JP2019216450A - Method for adjusting physical quantity sensor device - Google Patents

Abstract

To provide a method for adjusting a physical quantity sensor device capable of correcting variation in characteristics with high accuracy.SOLUTION: An analog signal that is input from an analog input-output unit 112 to a first conversion unit 106 via wiring 113 is digitized to be used as an initial output value of the first conversion unit 106. Adjustment information for the first conversion unit 106 is calculated on the basis of an error between the initial output value of the first conversion unit 106 and a target output value. Before measuring an initial output value of a physical quantity sensor 101 for calculating initial setting information for a physical quantity sensor device 100, the first conversion unit 106 is adjusted on the basis of the adjustment information for the first conversion unit 106.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for adjusting a physical quantity sensor device.

  2. Description of the Related Art Conventionally, as a physical quantity sensor device, for example, an analog signal output from a physical quantity sensor element is converted into a digital signal by an A / D converter (ADC: Analog-to-Digital Converter), and the CPU (Central Processing Unit) or DSP (Digital) is used. 2. Description of the Related Art A digital operation type physical quantity sensor device that corrects an output value of a physical quantity sensor element by performing an arithmetic process using a digital operation circuit such as a signal processor is known.

  The present inventors have proposed the following device as this physical quantity sensor device. Based on the initial output value and the target output value of the physical quantity sensor (sensor element), a secondary first characteristic equation indicating the corrected output characteristic of the physical quantity sensor is calculated, and after extracting the first characteristic value, a predetermined A second characteristic equation for correcting the first characteristic value is calculated based on the temperature and the first characteristic value, and the second characteristic value is extracted. Then, the corrected output value of the physical quantity sensor is calculated based on the corrected first characteristic expression by inputting the second characteristic value to the second characteristic expression, and the calculation result is output as a digital signal (for example, And Patent Document 1 below.)

  The physical quantity sensor device of Patent Document 1 below will be described in detail. FIG. 9 is a block diagram showing a functional configuration of a conventional physical quantity sensor device. A conventional physical quantity sensor device 1100 is an integrated circuit (IC: Integrated Circuit) including a physical quantity sensor 1101, a temperature sensor (sensor element) 1102, a Vcc voltage divider 1103, an arithmetic unit 1104, a storage unit 1105, and an input / output unit 1106. It is. The setting device 1110 calculates initial setting information (first and second characteristic values) for correcting the output value of the physical quantity sensor device 1100, and outputs it to the input / output unit 1106 of the physical quantity sensor device 1100.

  The physical quantity sensor 1101 is a sensor element that generates an output signal according to the detected physical quantity of the medium to be measured. Vcc voltage dividing section 1103 divides the power supply voltage supplied via the Vcc terminal. The calculation unit 1104 calculates the corrected output value of the physical quantity sensor 1101 based on the output value of the physical quantity sensor 1101, the output value of the temperature sensor 1102, and the initial setting information written in the storage unit 1105. The input / output unit 1106 outputs the corrected output value of the physical quantity sensor 1101, the output value of the temperature sensor 1102, and the output value of the Vcc voltage dividing unit 1103 to the outside.

  The setting device 1110 includes a first obtaining unit 1111, a second obtaining unit 1112, a first calculating unit 1113, a second calculating unit 1114, and an input / output unit 1115. The first acquisition unit 1111 acquires a plurality of initial output values from the input / output unit 1106 of the physical quantity sensor device 1100 via the input / output unit 1115. The second acquisition unit 1112 acquires a target output value of the physical quantity sensor 1101 set in advance corresponding to a plurality of initial output values of the physical quantity sensor 1101. The first and second calculation units 1113 and 1114 calculate first and second characteristic values, respectively.

  FIG. 10 is a block diagram showing an example of the entire configuration of a semiconductor physical quantity sensor device formed on a semiconductor chip by applying the invention of FIG. The physical quantity sensor device 1200 includes a physical quantity sensor 1201, a temperature sensor 1202, a Vcc voltage dividing unit 1203, an arithmetic circuit 1204, a data storage unit 1205, an I / O (Input / Output) interface 1206, first to third sample holds 1211 to 1213, The first and second selectors 1214 and 1219, the A / D converter 1215, and the first to third latches 1216 to 1218 are provided.

  The physical quantity sensor 1201, temperature sensor 1202, and Vcc voltage divider 1203 correspond to the above-described physical quantity sensor 1101, temperature sensor 1102, and Vcc voltage divider 1103 in FIG. Output signals of the physical quantity sensor 1201, the temperature sensor 1202, and the Vcc voltage divider 1203 are analog signals. At the subsequent stage of the physical quantity sensor 1201, the temperature sensor 1202, and the Vcc voltage dividing unit 1203, the first to third sample holds 1211 to 1213 are arranged, respectively, and each analog signal continuously inputted from the preceding stage is converted at regular time intervals. (Holding) for a certain time (sampling: sampling).

  An A / D converter 1215 is disposed downstream of the first to third sample hold circuits 1211 to 1213 via a first selector 1214. The first selector 1214 selects one of the analog signals input from the first to third sample hold circuits 1211 to 1213 and outputs the selected analog signal to the A / D converter 1215. The A / D converter 1215 converts the analog signal selected by the first selector 1214 into a digital signal and outputs the digital signal to the arithmetic circuit 1204. The arithmetic circuit 1204 and the data storage unit 1205 correspond to the arithmetic unit 1104 and the storage unit 1105 in FIG. 9 described above, respectively.

  The first to third latches 1216 to 1218 hold digital signals of the physical quantity sensor 1201, the temperature sensor 1202, and the Vcc voltage divider 1203, respectively, for a certain period of time. The second selector 1219 selects one of the digital signals input from the first to third latches 1216 to 1218 and outputs it to the I / O interface 1206. The I / O interface 1206 corresponds to the input / output unit 1106 in FIG. 9 described above, and performs digital signal input / output between the second selector 1219 and the outside. Reference numerals 1221 to 1223 denote a reference voltage source, a sensor drive circuit, and an oscillator, respectively.

  That is, the physical quantity sensor device disclosed in Patent Document 1 below is a digital output system that outputs a digital operation result as a digital signal to the outside. However, as a market trend, a conventional analog output method for outputting an analog signal to the outside is still mainstream. The reason is that the standard of digital communication is not unified, the transmission speed of digital communication is lower than the transmission speed of analog communication, and the communication speed of digital signals output from the physical quantity sensor device to the outside (for example, in-vehicle network ( Data transfer speed of CAN (Controller Area Network) or LIN (Local Interconnect Network) is reduced, and costs are increased.

  In order to solve the problem in the digital output type physical quantity sensor device, various studies have been made on a physical quantity sensor device combining a digital operation for improving the correction accuracy and an analog output type with high market needs. As such a physical quantity sensor device, a flow rate signal analog / digital conversion circuit, an adjustment operation circuit, and a chip temperature sensor circuit are integrated on a single semiconductor chip, and a chip temperature signal output from the chip temperature sensor circuit is applied to the adjustment operation circuit. There has been proposed an apparatus that performs input and performs correction to reduce a temperature-dependent error of a signal processing system (for example, see Patent Document 2 below).

  Patent Literature 2 below discloses a flow sensor device for measuring a gas flow rate, in which an output value of a flow sensor (sensor element) and an output value of a temperature sensor arranged on the same chip as the flow sensor are converted by an A / D converter. A method is disclosed in which each of the output values is converted into a digital signal, and the corrected output value of the flow rate sensor is obtained by digital calculation based on information stored in a memory. The physical quantity sensor device of Patent Document 2 below differs from the physical quantity sensor device of Patent Document 1 in the following three points.

  The first difference is that a D / A converter (DAC: Digital-to-Analog Converter) for converting a digital signal (operation result) into an analog signal is provided between the digital operation circuit and the output terminal. It is. The second difference is that the output terminal is for analog output and a digital I / O terminal is provided. The third difference is that the information converted into a digital signal by the A / D converter for use in the digital operation is only the output signal of the flow rate sensor to be corrected and the output signal of the temperature sensor. The point is that no pressure output signal is used.

  The following device has been proposed as a device for correcting a converted digital signal or analog signal. In the A / D converter, a correction value is obtained from a difference between a digital signal obtained by converting the analog signal into a digital signal using the least squares method and a predetermined ideal digital signal. . Further, in the D / A converter, the values of the three or more digital signals obtained by converting the values of the three or more different input analog signals and the accurate values of the three or more different input analog signals respectively correspond to the different values. A correction value is obtained from a difference between the values of the input analog signals at three or more points and the values of the digital signals at three or more points respectively converted (for example, see Patent Document 3 below).

International Publication No. 2013/100156 JP 2003-166865 A JP-A-10-145231

  However, the correction target in the physical quantity sensor device includes not only the output value of the physical quantity sensor but also the output value of the peripheral circuit. In particular, in a physical quantity sensor device of an analog output type, a D / A converter is further provided as compared with a physical quantity sensor device of a digital output type, so that a factor causing a variation in an output value of a physical quantity sensor increases. In Patent Literature 2 which discloses an analog output type physical quantity sensor device, the characteristic variations of the physical quantity sensor, the A / D converter, and the D / A converter are converted into one arithmetic expression and corrected collectively. There are two problems.

  The first problem is that it is not possible to individually grasp the characteristic variations of the physical quantity sensor, the A / D converter, and the D / A converter. For this reason, information that can be fed back to the manufacturing process of the physical quantity sensor and an IC (physical quantity sensor device) on which the physical quantity sensor is mounted is limited, and a problem in manufacturing management arises. Further, even if the physical quantity sensor shows abnormal characteristic variation outside the error range, the characteristics of the A / D converter and the D / A converter vary so as to offset the abnormal characteristic variation of the physical quantity sensor. However, variations in the characteristics of the physical quantity sensor cannot be detected, causing a problem in quality characteristics.

  The second problem is that when the conversion accuracy of the A / D converter or the D / A converter is low, the overall accuracy (correction accuracy of the output characteristic) of the physical quantity sensor device cannot be improved. For this reason, an arithmetic expression for using an A / D converter or a D / A converter with high accuracy, increasing the resolution (number of bits) of the A / D converter or the D / A converter, and correcting the output characteristics of the physical quantity sensor device. There may be a need to take measures to increase the overall conversion accuracy of the physical quantity sensor device, such as increasing the order. Therefore, there is a problem that the cost is increased.

  An object of the present invention is to provide a method for adjusting a physical quantity sensor device capable of correcting a characteristic variation with high accuracy in order to solve the above-mentioned problems caused by the conventional technology.

  In order to solve the above-described problems and achieve the object of the present invention, a method for adjusting a physical quantity sensor device according to the present invention includes: a physical quantity sensor that outputs an electric signal corresponding to a detected physical quantity; and an output value of the physical quantity sensor. A method for adjusting a physical quantity sensor device, comprising: a first conversion unit that performs digital conversion; and has the following characteristics. A step of obtaining an initial output characteristic of the first conversion unit obtained by digitally converting a predetermined analog signal input to the first conversion unit by the first conversion unit; A step of calculating first adjustment information for adjusting an output characteristic of the first conversion unit based on an initial output characteristic of the first conversion unit; A step of obtaining an initial output value obtained by digitally converting the output of the physical quantity sensor by the first conversion unit in which the first adjustment information is reflected. A step of calculating initial setting information of the physical quantity sensor based on the initial output value;

  Further, in the adjustment method of the physical quantity sensor device according to the present invention, in the above-described invention, the physical quantity sensor is provided on a semiconductor chip, and acquires the initial output value after incorporating the physical quantity sensor device into a package. And a step of calculating the initial setting information.

  Further, in the adjustment method of the physical quantity sensor device according to the present invention, in the above-mentioned invention, the physical quantity sensor device is a digital signal for correcting an output value of the physical quantity sensor digitally converted by the first conversion unit to a predetermined value. It further includes a calculation unit that performs calculation processing. It is characterized in that the calculation unit corrects the value to a predetermined value based on the initial setting information.

Further, the adjustment method of the physical quantity sensor device according to the present invention, in the above-described invention, wherein the physical quantity sensor device further includes a second conversion unit that performs analog conversion of a calculation result by the digital calculation processing,
Prior to the step of obtaining the initial output value, the predetermined digital signal input to the second conversion unit is converted into an analog signal by the second conversion unit, thereby obtaining an initial output characteristic of the second conversion unit. The method further includes a step.

  Further, in the adjustment method of the physical quantity sensor device according to the present invention, in the above-described invention, the step of calculating second adjustment information for adjusting the output characteristic of the second conversion unit based on the initial output characteristic of the second conversion unit. Is further included.

  Further, the adjustment method of the physical quantity sensor device according to the present invention is characterized in that in the above-described invention, the reflection of the first adjustment information is weighted with the resolution of the first conversion unit.

  In the method for adjusting a physical quantity sensor device according to the present invention, in the above-described invention, the weighting of the resolution is performed by electrically connecting or disconnecting routes of a plurality of redundant circuits.

  ADVANTAGE OF THE INVENTION According to the adjustment method of the physical quantity sensor device concerning this invention, digital arithmetic processing can be performed in the state which reflected the adjustment information of the 1st conversion part, and the characteristic variation of the physical quantity sensor and peripheral equipment was corrected with high precision. There is an effect that a physical quantity sensor device can be provided.

FIG. 2 is a block diagram showing a functional configuration of the physical quantity sensor device according to the first embodiment. It is a block diagram showing an example of the whole composition of the semiconductor physical quantity sensor device formed on the semiconductor chip by applying the present invention. 3 is a chart for explaining an operation mode of the physical quantity sensor device according to the first embodiment. FIG. 3 is an explanatory diagram illustrating signal paths in an operation mode 5 of the physical quantity sensor device according to the first embodiment; FIG. 3 is an explanatory diagram illustrating signal paths in an operation mode 6 of the physical quantity sensor device according to the first embodiment; 6 is a flowchart illustrating a procedure of an output value correction process of the physical quantity sensor device according to the first embodiment (part 1). 9 is a flowchart illustrating a procedure of an output value correction process of the physical quantity sensor device according to the first embodiment (part 2). 9 is a flowchart illustrating a procedure of an output value correction process of the physical quantity sensor device according to the first embodiment (part 3). FIG. 7 is a block diagram showing an example of the entire configuration of a semiconductor physical quantity sensor device according to a second embodiment. 9 is a flowchart illustrating a procedure of an output value correction process of the physical quantity sensor device according to the second embodiment. It is a block diagram showing the functional composition of the conventional physical quantity sensor device. FIG. 10 is a block diagram showing an example of an overall configuration of a semiconductor physical quantity sensor device formed on a semiconductor chip by applying the invention of FIG. 9.

  Hereinafter, preferred embodiments of a method for adjusting a physical quantity sensor device according to the present invention will be described in detail with reference to the accompanying drawings. In the following description of the embodiments and the accompanying drawings, the same components are denoted by the same reference numerals, and overlapping description will be omitted.

(Embodiment 1)
A functional configuration of the physical quantity sensor device according to the first embodiment will be described. FIG. 1 is a block diagram illustrating a functional configuration of the physical quantity sensor device according to the first embodiment. The physical quantity sensor device 100 shown in FIG. 1 has a function of correcting the output signal of the physical quantity sensor 101 to a desired output value by digital calculation, converting the calculation result into an analog signal, and outputting the analog result to the outside. The desired output value is, for example, an output value of the physical quantity sensor device 100 at the time of actual use or a test before shipment based on output characteristics set in advance based on design specifications of the physical quantity sensor device 100. Specifically, the physical quantity sensor device 100 includes a physical quantity sensor 101, a temperature sensor 102, a Vcc voltage dividing unit 103, a calculation unit 104, a storage unit 105, first and second conversion units 106 and 107, and first and second correction units 108. , 109, a control unit 110, a digital input / output unit 111, and an analog input / output unit 112.

  The physical quantity sensor 101 is a sensor element that generates an output signal according to the detected physical quantity of the medium to be measured. The physical quantity detected by the physical quantity sensor 101 is a physical quantity other than the temperature that depends on the temperature. Specifically, the physical quantity sensor 101 is, for example, a pressure sensor, an acceleration sensor, a gyro (angle or angular velocity) sensor, a flow rate sensor, or the like. The temperature sensor 102 is a sensor element that generates an output signal according to the detected temperature of the medium to be measured. The Vcc voltage divider 103 divides a power supply voltage supplied to the physical quantity sensor device 100 via a Vcc terminal (not shown). Well-known sensor elements may be used for the physical quantity sensor 101 and the temperature sensor 102.

  Each initial output value of the physical quantity sensor 101, the temperature sensor 102, and the Vcc voltage divider 103 is used for calculating initial setting information by the setting device 120 described later. The initial setting information is information for obtaining an initial output characteristic of the physical quantity sensor device 100 (at the time of pre-shipment adjustment for adjusting the initial setting), and at least a second characteristic value of the following first and second characteristic values. Is included. The first characteristic value is information for correcting the output characteristic of the physical quantity sensor 101 that changes non-linearly with respect to the detected physical quantity, and includes a coefficient of a first specific expression indicating the corrected output characteristic of the physical quantity sensor 101 and It is a constant term.

  The second characteristic value is information for correcting the first characteristic value that changes non-linearly with respect to the temperature detected by the temperature sensor 102. The second characteristic value is a second characteristic expression indicating the temperature dependence of the first characteristic value. Coefficients and constant terms. The first characteristic equation is a second-order or higher-order polynomial using the output value of the physical quantity sensor 101 as a variable. The second characteristic equation is a second-order or higher polynomial using the output value of the temperature sensor 102 as a variable. The initial setting information is calculated by the first and second calculation units 124 and 125 of the setting device 120 described later, and is stored in the storage unit 105. The output values of the physical quantity sensor 101, the temperature sensor 102, and the Vcc voltage divider 103 (physical quantities detected during actual use or during a test before shipment) are input to the calculator 104.

  The arithmetic unit 104 performs arithmetic processing based on the output value of the physical quantity sensor 101, the output value of the temperature sensor 102, and the initial setting information read from the storage unit 105, and calculates the corrected output value of the physical quantity sensor 101. Specifically, the calculation unit 104 is configured by a calculation circuit equivalent to one transfer function formula including the first and second specific expressions and a circuit for processing a calculation program. Then, when the output value of the temperature sensor 102 and the second characteristic value are input, the calculation unit 104 calculates the corrected first characteristic value based on the second characteristic equation. Further, the arithmetic unit 104 receives the corrected first characteristic value and the output value of the physical quantity sensor 101, and based on the first characteristic expression in a state where the coefficient and the constant term (first characteristic value) are corrected. Then, the corrected output value of the physical quantity sensor 101 is calculated.

  The arithmetic unit 104 further receives the input of the output signal of the Vcc voltage dividing unit 103, and increases or decreases the amplification value in proportion to the power supply voltage supplied to the physical quantity sensor device 100, and outputs the corrected output value of the physical quantity sensor 101. May be calculated. In this case, the arithmetic unit 104 increases or decreases the corrected output value of the physical quantity sensor 101 by an amplification factor (= Vcc / Vcc0) of the output value Vcc of the Vcc voltage dividing unit 103 with respect to the reference output value Vcc0 of the Vcc voltage dividing unit 103. do it. Specifically, when the amplification factor of the output value Vcc of the Vcc voltage dividing unit 103 is + 10%, the calculation unit 104 also amplifies the corrected output value of the physical quantity sensor 101 by + 10%.

  The storage unit 105 stores at least the above-described initial setting information input from outside via the digital input / output unit 111 and adjustment information of the first and second conversion units 106 and 107 described below. The first converter 106 is, for example, an A / D converter that converts an analog signal into a digital signal. Specifically, the first conversion unit 106 is disposed at a stage subsequent to the physical quantity sensor 101, the temperature sensor 102, the Vcc voltage dividing unit 103, and the analog input / output unit 112, digitizes these analog output signals, and performs a subsequent operation. Output to the unit 104. The second converter 107 is, for example, a D / A converter that converts a digital signal into an analog signal. Specifically, the second conversion unit 107 is disposed at a stage subsequent to the storage unit 105 and converts an output signal of the digital input / output unit 111 input via the storage unit 105 or a digital value read from the storage unit 105 into an analog signal. And outputs it to the analog input / output unit 112 at the subsequent stage.

  The initial output value of the first conversion unit 106 is used for calculating adjustment information for adjusting the conversion error by the first conversion unit 106. The adjustment information of the first conversion unit 106 is, for example, a correction value for correcting an error between an initial output characteristic of the first conversion unit 106 and a target output characteristic of the first conversion unit 106. The output characteristic of the first conversion unit 106 is usually represented by a transfer function indicating linearity based on a digital output (a plot of a digital output code) with respect to an analog input. Therefore, specifically, the initial output value of the first conversion unit 106 is used for calculating the initial output characteristic of the first conversion unit 106 to obtain the adjustment information of the first conversion unit 106.

  The initial output value of the second conversion unit 107 is used for calculating adjustment information for adjusting the conversion error by the second conversion unit 107. Specifically, the adjustment information of the second conversion unit 107 is, for example, a correction value for correcting an error between an initial output characteristic of the second conversion unit 107 and a target output characteristic of the second conversion unit 107. The output characteristic of the second conversion unit 107 is usually represented by a transfer function indicating linearity based on an analog output (a plot of an analog output) with respect to a digital input. Therefore, specifically, the initial output value of the second conversion unit 107 is used for calculating the initial output characteristic of the second conversion unit 107 to obtain the adjustment information of the second conversion unit 107.

  Each adjustment information of the first and second conversion units 106 and 107 is calculated by, for example, a third calculation unit 126 of the setting device 120 described later, and is stored in the storage unit 105. The first correction unit 108 is connected to the first conversion unit 106, and before the first conversion unit 106 performs a process of digitizing the initial output values of the physical quantity sensor 101, the temperature sensor 102, and the Vcc voltage dividing unit 103. The output characteristic of the first conversion unit 106 is corrected based on the adjustment information of the first conversion unit 106 read from the storage unit 105. Specifically, the first correction unit 108 corrects a gain error, an offset error, and a linearity error of the first conversion unit 106. The second correction unit 109 is connected to the second conversion unit 107, and before the second conversion unit 107 performs a process of digitizing each of the initial output values of the physical quantity sensor 101, the temperature sensor 102, and the Vcc voltage dividing unit 103. The output characteristic of the second conversion unit 107 is corrected based on the adjustment information of the second conversion unit 107 read from the storage unit 105. Specifically, the second correction unit 109 corrects a gain error, an offset error, and a linearity error of the second conversion unit 107.

  The control unit 110 selects an operation mode of the physical quantity sensor device 100 and controls the operation of the physical quantity sensor device 100. Specifically, the control unit 110 switches input / output between the digital input / output unit 111 and the analog input / output unit 112, and switches input to the first conversion unit 106. The input switching to the first conversion unit 106 means that the first conversion unit 106 switches which of the physical quantity sensor 101, the temperature sensor 102, the Vcc voltage dividing unit 103, and the analog input / output unit 112 receives the output signal. That is. The operation mode of the physical quantity sensor device 100 includes an operation mode for correcting the output value of the physical quantity sensor device 100 when the physical quantity sensor device 100 is actually used, and a physical quantity sensor 101, the digital input / output unit 111, and The operation mode is roughly classified into an operation mode for adjusting the initial output characteristic of the analog input / output unit 112. Details of the operation mode of the physical quantity sensor device 100 will be described later.

  The digital input / output unit 111 is switchable between an input mode for receiving a digital input from the outside and an output mode for digitally outputting to the outside. In the input mode, the digital input / output unit 111 receives input of the initial setting information of the physical quantity sensor device 100 from the setting device 120. The digital input / output unit 111 receives a predetermined voltage when measuring the initial output value of the second conversion unit 107. On the other hand, in the output mode, the digital input / output unit 111 outputs the corrected output value of the physical quantity sensor 101, the initial output values of the physical quantity sensor 101, the temperature sensor 102, and the Vcc voltage dividing unit 103, and the initial value of the first conversion unit 106. Digital output of output value.

  The analog input / output unit 112 is switchable between an input mode for receiving a digital input from the outside and an output mode for digitally outputting to the outside. In the input mode, the analog input / output unit 112 receives an input of a predetermined voltage when measuring the initial output value of the first conversion unit 106. On the other hand, in the output mode, the analog input / output unit 112 externally outputs the corrected output value of the physical quantity sensor 101 and the initial output value of the second conversion unit 107 for calculating adjustment information of the second conversion unit 107 to the outside. Output. The analog input / output unit 112 and the first conversion unit 106 are electrically connected to each other via a wiring 113, and the control unit 110 performs input switching between the analog input / output unit 112 and the first conversion unit 106, so that the analog The voltage signal (analog signal) input to the input / output unit 112 is input to the first conversion unit 106 via the wiring 113.

  The initial output value of the first conversion unit 106 output from the digital input / output unit 111 to the outside is information for calculating adjustment information of the first conversion unit 106. The initial output value of the first conversion unit 106 is obtained by converting a voltage signal (analog signal) input to the analog input / output unit 112 into a digital signal by the first conversion unit 106 and converting the voltage value of the digital signal into a digital input / output unit. It can be obtained by measuring by a measuring means (not shown) externally connected to 111. The conversion accuracy of the first conversion unit 106 can be grasped from the error between the initial output value of the first conversion unit 106 and the target output value. Further, by measuring a plurality of initial output values of the first conversion unit 106, it is possible to grasp the initial output characteristics of the first conversion unit 106, that is, the adjustment information of the first conversion unit 106.

  The initial output value of the second conversion unit 107 output from the analog input / output unit 112 to the outside is information for calculating adjustment information of the second conversion unit 107. The initial output value of the second conversion unit 107 is obtained by converting a voltage signal (digital signal) input to the digital input / output unit 111 into an analog signal by the second conversion unit 107, and converting the voltage value of the analog signal into an analog input / output unit. It is obtained by performing measurement by a measuring unit (not shown) externally connected to 112. The conversion accuracy of the second conversion unit 107 can be grasped from the error between the initial output value of the second conversion unit 107 and the target output value. Further, by measuring a plurality of initial output values of the second conversion unit 107, the initial output characteristics of the second conversion unit 107 can be grasped.

  The setting device 120 includes first to third acquisition units 121 to 123, first to third calculation units 124 to 126, and an input / output unit 127. The first acquisition unit 121 outputs at least three or more initial output values output by the physical quantity sensor 101 from the digital input / output unit 111 of the physical quantity sensor device 100 via the input / output unit 127 for at least three or more predetermined temperatures. Respectively. That is, the first obtaining unit 121 obtains the initial output values of at least nine or more physical quantity sensors 101. The first obtaining unit 121 may obtain the output value of the Vcc voltage dividing unit 103.

  The second acquisition unit 122 acquires a target output value of the physical quantity sensor 101 set in advance corresponding to a plurality of initial output values of the physical quantity sensor 101. That is, the second obtaining unit 122 obtains at least nine or more target output values of the physical quantity sensors 101. The predetermined temperature and the target output value of the physical quantity sensor 101 may be stored in advance in a storage unit (not shown) of the setting device 120, or an input may be received by an input unit (not shown).

  The third obtaining unit 123 obtains a plurality of initial output values of the first converting unit 106 and a plurality of target output values of the first converting unit 106 via the input / output unit 127. The target output value of the first conversion unit 106 is, for example, an output value on a straight line connecting the zero value and the output value of the first output unit 106 at the full scale (FS) of the target output characteristic. . Further, the third obtaining unit 123 obtains a plurality of initial output values of the second converting unit 107 and a plurality of target output values of the second converting unit 107. The target output value of the second conversion unit 107 is, for example, an output value on a straight line connecting the zero value and the output value of the target output characteristic of the second conversion unit 107 at full scale. The third acquisition unit 123 may acquire the initial output values of the first and second conversion units 106 and 107 stored in the storage unit 105 via the digital input / output unit 111 and the input / output unit 127, or may acquire the first output values. , 2 conversion units 106 and 107 may be obtained from measurement means (not shown) when measuring the initial output values. Further, the target output values of the first and second conversion units 106 and 107 may be stored in advance in a storage unit (not shown) of the setting device 120, or an input may be received by an input unit (not shown).

  The first calculation unit 124 calculates a corrected output value of the physical quantity sensor 101 based on the initial output value and the target output value of the physical quantity sensor 101 acquired by the first and second acquisition units 121 and 122. 1 Calculate the characteristic value. Specifically, the first calculator 124 approximates the initial output value of the physical quantity sensor 101 and the target output value of the physical quantity sensor 101 to a second-order or higher-order polynomial by, for example, the least-squares method for each predetermined temperature to obtain the first characteristic. Calculate the formula. Then, the first calculator 124 sets the coefficient and the constant term of the first characteristic equation calculated for each predetermined temperature as the first characteristic value.

  More specifically, the first calculating unit 124 determines that the first obtaining unit 121 obtains the initial output values of the physical quantity sensor 101 at n predetermined physical quantities at every m predetermined temperatures (the output value of the physical quantity sensor). , And the number of measurement points of the output value of the temperature sensor is n), and for each of m predetermined temperatures, a polynomial of degree X (2 ≦ X ≦ n−1: n ≧ 3) is calculated. The following equation (1) is calculated based on the X-th order polynomial. The following equation (1) is a first characteristic equation configured by the arithmetic unit 104.

In the following equation (1), Vd is the output value of the physical quantity sensor 101 after the initial setting of the physical quantity sensor device 100, and ΔT is the detected temperature of the temperature sensor 102 (the output value of the temperature sensor 102) after the initial setting ( The same applies to the following equations (2) and (3)). The term "after the initial setting" refers to the time after the initial setting information has been written into the storage unit 105, for example, at the time of actual use of the physical quantity sensor device 100 or at the time of a test before shipment. The detected temperature ΔT is an output value of the temperature sensor 102 based on the reference temperature T0 = 25 ° C. Then, the first calculator 124 calculates the coefficients of the X-th order polynomial and the constant terms k _ij , i = 1, 2,... N, j = X, X−1, .., 1, 0 are the first characteristic values.

Vout _i (ΔT, Vd) = K _iX (ΔT) × Vd ^X + K _ix-1 (ΔT) × Vd ^X-1 +... + K _i1 (ΔT) × Vd + K _i0 (ΔT) (i = 1, 2, ..., n) ... (1)

The first calculator 124 may further calculate a first characteristic equation based on the output value of the Vcc voltage divider 103. In this case, the first calculating unit 124 calculates a first characteristic equation shown in the following equation (2). In the following equation (2), Vcc is the output value of the Vcc voltage divider 103 after the initial setting of the physical quantity sensor device 100. In this case, the first characteristic values are k _ij × Vcc / Vcc0, i = 1, 2,..., N, and j = X, X−1,.

Vout _i (ΔT, Vd) = {K _ix (ΔT) × Vd ^X + K _ix-1 (ΔT) × Vd ^X-1 +... + K _i1 (ΔT) × Vd + K _i0 (ΔT)} × Vcc / Vcc0 ( i = 1, 2,..., n) (2)

The second calculator 125 calculates a second characteristic for calculating an approximate expression K _i (ΔT), i = 1, 2,..., N of the first characteristic value based on the predetermined temperature and the first characteristic value. Calculate the value. Specifically, the second calculation unit 125 approximates the predetermined temperature and the first characteristic value k _ij for each first characteristic value k _ij the second or higher polynomial, for example, by the least squares method, the following (3) A second characteristic equation shown in the equation is calculated. Then, the second calculator 125 calculates the coefficient and the constant term kT _{ij of} the second characteristic equation, i = 1, 2,..., N, j = Y (2 ≦ Y ≦ m−1: m ≧ 3), .., 0 are the second characteristic values. The second characteristic value calculated by the second calculator 125 is output to the digital input / output unit 111 of the physical quantity sensor device 100 via the input / output unit 127.

K _i (ΔT) = kT _iY × ΔT ^x + kT _iY-1 × ΔT ^x-1 + ... + kT _i1 × ΔT + kT _i0 (i = 1, 2,..., N) (3)

  The third calculating unit 126 calculates adjustment information of the first converting unit 106 based on the initial output value and the target output value of the first converting unit 106 acquired by the third acquiring unit 123. Specifically, the third calculating unit 126 determines a transfer function (proportional expression between analog input and digital output) representing an initial output characteristic of the first conversion unit 106 based on a plurality of initial output values of the first conversion unit 106. Is calculated. Then, the third calculating unit 126 compares the transfer function representing the target output characteristic of the first converting unit 106 with the transfer function representing the initial output characteristic of the first converting unit 106, and adjusts the adjustment information of the first converting unit 106. Is calculated.

  The third calculation unit 126 calculates adjustment information of the second conversion unit 107 based on the initial output value and the target output value of the second conversion unit 107 acquired by the third acquisition unit 123. Specifically, the third calculation unit 126 calculates a transfer function representing the initial output characteristics of the second conversion unit 107 based on, for example, a plurality of initial output values of the second conversion unit 107. Then, the third calculator 126 compares, for example, a transfer function representing the target output characteristic of the second converter 107 with a transfer function representing the initial output characteristic of the second converter 107, and Calculate adjustment information. The adjustment information of the first and second conversion units 106 and 107 includes, for example, a gain error (rotational movement amount), an offset error (parallel movement amount), and a linearity error (a change amount of a step of an output code). Therefore, for example, the third calculator 126 may calculate the amount of rotation and translation of the initial output characteristics with respect to the target output characteristics, the amount of step change in the output code, and the like.

  Next, an example of the entire configuration of the physical quantity sensor device 100 shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a block diagram showing an example of the overall configuration of a semiconductor physical quantity sensor device formed on a semiconductor chip by applying the present invention. The physical quantity sensor device 200 includes a physical quantity sensor 201, a temperature sensor 202, a Vcc voltage divider 203, an arithmetic circuit 204, a data storage unit 205, an A / D converter 206, a D / A converter 207, and first and second correction circuits 208 and 209. , Control circuit 210, digital I / O interface (hereinafter, referred to as digital I / O) 211, analog I / O interface (hereinafter, referred to as analog I / O) 212, preamplifier (preamplifier) 214, It comprises three sample-holds 215 to 217, first and second selectors 218 and 219, a reference voltage source 220, a sensor drive circuit 221, and an oscillator 222.

  The physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage dividing section 203 correspond to the above-described physical quantity sensor 101, temperature sensor 102, and Vcc voltage dividing section 103 in FIG. 1, respectively. The arithmetic circuit 204 and the data storage unit 205 correspond to the arithmetic unit 104 and the storage unit 105 in FIG. 1 described above, respectively. The A / D converter 206, the D / A converter 207, and the first and second correction circuits 208 and 209 correspond to the first conversion units 106 and 107 and the first correction units 108 and 109 in FIG. 1 described above, respectively. The control circuit 210, the digital I / O 211, and the analog I / O 212 correspond to the control unit 110, the digital input / output unit 111, and the analog input / output unit 112 in FIG. 1 described above, respectively.

  The output signals of the physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage divider 203 are analog signals. A first sample hold 215 is disposed downstream of the physical quantity sensor 201 via a preamplifier 214. The preamplifier 214 has a function of amplifying the output signal of the physical quantity sensor 201. At the subsequent stage of the temperature sensor 202 and the Vcc voltage dividing section 203, second and third sample holds 216 and 217 are arranged, respectively. An A / D converter 206 is disposed downstream of the first to third sample / holds 215 to 217 via a first selector 218.

  The first sample hold 215 takes out an analog signal continuously input from the physical quantity sensor 201 at predetermined time intervals (sampling: sampling) and holds (holds) for a predetermined time. The second sample hold 216 takes out an analog signal continuously input from the temperature sensor 202 at certain time intervals and holds it for a certain time. The third sample hold 217 takes out an analog signal continuously input from the Vcc voltage divider 203 at a certain time interval and holds it for a certain time. The first selector 218 receives inputs from the first to third sample and hold 215 to 217. The first selector 218 is connected to the analog I / O 212 via the wiring 213, and receives an input from the analog I / O 212.

  The first selector 218 selects one of the analog signals input from the first to third sample / holds 215 to 217 and the analog I / O 212 and outputs the selected signal to the A / D converter 206. The A / D converter 206 digitizes the output signal (analog signal) of the physical quantity sensor 201 selected by the first selector 218 and outputs it to the arithmetic circuit 204. Further, the A / D converter 206 digitizes each output signal (analog signal) of the temperature sensor 202, the Vcc voltage divider 203 and the analog I / O 212 selected by the first selector 218, and outputs the digitized signal to the arithmetic circuit 204. The output signal of the analog I / O 212 is a voltage signal externally input to the analog I / O 212 in the output mode of the analog I / O 212.

  When the physical quantity sensor device 200 is actually used, the arithmetic circuit 204 reads out the initial setting information stored in the data storage unit 205 in advance, and based on the initial setting information, outputs the digitized output signal of the physical quantity sensor 201 (hereinafter referred to as digital signal). Signal) is amplified at a predetermined amplification rate and output. When the physical quantity sensor device 200 is adjusted before shipment, the arithmetic circuit 204 does not perform any arithmetic processing, and outputs the digitized output signals of the physical quantity sensor 201, the temperature sensor 202, the Vcc voltage divider 203, and the analog I / O 212. (Digital signal) is output as the initial output value. The output signal (digital signal) of the arithmetic circuit 204 is stored in the data storage unit 205 at the subsequent stage.

  The digital signal input to the data storage unit 205 is semi-permanently stored in the data storage unit 205 by applying a predetermined voltage from the write / I / O terminal to the data storage unit 205. The data storage unit 205 further stores a digital signal externally input to the digital I / O 211. A digital signal input to the digital I / O 211 from the outside includes a voltage signal for measuring an initial output value of the D / A converter 207 and a value calculated by the setting device 120 (initial setting information, adjustment of the A / D converter 206). And adjustment information of the D / A converter 207).

  When the physical quantity sensor device 200 is actually used, the D / A converter 207 reads out a calculation result by the calculation circuit 204 stored in the data storage unit 205, converts the result into an analog signal, and outputs the analog result to the analog I / O 212. Further, the D / A converter 207 converts a voltage signal input from, for example, a voltage source connected to the digital I / O 211 via the digital I / O 211 and the data storage unit 205 into an analog signal when the physical quantity sensor device 200 is adjusted before shipment. , And outputs the initial output value of the D / A converter 207 to the analog I / O 212. The adjustment information of the A / D converter 206 is calculated from the initial output value of the D / A converter 207.

  The first correction circuit 208 stores data before the A / D converter 206 digitizes the initial output values of the physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage divider 203 during the pre-shipment adjustment of the physical quantity sensor device 200. The adjustment information of the A / D converter 206 stored in the unit 205 is read, and the output characteristic value of the A / D converter 206 is corrected. Therefore, during the pre-shipment adjustment of the physical quantity sensor device 200, the initial output values of the physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage dividing section 203 are different from the output value reflecting the adjusted output characteristics of the A / D converter 206. Become. The first correction circuit 208 weights the resolution (the number of bits) based on the adjustment information of the first correction circuit 208, for example, by electrically connecting or disconnecting routes of a plurality of redundant circuits prepared in advance. May be used.

  The second correction circuit 209 outputs the D / A converter 207 stored in the data storage unit 205 before the D / A converter 207 converts the digital operation result of the operation circuit 204 into an analog signal at the time of adjustment before shipment of the physical quantity sensor device 200. Is read, and the output characteristics of the D / A converter 207 are corrected. Therefore, when the physical quantity sensor device 200 is actually used, the corrected output value of the physical quantity sensor 101 calculated by the calculation circuit 204 is an output value reflecting the adjusted output characteristic of the D / A converter 207. The second correction circuit 209 weights the resolution based on, for example, each adjustment information of the second correction circuit 209, for example, by electrically connecting or disconnecting routes of a plurality of redundant circuits prepared in advance. A forward load method may be used.

  In the output mode of the digital I / O 211, the second selector 219 reads the digital values of the physical quantity sensor 201, the temperature sensor 202, the Vcc voltage divider 203, and the analog I / O 212 stored in the data storage unit 205, and Output to O211. Further, the second selector 219 outputs a digital signal input to the digital I / O 211 to the data storage unit 205 in the input mode of the digital I / O 211. The control circuit 210 switches inputs of the first and second selectors 218 and 219, the digital I / O 211, and the analog I / O 212 based on, for example, an operation mode selected by program control.

  In the output mode, the digital I / O 211 writes the digital signal input from the second selector 219 and outputs the digital signal from the I / O terminal to the outside. Information output from the write / I / O terminal to the outside is an initial output value of the physical quantity sensor 201, the temperature sensor 202, the Vcc voltage divider 203, and the A / D converter 206, and a digital operation result by the operation circuit 204. On the other hand, the digital I / O 211 outputs a digital signal input from the outside to the second selector 219 in the input mode. The digital signal externally input to the digital I / O 211 is a voltage signal for obtaining a value calculated by the setting device 120 or an initial output value of the D / A converter 207.

  In the output mode, the analog I / O 212 outputs an analog signal output from the D / A converter 207 from the Vout terminal to the outside. The information output from the analog I / O 212 to the outside is the result of the analog operation by the operation circuit 204 and the initial output value of the D / A converter 207. On the other hand, in the input mode, the analog I / O 212 outputs an externally input analog signal to the first selector 218 via the wiring 213. An analog signal externally input to the analog I / O 212 is a voltage signal for obtaining an initial output value of the A / D converter 206.

  The reference voltage source 220 equalizes the noise of the power supply voltage supplied from the Vcc terminal, generates a reference voltage suitable for driving the sensor drive circuit 221, and supplies the reference voltage to the sensor drive circuit 221. The reference voltage source 220 supplies the voltage VDD to the oscillator 222 and each circuit in the physical quantity sensor device 200. The sensor drive circuit 221 generates a voltage of a predetermined magnitude for driving the physical quantity sensor 201 and the temperature sensor 202, and supplies the voltage to the physical quantity sensor 201 and the temperature sensor 202. The oscillator 222 generates a clock signal for driving the A / D converter 206, the D / A converter 207, and the arithmetic circuit 204, and supplies the clock signal to the A / D converter 206, the D / A converter 207, and the arithmetic circuit 204.

  Next, the operation modes 1 to 6 of the physical quantity sensor device 200 controlled by the control circuit 210 will be described in detail. FIG. 3 is a chart for explaining an operation mode of the physical quantity sensor device according to the first embodiment. The operation mode 1 is an operation mode for obtaining an initial output characteristic of the physical quantity sensor 201 at the time of adjustment before shipment of the physical quantity sensor device 200. When the operation mode 1 is selected by the control circuit 210, each initial output value of the physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage divider 203 is digitized by the A / D converter 206, and transmitted from the digital I / O 211 to the setting device 120. Output control is performed.

  Specifically, the operation in the operation mode 1 of the physical quantity sensor device 200 is as follows. First, output signals (analog signals) of the physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage divider 203 are respectively held in the first to third sample hold units 215 to 217 for a certain period of time. Next, the output signals held in the first to third sample hold circuits 215 to 217 are input to the A / D converter 206 by the first selector 218 in a selection order set in advance, for example, and are digitized. I do. The digital signal input to the arithmetic circuit 204 is stored as it is in the data storage unit 205 without performing the arithmetic processing by the arithmetic circuit 204. In this state, by applying a predetermined voltage to the data storage unit 205 from the write / I / O terminal, the information stored in the data storage unit 205 is transferred to the nonvolatile memory in the data storage unit 205 (writing). (Rare), the initial setting information is held semi-permanently in the data storage unit 205 (hereinafter, writing to the data storage unit 205 is simply referred to as “store”). Then, the second selector 219 reads the initial output values of the physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage divider 203 stored in the data storage unit 205, and sequentially reads the initial output values into the digital I / O 211 in a preset selection order, for example. Output and output from the write / I / O terminal to the outside. Thus, the operation mode 1 of the physical quantity sensor device 200 ends.

  As described above, in the operation mode 1, the output values of the physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage dividing unit 203 are not corrected and are output to the outside as initial output values. Each initial output value of the physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage divider 203 obtained in the operation mode 1 is input to the setting device 120. The setting device 120 calculates the initial setting information of the physical quantity sensor device 200 for calculating the above formula (1) (or the above formula (2)) and the above formula (3) based on these initial output values. You. The predetermined temperature at which the initial output value of the physical quantity sensor 201 is output from the physical quantity sensor device 200 to the outside is confirmed by, for example, the initial output value of the temperature sensor 202.

  The control circuit 210 selects the operation mode 1 after selecting the operation mode 5 (mode for acquiring the initial output value of the A / D converter 206) described later. As a result, it is possible to acquire the initial output values of the physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage dividing unit 203 in which the adjustment information of the A / D converter 206 is reflected. Further, after selecting the operation mode 1, the control circuit 210 selects, for example, an operation mode 3 (a mode in which the output value after the correction of the physical quantity sensor 101 is digitally calculated and analog output to the outside) before the operation mode 3 is described later. Operation mode 4 (a mode in which data is written to the data storage unit 205) is selected, and the initial setting information of the physical quantity sensor device 200 is stored in the data storage unit 205. Thus, in the operation mode 3, the arithmetic circuit 204 can calculate the corrected output value of the physical quantity sensor 201.

The operation mode 2 is an operation mode in which the corrected output value of the physical quantity sensor 201 is digitally output to the outside. When the operation mode 2 is selected by the control circuit 210, control is performed such that the output value of the physical quantity sensor 201 is corrected by the arithmetic circuit 204, and the arithmetic result is digitally output from the digital I / O 211 to the outside. Specifically, the operation in the operation mode 2 of the physical quantity sensor device 200 is as follows. First, similarly to the operation mode 1, analog signals of the physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage divider 203 are digitized and input to the arithmetic circuit 204. Further, it reads out the initial setting information (the second characteristic value calculated by the second calculating unit 125) stored in the data storage unit 205 and inputs it to the arithmetic circuit 204. As a result, the output value Vd of the physical quantity sensor 201, the detected temperature ΔT of the temperature sensor 202, and the Vcc partial pressure are added to the equations (1) (or (2)) and (3) constituted by the arithmetic circuit 204. The output value Vcc of the unit 203 and the second characteristic value kT _ij , i = 1, 2,..., N, j = Y, Y−1,. Is calculated. Next, the calculation result of the calculation circuit 204 (the corrected output value of the physical quantity sensor 201) is stored in the data storage unit 205. After that, the corrected output value of the physical quantity sensor 201 is read from the data storage unit 205 by the second selector 219, input to the digital I / O 211, and digitally output from the write / I / O terminal to the outside. Thus, the operation mode 2 of the physical quantity sensor device 200 ends. As described above, in the present invention, it is possible to digitally output the corrected output value of the physical quantity sensor 201.

  The operation mode 3 is an operation mode in which the corrected output value of the physical quantity sensor 201 is externally output as an analog signal during actual use of the physical quantity sensor device 200 or during a test before shipping. When the operation mode 3 is selected by the control circuit 210, the output value of the physical quantity sensor 201 is corrected by the arithmetic circuit 204, the arithmetic result is converted into an analog signal by the D / A converter 207, and output from the analog I / O 212 to the outside. Is made. Specifically, the operation of the physical quantity sensor device 200 in the operation mode 3 is as follows. First, similarly to the operation mode 2, the digital signals of the physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage dividing unit 203 and the initial setting information stored in the data storage unit 205 are input to the arithmetic circuit 204, and the physical quantity sensor The corrected output value of 201 is calculated, and the calculation result is stored in the data storage unit 205. After that, the corrected output value of the physical quantity sensor 201 is read from the data storage unit 205, converted into an analog signal by the D / A converter 207, and output to the outside from the Vout terminal via the analog I / O 212. Thus, the operation mode 3 of the physical quantity sensor device 200 ends. After selecting operation mode 5, control circuit 210 selects operation mode 6 (mode for acquiring an initial output value of D / A converter 207) and operation mode 1 described later, and then selects operation mode 3. The control circuit 210 may select the operation mode 6 before selecting the operation mode 3, and the timing for selecting the operation mode 6 may be before the operation mode 5 or after the operation mode 1. There may be. Thereby, the physical quantity sensor device 200 can output the corrected output value of the physical quantity sensor 201 in which the adjustment information of the A / D converter 206 and the D / A converter 207 is reflected.

  The operation mode 4 is an operation mode for storing (writing) information input from the outside in the data storage unit 205. When the operation mode 4 is selected by the control circuit 210, control for storing information input from the outside to the digital I / O 211 in the data storage unit 205 is performed. Specifically, the operation in the operation mode 4 of the physical quantity sensor device 200 is as follows. First, the digital I / O 211 is switched to the input mode by the control circuit 210, and an external input signal is written to the digital I / O 211 via the I / O terminal. The external input signal is a voltage signal for measuring initial setting information of the physical quantity sensor device 200 (information calculated by the second calculating unit 125) and an initial output value of the D / A converter 207. The information input to the digital I / O 211 is stored in the data storage unit 205 via the second selector 219. Thus, the operation mode 4 of the physical quantity sensor device 200 ends.

  The operation mode 5 is an operation mode for obtaining an initial output value of the A / D converter 206. FIG. 4 is an explanatory diagram illustrating signal paths in the operation mode 5 of the physical quantity sensor device 200 according to the first embodiment. FIG. 4 shows a signal transmission path in the operation mode 5 by a thick line. When the operation mode 5 is selected by the control circuit 210, the voltage signal input from the analog I / O 212 in the input mode is digitized by the A / D converter 206, and the digital signal is output from the digital I / O 211 in the output mode to the external measuring means 232. Output control is performed. Specifically, the operation in the operation mode 5 of the physical quantity sensor device 200 is as follows. First, as shown in FIG. 4, the control circuit 210 switches the analog I / O 212 to the input mode and switches the digital I / O 211 to the output mode. Further, the control circuit 210 switches so that an analog signal from the analog I / O 212 is input to the A / D converter 206 via the wiring 213. Then, an analog signal of a predetermined voltage is input to the analog I / O 212 from a voltage source 231 externally connected to the Vout terminal. Since the analog I / O 212 and the A / D converter 206 are electrically connected to each other by the control circuit 210, the analog signal of a predetermined voltage input from the analog I / O 212 passes through the wiring 213 to the subsequent A / D converter. The data is input to the converter 206 and digitized. A signal digitized by the A / D converter 206 (output signal of the A / D converter 206) is input to the digital I / O 211 via the arithmetic circuit 204, the data storage unit 205, and the second selector 219, and is written / I / O It is digitally output from the O terminal to the measuring means 232. At this time, since the output signal of the physical quantity sensor 201 is not input to the arithmetic circuit 204, the arithmetic processing is not performed. As a result, the initial output value of the A / D converter 206 is obtained as a measurement result by the measuring unit 232, and the operation mode 5 of the physical quantity sensor device 200 ends.

  The initial output value of the A / D converter 206 obtained in the operation mode 5 is input to the setting device 120, and the setting device 120 calculates adjustment information of the A / D converter 206. Before selecting the operation mode 1 by the control circuit 210, the physical quantity sensor device 200 selects, for example, the operation mode 4 and causes the data storage unit 205 to store the adjustment information of the A / D converter 206. That is, the control circuit 210 selects the operation mode 5, the operation mode 4, and the operation mode 1 in this order. The reason is that, as described above, it is possible to obtain the initial output values of the physical quantity sensor 201, the temperature sensor 202, and the Vcc voltage dividing unit 203 in which the adjustment information of the A / D converter 206 is reflected.

  The operation mode 6 is an operation mode for obtaining an initial output value of the D / A converter 207. FIG. 5 is an explanatory diagram illustrating a signal path in the operation mode 6 of the physical quantity sensor device 200 according to the first embodiment. FIG. 5 shows a signal transmission path in the operation mode 6 by a thick line. When the operation mode 6 is selected by the control circuit 210, the voltage signal input from the digital I / O 211 in the input mode is converted into an analog signal by the D / A converter 207, and the analog signal from the analog I / O 212 in the output mode is transmitted to the external measuring means 234. Output control is performed. Specifically, the operation in the operation mode 6 of the physical quantity sensor device 200 is as follows. First, as shown in FIG. 5, the control circuit 210 switches the digital I / O 211 to the input mode and switches the analog I / O 212 to the output mode. Further, the control circuit 210 switches so that the digital signal from the digital I / O 211 is input to the D / A converter 207 via the data storage unit 205. Then, a digital signal of a predetermined voltage is input to the digital I / O 211 from the input means 233 externally connected to the write / I / O terminal. Since the control circuit 210 switches the signal transmission from the data storage unit 205 to the D / A converter 207, the digital signal of a predetermined voltage input from the digital I / O 211 is transmitted to the data storage unit 205. After that, it is input to the D / A converter 207 in the subsequent stage and is converted into an analog signal. The signal converted into an analog signal by the D / A converter 207 (the output signal of the D / A converter 207) is input to the analog I / O 212, and is output from the Vout terminal to the measuring unit 234. As a result, the initial output value of the D / A converter 207 is obtained as a measurement result by the measuring unit 234, and the operation mode 6 of the physical quantity sensor device 200 ends.

  The initial output value of the D / A converter 207 obtained in the operation mode 6 is input to the setting device 120, and the setting device 120 calculates adjustment information of the A / D converter 206. Before selecting the operation mode 3 by the control circuit 210, the physical quantity sensor device 200 causes the data storage unit 205 to store the adjustment information of the D / A converter 207 by selecting, for example, the operation mode 4. Further, as described above, the physical quantity sensor device 200 selects the operation mode 1 before selecting the operation mode 3 by the control circuit 210, and selects the operation mode 5 before selecting the operation mode 1. That is, it is preferable that the control circuit 210 selects the operation mode 5, the operation mode 6, the operation mode 1, the operation mode 4, and the operation mode 3 in this order (the order of the operation modes 1 and 6 can be switched). The reason is that, as described above, a corrected output value of the physical quantity sensor 201 in which the adjustment information of the A / D converter 206 and the D / A converter 207 is reflected can be obtained. The operation mode 4 may be selected each time the operation mode 5, the operation mode 6, or the operation mode 1 is selected by the control circuit 210.

  Next, a procedure of an output value correction process of the physical quantity sensor device 200 according to the first embodiment will be described, for example, in a case where the physical quantity sensor 201 is a pressure sensor (hereinafter, referred to as a pressure sensor 201). 6A to 6C are flowcharts illustrating a procedure of an output value correction process of the physical quantity sensor device according to the first embodiment. 6A to 6C show processing for calculating the adjustment information of the A / D converter 206 and the D / A converter 207 and the initial setting conditions of the physical quantity sensor device 200. First, as shown in FIG. 6A, the number of measurements n (≧ 3) of the output value of the pressure sensor 201, the number of measurements m (≧ 3) of the output value of the temperature sensor 202, the A / D converter 206 and the D / A converter 207 The number of measurements p (≧ 2) of the output value is obtained (step S101). Next, 1 is substituted for the variable i (step S102).

  Next, when the variable i is 1 (step S103: Yes), 1 is substituted for the variable k (step S121). Next, the operation mode 5 is selected by the control circuit 210, and the analog data Vad (k) is input from the analog I / O 212 and the digital conversion result Dad (k) of the A / D converter 206 is measured as described above. (Step S122). Next, the operation mode 6 is selected by the control circuit 210, digital data Dda (k) is input from the digital I / O 211, and the analog conversion result Vda (k) of the D / A converter 207 is measured (step S123). Then, the variable k is incremented (step S124), and the processing of steps S122 to S124 is repeated until the variable k becomes larger than the number of measurements p (step S125: No). The processes so far are the operation modes 5 and 6 of the physical quantity sensor device 200. Steps S123 and S122 may be performed in this order.

  If the variable k has become larger than the number of measurements p (step S125: Yes), the A / D converter based on the digital conversion result Dad (k) of the A / D converter 206, k = 1,. An adjustment parameter (adjustment information) Bit_adc of 206 is calculated (step S126). Next, an adjustment parameter (adjustment information) Bit_dac of the D / A converter 207 is calculated based on the analog conversion result Vda (k) of the D / A converter 207, k = 1,..., P (step S127). . Next, the operation mode 4 is selected by the control circuit 210, and the adjustment parameter Bit_adc of the A / D converter 206 and the adjustment parameter Bit_dac of the D / A converter 207 are stored in the data storage unit 205 (step S128).

The A / D converter 206 and the D / A converter 207 are adjusted based on the data storage unit 205 based on the adjustment parameter Bit_adc of the A / D converter 206 and the adjustment parameter Bit_dac of the D / A converter 207. For this reason, an initial output value V ₀ #ij described later is measured in a state where the adjustment parameter Bit_adc of the A / D converter 206 and the adjustment parameter Bit_dac of the D / A converter 207 are reflected in the processing of steps S104 to S111. Can be.

Next, the operation mode 1 is selected by the control circuit 210, and the temperature T (i) detected by the temperature sensor 202 (that is, the detected temperature ΔT based on the reference temperature T0) and the temperature T (i) Is measured with the output value Vcc (i) of the Vcc voltage divider 203 (steps S104 and S105). Next, after substituting 1 for the variable j (step S106), the initial output value V0 _{# ij} of the pressure sensor 201 at the temperature T (i) and the pressure P (j) is measured (step S107). Next, the variable j is incremented (step S108), and the processing of steps S107 and S108 is repeated until the variable j becomes larger than the number of measurements n (step S109: No).

If the variable j has become larger than the number of measurements n (step S109: Yes), the variable i is incremented (step S110), and the processes of steps S103 to S110 are repeated until the variable i becomes larger than the number of measurements m. (Step S111: No). Thereby, n pressures are measured at m temperatures, and a total of m × n or more initial output values V _{0 #ij} , i = 1, 2,..., M, j = 1, 2,. n is measured and output to the outside of the physical quantity sensor device 200. The processing so far is the operation mode 1 of the physical quantity sensor device 200. The plurality of initial output values V _{0 #ij} measured in the processing so far are acquired by the first acquisition unit 121 of the setting device 120.

Next, when the variable i becomes larger than the number of measurements m (Step S111: Yes), the target output value V of the pressure sensor 201 corresponding to the initial output value V _{0 #ij} by the second acquisition unit 122 of the setting device 120. _{1 # ij, i = 1,2,} ..., m, j = 1,2, ..., reads the n (step S112). Next, an approximate expression V ₁ (Ti) of the target output value is calculated for each temperature Ti based on the initial output value V _{0 #ij} and the target output value V _{1 #ij} (step S113). Next, the coefficient of the approximate expression V ₁ (Ti) of the target output value and the constant term k _ij , i = 1, 2,..., M, j = X, X−1,. (Step S114).

Next, 1 is substituted into the variable i (step S115), and calculates an approximate expression K _i of the first characteristic value as shown in equation (1) (step S116). Next, each parameter kT _ij , i = 0, 1,..., M, j = Y, Y-1,..., 1, 0 (2 ≦ Y ≦ n−1: n ≧ 2) of the approximate expression of the first characteristic value 3) is acquired as the second characteristic value (step S117). Then, the variable i is incremented (step S118), and the processes of steps S116 to S118 are repeated until the variable i becomes larger than the number of measurements m (step S119: No).

Then, if the variable i is greater than the number of measurements m (step S119: Yes), the coefficient of the approximate expression K _i and the constant term (the second characteristic value) kT _ij, as correction parameters (initial setting information) The data is written into the data storage unit 205 of the physical quantity sensor device 200 (Step S120). The process of step S120 is the operation mode 4 of the physical quantity sensor device 200. After that, the processing according to this flowchart ends. Thereafter, the operation mode 3 is selected by the control circuit 210, and the physical quantity sensor device 200 is operated in the operation mode 3, whereby the pressure sensor 201 of the pressure sensor 201 in which each adjustment information of the A / D converter 206 and the D / A converter 207 is reflected. The corrected output value can be output from the analog I / O 212 as an analog output.

  As described above, according to the first embodiment, before measuring the initial output values of the physical sensor, the temperature sensor, and the Vcc voltage dividing unit used in the digital calculation processing for correcting the output value of the physical quantity sensor, Since the A / D converter can be adjusted based on the adjustment information of the A / D converter, the initial output values of the physical sensor, the temperature sensor, and the Vcc voltage dividing unit are reflected by reflecting the adjustment information of the A / D converter. Since the measurement can be performed and the digital operation processing can be performed based on the initial output value, the output value of the physical sensor can be corrected with high accuracy. Further, even when the corrected output value of the physical sensor calculated by the digital arithmetic processing is converted into an analog signal and output to the outside, the corrected output value of the physical sensor is reflected by reflecting the adjustment information of the D / A converter. Can be output in analog form. Therefore, it is possible to provide the physical quantity sensor device 200 capable of outputting an analog output signal in which the characteristic variation of the physical sensor and the peripheral device is corrected with high accuracy.

According to the first embodiment, after the physical quantity sensor device is completed, the A / D converter and the D / A converter are controlled by the first and second correction circuits based on the adjustment information of the A / D converter and the D / A converter. Can be adjusted. For this reason, even if the output characteristics of the physical quantity sensor device change due to, for example, the pressure applied when the physical quantity sensor device is incorporated into the package, the physical property value is also taken into account after the package is incorporated, taking into account the change in the output characteristics that occurs when the physical quantity sensor device is incorporated into the package. The output characteristics of the sensor device, the A / D converter, and the D / A converter can be corrected. According to the first embodiment, since the output characteristics of the A / D converter and the D / A converter can be corrected, the resolution (number of bits) of the A / D converter and the D / A converter is increased. The output value of the physical quantity sensor can be accurately corrected without improving the overall conversion accuracy of the / D converter and the D / A converter.
For this reason, cost can be reduced.

(Embodiment 2)
Next, a physical quantity sensor device according to a second embodiment will be described. FIG. 7 is a block diagram illustrating an example of the entire configuration of the semiconductor physical quantity sensor device according to the second embodiment. FIG. 7 shows an example of the overall configuration of a semiconductor physical quantity sensor device formed on a semiconductor chip by applying the present invention. The physical quantity sensor device according to the second embodiment differs from the physical quantity sensor device according to the first embodiment in that the first and second correction circuits are not provided. As in the first embodiment, the initial output values of A / D converter 206 and D / A converter 207 are measured in operation modes 5 and 6, respectively. Then, it is determined whether the A / D converter 206 or the D / A converter 207 is defective based on an error (adjustment information) between the initial output characteristics and the target output characteristics.

  Next, a procedure of an output value correction process of the physical quantity sensor device according to the second embodiment will be described. FIG. 8 is a flowchart illustrating a procedure of an output value correction process of the physical quantity sensor device according to the second embodiment. First, similarly to Embodiment 1, as shown in FIG. 6A, the number of measurements n, m, and p are obtained (Step S101), and 1 is substituted into a variable i (Step S102), and 1 is substituted into a variable k. The process from the substitution process (step S121) to the process of calculating the adjustment parameter (adjustment information) Bit_adc of the A / D converter 206 and the adjustment parameter (adjustment information) Bit_dac of the D / A converter 207 (steps S126 and S127) are performed.

  Next, as shown in FIG. 8, when the adjustment parameter Bit_adc of the A / D converter 206 is larger than a predetermined value r, or when the adjustment parameter Bit_dac of the D / A converter 207 is set to a predetermined value. If it is larger than s (step S129: Yes), the A / D converter 206 or the D / A converter 207 is determined to be defective, and the processing according to this flowchart ends. Thereafter, the semiconductor chip in which the A / D converter 206 or the D / A converter 207 is determined to be defective may be discarded, for example.

  On the other hand, when the adjustment parameter Bit_adc of the A / D converter 206 is equal to or less than a predetermined value r, and the adjustment parameter Bit_dac of the D / A converter 207 is equal to or less than a predetermined value s (step S129). No), as shown in FIGS. 6A and 6C, the process proceeds to step S104 as in the first embodiment, performs the subsequent processes up to step S120 as in the first embodiment, and ends the process according to this flowchart.

  As described above, according to the second embodiment, the A / D converter and the D / A converter can be easily determined by calculating the adjustment information of the A / D converter and the D / A converter. Therefore, the same effect as in the first embodiment can be obtained.

  Note that the adjustment method of the physical quantity sensor device described in the present embodiment can be realized by executing a prepared program on a computer such as a personal computer or a workstation. This program is recorded on a computer-readable recording medium such as a solid state drive (SSD: Solid State Drive), a hard disk, a flexible disk, a CD-ROM, an MO, and a DVD, and is executed by being read from the recording medium by the computer. Is done. The program may be a transmission medium that can be distributed via a network such as the Internet.

  In the above, the present invention is not limited to the above-described embodiment, but can be variously modified. For example, a setting device for calculating the correction parameter may be provided in the physical quantity sensor device. In this case, for example, when the peripheral device is changed in the operation mode 3 of the physical quantity sensor device, the configuration may be such that the correction parameter is calculated again by the setting device. Further, among the physical quantity sensor devices shown in FIG. 1, the physical quantity sensor and another device (the output value correction device of the physical quantity sensor) may be provided on the same semiconductor chip or may be provided on different semiconductor chips. . When the physical quantity sensor and the output value correction device of the physical quantity sensor are provided on different semiconductor chips, the temperature sensor may be provided on the same semiconductor chip as the physical quantity sensor, or may be constituted by a thermistor or the like to correct the output value of the physical quantity sensor. The device and the physical quantity sensor need not be provided on the same semiconductor chip. Further, the physical quantity sensor need not be formed on the semiconductor chip.

  As described above, the adjustment method of the physical quantity sensor device according to the present invention detects the physical quantity other than the temperature depending on the temperature, and corrects the characteristic variation due to the temperature of the detected physical quantity and the characteristic variation of the peripheral device by digital calculation. Useful for sensor devices.

100, 200 Physical quantity sensor device 101, 201 Physical quantity sensor 102, 202 Temperature sensor 103, 203 Vcc voltage dividing unit 104 Operation unit 105 Storage unit 106 First conversion unit 107 Second conversion unit 108 First correction unit 109 Second correction unit 110 Control unit 111 Digital input / output unit 112 Analog input / output unit 113,213 Wiring 120 Setting device 121 First acquisition unit 122 Second acquisition unit 123 Third acquisition unit 124 First calculation unit 125 Second calculation unit 126 Third calculation unit 127 I / O unit 204 arithmetic circuit 205 data storage unit 206 A / D converter 207 D / A converter 208 first correction circuit 209 second correction circuit 210 control circuit 211 digital I / O
212 Analog I / O
214 Preamplifier 215 First sample and hold 216 Second sample and hold 217 Third sample and hold 218 First selector 219 Second selector 220 Reference voltage source 221 Sensor driving circuit 222 Oscillator 231 Voltage source 232, 234 Measurement means 233 Input means

Claims (7)

A physical quantity sensor that outputs an electric signal according to a detected physical quantity, and a first conversion unit that digitally converts an output value of the physical quantity sensor, and a method for adjusting a physical quantity sensor device including:
A step of obtaining an initial output characteristic of the first converter obtained by digitally converting a predetermined analog signal input to the first converter by the first converter;
Calculating first adjustment information for adjusting an output characteristic of the first conversion unit based on an initial output characteristic of the first conversion unit;
A step of obtaining an initial output value obtained by digitally converting the output of the physical quantity sensor by the first conversion unit in which the first adjustment information is reflected;
Calculating initial setting information of the physical quantity sensor based on the initial output value,
A method for adjusting a physical quantity sensor device, comprising:   The physical quantity sensor is provided on a semiconductor chip, and performs a step of obtaining the initial output value and a step of calculating the initial setting information after incorporating the physical quantity sensor device into a package. The method for adjusting a physical quantity sensor device according to claim 1. The physical quantity sensor device further includes a calculation unit that performs digital calculation processing for correcting an output value of the physical quantity sensor digitally converted by the first conversion unit to a predetermined value,
3. The adjustment method for a physical quantity sensor device according to claim 1, wherein the calculation unit corrects to a predetermined value based on the initial setting information. The physical quantity sensor device further includes a second conversion unit that performs analog conversion of a calculation result obtained by the digital calculation processing,
Prior to the step of obtaining the initial output value, the predetermined digital signal input to the second conversion unit is converted into an analog signal by the second conversion unit, thereby obtaining an initial output characteristic of the second conversion unit. The method for adjusting a physical quantity sensor device according to claim 3, further comprising a step.   The adjustment of the physical quantity sensor device according to claim 4, further comprising calculating second adjustment information for adjusting an output characteristic of the second conversion unit based on an initial output characteristic of the second conversion unit. Method.   The adjustment method of the physical quantity sensor device according to claim 1, wherein the reflection of the first adjustment information is weighted with the resolution of the first conversion unit.   The method according to claim 6, wherein the weighting of the resolution is performed by electrically connecting or disconnecting routes of a plurality of redundant circuits.

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