Sensor system, method for operating a sensor system

Abstract

A sensor system is claimed, comprising a chip arrangement, wherein the chip arrangement has a sensor and an acceleration sensor, wherein the sensor system has a processor circuit, characterized in that the processor circuit is configured in such a way that one or more temperature-dependent quantities and / or properties of the sensor are determined and, by means of the determined one or more temperature-dependent quantities and / or properties of the sensor, a temperature gradient-induced offset of the signal of the acceleration sensor is corrected.

Description

Technical Field

[0001] The present invention relates to a sensor system comprising a chip arrangement having a sensor and an accelerometer, wherein the sensor system has a processor circuit. Background Technology

[0002] For example, microelectromechanical systems (MEMS) used to measure acceleration and / or rotational speed, such as inertial sensors, are mass-produced for various applications. Thus, such sensors are also used extensively in the automotive and consumer sectors. A "balance bar" is typically used for capacitive accelerometers with a detection direction (z-direction) perpendicular to the wafer plane. The sensor principle of these balance bars is based on a spring-mass system in which, in the simplest case, a movable vibrating mass with two opposing electrodes fixed to a substrate forms two parallel-plate capacitors. The vibrating mass is connected to a base via one or more torsion springs. If the mass structures on both sides of the torsion spring are of different sizes (e.g., due to an additional mass on one side), then under z-acceleration, this mass will rotate relative to the torsion spring, which acts as a rotation axis, causing the balance bar to move. Therefore, the electrode spacing becomes smaller on the side with the larger mass structure and larger on the other side. The change in capacitance is a measure of the applied acceleration. Such accelerometers are disclosed, for example, in EP 0 244 581 A1 and EP 0 773 443 B1. Accelerometers are typically hermetically sealed to protect them from environmental influences and to ensure defined fluid damping, which together determines the transmission characteristics of the sensor, wherein a defined air pressure is sealed within the sensor cavity.

[0003] Such stabilizer bars are common, but they present several technical challenges that make application difficult due to the very high requirements for offset stability. While offset stability can be significantly improved through modern construction methods of stabilizer bars, for example, according to DE 10 2009 000 167 A1, the requirements for offset stability continue to increase for different applications. Therefore, this parameter remains a particularly critical performance aspect.

[0004] A crucial error mechanism related to the offset stability of accelerometers is the emergence of radiance forces, generated when the temperature distribution within the sensor cavity is uneven. For example, if the sensor is near a heat source, such as an application processor on a smartphone's printed circuit board (PCB), vertical or lateral temperature gradients, or combinations thereof, can be generated within the sensor module depending on the sensor's relative position to the heat source. Consequently, a temperature gradient is also generated within the MEMS accelerometer chip itself. Therefore, the temperature of the movable counterweight and the MEMS substrate are not in thermal equilibrium. For example, the MEMS substrate with the bottom electrode may be slightly hotter than the counterweight structure. This thermal gradient induces the movement of gas particles within the sensor cavity, whose collisions with the movable sensor structure can lead to a measurable parasitic deflection of the counterweight and thus an offset signal. This effect is described in C. Nagel, T. Zoller, F. Ante, J. Classen, M. Putnik, and J. Mehner's "Radiometric effects in MEMS accelerometers" (IEEE Sensors 2017, Glasgow, 2017, pp. 1-3, doi: 10.1109 / ICSENS.2017.8233871). Here, TGO (temperature gradient offset, i.e., the offset caused by a temperature gradient) is introduced as a characteristic parameter. The change in offset due to the temperature gradient is sensitive to the fabrication technology, especially the pressure and type of the enclosed gas, and the properties of the MEMS structure, especially its symmetry, but also, for example, the number and size of perforations in movable structures.

[0005] Different methods for minimizing the TGO effect in accelerometers are described in the prior art. The lateral temperature gradient within the MEMS chip can be largely compensated for by an arrangement of two balance bar structures twisted by 180°, as described in US 2019 0 100 426 A1. Although the two balance bars are slightly deflected, the parasitic electrical signals of the two balance bars are precisely compensated for each other again due to the 180° rotation arrangement, since the lighter balance bar side faces the hot side and the heavier balance bar side faces the hot side.

[0006] However, the dual arrangement is not helpful in the vertical temperature gradient because the heavier of the two stabilizers deflects in the same direction. This, however, corresponds precisely to the motion of the two stabilizers during acceleration in the z-direction, thus failing to distinguish the parasitic TGO signal from the true acceleration.

[0007] A compensation method is proposed in US 2020 0 039 818 A1, in which at least one thermocouple is implemented by additional bonding wires arranged on the outside of the MEMS chip to compare the local temperature on the back side of the MEMS with the ASIC (Application-Specific Integrated Circuit) temperature, and a correction value for the offset of the accelerometer is derived from the obtained temperature difference. However, this method is technically expensive because, on the one hand, it requires additional bonding wires, which limit the minimum package thickness that can be achieved, and on the other hand, additional areas are needed in the analog section of the ASIC for reading the thermocouple.

[0008] So far, temperature gradients have been discussed in conjunction with z-accelerometers. However, the TGO effect may also occur in lateral accelerometers (or x / y sensors), i.e., sensors with a detection direction parallel to the substrate surface of the MEMS chip. Summary of the Invention

[0009] The objective of this invention is to provide a sensor system and a method for operating the sensor system, by means of which the performance of an accelerometer, particularly the offset stability of the accelerometer, can be effectively improved.

[0010] The sensor system according to the invention has the following advantages over the prior art: It can correct for temperature gradient-induced offsets in the accelerometer signal. This enables cost-effective and high-quality offset correction of the accelerometer, which can be advantageously achieved without significant additional technical or manufacturing costs. According to the invention, parasitic TGO effects in the accelerometer within a sensor system, such as an IMU (Inertial Measurement Unit) comprising a sensor and at least a single-axis accelerometer, can therefore be effectively corrected.

[0011] The embodiments and advantages of the present invention can be applied to z-accelerometers, but can also be applied to lateral accelerometers or combined accelerometers, wherein the combined accelerometer has a detection axis in the z-direction and at least one lateral detection axis.

[0012] It is known from the prior art that ASIC analysis processing chips or ASIC structures for inertial sensors can have integrated temperature sensors to enable, for example, temperature-based correction of offset errors and / or sensitivity errors. For instance, such temperature sensors can be used to compensate for the slight increase in sensitivity of MEMS accelerometers with increasing temperature due to the softening of the silicon spring (the temperature coefficient of silicon E-module is in the range of 60 to 70 ppm / K). However, temperature gradients cannot be calculated to compensate for the TGO of the accelerometer using only a temperature sensor integrated in the ASIC.

[0013] Conversely, according to the present invention, the offset of the accelerometer signal caused by the temperature gradient can be corrected or compensated. To this end, according to the present invention, one or more temperature-related parameters and / or properties of the sensor are obtained. The offset of the accelerometer signal caused by the temperature gradient is corrected using the obtained one or more temperature-related parameters and / or properties of the sensor.

[0014] Advantageous configurations and extensions of the invention can be derived from the preferred embodiments and the description with reference to the accompanying drawings.

[0015] According to one embodiment of the invention, the chip arrangement includes a MEMS chip arrangement, wherein the MEMS chip arrangement includes at least one MEMS chip with an accelerometer sensor, thereby advantageously enabling, in particular, estimation of temperature in the MEMS functional layer of the accelerometer sensor by means of the sensor. Here, the sensor is preferably also part of the MEMS chip arrangement. It is conceivable that the sensor and the accelerometer sensor are constructed in the same MEMS chip. In this case, it is conceivable that the MEMS chip arrangement includes only one chip, i.e., a common MEMS chip. However, it is also conceivable that the sensor is constructed in another MEMS chip of the MEMS arrangement, thus the MEMS chip arrangement includes at least two chips, i.e., one MEMS chip and another MEMS chip.

[0016] According to one embodiment of the present invention, the offset of the accelerometer signal caused by the temperature gradient is determined by the temperature gradient in the vertical direction perpendicular to the main extension plane of the MEMS chip having the accelerometer, wherein, preferably, the MEMS chip having the accelerometer has a temperature gradient in the vertical direction, particularly preferably between the substrate and the cover of the MEMS chip, thereby enabling correction or compensation of the TGO effect caused by the vertical temperature gradient.

[0017] According to one embodiment of the invention, the chip arrangement includes an ASIC structure, wherein, preferably, the MEMS chip arrangement and the ASIC structure are staggered in the vertical direction, wherein the processor circuitry is configured such that the temperature gradient-induced offset of the accelerometer signal is corrected.

[0018] - This enables the determination and / or estimation of the temperature difference between the ASIC structure and the sensor using one or more temperature-related parameters and / or properties of the sensor, and

[0019] This allows for the correction of temperature gradient-induced offsets in the accelerometer signal using the determined and / or estimated temperature differences. It enables the determination of the sensor's temperature or the temperature of its functional layer using determined, temperature-related parameters and / or properties, and comparison with the ASIC temperature. Here, the ASIC structure is preferably arranged at least vertically, i.e., perpendicularly to the MEMS chip and thus misaligned with both the sensor and the accelerometer. Therefore, the temperature difference between the MEMS chip arrangement and the ASIC structure can be determined. This allows for the estimation of the vertical temperature gradient present in the MEMS chip.

[0020] According to one embodiment of the invention, an ASIC structure has an integrated temperature sensor or is equipped with a temperature sensor, wherein the temperature sensor is configured such that the temperature of the ASIC structure is determined by means of the temperature sensor, and the processor circuit is configured such that, using the determined temperature of one or more temperature-related parameters and / or properties of the sensor, and additionally using the determined temperature of the ASIC structure, the temperature difference between the ASIC structure and the sensor can be determined and / or estimated, thereby enabling the temperature of the ASIC structure to be measured or determined by the temperature sensor. The measured temperature of the ASIC structure can then be used in conjunction with the sensor temperature, which can be determined by one or more temperature-related parameters and / or properties of the sensor, to calculate the temperature difference between the ASIC structure and the sensor. The temperature difference thus determined can then be used to compensate for the offset of the accelerometer caused by the temperature gradient.

[0021] According to one embodiment of the invention, the processor circuit is configured such that the offset of the accelerometer signal caused by the temperature gradient is corrected by means of the following relationship:

[0022] Offset korrigiert =Offset gemessen -const TGO *dT,

[0023] Among them, Offset korrigiert It is a corrected offset of the accelerometer signal.

[0024] Among them, Offset gemessen It is the measured offset of the signal from the accelerometer.

[0025] Among them, const TGO It is a constant factor.

[0026] Where dT is the temperature difference between the ASIC structure and the sensor.

[0027] Among them, const TGO In particular, factors specific to sensor type and / or specific to sensor channel, where const TGO Preferably, it can be obtained during the qualification phase and / or startup phase of the sensor system, which particularly advantageously enables TGO compensation for the offset of the accelerometer caused by the vertical temperature gradient in the MEMS chip.

[0028] According to one embodiment of the invention, the signal of the accelerometer is the signal of a first axis of the accelerometer, wherein the accelerometer has at least one second axis, and wherein the processor circuitry is configured such that a temperature gradient-induced offset of another signal of the second axis of the accelerometer is corrected by means of one or more temperature-related parameters and / or properties of the sensor, thereby enabling correction of the TGO effect for a multi-axis accelerometer. Correspondingly, temperature gradient-induced offsets can also be corrected for the third axis of the accelerometer.

[0029] According to one embodiment of the invention, the sensor is a rotation speed sensor, which advantageously allows the application of correction methods according to different embodiments of the invention to a sensor system including an acceleration sensor and a rotation speed sensor. Therefore, the local temperature gradient within the combined rotation speed sensor and acceleration sensor can be estimated using temperature-related parameters and / or properties of the rotation speed sensor, and the information obtained therefrom can be used to correct the offset signal of the acceleration sensor. The rotation speed sensor may have one or more sensing axes.

[0030] Typically, temperature gradients within the MEMS chip where the speed sensor is housed do not cause any significant signal changes in the speed sensor, neither in terms of sensitivity nor in terms of offset or noise. Therefore, in an IMU (Inertial Measurement Unit) where the accelerometer and speed sensor are housed in the same housing, only the acceleration channel is affected by the temperature gradient. For this reason, speed sensors can be particularly advantageous for determining the temperature of MEMS functional layers.

[0031] According to one embodiment of the present invention, one or more temperature-related parameters and / or properties include one or more of the following parameters and / or properties:

[0032] - The drive frequency of the speed sensor,

[0033] - Driving quality of the drive oscillation of the speed sensor (Antriebsgüte)

[0034] - The drive voltage required to maintain a fixed oscillation amplitude for the drive oscillation of the speed sensor.

[0035] - The quadraturation of the speed sensor advantageously allows for the measurement of the temperature within the functional layer of the speed sensor itself using temperature-related parameters and / or properties. In many cases, this temperature can be read anyway, or at least without significant overhead. Therefore, in a particularly advantageous manner, additional technical precautions (e.g., additional bonding wires and / or additional analog analysis processing circuitry) are unnecessary.

[0036] According to one embodiment of the invention, the processor circuit includes or is configured as a microcontroller, thereby enabling an advantageous processor circuit capable of performing signal reading and signal correction for signal offset from the accelerometer.

[0037] Another subject of the present invention is a method for operating a sensor system according to one embodiment of the present invention.

[0038] -In the determination step, one or more temperature-related parameters and / or properties of the sensor are determined, and

[0039] - In the calibration step, the offset of the accelerometer signal caused by the temperature gradient is corrected by using one or more temperature-related parameters and / or properties of the sensor obtained from the calibration step.

[0040] According to one embodiment of the present invention, and particularly the method, a chip arrangement can include an ASIC structure, wherein the ASIC structure has an integrated temperature sensor, or wherein the ASIC structure is equipped with a temperature sensor.

[0041] - In the ASIC temperature determination step, the temperature of the ASIC structure is determined using a temperature sensor.

[0042] - In the temperature difference calculation step, the processor circuit, using one or more temperature-related parameters and / or attributes of the sensor and the calculated temperature of the ASIC structure, calculates and / or estimates the temperature difference between the ASIC structure and the sensor.

[0043] In the calibration step, using a processor circuit, the offset of the accelerometer signal caused by the temperature gradient is corrected based on the temperature difference obtained in the temperature difference calculation step and / or the estimated temperature difference. Advantageously, this allows for effective correction of the offset of the accelerometer signal caused by the temperature gradient. Here, the sensor preferably relates to a rotational speed sensor.

[0044] According to a preferred embodiment of the invention, it is particularly possible to determine the temperature within the MEMS functional layer of the speed sensor using temperature-related parameters and / or properties of the speed sensor. The temperature-related parameters and / or properties (or parameters) of the speed sensor can be read by a processor circuit, preferably by a microcontroller. Additionally, the ASIC temperature can be analyzed and processed by the processor circuit. If the two temperatures are consistent, for example, in thermal equilibrium between the ASIC chip and the MEMS chip, the accelerometer signal is output unchanged and, in particular, without correction. Conversely, in the case of a temperature difference between the ASIC structure and the speed sensor, the temperature gradient within the MEMS chip is estimated by the processor circuit, and the offset signal of the accelerometer channel is output with appropriate correction, which precisely compensates for the error signal defined by the TGO. The temperature-related parameters and / or properties of the speed sensor can, in particular, be the drive frequency and / or drive quality of the speed sensor and / or the drive voltage required to maintain a fixed oscillation amplitude of the speed sensor and / or the quadrature of the speed sensor (especially when the quadrature of the speed sensor is temperature-dependent).

[0045] For methods of operating a sensor system, the advantages and configurations already described in conjunction with the sensor system according to the invention or in conjunction with embodiments of the sensor system according to the invention can be used. Attached Figure Description

[0046] Embodiments of the present invention are shown in the accompanying drawings and described in more detail in the following description.

[0047] Figure 1 A schematic diagram showing the heat source that causes the temperature gradient is shown;

[0048] Figure 2a and 2b Schematic diagrams showing chip arrangements according to different embodiments of the present invention;

[0049] Figure 3This illustration schematically depicts a method according to one embodiment of the present invention;

[0050] Figure 4 This illustration schematically demonstrates the determination of temperature difference according to one embodiment of the present invention;

[0051] Figure 5a , 5b Figures 5c and 5c show schematic diagrams of sensor systems according to different embodiments of the present invention.

[0052] In different figures, the same parts are always given the same reference numerals and are therefore usually listed or mentioned only once. Detailed Implementation

[0053] exist Figure 1 The diagram illustrates a heat source 103 that can cause a temperature gradient in a sensor or chip arrangement 100. The chip arrangement 100 is located near the heat source 103, for example, near the application processor 103 on a printed circuit board (PCB) of a smartphone. Depending on the relative position of the chip arrangement 100 with respect to the heat source 103, a vertical or lateral temperature gradient, or a combination thereof, can be formed in the sensor module. For example, for a sensor arrangement based on… Figure 1 When the chip arrangement 100 is positioned at the first location 101, a vertical temperature gradient appears within the MEMS chip 100, indicated by the box arrow 101'. For according to Figure 1 With the chip arrangement 100 positioned at the second location 102, a lateral temperature gradient occurs within the MEMS chip 100, indicated by the box arrow 102'. Here, the chip arrangement 100 refers to one or more integral sensors, including the MEMS chip, the analytical processing ASIC, and the outer packaging (e.g., LGA substrate and mold mass). Therefore, a temperature gradient is also generated in the MEMS chip 13, which has the accelerometer 11 and is part of the chip arrangement 100. Consequently, the temperature of the movable structure of the accelerometer (e.g., the balance bar structure) and the temperature of the substrate 13' of the MEMS chip 13 are not in thermal equilibrium. The substrate 13' with the bottom electrode may, for example, be slightly hotter than the movable structure of the accelerometer 11. The movement of gas particles in the sensor cavity caused by the thermal gradient, and their collisions with the movable sensor structure, may result in a measurable parasitic deflection of the movable sensor structure (e.g., the balance bar) and thus may cause an offset signal.

[0054] exist Figure 2a The diagram shows a schematic of a chip arrangement 1 according to an embodiment of the present invention. Figure 2aThis diagram shows a MEMS chip arrangement 10 with sensor 12 configured as speed sensor 12' and acceleration sensor 11. Speed ​​sensor 12' and acceleration sensor 11 are arranged on the same MEMS chip 13. Chip arrangement 1 or MEMS chip arrangement 10 therefore includes only a single MEMS chip 13, which in turn has sensors 11 and 12'. MEMS chip 13 includes a substrate 13' and a cover 13', which form cavities for sensors 11, 12'. MEMS chip 13 is mechanically (e.g., by adhesive) and electrically (e.g., by bonding wires not shown in the image or alternatively by solder balls) connected to an analytical processing ASIC structure 20. ASIC structure 20 is arranged below MEMS chip 13 in a vertical direction 200 perpendicular to the main extension plane 210 (or perpendicular to the substrate plane). ASIC structure 20 is mechanically connected to the substrate 21 of the LGA housing via another adhesive layer 22. MEMS chip 13 and ASIC structure 20 are cast with a molding quality 25 for mechanical protection. Sensors 11, 12' are mechanically and electrically connected to printed circuit board 204 via solder contacts 26 on LGA substrate 21. ASIC structure 20 includes an integrated temperature sensor 20', by which the temperature of ASIC structure 20 can be determined or measured.

[0055] exist Figure 2b A schematic diagram of a chip arrangement 1 according to another embodiment of the present invention is shown. According to... Figure 2b Another implementation method and in Figure 2a The difference in the embodiment shown is that the sensor 12, configured as a rotation speed sensor 12', and the acceleration sensor 11 are respectively arranged in their own MEMS chips 13 and 14. Chip arrangement 1 therefore includes MEMS chip arrangement 10, which has a MEMS chip 13 with acceleration sensor 11 and another MEMS chip 14 with rotation speed sensor 12'. Chip arrangement 1 or MEMS chip arrangement 10 therefore includes two separate MEMS chips 13 and 14 arranged adjacent to each other. The two MEMS chips 13 and 14 are cast together with molding quality 25.

[0056] exist Figure 3 The diagram illustrates a flowchart of a method according to an embodiment of the present invention, by which the TGO of the accelerometer 11 can be compensated or corrected.

[0057] In the ASIC temperature determination step 301, the temperature of the ASIC structure 20 is determined by the temperature sensor 20' and read by the processor circuit 40 (e.g., a microcontroller).

[0058] In step 302, one or more temperature-related parameters and / or attributes of the speed sensor 12 are obtained or read by the processor circuitry 40 before, during, and / or after the ASIC temperature determination step 301. The one or more temperature-related parameters and / or attributes may relate to, for example, the drive frequency of the speed sensor 12'. The following embodiments are illustrated based on the drive frequency of the speed sensor 12'. However, alternatively or additionally, other temperature-related parameters and / or attributes of the speed sensor 12' may also be used.

[0059] Based on the driving frequency of the speed sensor 12', the processor circuit 40 calculates the local temperature in the region of the MEMS functional layer of the speed sensor 12' or the temperature (T) of the MEMS functional layer of the speed sensor 12' in the temperature difference calculation step 303 using a stored algorithm. MEMS ) and the temperature of the ASIC structure (T) ASIC The temperature difference between them.

[0060] The corresponding calculations can be performed as follows:

[0061]

[0062] Here:

[0063] -Freq(T+dT), the current drive frequency read by processor circuit 40.

[0064] -Freq(T), the drive frequency, the speed sensor 12' has this drive frequency at temperature T in thermal equilibrium (ASIC temperature = MEMS temperature), and

[0065] -dFreq(T) / dT, the temperature dependence of the driving frequency in thermal equilibrium. In the silicon-based MEMS speed sensor 12', this is mainly determined by the aforementioned temperature dependence of the elastic coefficient E of silicon, and therefore (due to the relationship Freq~E^0.5) lies in the range of -30 to 35 ppm / K.

[0066] Since the speed sensor 12' and the acceleration sensor 11 are arranged on the same MEMS chip 13 or on different MEMS chips 13 and 14 arranged on the same MEMS chip 10, the MEMS functional layer of the acceleration sensor 11 has a similar temperature to the MEMS functional layer of the speed sensor 12'. Therefore, the local temperature of the acceleration sensor 11 can also be derived from the local temperature of the speed sensor 12'.

[0067] In calibration step 304, the calibrated offset of the accelerometer 11 is now calculated in the processor circuit 40 from the calculated temperature difference dT or the calculated temperature difference between the speed sensor 12 and the ASIC structure 20, preferably according to the following formula proportional to the calculated temperature difference:

[0068] Offset korrigiert,i =Offset gemessen,i -const TGO,i *dT,

[0069] Among them, Offset korrigiert,i It is a corrected offset of the accelerometer signal.

[0070] Among them, Offset gemessen,i It is the measured offset of the signal from the accelerometer.

[0071] Among them, const TGO,i It is a constant factor that is particularly specific to the sensor type and / or to the sensor channel.

[0072] Where dT is the temperature difference T between the ASIC structure 20 and the speed sensor 12'. MEMS -T ASIC Factor const TGO,i This can be determined during the identification and / or startup phases of the sensor system. In the above equation, index i represents the possible detection axis or sensing direction x, y, z. Each channel of the accelerometer 11 typically requires its own correction coefficient.

[0073] Steps 301, 302, 303, and 304 can preferably be performed by or with the aid of a processor circuit 40 configured as a microcontroller.

[0074] exist Figure 4The temperature difference dT between the speed sensor 12' and the ASIC structure 20 is illustrated graphically according to an embodiment of the present invention. Here, the temperature of the ASIC structure is plotted on the x-axis and the drive frequency of the speed sensor 12' is plotted on the y-axis. In thermal equilibrium (where the speed sensor 12' and the ASIC structure 20 have the same temperature), the drive frequency of the speed sensor 12' follows characteristic curve 401. If a value T1 is measured for the temperature of the ASIC structure, the drive frequency of the speed sensor 12' should therefore be located at point 411. If a higher drive frequency of the speed sensor 12' is now actually measured / obtained at point 412, this indicates that the local temperature in the MEMS functional layer of the speed sensor 12' is lower than the measured temperature value T1 of the ASIC structure. In thermal equilibrium between the MEMS and the ASIC, the measured drive frequency will be set at the lower ASIC temperature T2 (point 413 on characteristic curve 401). Therefore, the temperature difference dT = T2 - T1 corresponds to the temperature difference between the MEMS functional layer of the speed sensor 12' and the ASIC structure 20, and is also a measure of the local temperature gradient within the MEMS chip 13 with the acceleration sensor 11 due to the vertical (i.e., in the vertical direction 200) stacking arrangement of the ASIC structure 20 and the MEMS chip arrangement 10, which is responsible for the magnitude of the parasitic TGO effect.

[0075] Ideally, it is conceivable that the correction coefficients or factors are identical for all samples of the same sensor or sensor type during mass production. However, if fundamental properties in the sensor structure that may affect the temperature distribution within the sensor change, such as the thickness of the ASIC structure 20, the thickness of the MEMS substrate, or the thickness of the molding quality above the MEMS chips 13, 14, then re-determination of the correction coefficients is often necessary or at least advantageous.

[0076] To accurately measure the drive frequency of the speed sensor directly, it may be advantageous for the processor circuitry 40 or microcontroller, in addition to the parameters internal to the ASIC, to additionally intercept the signal from an external clock generator (e.g., a frequency-stabilized oscillator) and compare it with the internal signal of the ASIC. Such an oscillator is typically not integrated into the sensor module itself.

[0077] exist Figure 3 and Figure 4In this process, one embodiment of the method is described, in which the driving frequency of the speed sensor 12' is used as a temperature-dependent parameter or attribute of the speed sensor 12'. However, other parameters of the sensor 12 or the speed sensor 12' can also be used as an alternative or addition to the driving frequency. Alternative parameters or attributes of the speed sensor 12' for determining the local MEMS temperature can be, for example, the driving quality or driving voltage of the speed sensor 12'. In a closed cavity, the quality of the mechanical resonator (i.e., also particularly the speed sensor 12') varies with temperature T. The driving voltage of the sensor is typically tracked in a proportional manner as temperature changes, so that the oscillation amplitude remains constant, ensuring that the mechanical and electrical sensitivity of the sensor remains unchanged. In this case, the driving voltage varies according to T^0.25, since the driving force is proportional to the square of the driving voltage. By precisely measuring the required driving voltage, the local temperature of the MEMS functional layer of the sensor can also be derived. In some speed sensors, the orthogonal quantity (the interference signal that is 90° phase-shifted from the useful signal) varies with temperature. If the relationship between the orthogonal quantity and temperature is known, the local temperature of the speed sensor 12' can also be derived from the measurement of the orthogonal quantity (or the voltage or signal required to compensate for the orthogonal quantity).

[0078] When using measurement parameters different from the driving frequency, the above formula is matched accordingly and other or new correction coefficients or factors are obtained.

[0079] Therefore, a sensor system including chip arrangement 1 can be implemented, wherein chip arrangement 1 has sensor 12 and acceleration sensor 11, wherein the sensor system has processor circuitry 40, and processor circuitry 40 is configured such that:

[0080] - Determine one or more temperature-related parameters and / or properties of sensor 12, and

[0081] - The offset of the signal from the accelerometer 11 caused by the temperature gradient is corrected by using one or more temperature-related parameters and / or properties of the sensor 12 obtained.

[0082] exist Figure 5a , 5b Schematic diagrams of sensor systems 1 according to different embodiments of the present invention are shown in Figures 5c and 5c, respectively, as top views on the main extension plane 210. The processor circuit 40 is configured as a microcontroller in each of these embodiments.

[0083] exist Figure 5aIn this configuration, the microcontroller used for data correction is located outside of chip arrangement 1, which includes MEMS chip arrangement 10 having sensor 12 and accelerometer 11. The microcontroller is mounted as a separate component 500 on application printed circuit board 30. The separate component 500 (i.e., processor circuitry 40) may relate to, for example, an application processor in a smartphone.

[0084] exist Figure 5b In this sensor module, the microcontroller used for data correction is housed together with sensor 12 (or speed sensor 12') and acceleration sensor 11. Specifically, the microcontroller can be integrated into or connected to an ASIC architecture 20 or an ASIC analysis processing chip. The sensor module then contains, for example, three chips 13, 14, and 20.

[0085] exist Figure 5c Another alternative arrangement is shown. The microcontroller, as its own chip 520, is separately integrated into the same sensor module along with the ASIC architecture 20 or ASIC analysis processing chip. The sensor module then contains four chips 13, 14, 20, and 520. Figure 5b and 5c An alternative to the example shown could be to integrate the accelerometer 11 and the sensor 12 onto a common MEMS chip 13, respectively.

Claims

1. A sensor system comprising a chip arrangement (1), wherein, The chip arrangement (1) has a sensor (12) and an acceleration sensor (11), wherein the sensor system has a processor circuit (40). The processor circuit (40) is characterized in that it is configured such that: - Determine one or more temperature-related parameters and / or properties of the sensor (12), and - The temperature gradient-induced offset of the signal from the accelerometer (11) is corrected using one or more temperature-related parameters and / or properties of the sensor (12). The chip arrangement (1) includes an ASIC structure (20), wherein the ASIC structure (20) has an integrated temperature sensor (20') or the ASIC structure (20) is associated with a temperature sensor (20'), wherein the temperature sensor (20') is configured such that the temperature of the ASIC structure (20) is determined by means of the temperature sensor (20'), wherein the processor circuit is configured such that the temperature difference between the ASIC structure (20) and the sensor (12) is determined and / or estimated by means of one or more temperature-related parameters and / or properties of the sensor (12) and by means of the determined temperature of the ASIC structure (20), and the offset of the signal of the accelerometer (11) caused by the temperature gradient is corrected according to the determined and / or estimated temperature difference.

2. The sensor system according to claim 1, characterized in that, The chip arrangement (1) includes a MEMS chip arrangement (10), wherein the MEMS chip arrangement (10) includes at least one MEMS chip (13), wherein the at least one MEMS chip (13) has the acceleration sensor (11).

3. The sensor system according to claim 2, characterized in that, The offset of the signal of the accelerometer (11) caused by the temperature gradient is determined by the temperature gradient in the following vertical direction (200): the vertical direction (200) is perpendicular to the main extension plane (210) of the MEMS chip (13) having the accelerometer (11).

4. The sensor system according to claim 3, characterized in that, The MEMS chip arrangement (10) and the ASIC structure (20) are arranged in a staggered manner in the vertical direction (200).

5. The sensor system according to claim 3, characterized in that, The MEMS chip (13) with the acceleration sensor (11) has a temperature gradient in the vertical direction (200).

6. The sensor system according to claim 5, characterized in that, The MEMS chip (13) has a temperature gradient between the substrate (13') and the cover (13'') of the MEMS chip (13).

7. The sensor system according to any one of claims 1 to 6, characterized in that, The processor circuit (40) is configured such that the temperature gradient-induced offset of the signal from the accelerometer (11) is corrected by means of the following relationship: ， Among them, Offset korrigiert It is the corrected offset of the signal from the accelerometer. Among them, Offset gemessen It is the measured offset of the signal from the acceleration sensor. Among them, const TGO It is a constant factor. Wherein, dT is the temperature difference between the ASIC structure (20) and the sensor (12).

8. The sensor system according to claim 7, characterized in that, const TGO It is a sensor type-specific and / or sensor channel-specific factor.

9. The sensor system according to claim 8, characterized in that, const TGO It can be obtained during the identification phase and / or the startup phase of the sensor system.

10. The sensor system according to any one of claims 1 to 6, characterized in that, The signal of the accelerometer (11) is the signal of the first axis of the accelerometer (11), wherein the accelerometer (11) has at least one second axis, wherein the processor circuit (40) is configured such that the offset of another signal of the second axis of the accelerometer (11) caused by the temperature gradient is corrected by means of one or more temperature-related parameters and / or properties of the sensor (12).

11. The sensor system according to any one of claims 1 to 6, characterized in that, The sensor (12) is a speed sensor (12').

12. The sensor system according to claim 11, characterized in that, The one or more temperature-related parameters and / or properties include one or more of the following parameters and / or properties: - The driving frequency of the speed sensor (12'); - The driving quality of the driving oscillation of the speed sensor (12'), - The driving voltage required to maintain a fixed oscillation amplitude for the driving oscillation of the speed sensor (12'); - The orthogonality of the speed sensor (12').

13. The sensor system according to any one of claims 1 to 6, characterized in that, The processor circuit (40) includes or is configured as a microcontroller.

14. A method for operating a sensor system according to any one of claims 1 to 13, - In step (302), one or more temperature-related parameters and / or properties of the sensor (12) are determined. - in, In the calibration step (304), the offset of the signal of the accelerometer (11) caused by the temperature gradient is corrected by means of one or more temperature-related parameters and / or properties of the sensor (12).

15. The method according to claim 14, characterized in that, The chip arrangement (1) includes an ASIC structure (20), wherein the ASIC structure (20) has an integrated temperature sensor (20'), or wherein the ASIC structure (20) is equipped with a temperature sensor (20'). - In the ASIC temperature determination step (301), the temperature of the ASIC structure (20) is determined using the temperature sensor (20'). - In the temperature difference calculation step (303), the temperature difference between the ASIC structure (20) and the sensor (12) is calculated and / or estimated by means of the processor circuit (40), by means of one or more temperature-related parameters and / or attributes of the sensor (12) and by means of the temperature of the ASIC structure (20). - In the correction step (304), the processor circuit (40) performs correction of the offset of the signal of the accelerometer (11) caused by the temperature gradient based on the temperature difference obtained and / or estimated in the temperature difference calculation step (303).

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