeltaR ₂Variation Δ R opposite to the first trimming resistance R1₁. The trimming change is performed according to the following relation: delta R₂*R₁＝-△R₁*R₂。

The linear analog output Vout expression is as follows:

wherein Vptat is included to determine the slope value, VBG is included to determine the intercept value, and R is changed₁The intercept value is changed, and the simultaneous change R is obtained by setting the following calculation to be vertical₂Then makeKeeping the same:

the following equation is obtained:

the band-gap reference voltage circuit Bandgap comprises a first NPN triode BQ1 and a second NPN triode BQ2, bases of the first NPN triode BQ1 and the second NPN triode BQ2 are interconnected, the ratio of the number of the triodes in the first NPN triode BQ1 to the number of the triodes in the second NPN triode BQ2 is n:1, n is a natural number greater than 1, the base of the second NPN triode BQ2 is connected with the zero-temperature-coefficient band-gap reference voltage end VBG, and an emitter of the first NPN triode BQ1 is connected with the positive-temperature-coefficient voltage end V through a fourth resistor R4_ptatThe emitter of the second NPN triode BQ2 is connected with the positive temperature coefficient voltage end V_ptatThe positive temperature coefficient voltage terminal V_ptatThe linear analog output voltage terminal Vout is connected with a ground terminal GND through a fifth resistor R5, the collector of the first NPN triode BQ1 is respectively connected with the drain and the gate of a first PMOS tube Mp1 and the gate of a second PMOS tube Mp2, the source of the first PMOS tube Mp1 and the source of the second PMOS tube Mp2 are both connected with a power supply voltage terminal VDD, the drain of the second PMOS tube Mp2 is connected with the collector of the second NPN triode BQ2, and the linear analog output voltage terminal Vout is connected with the ground terminal GND through a load capacitor CL.

As shown in fig. 1, the circuit configuration is composed of two parts, the left side is a Bandgap generation circuit, and the right side is an operation circuit composed of an OPA and a resistor. The circuit shown in the left block diagram is the core part of the Bandgap circuit, and the circuit is simplified here to better illustrate the working principle of the Trim method of the present invention. By setting a suitable resistance R₁～R₃The resistance value of the temperature sensor can be flexibly designed into V which has different slope values and intercept and has a linear relation with the temperature_out. The output expression from FIG. 1 can be:

wherein V_ptatThe term determines the slope value, V_BGThe term determines the intercept value. As shown in the formula (1-1), the Trim resistor R₁The value of (c) may directly change the intercept but at the same time cause a change in the slope value. In order to keep the slope constant, the resistance R is set at Trim₁While the resistance R is₂Trim was performed so that the slope remained constant, and the following formula was derived:

assumed resistance R₁Relative to R₁The amount of change of (D) is Δ R₁To ensure constant slope value, resistor R₂Relative to R₂The amount of change of (D) is Δ R₂. Assuming the slope remains unchanged, one can obtain:

the formula is simplified and the minimum value is reduced to obtain the final product:

wherein the "-" sign indicates that the resistance R₁And a resistance R₂The opposite is true, i.e., one increases and the other decreases. Thus, it can be seen that the resistance R is measured by the Trim ₁When the intercept adjustment of the temperature sensor is realized, the resistance R is changed according to a certain proportion₂Can achieve a constant slope. Therefore, the invention starts from the output expression of the temperature sensor, and confirms the feasibility of ensuring the unchanged slope while carrying out intercept Trim through accurate formula derivation, thereby obtaining the effective Trim method which can be realized by the invention.

It is pointed out here that the above description is helpful for the person skilled in the art to understand the invention, but does not limit the scope of protection of the invention. Any such equivalents, modifications and/or omissions as may be made without departing from the spirit and scope of the invention may be resorted to.