Device, system and method for sensor-assisted microphones

Abstract

Device comprising: a converter (104); an amplifier (502) having an input configured to be coupled to the converter (104) and an output coupled to an analog interface to output a converted electrical signal from the converter (104); a data bus (504) configured to be coupled to an environmental sensor (106); a calibration parameter storage circuit coupled to the data bus (504), the calibration parameter storage circuit comprising calibration data relating a sensitivity of the transducer (104) to environmental measurements provided by the environmental sensor (106); and a digital interface (I 2 C) coupled to the data bus (504) and configured to output the calibration data and the environmental measurements, where the digital interface (I 2C) provides a coupling to an external user device (304), where the digital interface (I 2 C) is configured to receive control signals from the external user device (304) for configuring the device.

Description

TECHNICAL FIELD

[0001] The present invention generally relates to an apparatus, system, and method for sensor-assisted microphones using sensors and transducers, and in particular embodiments relates to techniques and mechanisms for a sensor-assisted microphone. BACKGROUND

[0002] Transducers convert signals from one domain to another and are often used in sensors. Common examples of sensors include microphones and thermometers. Such devices convert environmental phenomena (sound, heat, etc.) into electrical signals.

[0003] Microelectromechanical system (MEMS)-based sensors include a family of transducers produced using microfabrication techniques. MEMS devices, such as MEMS microphones, capture information from the environment by measuring changes in the physical state within the transducer and transmit a converted electrical signal to processing electronics connected to the MEMS sensor. Many MEMS devices detect changes in capacitance within the sensor, which can be converted into a voltage signal using interface circuits. MEMS devices can be manufactured using microfabrication manufacturing techniques similar to those used for integrated circuits. Common MEMS devices include oscillators, resonators, accelerometers, gyroscopes, pressure sensors, microphones, and micromirrors.

[0004] The performance of MEMS devices can be affected by the environment. Environmental dependence can be reduced by designing certain aspects of MEMS devices and components, such as substrate thickness or adhesive properties.

[0005] WO 2015 / 161874 A1 describes an arrangement in which a MEMS microphone and the associated voltage generator as well as a temperature sensor are arranged together in a microphone arrangement, wherein a bias voltage is supplied to the MEMS microphone by the voltage generator as a function of the temperature, so that changes in the sensitivity of the microphone arrangement caused by temperature fluctuations can be compensated.

[0006] WO 2011 / 001195 A1 describes the elimination of increased noise due to temperature changes in a microphone, wherein the noise components of the signal are subtracted from the converted signal by means of a second microphone and thus the remaining signal component is amplified by changing the gain of the amplifier. SUMMARY OF THE INVENTION

[0007] Technical advantages are generally achieved by the embodiments of this disclosure describing systems and methods for sensor-assisted microphones.

[0008] A device according to the main claim, a system according to the independent claim 9 and a method according to the independent claim 15 are provided. Advantageous further developments emerge from the dependent claims.

[0009] According to one embodiment, a device is provided. The device includes a transducer, an amplifier having an input configured to be coupled to the transducer and an output coupled to an analog interface for outputting a converted electrical signal from the transducer, a data bus configured to be coupled to an environmental sensor, a calibration parameter storage circuit coupled to the data bus, the calibration parameter storage circuit including calibration data relating a sensitivity of the transducer to environmental measurements provided by the environmental sensor, and a digital interface coupled to the data bus and configured to output the calibration data and the environmental measurements, the digital interface providing a coupling to an external user device.wherein the digital interface is configured to receive control signals from the external user device for configuring the device.,

[0010] In some embodiments, the device includes an amplifier gain control circuit coupled to the amplifier and a main logic unit coupled to the data bus and the amplifier gain control circuit, the main logic unit configured to adjust the gain of the amplifier based on the calibration data and the environmental measurements. In some embodiments, the device includes the environmental sensor. In some embodiments, the environmental sensor is a temperature sensor. In some embodiments, the environmental sensor is a mechanical stress sensor. In some embodiments, the environmental sensor is on the same semiconductor die as the amplifier and the calibration parameter storage circuit. In some embodiments, the transducer includes a MEMS microphone.In some embodiments, the environmental measurements include temperature measurements, and in some embodiments, the calibration data includes coefficients of a polynomial that correlates a sensitivity of the MEMS microphone with the temperature measurements according to s. mic = k(1 + a * (T - T0) + b * (T - T0) 2), where k is a constant, a and b are the coefficients, T is one of the temperature measurements, and T0 is an ideal temperature measurement. In some embodiments, the calibration data comprises coefficients of a polynomial, the polynomial relating a sensitivity of the transducer to environmental measurements. In some embodiments, the calibration parameter storage circuit comprises a memory. In some embodiments, the apparatus further comprises an application-specific integrated circuit including the calibration parameter storage circuit, the amplifier, the data bus, and the digital interface, and an environmental opening, the transducer being disposed adjacent to the environmental opening, the environmental sensor being disposed proximate the transducer.

[0011] According to another embodiment, a system is provided. The system comprises a device according to any of the embodiments described above and the external user device coupled to the digital interface and the analog interface, wherein the external user device is configured to adjust a level of the converted electrical signal in response to the calibration data and the environmental measurements.

[0012] In some embodiments, the environmental sensor comprises a temperature sensor. In some embodiments, the environmental sensor comprises a mechanical stress sensor. In some embodiments, the calibration data comprises coefficients of a polynomial. In some embodiments, the polynomial sets a sensitivity of the transducer according to s = k(1 + a * (M - M0) + b * (M - M0) 2) with the environmental measurements, where k is a constant, a and b are the coefficients, M is one of the environmental measurements, and M0 is an ideal environmental measurement. In some embodiments, the external user device is configured to receive a converted electrical signal, the calibration data, and the environmental measurements from the device. In some embodiments, the ASIC is configured to adjust a gain of the amplifier in response to the calibration data and the environmental measurements.

[0013] According to yet another embodiment, a method is provided. The method comprises receiving a function relating a sensitivity of the transducer to ambient conditions surrounding the transducer, detecting ambient conditions surrounding the transducer, calculating a drift in the responsiveness of the transducer according to the function and the detected ambient conditions, and adjusting an output electrical signal from the transducer according to the drift in responsiveness, wherein adjusting the output electrical signal from the transducer comprises adjusting the output electrical signal by a user device, the method being performed in a device or system recited above.

[0014] In some embodiments, adjusting the output electrical signal from the transducer comprises adjusting a gain of an amplifier coupled to the transducer and amplifying the output electrical signal using the amplifier coupled to the transducer. In some embodiments, calculating the drift of the transducer's responsiveness comprises evaluating the function with the detected ambient environmental conditions. In some embodiments, receiving the function comprises receiving coefficients of a polynomial that relates a sensitivity of the transducer to ambient environmental conditions of the transducer.

[0015] Various embodiments integrate an environmental sensor with a transducer chip for a MEMS device. Properties of the MEMS device, such as sensitivity, offset, distortion, etc., can be calibrated by combining output from the environmental sensor with a function that relates the environmental sensor to properties of the MEMS device. The function can be a polynomial, for example, and devices can perform calibration by receiving coefficients for the polynomial. Drift in the output signal from the transducer chip can then be corrected according to the calculated change in the properties of the MEMS device. In some embodiments, a system with which the transducer chip is integrated can receive the sensor output and polynomial coefficients along with the output signal of the MEMS device from the transducer chip and perform correction at the system or application level.In some embodiments, the converter chip itself may use the sensor output and the polynomial coefficients to correct the MEMS device output signal at the chip level before it is output to the system.

[0016] Embodiments may also allow for correction of drifts of other components in a converter package. For example, a converter package may include other devices such as an application-specific integrated circuit (ASIC). Performance parameters of these devices may drift depending on the ambient environmental conditions. Inclusion of the environmental sensor may also allow for correction of drifts in the performance parameters of these devices. Such performance parameters may include, for example, bias current, bias impedance, power consumption, gain, skew, clock frequency, etc.

[0017] Various embodiments can achieve advantages. MEMS devices and packages can suffer from relatively greater sensitivity to environmental conditions such as temperature and stress. This sensitivity to the environment can increase as the devices are further reduced in size. Correcting the output electrical signals of MEMS devices can reduce drift of MEMS devices, thereby increasing the accuracy and reliability of such devices. Performing correction at the system or application level can allow for relatively simple circuitry for correcting device outputs in the converter package, while performing correction at the device level can allow for relatively simple programming at the system or application level. Environmental drifts have traditionally imposed design constraints on MEMS packages.Correcting for environmental drifts in the output of a MEMS device can allow MEMS devices to be designed free of these limitations. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] For a more complete understanding of the present invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which: Fig. 1 shows a block diagram of a converter module of an embodiment; Fig. Figure 2 schematically shows cross sections of a converter module of another embodiment; Fig. 3 shows an integrated system of another embodiment; Fig. 4 shows a temperature sensor core; Fig. 5 shows a schematic diagram of a converter system of another embodiment; Fig. 6 shows an audio signal reading method of another embodiment; Fig. 7A shows an audio signal correction method of another embodiment; and Fig. 7B shows a reading method of the corrected audio signal of another embodiment.

[0019] Corresponding reference numerals and symbols in the various figures generally refer to corresponding parts, unless otherwise indicated. The figures have been drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0020] The making and using of embodiments of this disclosure are discussed in detail below. However, it should be noted that the concepts disclosed herein may be embodied in a wide variety of specific contexts, and that the specific embodiments discussed herein are merely illustrative and not intended to limit the scope of the claims. Furthermore, it should be understood that various changes, substitutions, and alterations may be made herein without departing from the spirit and scope of this disclosure as defined by the appended claims.

[0021] While the illustrated embodiments are presented in the context of microphone sensitivity and temperature sensors, it should be recognized that techniques presented herein could be used to correct a wide variety of electrical signals from MEMS devices, and that this correction could be performed on many types of environmental sensors. For example, electrical signals from accelerometers or gyroscopes could also be corrected, and other environmental sensors such as pressure sensors, humidity sensors, resistance sensors, or mechanical stress sensors could be used. Furthermore, more than one sensor and / or sensor type could be used.

[0022] Fig. Figure 1 shows a block diagram of a transducer package 100 of the embodiment. The transducer package 100 includes an ASIC 102, a MEMS microphone 104, a temperature sensor 106, and a housing 108. The housing 108 has an opening 110 that allows coupling of the MEMS microphone 104 to the surrounding environment through acoustic coupling 112 and coupling of the temperature sensor 106 to the surrounding environment through thermal coupling 114. In various embodiments, the positioning and integration of the MEMS microphone 104 and the temperature sensor 106 may vary, as described below.

[0023] ASIC 102 includes a microphone circuit 116 and a sensor circuit 118. MEMS microphone 104 is coupled to microphone circuit 116, and temperature sensor 106 is coupled to sensor circuit 118. Microphone circuit 116 interconnects MEMS microphone 104 to ASIC 102 and other devices. Sensor circuit 118 interconnects temperature sensor 106 to ASIC 102 and other devices. In some embodiments, temperature sensor 106 may be a device integrated with ASIC 102. While the illustrated embodiments show the MEMS microphone 104 and the temperature sensor 106 coupled to the environment through a shared opening and coupled to the ASIC 102, it should be appreciated that the device may have multiple openings and / or may have various interface circuits that are not integrated into a single ASIC die or circuit board.

[0024] Fig. Figure 2 schematically shows cross-sections of a transducer package 200 of the embodiment. The transducer package 200 includes the ASIC 102, the MEMS microphone 104, the temperature sensor 106, a circuit board 202, a cover 204, and an aperture structure 206. The aperture structure 206 may be included in the circuit board 202 so that sound from the surrounding environment can be transmitted through the aperture structure 206 to the MEMS microphone 104. The ASIC 102, the MEMS microphone 104, and the cover 204 may be attached to the circuit board 202 using adhesive or a conductive paste.

[0025] The MEMS microphone 104 includes a diaphragm 208, a backplate 210, and a cavity 212. The diaphragm 208 separates the space or region enclosed by the circuit board 202 and the cover 204 from the surrounding environment available through the aperture structure 206. In some embodiments, acoustic signals propagate through the aperture structure 206 into the cavity 212 of the MEMS microphone 104. Such acoustic signals cause deflection of the diaphragm 208, thereby causing the MEMS microphone 104 to generate transduced electrical signals based on the incoming acoustic signals.

[0026] In the illustrated embodiment, the ASIC 102 and the MEMS microphone 104 are formed on different semiconductor devices and integrated into a single package. In such embodiments, the transducer package 200 includes interconnecting conductive lines 214. The interconnecting conductive lines 214 couple the MEMS microphone 104 to the ASIC 102. The interconnecting conductive lines 214 may also couple the ASIC 102 to conductive lines (not shown) on the circuit board 202, which may be a printed circuit board (PCB). In some embodiments, the ASIC 102 and the MEMS microphone 104 may be formed on the same semiconductor die, and thus the transducer package 200 may not include the interconnecting conductive lines 214.

[0027] Fig. 3 shows an integrated system 300 of the embodiment. The integrated system 300 includes a converter module 302, a user device 304, output signals 306, and sensor and control signals 308. The converter module 302 may, for example, be a module that includes a MEMS device, an environmental sensor, and corresponding support circuitry for correcting the MEMS device with output from the environmental sensor (not shown).

[0028] User device 304 may be a system with which converter module 302 is integrated. While user device 304 is depicted as a single block, it should be appreciated that converter module 302 could be integrated with a system that includes many other functional blocks or devices. For example, user device 304 may be a phone, tablet, computer, or the like. User device 304 receives output signals 306 from converter module 302.

[0029] Output signals 306 include electrical MEMS device output signals from converter chip 302. In some embodiments, output signals 306 are analog signals. Output signals 306 may be, for example, audio signals from a microphone. In some embodiments, converter chip 302 may perform analog-to-digital conversion so that output signals 306 are digital.

[0030] The sensor and control signals 308 are digital signals containing values from the environmental sensor that is integrated with the MEMS device on the converter module 302. The sensor and control signals 308 are transmitted via a digital interface such as an inter-integrated circuit (I 2C), which also allows the user device 304 to configure the converter module 302. In some embodiments, the output signals 306 and the sensor and control signals 308 may be separate output signals. In some embodiments, the signals may share a combined interface such as SoundWire. Alternatively, other digital interface bus types such as I 2 S or pulse code modulation (PCM) can be used.

[0031] The output signals 306 may be corrected by the transducer module 302 or the user device 304. The correction may be performed by identifying a property of the MEMS device in the transducer module 302 as a function of the environmental conditions. For example, the sensitivity of a MEMS microphone may be identified as a function of temperature in some embodiments. Such a function may be determined, for example, according to smic=k(1+a∗(T−T0)+b∗(T−T0)2) where T is the measured temperature, T0 is a reference temperature, k is a constant relating stress to pressure at the reference temperature, and a and b are polynomial coefficients. In some embodiments, k may be approximately 12 mV / Pa. The polynomial coefficients a and b may be stored in the memory of the transducer module 302 or distributed to the user device 304 (discussed below). After the sensitivity of the MEMS microphone has been calculated, a correction amount for the microphone may be calculated according to omic,corrected=omic∗ksmic be calculated, where o mic , corrected the corrected output of the microphone is, o mic the output signal of the microphone is micis the calculated sensitivity of the microphone (discussed above) and k is the constant relating stress to pressure (discussed above). In some embodiments, s mic be recalculated whenever a significant change in temperature occurs.

[0032] In some embodiments, user device 304 performs the correction of output signals 306. In such embodiments, user device 304 also receives the function that relates the sensitivity of the MEMS device to environmental conditions. The function may be provided to user device 304, for example, as coefficients of the polynomial. In some embodiments, the coefficients may be stored in memory in converter chip 302 and included in the sensor and control signals 308 read by user device 304. This memory may, for example, include non-volatile memory such as EEPROM or may be implemented using fuses, electronic fuses (e-fuses), or one-time programmable (OTP) memory. In some embodiments, the memory includes a metal mask.In some embodiments, the coefficients may be in the user device 304. For example, the coefficients may be supplied using an audio encoder / decoder (codec) used by the user device 304. The coefficients may be supplied using mass calibration; for example, the user device 304 may select the coefficients according to an identifier and / or version number encoded in the converter chip 302. The user device 304 corrects the output signals 306, for example, by adjusting the signal levels. The level of the output signals 306 may be adjusted by an amplifier or may be adjusted digitally.

[0033] In some embodiments, converter module 302 performs the correction of output signals 306. Such correction may be performed before output signals 306 are output to user device 304. In such embodiments, the coefficients are stored in memory within converter module 302, and correction calculations are performed by a processor, microcontroller, or state machine included within converter module 302.

[0034] Fig. 4 shows a temperature sensor core 400 which detects a voltage ΔV bewhich is proportional to the temperature. The temperature sensor core 400 includes a first current source 402, a second current source 404, and diodes 406. The diodes 406 may be implemented using diode-connected BJT transistors. In some embodiments, the diodes 406 may be implemented using multiple PNP transistors. The first current source 402 and the second current source 404 are configured to have a fixed ratio m and are supplied to the diodes 406. The temperature sensor core 400 includes node V be1 and V be2 to measure the change in the differential voltage ΔV be of the diodes 406. The temperature of the temperature sensor core 400 can thus be determined according to the ratio ΔVbe=kTq⋅ln(m), where T is the temperature in Kelvin, k is Boltzmann's constant, q is the charge of an electron, and m is the fixed ratio of the first current source 402 to the second current source 404. In some embodiments, the first current source 402 and the second current source 404 may produce the same current, and the diodes 406 may be unequal sizes. In some embodiments, any suitable temperature sensor known in the art may be used.

[0035] Fig. Figure 5 shows a schematic diagram of a transducer system 500 of the embodiment. The transducer system 500 includes the ASIC 102, the MEMS microphone 104, and the temperature sensor 106. In some embodiments, the transducer system 500 may be incorporated into a single transducer package such as that described above with reference to Fig. 1-3 and may be implemented on several different microfabricated dies with circuit elements. In some embodiments, the temperature sensor 106 may be formed on the same microfabricated die as the ASIC 102 and / or the MEMS microphone 104.

[0036] The MEMS microphone 104 contains a bias voltage V mic and differential outputs V inp and Vi nn , which are amplified by the ASIC 102. The MEMS microphone 104 has differential outputs in some embodiments, e.g., when the MEMS microphone 104 is a dual backplate device. In some embodiments, the MEMS microphone may have a single backplate and may have only one output. The bias voltage V mic can be controlled by the ASIC 102 and the differential outputs V inp and V inncan be amplified by the ASIC 102 before being output to a system or application.

[0037] The ASIC 102 contains an amplifier 502, a bus 504, an I 2 C interface 506, a main logic unit 508, a memory 510, a microphone bias circuit 512, and a gain control circuit 514. The amplifier 502 performs signal amplification of the outputs of the MEMS microphone 104, e.g., it amplifies the differential outputs V inp and V inn to provide amplified outputs V outp or V outn In the illustrated embodiment, amplifier 502 is a differential amplifier. In some embodiments, amplifier 502 may be a dual amplifier that provides each respective differential output V inp and V inn In some embodiments, amplifier 502 may amplify the differential outputs V inp and V inncombine to produce a single amplified output. In some embodiments, amplifier 502 includes a single input and dual outputs.

[0038] Devices in the ASIC 102 may be interconnected in the bus 504 (but do not have to be). The I 2 C interface 506 is connected to bus 504 and provides a digital interface for external devices to interact with converter system 500. For example, the I 2 C interface 506 outputs sensor data and / or calibration data to be read by a system with which the transducer system 500 is integrated and may also receive control signals for the ASIC 102.

[0039] The main logic unit 508 is the main processing line for the ASIC 102. It includes functional units and / or circuits for performing power-up procedures, controlling power modes, optimizing, testing, and debugging in the ASIC 102. The main logic unit 508 may also include functions for calibrating the MEMS microphone 104 or other sensors that may be included in the transducer system 500. In some embodiments, the main logic unit 508 performs calculations necessary to correct the differential outputs V inp and V inn The main logic unit 508 may include a control state machine that outputs temperature values or calibration values in the I 2C interface 506. In embodiments where signal correction is performed by ASIC 102, main logic unit 508 may evaluate a function that relates the sensitivity of MEMS microphone 104 to values from temperature sensor 106. Main logic unit 508 may then adjust the gain of amplifier 502 according to the calculated sensitivity of MEMS microphone 104.

[0040] The memory 510 stores values used by the main logic unit 508 or external systems for calibration and / or correction of the output signal. Values in the memory 510 can be used by the main logic unit 508 or can be stored in the I 2C interface 506 to be read by a system or application with which the converter system 500 is integrated. The memory 510 may be volatile memory, such as random access memory (RAM), or may be non-volatile memory, such as flash memory.

[0041] Microphone bias circuit 512 provides a bias voltage to MEMS microphone 104. In some embodiments, microphone bias circuit 512 may be connected to bus 504 and controlled by main logic unit 508. For example, in embodiments where ASIC 102 performs signal correction, main logic unit 508 may perform correction of the output signal by adjusting the sensitivity of MEMS microphone 104. Such adjustment may be achieved by adjusting the bias voltages of MEMS microphone 104. Microphone bias circuit 512 may include devices commonly used in the art for adjusting electrical bias voltage, such as a charge pump.

[0042] Gain control circuitry 514 controls the gain of amplifier 502. The gain control circuitry may be connected to bus 504 and controlled by main logic unit 508. For example, in embodiments where ASIC 102 performs signal correction, main logic unit 508 may perform correction of the output signal by adjusting the gain of amplifier 502. Gain control circuitry 514 may adjust the gain by, for example, including a programmable bias circuit or a switched control element used to select and deselect gain-adjusting components in amplifier 502, such as resistors, capacitors, or selectable gain stages.

[0043] The temperature sensor 106 includes a sensor element 516, an analog-to-digital converter (ADC) 518, and a digital interface 520. In some embodiments, the temperature sensor 106 may be connected to the bus 504 of the ASIC 102. In some embodiments, it may be connected through other mechanisms such as the I 2 C interface 506 is connected to the ASIC 102.

[0044] The sensor element 516 detects temperature changes. It may be a semiconductor device such as the temperature sensor core 400 discussed above. In some embodiments, the transducer system 500 may be arranged such that the sensor element 516 is close to the MEMS microphone 104. Such a configuration allows data acquired by the temperature sensor 106 to be more accurately used to correct for errors or changes in the sensitivity of the output of the MEMS microphone 104. In some embodiments, the sensor element 516 may be part of the MEMS microphone 104. For example, in embodiments where the sensor element 516 is a resistive sensor, the diaphragm of the MEMS microphone 104 may be part of the sensor element 516.In some embodiments, more than one sensor element 516 may be present; for example, there may be one sensor element integrated with the MEMS microphone 104 and another sensor element integrated with the ASIC 102. The electrical output signal from the sensor element 516 may be a voltage representing the change in voltage ΔV. be of diodes 406 in the temperature sensor core 400.

[0045] The ADC 518 converts the electrical output signal from the sensor element 516 into data samples usable by the main logic unit 508. Data can be sampled by the ADC 518 continuously or on demand, for example, by the main logic unit 508.

[0046] The digital interface 520 receives the data samples from the ADC 518, processes them, and provides them to the main logic unit 508. Data samples from the ADC 518 may be digitally filtered by the digital interface 520 using, for example, a low-pass filter function. In some embodiments, the ADC 518 is a sigma-delta (ΣΔ) module, and the digital interface 520 includes a decimation filter for the ADC 518. This decimation filter may be implemented, for example, as a cascaded integrator comb (CIC) filter. Alternatively, the ADC 518 may be implemented using other ADC architectures known in the art. The digital interface 520 may include memory for storing values or coefficients to be used by digital filters. After data samples have been captured and optionally filtered, they are made available to the main logic unit 508.The digital interface 520 may include output registers for forwarding the output temperature values from the temperature sensor 106 to the main logic unit 508.

[0047] Fig. 6 shows an audio signal reading method 600 of the embodiment. The audio signal reading method 600 may indicate operations performed in a system with a sensor-assisted microphone such as the one shown in Fig. 3 shown integrated system 300.

[0048] The audio signal reading method 600 begins by converting an acoustic signal into an analog electrical signal (step 602). Conversion of the acoustic signal can be performed by a MEMS microphone or a transducer component. Next, the system receives a function relating temperature and sensitivity of the MEMS microphone from the transducer component (step 604). The received function can include, for example, coefficients of a polynomial. Next, the system reads values from the temperature sensor on the transducer component (step 606). Next, the system calculates a correction for the analog electrical signal using the temperature sensor values and the function (step 608). Finally, the system applies the correction to the analog electrical signal (step 610). As in Fig. As shown in Figure 6, some operations are performed by the converter module, while others are outsourced to the system. Performing correction of the analog electrical signal in the system allows for simplification of the converter module.

[0049] Fig. 7A shows an audio signal correction method 700 of the embodiment. The audio signal correction method 700 may indicate operations performed in a converter with a supporting sensor such as the one shown in Fig. 5 shown converter system 500.

[0050] The audio signal correction method 700 begins by converting an acoustic signal into an analog electrical signal (step 702). Next, a function relating temperature and sensitivity of the MEMS microphone is received (step 704). The received function may, for example, include coefficients of a polynomial and may be read from memory. Next, sensor values from the temperature sensor are read (step 706). Next, a correction for the analog electrical signal is calculated using the temperature sensor values and the function (step 708). Next, the analog electrical signal is corrected by adjusting the gain of the analog electrical signal (step 710). Adjusting the gain may be performed, for example, by adjusting the bias voltage for the MEMS microphone or adjusting the gain of an amplifier that amplifies the analog electrical signal.Finally, the corrected analog electrical signal is output to a system or application (step 712).

[0051] Fig. 7B shows a corrected audio signal reading method 750 of the embodiment. The corrected audio signal reading method 750 may indicate operations occurring in an application or system that includes a transducer device with a sensor-assisted microphone such as the one shown in Fig. 3 contains user equipment 304 shown.

[0052] The audio signal reading method 750 begins by receiving a corrected analog electrical signal from a converter module (step 752). This concludes the audio signal reading method 750. As shown in the Fig. 7A and Fig.As shown in Figure 7B, correction operations are performed by the converter chip while the system or application reads a corrected signal. Performing correction of the analog electrical signal in the converter chip allows for simplification of the system or application.

[0053] Although the description has been described in detail, it should be understood that various changes, substitutions, and modifications may be made without departing from the spirit and scope of this disclosure as defined by the appended claims. Furthermore, it is not intended that the scope of the disclosure be limited to the particular embodiments described herein, as one of ordinary skill in the art will readily appreciate from this disclosure that processes, machines, methods of manufacture, compositions of matter, means, methods, or steps now existing or later developed may perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein.Accordingly, the appended claims are intended to include within their scope such processes, machines, methods of manufacture, compositions of matter, means, methods, or steps.

Claims

[1] Device comprising: a converter (104); an amplifier (502) having an input configured to be coupled to the converter (104) and an output coupled to an analog interface to output a converted electrical signal from the converter (104); a data bus (504) configured to be coupled to an environmental sensor (106); a calibration parameter storage circuit coupled to the data bus (504), the calibration parameter storage circuit comprising calibration data relating a sensitivity of the transducer (104) to environmental measurements provided by the environmental sensor (106); and a digital interface (I 2 C) coupled to the data bus (504) and configured to output the calibration data and the environmental measurements, where the digital interface (I 2C) provides a coupling to an external user device (304), where the digital interface (I 2 C) is configured to receive control signals from the external user device (304) for configuring the device. [2] The device of claim 1, further comprising: an amplifier gain control circuit (514) coupled to the amplifier (502); and a main logic unit (508) coupled to the data bus (504) and the amplifier gain control circuit (514), the main logic unit (508) configured to adjust a gain of the amplifier (502) based on the calibration data and the environmental measurements. [3] Device according to one of claims 1 to 2, further comprising the environmental sensor (106), wherein optionally the environmental sensor (106) is a temperature sensor or a sensor for mechanical stress. [4] The apparatus of claim 3, wherein the environmental sensor (106) is on the same semiconductor die as the amplifier (502) and the calibration parameter storage circuit. [5] Device according to one of claims 1 to 4, wherein the transducer (104) comprises a MEMS microphone, wherein optionally the environmental measurements comprise temperature measurements and wherein the calibration data comprise coefficients of a polynomial that compares a sensitivity of the MEMS microphone with the temperature measurements according to smic=k(1+a∗(T−T0)+b∗(T−T0)2) where k is a constant, a and b are the coefficients, T is one of the temperature measurements, and T0 is an ideal temperature measurement. [6] The apparatus of any one of claims 1 to 5, wherein the calibration data comprises coefficients of a polynomial, the polynomial relating a sensitivity of the transducer (104) to environmental measurements. [7] The apparatus of any one of claims 1 to 6, wherein the calibration parameter storage circuit comprises a memory (510). [8] Device according to one of claims 1 to 7, wherein the device further comprises: an application-specific integrated circuit (ASIC, (102)) comprising the calibration parameter storage circuit, the amplifier (502), the data bus (504) and the digital interface (I 2 C) contains, and an ambient opening (206), wherein the transducer (104) is arranged adjacent to the ambient opening (206), wherein the environmental sensor (106) is arranged near the transducer (104). [9] System (500), comprising: the device according to one of claims 1 to 8, and the external user device (304) connected to the digital interface (I 2C) and the analog interface, wherein the external user device (304) is configured to adjust a level of the converted electrical signal in response to the calibration data and the environmental measurements. [10] The system of claim 9, wherein the environmental sensor (106) comprises a temperature sensor. [11] The system of claim 9 or 10, wherein the environmental sensor (106) comprises a mechanical stress sensor. [12] The system of any one of claims 9 to 11, wherein the calibration data comprises coefficients of a polynomial, optionally wherein the polynomial determines a sensitivity of the transducer (104) to the environmental measurements according to s=k(1+a∗(M−M0)+b∗(M−M0)2) where k is a constant, a and b are the coefficients, M is one of the environmental measurements, and M0 is an ideal environmental measurement. [13] The system of any one of claims 9 to 12, wherein the external user device (304) is configured to receive a converted electrical signal, the calibration data, and the environmental measurements from the device. [14] The system of any of claims 9 to 13, wherein the ASIC (102) is configured to adjust a gain of the amplifier (502) in response to the calibration data and the environmental measurements. [15] Method comprising: Receiving a function relating a sensitivity of a transducer (104) to ambient conditions of the transducer (104); Detecting ambient conditions of the transducer; Calculating a drift of the responsiveness of the transducer (104) according to the function and the detected ambient conditions; and adjusting an output electrical signal from the transducer (104) according to the drift of the responsiveness, wherein adjusting the output electrical signal from the transducer (104) comprises adjusting the output electrical signal by an external user device (304), wherein the method is carried out in an apparatus according to any one of claims 1 to 8 or in a system according to any one of claims 9 to 14. [16] The method of claim 15, wherein adjusting the output electrical signal from the transducer (104) comprises: Adjusting a gain of an amplifier (502) coupled to the converter (104); and Amplifying, using the amplifier (502) coupled to the transducer (104), the output electrical signal. [17] The method of claim 15 or 16, wherein calculating the drift of the responsiveness of the transducer (104) comprises evaluating the function with the detected ambient environmental conditions. [18] The method of any one of claims 15 to 17, wherein receiving the function comprises receiving coefficients of a polynomial relating a sensitivity of the transducer (104) to ambient environmental conditions of the transducer (104).

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