WO2016008370A1 - Tmr近场磁通信系统 - Google Patents

Tmr近场磁通信系统 Download PDF

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Publication number
WO2016008370A1
WO2016008370A1 PCT/CN2015/083461 CN2015083461W WO2016008370A1 WO 2016008370 A1 WO2016008370 A1 WO 2016008370A1 CN 2015083461 W CN2015083461 W CN 2015083461W WO 2016008370 A1 WO2016008370 A1 WO 2016008370A1
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Prior art keywords
tmr
magnetoresistive sensor
bridge
communication system
output
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PCT/CN2015/083461
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English (en)
French (fr)
Inventor
迪克·詹姆斯·G
郭海平
薛松生
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江苏多维科技有限公司
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Priority to EP15821664.8A priority Critical patent/EP3171615B1/en
Priority to JP2017502711A priority patent/JP6609305B2/ja
Priority to US15/326,587 priority patent/US10277992B2/en
Publication of WO2016008370A1 publication Critical patent/WO2016008370A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
    • H04R25/55—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception using an external connection, either wireless or wired
    • H04R25/554—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception using an external connection, either wireless or wired using a wireless connection, e.g. between microphone and amplifier or using Tcoils
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09—Magnetoresistive devices
    • G01R33/098—Magnetoresistive devices comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
    • H04R25/30—Monitoring or testing of hearing aids, e.g. functioning, settings, battery power
    • H04R25/305—Self-monitoring or self-testing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/80—Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication

Definitions

  • the invention relates to a device for detecting an audio signal in a near field magnetic communication system, in particular to a design and a combination method of a magnetoresistive sensor for signal detection, so as to increase the signal to noise ratio, increase the working DC magnetic field range, and reduce the work. Consumption and the effect of implementing multiple sensing axes.
  • hearing aids mostly use an inductive coil (T-coil) sound collecting device to receive an alternating magnetic signal from an earpiece of a telephone base station.
  • T-coil inductive coil
  • the T-coil sensor helps the hearing aid user to eliminate the background signal that is audible to the human ear while avoiding a reduction in sound quality.
  • the acoustical hearing aid and the telephone handset are used simultaneously, the degradation of sound quality often occurs.
  • the best solution is to use the DC magnetic field in the handset to trigger the magnetic switch in the hearing aid, turn off the microphone of the hearing aid, and activate the T-coil sound system instead of using the manual switch to turn off the microphone.
  • hearing aids are gradually being used in high-end consumer audio systems and public address audio transmission systems, where the T-coil sensor acts as a detector for the near-field magnetic communication system and has dual functions in the loop system.
  • an analog audio signal in a near field magnetic communication system such as a telephone signal pickup system, a public address system, and a home audio system is carried by a magnetic field, and the magnetic field is very close to the transmission coil.
  • the traditional induction coil can only detect the AC magnetic field.
  • the induction coil has two forms, one is passive, composed of a coil wound around the core, and the other is active, which includes a preamplifier. .
  • the inductor used for signal pickup is bulky and expensive; in addition, the induction coil itself cannot induce the presence of a DC magnetic field, and additional circuitry must be used to detect the presence of a DC magnetic field from the near field communication device. These devices are large and take up a large space for hearing aids that could otherwise be used for other applications of hearing aids or to increase battery space.
  • the conventional induction coil type sensor is a vector, not a scalar type sensor, so it can only measure the change of the magnetic field in one direction. Sensitivity to a single axis is not necessarily bad, but due to the large volume of the coil, the length of the coil along the axis of induction is longer than the length along the non-inductive axis, making it difficult to make conventional T-Coil and landline phones. The earpieces match.
  • the present invention discloses a method of fabricating a single sensitive or dual sensitive axis sensor system using a TMR sensor that integrates a magnetic switch, a T-coil, and a loop system unit in a small package.
  • the TMR near field magnetic communication system is used to detect AC and DC magnetic fields generated by a near field magnetic communication system and convert the magnetic signal into an electrical signal received by an audio electroacoustic device.
  • the TMR near field magnetic communication system includes
  • a power supply circuit connected to the bridge magnetoresistive sensor TMR[A] and the analog signal circuit and a power input terminal for supplying power to the power supply circuit;
  • the bridge magnetoresistive sensor TMR[A] is a low sensitivity linear TMR magnetoresistive sensor, a high sensitivity linear TMR magnetoresistive sensor or a non-linear TMR magnetoresistive sensor.
  • the TMR near field magnetic communication system further comprises:
  • the digital signal output end transmits information of the DC component outputted by the bridge magnetoresistive sensor TMR[A] to the audio electroacoustic device.
  • the power supply circuit includes a duty cycle controller to control the high-flat duty ratio of the bridge magnetoresistive sensor TMR[A]; and the digital signal circuit includes detecting a large DC electrical signal in the output signal of the bridge magnetoresistive sensor TMR[A] The comparator present; when the comparator detects a large DC electrical signal in the output of the TMR bridge magnetoresistive sensor [A], the duty cycle controller stops operating and its output remains the DC bias voltage.
  • the power supply circuit includes a voltage doubler.
  • the comparator detects a large DC electrical signal in the output of the bridge magnetoresistive sensor TMR[A]
  • the voltage doubler is turned on, and the bridge magnetoresistive sensor TMR[A] is added. Bias voltage.
  • the bridge magnetoresistive sensor TMR[B] connected to the power supply circuit is included.
  • the TMR near field magnetic communication system comprises:
  • the digital signal circuit connected to the bridge magnetoresistive sensor TMR[B] processes the DC electrical signal from the bridge magnetoresistive sensor TMR[B], and the digital signal circuit includes a bridge magnetoresistive sensor TMR[B] A comparator that outputs a large DC component.
  • the comparator detects a DC electrical signal in the output signal of the bridge magnetoresistive sensor TMR[B]
  • the comparator sends a signal to make the bridge magnetoresistive sensor TMR[A]
  • the bias voltage is turned on;
  • the digital output end transmits information of the DC component outputted by the bridge magnetoresistive sensor TMR[B] to the audio electro-acoustic device;
  • the resistance of the bridge magnetoresistive sensor TMR[B] is larger than that of the bridge magnetoresistive sensor TMR[A].
  • the power supply circuit includes a voltage multiplier, and when the comparator detects the DC electrical signal in the output of the bridge magnetoresistive sensor TMR[B], the voltage doubler is turned on to increase the bridge magnetoresistive sensor TMR [A ] The bias voltage.
  • the TMR near-field magnetic communication system includes a bridge magnetoresistive sensor TMR[C], a bridge magnetoresistive sensor TMR[C] and a magnetoresistive sensor TMR[B] respectively detecting two magnetic field components along mutually perpendicular directions
  • the magnetoresistive sensor TMR[C] is a high sensitivity linear TMR magnetoresistive sensor for detecting AC magnetic fields.
  • the analog signal circuit is connected to the output of the bridge magnetoresistive sensor TMR[C], and the analog signal circuit separates and amplifies the AC electrical signal output by the bridge magnetoresistive sensor TMR[C], and the processed AC electrical signal Passed to the analog signal output of the TMR near field magnetic communication system.
  • the bridge magnetoresistive sensor TMR[A] and the bridge magnetoresistive sensor TMR[B] are half bridges, full bridges, push-pull bridges, or any combination thereof; TMR near-field magnetic communication system is packaged into a film coating Crystal package, multi-chip package (COF), Or chip-on-board package (COB); bridge magnetoresistive sensor TMR [A] and bridge magnetoresistive sensor TMR [B] are fabricated by a die inversion process.
  • COF multi-chip package
  • COB chip-on-board package
  • the bridge magnetoresistive sensor is a half bridge, a full bridge, a push-pull bridge, or any combination thereof; the TMR near field magnetic communication system is packaged into a single semiconductor package, a multi-chip package (COF) , or chip-on-board package (COB); bridge magnetoresistive sensor is fabricated by a die flip process.
  • COF multi-chip package
  • COB chip-on-board package
  • the bridge magnetoresistive sensor TMR[A] is a nonlinear TMR sensor fabricated by a die inversion process, each of which has an offset magnetic field greater than its saturation magnetic field, and the sum of the offset magnetic field and the saturation magnetic field is equal to the bridge magnetic field.
  • the bridge magnetoresistive sensor TMR[A] is a nonlinear TMR sensor fabricated by a die inversion process, each of which has an offset magnetic field greater than its saturation magnetic field, and the sum of the offset magnetic field and the saturation magnetic field is equal to the bridge magnetic field.
  • the TMR near field magnetic communication system includes a digital input for manually switching between the TMR near field magnetic communication system in a loop system mode, a T-coil mode and a standby mode, wherein in the standby mode
  • the bridge magnetoresistive sensor TMR[A] does not work.
  • the TMR near field magnetic communication system includes a digital input for manually switching between the TMR near field magnetic communication system in a loop system mode, a T-coil mode and a standby mode, wherein in the standby mode
  • the bridge magnetoresistive sensor TMR[A] does not work.
  • the TMR near-field magnetic communication system includes a bridge magnetoresistive sensor TMR[C], a bridge magnetoresistive sensor TMR[C] and a bridge magnetoresistive sensor TMR[A] respectively detecting components of two mutually perpendicular magnetic fields
  • the magnetoresistive sensor TMR[C] is a high sensitivity linear TMR sensor for detecting an AC magnetic field, and the output of the bridge magnetoresistive sensor TMR[C] is buffered and coupled to an audio amplifier AC in an analog signal circuit.
  • the TMR near-field magnetic communication system includes a digital signal circuit
  • the digital signal circuit includes a comparator
  • the comparator receives DC from the output of the bridge magnetoresistive sensor TMR[C] and the bridge magnetoresistive sensor TMR[A].
  • the electrical signal, the output of the comparator is connected to the digital signal output, and the DC component information of the output signal of the bridge magnetoresistive sensor TMR[A] is transmitted to the audio electro-acoustic device through the digital signal output.
  • the TMR near field magnetic communication system includes one or more additional bridge magnetoresistive sensors TMR[A1], TMR[A2],...,TMR[Ai] (i is a positive integer); all magnetoresistive sensors TMR[Ai] have different Hsat; all bridge magnetoresistive sensors TMR[Ai] and bridge magnets
  • the resistance sensor TMR[A] detects the magnetic field component in the same direction;
  • the bridge magnetoresistive sensor TMR[Ai] is a high sensitivity linear TMR magnetoresistive sensor, a low sensitivity TMR magnetoresistive sensor or a nonlinear TMR magnetoresistive sensor; bridge magnetoresistance
  • the outputs of sensor TMR[A] and bridge magnetoresistive sensor TMR[Ai] are buffered and coupled to the audio amplifier AC in the analog signal circuit.
  • At least one bridge magnetoresistive sensor has an offset field larger than its saturation field and operates in a magnetic field range of 10 to 100 G to obtain an optimum signal to noise ratio.
  • the TMR near-field magnetic communication system is packaged into a single semiconductor package, a multi-chip package (COF), or a chip-on-board package (COB); a bridge magnetoresistive sensor TMR [A] and a bridge magnetic
  • the resistance sensor TMR[Ai] (i is a positive integer) is fabricated by a die inversion process.
  • Figure 1 is a cross-sectional view of the MTJ showing the layer structure of the MTJ and the circuit for measuring the resistance;
  • FIG. 2 is a schematic view showing a conversion curve of a conventional spin valve GMR, a magnetoresistance of a TMR as a function of an applied magnetic field, and a magnetization direction of the pinned layer is directed to a direction of -H;
  • FIG. 3 is a schematic view showing a conversion curve of a conventional spin valve GMR, a magnetoresistance of a TMR as a function of an applied magnetic field, and a magnetization direction of the pinned layer is directed to a direction of +H;
  • FIG. 4 is a simplified diagram of a method of connecting a plurality of TMR elements into one arm of a bridge
  • Figure 5 is a full bridge magnetoresistive sensor composed of four sensing arms
  • Figure 6 is a conversion curve of a linear TMR full bridge magnetoresistive sensor
  • Figure 7 is a conversion curve of a nonlinear TMR full bridge magnetoresistive sensor
  • FIG. 8 shows a TMR near-field magnetic communication system using only one TMR magnetoresistive sensor
  • FIG. 9 shows the use of two TMR magnetoresistive sensors, one of which is dedicated to the acquisition of telephone audio magnetic field signals.
  • Near field magnetic communication system
  • FIG 10 shows the use of three TMR magnetoresistive sensors, one dedicated to telephone audio magnetic field signal acquisition, at least one TMR near field magnetic communication system dedicated to hearing loop magnetic field signal acquisition;
  • FIG 11 shows a TMR near-field magnetic communication system using two TMR magnetoresistive sensors to detect the components of two mutually perpendicular magnetic fields, one of which is dedicated to telephone audio magnetic field signal acquisition, at least one dedicated to the hearing circuit magnetic field.
  • TMR near-field magnetic communication system using a plurality of TMR magnetoresistive sensors having different Hsats, increasing a DC magnetic field threshold range in which an AC magnetic field can be detected, and an AC magnetic field signal exceeding the DC magnetic field threshold can be detected.
  • Figure 13 is an alternative plurality of TMR magnetoresistive sensors that broaden the range of DC magnetic field thresholds at which AC magnetic fields can be detected, and AC magnetic signals can be detected with high sensitivity TMR sensors.
  • FIG. 1 is a schematic diagram showing the structure of a tunnel junction magnetoresistance (MTJ) element and its resistance measurement.
  • a standard MTJ layer structure 1 includes a magnetic pinned layer 2 formed by magnetic coupling of a ferromagnetic pinned layer 4 and a pinned layer 3 made of an antiferromagnetic material, and formed of MgO or Al 2 O 3 Tunnel barrier layer 5.
  • the tunnel barrier layer 5 is deposited directly on the ferromagnetic pinned layer 4.
  • a ferromagnetic layer 6 is deposited on top of the tunnel barrier layer 5.
  • the direction of the magnetic moment 8 of the magnetic pinned layer 2 and the direction of the magnetic moment 7 of the sensitive layer are indicated by arrows.
  • the magnetization direction 8 of the pinned layer is relatively fixedly pinned in one direction and does not change under conditions of not very strong magnetic field strength; in comparison, the magnetic moment direction 7 of the sensitive layer changes as the external magnetic field changes. .
  • the direction of the magnetic moment 7 of the magnetic free layer 6 is indicated by double arrows, and the direction 8 of the pinned layer 4 is indicated by a single arrow in order to indicate the difference in the degree of freedom of rotation.
  • the typical thickness of layers 3, 4, 5, 6 is from 0.1 nm to more than ten nm.
  • the bottom and top electrodes 16 and 17 are in direct contact with the upper layers 3 and 6 of the MTJ for measuring the magnetoresistance.
  • the bottom and top electrodes 16 and 17 are typically made of a non-magnetic, electrically conductive metal that must be capable of carrying current to the ohmmeter 18.
  • the ohmmeter 18 applies a known voltage (or current) to the entire layer structure of the MTJ and measures the current (or voltage) that is finally passed through the MTJ.
  • the tunnel barrier layer 5 provides most of the resistance, for example, the barrier layer resistance is 10,000 ohms, and the rest of the resistance is 10 ohms.
  • the bottom electrode 16 is on the insulating layer 9, and the insulating layer 9 is formed on the substrate 10.
  • Substrate 10 is most often made of silicon, but can also be glass, heat resistant glass, GaAs, AlTiC or any other material that provides suitable wafer integration characteristics. Although magnetoresistive sensors do not always require integrated circuits, silicon is favored for processing integrated circuits.
  • the output curve 30 is saturated in the low resistance state 21 and the high resistance state 22, and RL and RH represent the resistance values of the low resistance state 21 and the high resistance state 22, respectively. Between the two saturation states, the output curve is a linear curve of the applied magnetic field H.
  • the direction of the applied magnetic field H is parallel to the sensitive direction of the sensor. When the magnetization direction 8 of the pinning layer and the sensitive direction are anti-parallel, the magnetization direction of the pinning layer is directed to the direction of -H.
  • the measured resistance value of the entire element is in the low resistance state 21; when the magnetization direction 7 of the magnetic free layer is opposite to the magnetization direction 8 of the magnetic pinning layer When parallel, the measured resistance of the entire component is in the high resistance state 22.
  • the resistance of the MTJ element 1 takes a value between the high resistance and the low resistance.
  • the value of H 0 23 is related to the "orange effect" or “Neel coupling", and its value is usually between 1 and 25 Oe, and is related to the flatness of the ferromagnetic film in the MR element, and also depends on the material and the processing technique. H 0 23 can be reduced and increased by magnetic biasing of the TMJ element.
  • H s is the saturation field. Hs is quantitatively defined as the value of the magnetic field corresponding to the intersection of the tangent of the output curve at the low field and the tangent of the output curve at saturation, which is obtained with H 0 ignored.
  • Figure 3 is the output curve of the resistance-to-external magnetic field of the die in Figure 2 (the wafer is cut into individual grains, each of which has a sensor) rotated 180 degrees with respect to the axis perpendicular to the plane of the sensor. After rotation, the magnetization direction 8 of the pinned layer now points in the +H direction. As a result of this rotation, the slope of the R to H output curve is a negative value of the slope of the unrotated crystal grains under the same applied magnetic field conditions. Only by using this feature can you build a larger An output magnetoresistive sensor, this method is used to fabricate the sensor in the disclosed embodiments of the present invention.
  • the production of a linear TMR sensor by a method of rotating a crystal grain is disclosed in Chinese Patent Application No. 201310718969.8, 201310496945.2), 201120167350.9, and 201110134982.X.
  • a plurality of electrically connected MTJ elements 40 are positioned between the bottom electrode 41 and the top electrode 42 to form a sandwich structure electrically connected such that current 43 can flow longitudinally through the MTJ 40 and laterally through the top electrode alternately arranged at the bottom and top conductive layers. 42 and bottom electrode 41.
  • the bottom electrode 41 is located on the isolation layer 9 and there may be an additional substrate 10.
  • the reference arm of the bridge and the MTJ element 1 of the sensor arm are preferably the same size, which eliminates the offset caused by etching, and the design of the component string can be used differently between the sensing arm and the reference arm.
  • a number of MTJ elements 40 are used to obtain the best ratio of sensor arm/reference arm resistance values.
  • the bridge is used to convert the resistance conversion signal into a voltage signal that is easily amplified. This can improve the signal to noise ratio, eliminate common mode noise, reduce thermal effects, and more.
  • the MR element string of Figure 4 can be easily constructed into the Wheatstone bridge of Figure 5.
  • the "full bridge"50; the four arms of the full bridge 50 are sensed by the external magnetic field H and are referred to as the sensing arms.
  • the transmission curves of the sensing arms 52 and 52' are as shown in Fig. 2, and the slope thereof is positive; the transmission curves of the sensing arms 54 and 54' are as shown in Fig. 3, and the slope thereof is negative.
  • the resistance value of the bridge from V bias to GND is:
  • the output of the bridge magnetoresistive sensor is the difference between V1 and V2:
  • Vout in the above equation is the maximum output of the bridge magnetoresistive sensor when a forward magnetic field is applied, which is denoted as Vpeak 61 in FIG.
  • Vpeak 61 the maximum output of the bridge magnetoresistive sensor when a forward magnetic field is applied.
  • Figure 6 shows the output curves V1-V2 ⁇ H of a linear full-bridge sensor.
  • the saturation field of Figure 6 is defined as Hsat, and the offset field of each MTJ element needs to be added to correct the value of the saturation field as follows:
  • the sensitivity here is defined as Vp/Hsat. Note that as the field strength of the applied magnetic field to be measured increases, Hsat must also increase accordingly. This means that the sensitivity of the magnetoresistive sensor needs to be reduced when measuring a strong external magnetic field.
  • the Johnson noise model is a good description of the magnetic noise in the TMR sensor, integrating the Johnson noise into the bandwidth of the T-coil, and taking the root mean square:
  • F1 in the formula is the lowest frequency of the pass band
  • F2 is the highest frequency
  • k B is the Boltzmann constant
  • T is the temperature
  • R is the resistance of the bridge of the magnetoresistive sensor.
  • Vp is smaller than the bias voltage (Vbias) of the magnetoresistive sensor and is related to the structure of the bridge and the rate of change of the resistance of the magnetoresistive sensor.
  • the best sensitivity for push-pull full-bridge linear magnetoresistive sensors is:
  • Vbias and Hsat are limited by the practical considerations of DC magnetic field and power consumption. Therefore, the highest sensitivity is limited by design, and even if the slope of the linear transmission curve is increased, the sensitivity cannot be significantly improved.
  • the noise of the magnetoresistive sensor also affects the SNR, so we can consider reducing the noise of the magnetoresistive sensor.
  • Bns is determined by the bandwidth, but the bandwidth of the audio magnetic field signal cannot be changed by human voice and music.
  • the noise decreases with temperature, we cannot control the temperature.
  • the noise decreases as the resistance decreases.
  • reducing the resistance of the magnetoresistive sensor increases power consumption and reduces battery life, so the resistor cannot be designed too low.
  • the SNR can be optimized. However, optimization is limited by the practical values of R, Hsat, and Vbias. In a landline system, the Hsat minimum is about 35Oe, so only R and Vbias are changed. However, the smaller R and the larger Vbias cause a larger power consumption, so the SNR of the linear magnetoresistive sensor as shown in Fig. 6 is bound by the actual value possible of its parameters.
  • the TMR near-field magnetic communication system will only be used when it is close to the telephone.
  • Magnetic sensors are often used as proximity switches to detect the presence of a landline.
  • the DC magnetic field in the handset of the telephone triggers the magnetic switch, so that the magnetic switch is turned on at a magnetic field strength of less than 10Oe, so there are two ways to improve the SNR without increasing power consumption.
  • TMR T-coil sensor As a magnetic switch, turn on the low resistance linear TMR T-coil sensor. As shown in Figure 6, the TMR T-coil sensor is inactive in the region between the two switching threshold intervals 65A and 65B.
  • This sensitivity is higher than the sensitivity of the high sensitivity linear magnetoresistive sensor.
  • the advantage of this magnetoresistive sensor is that it has high sensitivity in the range of the magnetic field where the signal needs to be collected, and a higher resistance value can be taken in order to reduce power consumption.
  • This magnetoresistive sensor can be made by
  • the method of implementing Ho>Hs includes Neel coupling, setting a bias permanent magnet on the substrate, or exchanging coupling.
  • exchange coupling When exchange coupling is used, a second antiferromagnetic layer deposited on the free layer is used to generate a bias magnetic field.
  • a "high sensitivity linear sensor” is defined as a linear sensor having a Hsat ⁇ 10 Oe
  • a "low sensitivity linear sensor” or a linear TMR sensor is defined as a linear sensor having a Hsat > 20 Oe.
  • the highly sensitive TMR sensor can be used in hearing loop systems, mobile audio field signal acquisition, or magnetic switches.
  • the present invention uses three different types of TMR magnetoresistive sensors,
  • magnetoresistive sensors can form a combination of several different functions for telephone audio magnetic field signal acquisition or hearing loop systems.
  • the TMR linear magnetoresistive sensors of i and ii can be used in a variety of different design methods, including those related to reference bridge magnetoresistive sensors, see MDT2011.15 (CN102621504A), MDT2013.07.30 (201310719255.9), or MDT2013.01.14 (201310203311.3),
  • the related technology of the quasi-push-pull bridge linear magnetoresistive sensor can be found in MDT2011.09 (CN102331564A) or MDT2011.11 (CN102540112A).
  • the nonlinear TMR magnetoresistive sensor in iii must be designed using the pinning layer inversion method and disclosed in MDT2013.09.15.
  • Hearing aids typically include a microphone, a sound amplifier, and a receiver.
  • the microphone receives the sound and converts it into an electrical signal.
  • the sound amplifier amplifies the electrical signal from the microphone, and the amplified electrical signal is transmitted to the receiver, which converts the electrical signal back to the sound signal transmitted to the human ear.
  • the user uses the phone, he or she would like to turn off the microphone and receive the AC magnetic field from the handset.
  • Turning on the TMR T-Coil and turning off the microphone can be done manually or by detecting the magnetic switch of the DC magnetic field generated by the handset.
  • the TMR near-field magnetic communication system 11 capable of detecting a magnetic field includes: a bridge magnetoresistive sensor TMR[A]24A for detecting a magnetic field; and an output terminal of the bridge magnetoresistive sensor TMR[A]24A.
  • Analog signal circuit 37, analog signal circuit 37 includes filter 18 and amplifier 12, filter 18 can separate the AC and DC signals of bridge magnetoresistive sensor TMR[A] 24A, amplifier 12 amplifies AC signal; analog signal output 14 transmits the AC signal to the audio electro-acoustic device; the power supply circuit 19 is connected to the bridge magnetoresistive sensor TMR[A] 24A and the analog signal circuit 37; the power input terminal 20 supplies power to the power supply circuit 19.
  • the bridge magnetoresistive sensor TMR[A]24A is a low sensitivity linear TMR sensor, a high sensitivity linear TMR sensor, or a nonlinear TMR sensor.
  • the TMR near field magnetic communication system 11 additionally includes a digital signal circuit 27 coupled to the bridge magnetoresistive sensor TMR [A] 24A, which can process the DC signal from the output of the bridge magnetoresistive sensor TMR [A] 24A.
  • the electrical signal processed by the digital signal circuit 27 is passed through the digital output 15 to the audio electro-acoustic device.
  • the digital signal circuit 27 includes a comparator 29 which can detect the DC in the output signal of the bridge magnetoresistive sensor TMR[A]24A The existence of the component.
  • the duty cycle controller 36 can control the high-level duty cycle of the bias voltage of the magnetoresistive bridge sensor TMR[A] 24A when the comparator 29 is detected in the output of the bridge magnetoresistive sensor TMR[A] 24A.
  • the duty cycle controller 36 is turned off when the DC field is applied.
  • the power supply circuit 19 includes a voltage multiplier 28 which can increase the bias voltage of the bridge magnetoresistive sensor TMR[A] 24A; when the comparator 29 detects the output of the bridge magnetoresistive sensor TMR[A] 24A When a large DC magnetic field is applied, the voltage doubler 28 is turned on.
  • the bridge magnetoresistive sensor TMR[A] 24A is a half bridge, a full bridge, a push-pull bridge or any combination thereof.
  • the TMR T-Coil near-field magnetic communication system can be packaged in a flexible on-board package (COF), a single-semiconductor package, or a chip-on-board package (COB).
  • COF flexible on-board package
  • COB chip-on-board package
  • the TMR magnetoresistive sensor is fabricated using a die-flip die technique or a single die technique.
  • the TMR near-field magnetic communication system 11 includes: a bridge magnetoresistive sensor TMR[A]24A for measuring a magnetic field; and an output terminal of the bridge magnetoresistive sensor TMR[A]24A.
  • the analog signal circuit 37, the analog signal circuit 37 includes a filter 18 and an amplifier 12, which can separate the AC and DC electrical signals output by the bridge magnetoresistive sensor TMR[A] 24A, and the amplifier 12 amplifies the AC electrical signal;
  • the signal output terminal 14 transmits the AC electrical signal to the audio electro-acoustic device;
  • the power supply circuit 19 is connected to the bridge magnetoresistive sensor TMR[A] 24A and the analog signal circuit 37;
  • the power input terminal 20 is the power source of the TMR near-field magnetic communication system 11.
  • Circuit 19 provides a power supply.
  • the bridge magnetoresistive sensor TMR[A]24A is a low sensitivity linear TMR sensor, or a nonlinear TMR sensor.
  • the TMR near-field magnetic communication system 11 further includes a bridge magnetoresistive sensor TMR[B]24B, and the bridge magnetoresistive sensor TMR[B]24B is a high-sensitivity or low-sensitivity linear TMR magnetoresistance that can be detected in the handset of the telephone base station. DC magnetic field.
  • the bridge magnetoresistive sensor TMR[A]24A and the bridge magnetoresistive sensor TMR[B]24B detect magnetic field components in the same direction.
  • the TMR near field magnetic communication system 11 additionally includes a digital signal circuit 27 coupled to the bridge magnetoresistive sensor TMR[B] 24B, which can process DC electrical signals from the bridge magnetoresistive sensor TMR[B] 24B;
  • the output terminal 15 is configured to transmit the DC information of the bridge magnetoresistive sensor TMR[A] 24A to the audio electroacoustic device.
  • the digital signal circuit 27 includes a comparator 29 which can detect the presence of a DC magnetic field from the output signal of the bridge magnetoresistive sensor TMR[B] 24B.
  • the duty cycle controller 36 can control the bridge magnetoresistive sensor TMR[B]24B The high duty cycle of the bias voltage.
  • the power supply circuit 19 includes a voltage multiplier 28 that can increase the bias voltage of the bridge magnetoresistive sensor TMR[A] 24A; when the comparator 29 detects a larger output in the output of the bridge magnetoresistive sensor TMR[B] 24B When the DC component is present, the voltage doubler 28 is turned on to increase the bias voltage of the bridge magnetoresistive sensor TMR[A] 24A.
  • the TMR near field magnetic communication system 11 can also include a digital signal input for the TMR near field magnetic communication system 11 to manually switch between the hearing loop mode, the T-coil mode, and the standby mode, wherein the standby mode is TMR T-coil Not working.
  • the TMR near-field magnetic communication system sound 11 includes: a bridge magnetoresistive sensor TMR[A]24A for detecting a magnetic field; an analog signal circuit 37 connected to an output terminal of the bridge magnetoresistive sensor TMR[A]24A, an analog signal
  • the circuit 37 includes a filter 18 and an amplifier 12 that separates the AC and DC electrical signals of the output of the bridge magnetoresistive sensor TMR[A] 24A, the amplifier 12 amplifies the AC electrical signal; the analog signal output 14 converts the AC electrical The signal is transmitted to the audio electro-acoustic device; the power supply circuit 19 is connected to the bridge magnetoresistive sensor TMR[A] 24A and the analog signal circuit 37; the power input terminal 20 supplies power to the power supply circuit 19.
  • the bridge magnetoresistive sensor TMR[A]24A is a low sensitivity linear TMR sensor, or a nonlinear TMR sensor.
  • the TMR near-field magnetic communication system 11 further includes a bridge magnetoresistive sensor TMR[B]24B, and the bridge magnetoresistive sensor TMR[B]24B is a high-sensitivity or low-sensitivity linear TMR magnetoresistive sensor that can be detected in the handset of the telephone base station. DC magnetic field.
  • the bridge magnetoresistive sensor TMR[A]24A and the bridge magnetoresistive sensor TMR[B]24B detect magnetic field components in the same direction.
  • the power supply of the bridge magnetoresistive sensor TMR[B]24B may be a power signal after being chopped by the duty cycle controller to reduce energy consumption.
  • the TMR near field magnetic communication system 11 additionally includes a digital signal circuit 27 coupled to the bridge magnetoresistive sensor TMR[B] 24B, which can process a DC signal from a bridge magnetoresistive sensor; a digital output 15 will be a bridge magnetoresistance
  • the DC signal information of the sensor TMR[A]24A is transmitted to the audio electroacoustic device.
  • the digital signal circuit 27 includes a comparator 29 which can detect the presence of a DC component in the output signal of the bridge magnetoresistive sensor TMR[B] 24B.
  • the duty ratio controller 36 in 19 in the power supply circuit can control the high-level duty ratio of the bias voltage of the bridge magnetoresistive sensor TMR[B] 24B.
  • the power supply circuit 19 includes a voltage multiplier 28 that can increase bridge magnetoresistance sensing
  • the bias voltage of the TMR[A] 24A is turned on when the comparator 29 detects a large DC component in the output of the bridge magnetoresistive sensor TMR[B] 24B.
  • the TMR near field magnetic communication system 11 further includes a bridge magnetoresistive sensor TMR [C] 24C, a bridge magnetoresistive sensor TMR [C] 24C and a bridge magnetoresistive sensor TMR [B] 24B to detect two magnetic field components perpendicular to each other,
  • the bridge magnetoresistive sensor TMR[C]24C is a highly sensitive linear TMR magnetoresistive sensor for detecting AC magnetic fields.
  • the analog signal 37 further includes: a buffer 44C connected to the output of the bridge magnetoresistive sensor TMR[C] 24C; the filter 18 separates the AC electrical signal of the bridge magnetoresistive sensor TMR[C] 24C; the amplifier 12 amplifies the AC The electrical signal is passed to the output 14 of the analog signal of the TMR near field magnetic communication system 11. Further, the buffer 44A is connected to the output of the bridge magnetoresistive sensor TMR[A] 24A so as to be well isolated from the bridge magnetoresistive sensor TMR [C] 24C signal.
  • the power supply circuit 19 includes a voltage multiplier 28 to increase the bias voltages of the bridge magnetoresistive sensors TMR[A] 24A and TMR[C] 24C; only when the comparator 29 is at the output of the bridge magnetoresistive sensor TMR[B] 24B
  • the voltage doubler 28 is turned on when a DC component of a suitable intensity is detected.
  • the bridge magnetoresistive sensor TMR[A]24A, the bridge magnetoresistive sensor TMR[B]24B and the bridge magnetoresistive sensor TMR[C]24C are half bridges, full bridges, push-pull bridges, or any combination thereof.
  • the TMR near field magnetic communication system 11 may include another digital signal input for the TMR near field magnetic communication system 11 to manually switch between the hearing loop mode, the T-coil mode and the standby mode, wherein the standby mode is TMR T-coil Not working.
  • the TMR T-Coil near-field magnetic communication system can be packaged in a flexible on-board package (COF), a single-semiconductor package, or a chip-on-board package (COB).
  • COF flexible on-board package
  • COB chip-on-board package
  • the TMR near field magnetic communication system 11 is a fourth embodiment of a TMR near field magnetic communication system 11 for detecting AC and DC magnetic fields of a near field magnetic communication system to convert AC and DC magnetic fields into electrical signals that are acceptable to the audio electroacoustic device.
  • the TMR near field magnetic communication system 11 includes a pair of TMR sensors placed at 90 degrees to detect two mutually perpendicular magnetic field components.
  • the pair of TMR sensors are a bridge magnetoresistive sensor TMR[A]24A and a bridge magnetoresistive sensor TMR[C]24C.
  • Bridge magnetoresistive sensor The outputs of TMR[A]24A and bridge magnetoresistive sensor TMR[C]24C are each connected to a respective buffer, the AC and DC electrical signals are separated by a filter, and the AC electrical signals of the two sensors are used by amplifier 12. amplification.
  • the analog signal output 14 is used to pass an AC electrical signal to the audio electro-acoustic device.
  • the power supply circuit 19 is connected to the bridge magnetoresistive sensors TMR[A] 24A and TMR[C] 24C and the analog signal circuit 37, and the power input terminal 20 supplies power to the power supply circuit 19 of the TMR near field magnetic communication system 11.
  • the bridge magnetoresistive sensors TMR[A]24A and TMR[C]24C are low sensitivity linear TMR sensors, high sensitivity linear TMR sensors, or non-linear TMR sensors.
  • the TMR near field magnetic communication system 11 includes a digital signal circuit 27 including a comparator 29 to which DC output signals of the bridge magnetoresistive sensors TMR[A] 24A and TMR[C] 24C are transmitted.
  • the output of the comparator 29 is connected to a digital output terminal 15, which transmits the DC signal information of the bridge magnetoresistive sensors TMR[A] 24A and TMR[C] 24C to the audio electroacoustic device.
  • the power supply circuit 19 can include a voltage multiplier 28 that can increase the bias voltages of the bridge magnetoresistive sensors TMR[A] 24A and TMR [C] 24C.
  • the comparator 29 detects that there is a sufficient DC component in the outputs of the bridge magnetoresistive sensors TMR[A] 24A and TMR [C] 24C, the voltage multiplier 28 is turned on.
  • the power supply circuit 19 may include a duty cycle controller 36 that controls the bridge magnetoresistive sensor TMR[A] when there is insufficient DC component in the outputs of the bridge magnetoresistive sensors TMR[A] 24A and TMR[C] 24C. The high-level duty ratio of the bias voltage of 24A and TMR[C]24C.
  • the bridge magnetoresistive sensors TMR[A]24A, TMR[B]42B and TMR[C]24C are half bridges, full bridges, push-pull bridges, or any combination thereof.
  • the TMR near field magnetic communication system 11 may include another digital signal input for the TMR near field magnetic communication system 11 to manually switch between the hearing loop mode, the T-coil mode and the standby mode, wherein the standby mode is TMR T-coil Not working.
  • the TMR T-Coil near-field magnetic communication system can be packaged in a flexible on-board package (COF), a single-semiconductor package, or a chip-on-board package (COB).
  • COF flexible on-board package
  • COB chip-on-board package
  • the TMR near-field magnetic communication system 11 further includes a plurality of additional magnetoresistive sensors TMR[A1], TMR[A2], ..., TMR[Ai](i) for detecting magnetic field components in the same direction. Is a positive integer), and these additional magnetoresistive sensors TMR[A1], TMR[A2],...,TMR[Ai](i The positive direction of the positive integer is the same as the magnetoresistive sensor TMR[A]. Power is supplied from power supply circuit 19, the output of each sensor being coupled to the input of analog signal circuit 37 with a buffered input.
  • the power supply circuit 19 includes a voltage multiplier 28 that can increase the sensitivity of the magnetoresistive sensor and a duty ratio controller 36 that reduces power consumption.
  • the output of each magnetoresistive sensor is output to a high pass filter 18 via a buffer.
  • Each output of the filter 18 is electrically coupled to an amplifier 12 that amplifies the AC electrical signal from the magnetoresistive sensor and passes through an analog output. 14 Passing the processed AC electrical signal to the audio electro-acoustic device.

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Abstract

本发明公开了一种TMR近场磁通信系统，用于检测近场磁通信系统产生的AC和DC磁场，并将所述AC和DC磁场信号输入到音频电声装置并作为其输入信号，所述音频电声装置包括助听器、家庭娱乐系统的耳机，具有嵌入式听力器件的公共听力回路系统（public hearing loop system）等。TMR近场磁通信系统包括：一个或多个用于AC和DC磁场信号检测的桥式TMR传感器；包含滤波器的模拟信号电路，所述滤波器用于将TMR传感器输出的AC和DC信号分量进行分离；用于将AC电信号放大的放大器；模拟输出端用于将AC电信号传给音频电声装置。所述TMR传感器可以是线性或者非线性地TMR传感器，其中的TMR传感器被设计成在特定的DC磁场中具有最佳的信噪比。

Description

TMR近场磁通信系统 技术领域
本发明涉及一种检测近场磁通讯系统中音频信号的器件，尤其涉及一种用于信号检测的磁电阻传感器的设计、组合方法，以达到增加信噪比、提高工作直流磁场范围、降低功耗以及实现多感应轴的效果。
背景技术
目前，助听器多利用感应线圈式(T-coil)采声装置接收来自于电话座机的听筒中的交流磁信号。在使用电话时，其中的T-coil传感器可以帮助助听器使用者消除人耳可听见的背景信号，同时可以避免声音质量的降低。而当原声式助听器和电话机听筒同时使用时，声音质量的降低时常发生。最好的的解决方案是利用电话听筒中的DC磁场来触发助听器中的磁开关，关闭助听器的麦克风，激活感应线圈式(T-coil)采声装置，而不是使用手动开关关闭麦克风。
除了改善电话接听的声音质量，助听器正逐步应用于高端消费类音频系统和公共广播音频传输系统中，其中的T-coil传感器作为近场磁通信系统的检测器，在回路系统中具有双重功能。通常来说，电话信号拾取系统，公共广播系统，和家庭音响等近场磁通信系统中的模拟音频信号是由磁场承载，并且该磁场十分靠近传输线圈。这和常规的无线通信在几个方面有所不同，其中最大的不同在于：近场磁通信系统中承载音频信号的磁场不是容易扩散的电磁波。所以，近场磁通信可以只在一个房间或建筑物里进行，改善了私密性，因而允许相邻的系统只给各自本地传输信息。
传统的感应线圈(T-coil)只能检测AC磁场，感应线圈有两种形式，一种是被动式，由绕在磁芯上的线圈构成，另一种是主动式，其包括一前置放大器。但是，用于信号拾取的电感体积较大，价格昂贵；另外，感应线圈自身不能感应直流磁场的存在，必须使用附加的电路来检测来自于近场通信设备的直流磁场的存在。这些装置都很大，占据了助听器较大的空间，而这些空间本来可用于助听器的其它应用，或可用于增加电池的空间。传 统的感应线圈式采声装置的另一个缺点是，传统的感应线圈式传感器是矢量，不是标量型传感器，所以，其只能测量沿一个方向的磁场变化。只对单一轴向敏感不一定就不好，但是由于线圈的体积大，线圈在沿着感应轴的长度比沿着非感应轴的长度要长，导致很难使传统的T-Coil和固定电话的听筒匹配。
发明内容
因此，有必要在助听器中安装体积较小的传感器，以节约成本、减小体积、增加更多功能或电池和提高T-coil的性能，而用TMR传感器制成的T-coil正是较好的选择。另外，小的传感器可以使回路系统(loop system)检测互相垂直的两个磁场分量，且这种方案正越来越普遍。而且，由于感应线圈不能检测座机听筒中的直流磁场，于是需要额外的磁开关来触发T-coil模式。而TMR传感器可以检测DC分量，因此它可以有传感器/开关双重功能。本发明披露了用TMR传感器制造单敏感轴或双敏感轴传感器系统的方法，该传感器系统将磁开关、T-coil以及回路系统(loop system)单元集成在一个小的封装中。
TMR近场磁通信系统用于检测近场磁通信系统产生的AC和DC磁场，并将磁信号转换成被音频电声装置(audio electroacoustic device)接收的电信号，TMR近场磁通信系统包括
检测磁场的桥式磁电阻传感器TMR[A]；
与桥式磁电阻传感器TMR[A]的输出相连接的模拟信号电路，模拟信号电路包括滤波器和放大器，滤波器将桥式磁电阻传感器TMR[A]输出的AC和DC电信号分离，放大器放大AC电信号，模拟信号输出端将放大后的AC电信号传给音频电声装置；
与桥式磁电阻传感器TMR[A]及模拟信号电路相连的电源电路和为电源电路提供电力供应的电源输入端；
桥式磁电阻传感器TMR[A]是低灵敏度线性TMR磁电阻传感器，高灵敏度线性TMR磁电阻传感器或非线性TMR磁电阻传感器。
优选的，该TMR近场磁通信系统，还包括：
与桥式磁电阻传感器TMR[A]连接的数字信号电路，数字信号电路处理磁电阻传感器TMR[A]输出的电信号的直流分量；
数字信号输出端，将桥式磁电阻传感器TMR[A]输出的直流分量的信息传给音频电声装置。
优选的，电源电路包括占空比控制器控制桥式磁电阻传感器TMR[A]的高平占空比；数字信号电路包括检测桥式磁电阻传感器TMR[A]输出信号中的大的DC电信号的存在的比较器；当比较器在TMR桥式磁电阻传感器[A]的输出中检测到大的DC电信号时，占空比控制器停止工作，其输出仍为直流偏置电压。
优选的，电源电路包括倍压器，当比较器在桥式磁电阻传感器TMR[A]的输出中检测到大的DC电信号时，倍压器开启，增加桥式磁电阻传感器TMR[A]的偏置电压。
优选的，包括与电源电路相连的桥式磁电阻传感器TMR[B]。
优选的，TMR近场磁通信系统，包括：
与桥式磁电阻传感器TMR[B]连接的数字信号电路处理来自于桥式磁电阻传感器TMR[B]的DC电信号，数字信号电路包括一个用于检测桥式磁电阻传感器TMR[B]的输出中较大直流分量的比较器，当比较器在桥式磁电阻传感器TMR[B]的输出信号中的检测到DC电信号时，比较器发出信号，使桥式磁电阻传感器TMR[A]的偏置电压开启；
数字输出端，将桥式磁电阻传感器TMR[B]输出的直流分量的信息传给音频电声装置；
桥式磁电阻传感器TMR[B]的电阻比桥式磁电阻传感器TMR[A]的电阻大。
优选的，电源电路包括倍压器，当比较器在桥式磁电阻传感器TMR[B]的输出中检测到DC电信号时，倍压器就会开启，以增加桥式磁电阻传感器TMR[A]的偏置电压。
优选的，TMR近场磁通信系统，包括桥式磁电阻传感器TMR[C]，桥式磁电阻传感器TMR[C]和磁电阻传感器TMR[B]分别检测两个沿互相垂直方向的磁场分量，磁电阻传感器TMR[C]是高灵敏度线性TMR磁电阻传感器，用来检测AC磁场。
优选的，模拟信号电路连接到桥式磁电阻传感器TMR[C]的输出端，模拟信号电路分离和放大桥式磁电阻传感器TMR[C]输出的AC电信号，并将经过处理的AC电信号传给TMR近场磁通信系统的模拟信号输出端。
优选的，桥式磁电阻传感器TMR[A]和桥式磁电阻传感器TMR[B]是半桥，全桥，推挽桥，或它们的任意的结合；TMR近场磁通信系统封装成薄膜覆晶封装，多芯片封装(COF)， 或板上芯片封装(COB)；桥式磁电阻传感器TMR[A]和桥式磁电阻传感器TMR[B]用晶粒翻转工艺制作。
优选的，桥式磁电阻传感器是半桥，全桥，推挽桥，或它们的任意的结合；TMR近场磁通信系统封装成薄膜覆晶封装(single semiconductor package)，多芯片封装(COF)，或板上芯片封装(COB)；桥式磁电阻传感器用晶粒翻转工艺制作。
优选的，桥式磁电阻传感器TMR[A]是采用晶粒翻转工艺制作的非线性TMR传感器，每一个桥臂的偏移磁场大于其饱和磁场，偏移磁场与饱和磁场之和等于桥式磁电阻传感器TMR[A]的运行的最大DC磁场。
优选的，桥式磁电阻传感器TMR[A]是采用晶粒翻转工艺制作的非线性TMR传感器，每一个桥臂的偏移磁场大于其饱和磁场，偏移磁场与饱和磁场之和等于桥式磁电阻传感器TMR[A]的运行的最大DC磁场。
优选的，TMR近场磁通信系统，包括一个数字输入端，用于TMR近场磁通信系统在听力回路模式(Loop system mode)，T-coil模式和待机模式之间手动切换，其中待机模式中桥式磁电阻传感器TMR[A]不工作。
优选的，TMR近场磁通信系统，包括一个数字输入端，用于TMR近场磁通信系统在听力回路模式(Loop system mode)，T-coil模式和待机模式之间手动切换，其中待机模式中桥式磁电阻传感器TMR[A]不工作。
优选的，TMR近场磁通信系统，包括桥式磁电阻传感器TMR[C]，桥式磁电阻传感器TMR[C]和桥式磁电阻传感器TMR[A]分别检测两个相互垂直的磁场的分量，磁电阻传感器TMR[C]是高灵敏度线性TMR传感器，用于检测AC磁场，桥式磁电阻传感器TMR[C]的输出被缓冲并且与模拟信号电路中的音频放大器AC耦合。
优选的，TMR近场磁通信系统，包括数字信号电路，数字信号电路包括比较器，的比较器从桥式磁电阻传感器TMR[C]和桥式磁电阻传感器TMR[A]的输出端接收DC电信号，比较器的输出端连接到数字信号输出端，并通过数字信号输出端将的桥式磁电阻传感器TMR[A]输出信号的DC分量信息传输到音频电声装置。
优选的，TMR近场磁通信系统，包括一个或多个额外的桥式磁电阻传感器 TMR[A1]，TMR[A2]，…，TMR[Ai](i为正整数)；所有磁电阻传感器TMR[Ai]具有不同的Hsat；所有桥式磁电阻传感器TMR[Ai]与桥式磁电阻传感器TMR[A]检测相同方向的磁场分量；的桥式磁电阻传感器TMR[Ai]是高灵敏度线性TMR磁电阻传感器，低灵敏度TMR磁电阻传感器或非线性TMR磁电阻传感器；桥式磁电阻传感器TMR[A]和桥式磁电阻传感器TMR[Ai]的输出经过缓冲，与模拟信号电路中的音频放大器AC耦合。
优选的，TMR近场磁通信系统，至少一个桥式磁电阻传感器的偏移场大于其饱和场，并使其在位于10～100G的磁场范围内运行，以取得最佳信噪比。
优选的，TMR近场磁通信系统封装成薄膜覆晶封装(single semiconductor package)，多芯片封装(COF)，或板上芯片封装(COB)；桥式磁电阻传感器TMR[A]和桥式磁电阻传感器TMR[Ai](i为正整数)用晶粒翻转工艺制作。
附图说明
为了更清楚地说明本发明实施例技术中的技术方案，下面将对实施例技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为MTJ剖面图，显示MTJ的层结构和测量电阻的电路；
图2为常规的自旋阀GMR，TMR的磁电阻随外加磁场变化的转换曲线的示意图，其钉扎层的磁化方向指向-H的方向；
图3为常规的自旋阀GMR，TMR的磁电阻随外加磁场变化的转换曲线的的示意图，其钉扎层的磁化方向指向+H的方向；
图4为将多个TMR元件连接成电桥的一个臂的方法的简图；
图5为由4个感应臂构成的全桥磁电阻传感器；
图6为线性TMR全桥磁电阻传感器的转换曲线；
图7为非线性TMR全桥磁电阻传感器的转换曲线；
图8为只使用了一个TMR磁电阻传感器的TMR近场磁通信系统；
图9为使用了两个TMR磁电阻传感器，其中一个专用于电话音频磁场信号采集的TMR 近场磁通信系统；
图10为使用三个TMR磁电阻传感器，其中一个专用于电话音频磁场信号采集，至少一个专用于听力回路磁场信号采集的TMR近场磁通信系统；
图11为使用了两个TMR磁电阻传感器分别检测两个互相垂直的磁场的分量的TMR近场磁通信系统，其中一个TMR磁电阻传感器专用于电话音频磁场信号采集，至少一个专用于听力回路磁场信号采集的TMR近场磁通信系统；
图12为使用了多个具有不同的Hsat的TMR磁电阻传感器的TMR近场磁通信系统，增加了可检测到AC磁场的DC磁场阈值范围，超过该DC磁场阈值的AC磁场信号可以被检测到；
图13为可选的多个TMR磁电阻传感器，其拓宽了可检测到AC磁场的DC磁场阈值范围，且AC磁信号能够用高灵敏度TMR传感器来检测。
具体实施方式
图1是一个隧道结磁电阻(MTJ)元件的结构和其电阻值测量的示意图。一个标准的MTJ层结构1包括由铁磁性被钉扎釕层4和反铁磁材料制成的钉扎层3磁耦合而形成的磁性被钉扎层2，和由MgO或者Al2O3形成的隧道势垒层5。隧道势垒层5直接沉积在铁磁性被钉扎釕层4上。铁磁层6沉积在隧道势垒层5的上面。磁性被钉扎层2的磁矩方向8和敏感层的磁矩方向7的方向如箭头所示。钉扎层的磁化方向8相对固定地被钉在一个方向，在不是很强的磁场强度条件下不会发生改变；相比较而言，敏感层的磁矩方向7会随外部磁场的改变而变化。磁性自由层6的磁矩方向7用双箭头表示，被钉扎层4的方向8用单箭头表示就是为了表明这种旋转自由度的区别。层3，4，5，6的典型厚度是0.1nm到十几nm.
底部和顶部电极16和17与MTJ上层3和6直接接触，用来测量磁电阻。底部和顶部电极16和17通常由非磁性的导电的金属制成，必须能承载通向欧姆表18的电流。欧姆表18对MTJ的整个层结构施加一个已知的电压(或电流)，并测量最后通过MTJ的电流(或电压)。一般来说，隧道势垒层5提供大部分的电阻，例如：势垒层电阻为10,000ohms，其余部分电阻为10ohms。底部电极16位于绝缘层9上，绝缘层9则形成在基片10上， 绝缘层9的边缘伸出了底部电极16的边缘。基片10最常由硅制成，但也可以是玻璃，耐热玻璃，GaAs，AlTiC或任何其它提供适当的晶圆集成特性的物资。尽管磁电阻传感器并不总需要集成电路，但是硅由于适于加工集成电路而受青睐。
图2是GMR或M T J传感器的的电阻～外加磁场的常规输出曲线图，具有该曲线的传感器适于线性磁场的测量。输出曲线30在低阻态21和高阻态22时饱和，RL和RH分别代表低阻态21和高阻态22的电阻值。在介于两个饱和状态之间，输出曲线是外加磁场H的线性曲线。外加磁场H的方向和传感器的敏感方向平行。钉扎层的磁化方向8和敏感方向反平行时，钉扎层磁化方向指向-H的方向。当磁性自由层的磁化方向7与磁性钉扎层的磁化方向8平行时，整个元件的测量电阻值在低阻态21；当磁性自由层的磁化方向7与磁性钉扎层的磁化方向8反平行时，整个元件的测量电阻值在高阻态22。在下面的部分将会描述，在自由层6相对与被钉扎层4的方向为0-180度之间，MTJ元件1的电阻取得位于高电阻和低电阻之间的值。
]输出曲线30不必相对于H＝0点对称。典型的情况，饱和场25和26存在一个偏移量H0 23，使得低饱和场接近于H＝0点。H0 23值跟“桔子效应”或“Neel耦合”有关，其值通常在1-25Oe，且与MR元件中铁磁薄膜的平正度有关，也取决于材料和加工工艺。H0 23可以通过对TMJ元件的磁偏置来减小和增加。
为了说明TMR近场磁通信系统的工作原理，在饱和场25和26之间，图2的输出曲线可以近似地表示为：
Figure PCTCN2015083461-appb-000001
Hs是饱和场。Hs被定量地定义为低场时输出曲线的切线与饱和时输出曲线的切线的交点对应的磁场值，该值是在忽略H0的情况下所取得的。
图3为图2中晶粒(晶圆切割成一颗颗的晶粒，每一颗晶粒有一个传感器)相对于与传感器的平面垂直的轴旋转了180度后的电阻～外加磁场的输出曲线，经过旋转，被钉扎层的磁化方向8现在指向+H方向。此旋转的结果是，在相同的外加磁场条件下，R～H输出曲线的斜率是没有旋转的的晶粒的斜率的负值。只有利用这种特性，才可以构建较大 输出的磁电阻传感器，这一方法用于制作本发明所公开的实施例中的传感器。通过旋转晶粒的方法来制作线性TMR传感器已在申请号为201310718969.8，201310496945.2)，201120167350.9，和201110134982.X的中国专利申请中公开。
如图4所示，因为它们体积小，多个MTJ元件可以串联使用，提高灵敏度，减少1/F噪声，改进抗静电性能。多个电连接的MTJ元件40位于底部电极41和顶部电极42之间，构成三明治结构，其电连接方式使电流43可以纵向流过MTJ40并且横向流过位于底部和顶部导电层交替排列的顶部电极42和底部电极41。底部电极41位于隔离层9上并且可能会有额外的基片10。当使用电桥设计时，电桥的参考臂和感应臂的MTJ元件1的尺寸最好相同，这样可以消除蚀刻引起的偏移，而且利用元件串的设计，可以在感应臂和参考臂使用不同数量的MTJ元件40，以便获得最佳的感应臂/参考臂电阻值之比。
电桥用来将电阻转换信号转换成容易放大的电压信号。这可以改善信噪比，消除共模噪声，减少热效应，等等。图4的MR元件串可以很容易的用来构建成图5的惠斯通电桥。优选的的是“全桥”50；全桥50的4个臂都对外加磁场H有感应，被称作感应臂。感应臂52和52‘的传输曲线如图2所示，其斜率为正；感应臂54和54’的传输曲线如图3所示，其斜率为负。图5中的，感应臂52和54上的箭头方向表示它们的电阻值对外加磁场的强度的转换曲线的斜率的符号相反。另外，GHP：当将传感器制作在基板上时，需要以下电气连接焊盘：电压偏置焊盘(Vbias45)，接地焊盘(GND，46)，两个半桥电路的中心抽头焊盘(V1，47，V2，48)。全桥电路50的输出电压随外加磁场的变化关系见图6中的曲线60。
为了从图2和图3中的转换曲线30的RH和RL推导图6的曲线，需要首先计算在外加磁场H为正的很大的值时，电压的差值V1-V2。在此感应条件下，感应臂52和52’电阻值是PH；54，54’的电阻值是RL；
电桥的从Vbias到GND的电阻值是：
Rnet＝Parallel([RH+RL]，[RL+RH])＝[RL+RH]/2       (2)
既然电桥两侧有相等的电阻值，电桥两侧的电流也应该相同，根据分流关系，可得：
Figure PCTCN2015083461-appb-000002
左侧V1点的电势为：
Figure PCTCN2015083461-appb-000003
右侧V2点的电势为：
Figure PCTCN2015083461-appb-000004
桥式磁电阻传感器的输出为V1和V2的差值：
Figure PCTCN2015083461-appb-000005
上式中的Vout即为当外加正向磁场时，桥式磁电阻传感器的输出最大值，图6中记为Vpeak 61。且从图中可以看出，切线63经过原点，且与+Vpeak值所在的线相交于点H＝Hsat。桥式电路输出电压的敏感度定义为：在H＝0时桥式电路输出电压的斜率，如下式：
Figure PCTCN2015083461-appb-000006
图6为线性全桥传感器的输出曲线V1-V2～H。图6的饱和场定义为Hsat，需要加上每个MTJ元件的偏移场，以修正饱和场的值，如下式：
Hsat＝|Ho|+|Hs|          (8)
注意Hsat大于或等于单一的MTJ元件的或桥臂的Hs。同时，当电桥上的相邻的桥臂上的MTJ元件的钉扎层的方向相反时，单个的MTJ元件组的偏移场Ho就会被抵消。
使用磁电阻传感器作为音频磁场信号采集器时，从声音的质量角度考虑有两个重要的参数需要考虑：
(1)饱和场(Hsat)，和
(2)信噪比(SNR)。
这里灵敏度定义为Vp/Hsat。注意随着需要测量的外加磁场的场强的增加，Hsat也必须相应地增加。这意味着当测量较强的外磁场时，磁电阻传感器的灵敏度需要下降。
灵敏度降低的负面效果是采集的音频磁场信号的质量下降。在100Hz到10KHz的音频范围内，Johnson噪音模型能很好地描述TMR传感器中的磁噪声，将Johnson噪声在T-coil的带宽内做积分，再取均方根：
Figure PCTCN2015083461-appb-000007
公式中的F1是通带的最低频率，F2是最高频率，kB是Boltzmann常数，T是温度，R是磁电阻传感器的电桥的电阻。代表测定的信号质量的信噪比相对于测定的声波的幅度Btest可以表示为：
Figure PCTCN2015083461-appb-000008
随着Hsat增加，SNR减小。
在设计具有高信噪比的的磁电阻传感器时，还有其它要考虑的因素。Vp要小于磁电阻传感器的偏置电压(Vbias)，并且和电桥的结构和磁电阻传感器的电阻变化率相关。磁电阻传感器的电阻变化率有其实际的局限，Vp只能接近磁电阻传感器的偏置电压，不能等于磁电阻传感器的偏置电压。实际上，在最好的情况下，以推挽全桥为例，0.45Vbias＜＝Vp＜＝Vbias。推挽全桥线性磁电阻传感器的最佳灵敏度是：
Figure PCTCN2015083461-appb-000009
Vbias和Hsat受DC磁场的和电力消耗的实际考量的限制。因此最高灵敏度是受到设计限制的，即使提高线性传输曲线的斜率，也不能显著提高灵敏度。
当然磁电阻传感器的噪音也会影响SNR，所以我们可以考虑降低磁电阻传感器的噪音。从前面的介绍可知，Bns由带宽决定，可是由人类的声音和音乐决定了音频磁场信号的带宽是不能改变的。尽管噪音随温度降低，但我们无法掌控温度。最后，噪音随电阻的降低而降低。但是降低磁电阻传感器的电阻会增加电耗，减少电池的使用时间，所以电阻不能设计得太低。
影响SNR的参数可以总结在下面的公式里，
Figure PCTCN2015083461-appb-000010
Figure PCTCN2015083461-appb-000011
假设Vp～0.5Vbias
Figure PCTCN2015083461-appb-000012
通过设置较小R和Hsat，及较大Vbias，SNR可以得到优化。但是优化受到R，Hsat，和Vbias实际可行的取值的限制。在座机系统中，Hsat最小值大约为35Oe，所以只有改变R和Vbias。然而，较小R和较大Vbias会造成较大的电耗，因此如图6所示的线性磁电阻传感器的的SNR受到其参数可能的实际取值的束缚。
注意在座机应用中，TMR近场磁通信系统只有当靠近电话机时，才会被使用。磁传感器经常用作接近开关来检测座机的存在。电话机听筒中的DC磁场会触发磁开关，使磁开关在磁场强度小于10Oe开启，所以在不增加电耗的情况下，有两种办法可以改善SNR。
一种方案，当需要使用T-coil传感器时，用高灵敏度的高电阻值的线性传感器 作为磁开关，打开低电阻的线性TMR T-coil传感器。如图6，在两个开关阈值区间65A和65B之间的的区域，TMR T-coil传感器是不工作的。
另一种方案，改变TMR T-coil的磁场～电压转换曲线，使曲线当磁场强度低于10Oe变得更平(两条虚线之间的的区域)，而使曲线当磁场强度大约在10Oe到100Oe时变得更陡，(两条虚线之外的区域)。这一方案显示在图7。当磁电阻传感器在此范围采集音频磁场信号时，其灵敏度表示为，
Figure PCTCN2015083461-appb-000013
该灵敏度高于高灵敏度线性磁电阻传感器的灵敏度。这种磁电阻传感器的长处是：在需要采集信号的磁场范围内，具有高灵敏度，为了减小电耗，可以取较高的电阻值。这种磁电阻传感器可以通过使
Ho＞Hs                (16)
来实现。实现Ho＞Hs的方法包括Neel耦合，在基片上设置偏置永磁体，或交换耦合。在使用交换耦合时，沉积在自由层上的第二个反铁磁层用于产生偏置磁场。
为本发明的目的，“高灵敏度线性传感器”定义为Hsat＜10Oe的线性传感器，“低灵敏度线性传感器”或线性TMR传感器定义为Hsat＞20Oe的线性传感器。高灵敏度的TMR传感器可以用于听力回路系统、手机音频磁场信号采集，或磁开关。
本发明使用了三种不同类型的TMR磁电阻传感器，
i.高灵敏度线性传感器
ii.低灵敏度线性传感器
iii.非线性TMR磁电阻传感器，用作高SNR，低电耗的电话音频磁场信号采集器
上述几种类型的磁电阻传感器可以形成几种不同功能的组合，用于电话音频磁场信号采集或听力回路系统。
i和ii的TMR线性磁电阻传感器可以使用各种不同的设计方法，包括参考桥磁电阻传感器的相关技术见MDT2011.15(CN102621504A)，MDT2013.07.30(201310719255.9)，或MDT2013.01.14(201310203311.3)，准推挽桥线性磁电阻传感器的相关技术见MDT2011.09(CN102331564A)orMDT2011.11(CN102540112A)，iii中的非线性TMR磁电阻传感器必须使用钉扎层反转的设计方法，公开在MDT2013.09.15.X(201310718969.8)，MDT2013.08.20.X，MDT2011.24(CN202230192U)，MDT2011.06(CN102208530A)，MDT2011.05(CN102298125A)(CN102298125A)，or MDT2011.11.30(CN102565727A).
助听器通常包括麦克风，声音放大器，和受话器。麦克风接收声音并将其转换成电信号，声音放大器将来自于麦克风的电信号放大，然后放大了的电信号被传给受话器，受话器将电信号转换回传入人耳的声音信号。当使用者使用电话时，会想要关闭麦克风，接收来自于电话听筒产生的AC磁场。打开TMR T-Coil和关闭麦克风可以通过手动完成，也可以通过检测电话听筒产生的DC磁场的磁开关实现。下面结合4个实施例对本发明进行详细地说明。
实施例1
图8为实施例1.可以检测磁场的TMR近场磁通信系统11包括：检测磁场的桥式磁电阻传感器TMR[A]24A；与桥式磁电阻传感器TMR[A]24A的输出端相连接的模拟信号电路37，模拟信号电路37包括滤波器18和放大器12，滤波器18可以将桥式磁电阻传感器TMR[A]24A的AC和DC信号分离，放大器12放大AC信号；模拟信号输出端14将AC信号传给音频电声装置；电源电路19和与桥式磁电阻传感器TMR[A]24A及模拟信号电路37相连；电源输入端20为电源电路19提供电力供应。其中，桥式磁电阻传感器TMR[A]24A是低灵敏度线性TMR传感器，高灵敏度线性TMR传感器，或非线性TMR传感器。
TMR近场磁通信系统11另外还包括与桥式磁电阻传感器TMR[A]24A连接的数字信号电路27，其可以处理来自于桥式磁电阻传感器TMR[A]24A输出的DC信号。经数字信号电路27处理的电信号通过数字输出端15传给音频电声装置。此外，数字信号电路27包括比较器29，比较器29可以检测桥式磁电阻传感器TMR[A]24A输出信号中的DC 分量的存在。占空比控制器36可以控制磁电阻桥式传感器TMR[A]24A的偏置电压的高电平占空比，当比较器29在桥式磁电阻传感器TMR[A]24A的输出中检测到DC磁场时，占空比控制器36就会关闭。另外，电源电路19包括倍压器28，其可以增加桥式磁电阻传感器TMR[A]24A的偏置电压；当比较器29在桥式磁电阻传感器TMR[A]24A的输出中检测到较大的DC磁场时，倍压器28就会开启。
在第一实施例中，桥式磁电阻传感器TMR[A]24A是半桥，全桥，推挽桥或它们的任意的结合。TMR T-Coil近场磁通信系统可以封装成柔性板上芯片封装(COF)、多芯片封装(single semiconductor package)或板上芯片封装(COB)。TMR磁电阻传感器采用晶粒翻转(flip die)技术或单颗裸芯片(single die)技术制作。
实施例2
图9为第二个实施例，TMR近场磁通信系统11包括：用于测量磁场的桥式磁电阻传感器TMR[A]24A；与桥式磁电阻传感器TMR[A]24A的输出端相连接的模拟信号电路37，模拟信号电路37包括滤波器18和放大器12，滤波器18可以将桥式磁电阻传感器TMR[A]24A输出的AC和DC电信号分离，放大器12放大AC电信号；模拟信号输出端14将AC电信号传给音频电声装置；电源电路19和桥式磁电阻传感器TMR[A]24A及模拟信号电路37相连；电源输入端20为TMR近场磁通信系统11的电源电路19提供电力供应。其中，桥式磁电阻传感器TMR[A]24A是低灵敏度线性TMR传感器，或非线性TMR传感器。
TMR近场磁通信系统11还包括桥式磁电阻传感器TMR[B]24B，桥式磁电阻传感器TMR[B]24B是一高灵敏度或低灵敏度的线性TMR磁电阻，可以检测电话座机听筒中的DC磁场。桥式磁电阻传感器TMR[A]24A和桥式磁电阻传感器TMR[B]24B检测相同方向的磁场分量。
TMR近场磁通信系统11另外还包括：与桥式磁电阻传感器TMR[B]24B连接的数字信号电路27，其可以处理来自于桥式磁电阻传感器TMR[B]24B的DC电信号；数字输出端15，用于将桥式磁电阻传感器TMR[A]24A的直流信息传递给音频电声装置。其中，数字信号电路27包括比较器29，比较器29可以从桥式磁电阻传感器TMR[B]24B输出信号中检测DC磁场的存在。占空比控制器36可以控制桥式磁电阻传感器TMR[B]24B 的偏置电压的高电平占空比。电源电路19包括倍压器28，其可以增加桥式磁电阻传感器TMR[A]24A的偏置电压；当比较器29在桥式磁电阻传感器TMR[B]24B的输出中检测到较大的DC分量的存在时，倍压器28就会开启以增加桥式磁电阻传感器TMR[A]24A的偏置电压。
TMR近场磁通信系统11还可以包括一个数字信号输入端，用于TMR近场磁通信系统11在听力回路模式，T-coil模式和待机模式之间手动切换，其中待机模式中TMR T-coil不工作。
实施例3
图10是实施例3。TMR近场磁通信系统声音11包括：用于检测磁场的桥式磁电阻传感器TMR[A]24A；与桥式磁电阻传感器TMR[A]24A的输出端相连接的模拟信号电路37，模拟信号电路37包括滤波器18和放大器12，滤波器18可以将桥式磁电阻传感器TMR[A]24A的输出的AC和DC电信号分离，放大器12放大AC电信号；模拟信号输出端14将AC电信号传给音频电声装置；电源电路19与桥式磁电阻传感器TMR[A]24A及模拟信号电路37相连；电源输入端20为电源电路19提供电力供应。其中，桥式磁电阻传感器TMR[A]24A是低灵敏度线性TMR传感器，或非线性TMR传感器。
TMR近场磁通信系统11还包括桥式磁电阻传感器TMR[B]24B，桥式磁电阻传感器TMR[B]24B是一高灵敏度或低灵敏度的线性TMR磁电阻传感器，可以检测电话座机听筒中的DC磁场。桥式磁电阻传感器TMR[A]24A和桥式磁电阻传感器TMR[B]24B检测相同方向的磁场分量。桥式磁电阻传感器TMR[B]24B的供电可以是被占空比控制器斩波后的电源信号，以减小能量消耗。
TMR近场磁通信系统11另外包括：与桥式磁电阻传感器TMR[B]24B连接的数字信号电路27，其可以处理来自于桥式磁电阻传感器的DC信号；数字输出15将桥式磁电阻传感器TMR[A]24A的直流信号信息传输给音频电声装置。其中，数字信号电路27包括比较器29，比较器29可以检测桥式磁电阻传感器TMR[B]24B输出信号中的DC分量的存在。在电源电路中的19中的占空比控制器36可以控制桥式磁电阻传感器TMR[B]24B的偏置电压的高电平占空比。此外，电源电路19包括倍压器28，其可以增加桥式磁电阻传感 器TMR[A]24A的偏置电压，当比较器29在桥式磁电阻传感器TMR[B]24B的输出中检测到较大的DC分量时，倍压器28就会开启。
TMR近场磁通信系统11还包括桥式磁电阻传感器TMR[C]24C，桥式磁电阻传感器TMR[C]24C和桥式磁电阻传感器TMR[B]24B检测互相垂直的两个磁场分量，桥式磁电阻传感器TMR[C]24C是高灵敏线度的TMR磁电阻传感器，其用来检测AC磁场。
模拟信号37还包括：连接到桥式磁电阻传感器TMR[C]24C输出端的缓冲器44C；滤波器18将桥式磁电阻传感器TMR[C]24C的AC电信号分离出来；放大器12放大该AC电信号，并将放大了的信号传给TMR近场磁通信系统11的模拟信号的输出端14。另外，缓冲器44A连接于桥式磁电阻传感器TMR[A]24A的输出端，以使其较好地与桥式磁电阻传感器TMR[C]24C信号隔离。
电源电路19包括倍压器28，以增加桥式磁电阻传感器TMR[A]24A和TMR[C]24C的偏置电压；只有当比较器29在桥式磁电阻传感器TMR[B]24B的输出中检测到适当强度的DC分量时，倍压器28才会开启。
桥式磁电阻传感器TMR[A]24A，桥式磁电阻传感器TMR[B]24B和桥式磁电阻传感器TMR[C]24C是半桥，全桥，推挽桥，或它们的任意的结合。
TMR近场磁通信系统11可能包括另一个数字信号输入端，用于TMR近场磁通信系统11在听力回路模式，T-coil模式和待机模式之间手动切换，其中待机模式中TMR T-coil不工作。
TMR T-Coil近场磁通信系统可以封装成柔性板上芯片封装(COF)、多芯片封装(single semiconductor package)或板上芯片封装(COB)。
实施例4
图11为实施例4，TMR近场磁通信系统11用来检测近场磁通信系统的AC和DC磁场，把AC和DC磁场转换成可被音频电声装置接受的电信号。TMR近场磁通信系统11包括一对呈90度放置的TMR传感器，可分别检测两个相互垂直的磁场分量。该对TMR传感器是桥式磁电阻传感器TMR[A]24A，桥式磁电阻传感器TMR[C]24C。桥式磁电阻传感器 TMR[A]24A和桥式磁电阻传感器TMR[C]24C的输出均连接至有各自的缓冲器，通过滤波器使其AC和DC电信号分离，并且两个传感器的AC电信号被放大器12放大。模拟信号输出端14用来将AC电信号传给音频电声装置。电源电路19与桥式磁电阻传感器TMR[A]24A和TMR[C]24C及模拟信号电路37相连，电源输入端20为TMR近场磁通信系统11的电源电路19提供电力供应。桥式磁电阻传感器TMR[A]24A和TMR[C]24C是低灵敏度线性TMR传感器，高灵敏度线性TMR传感器，或非线性TMR传感器。
TMR近场磁通信系统11包括数字信号电路27，数字信号电路27包括比较器29，桥式磁电阻传感器TMR[A]24A和TMR[C]24C的直流输出信号传输给比较器29。比较器29的输出端连接到数字输出端15，数字输出端15将桥式磁电阻传感器TMR[A]24A和TMR[C]24C的DC信号信息传给音频电声装置。
电源电路19可以包括倍压器28，其可以增加桥式磁电阻传感器TMR[A]24A和TMR[C]24C的偏置电压。当比较器29检测桥式磁电阻传感器TMR[A]24A和TMR[C]24C的输出中有足够的DC分量时，倍压器28就会开启。电源电路19可以包括占空比控制器36，当在桥式磁电阻传感器TMR[A]24A和TMR[C]24C的输出中没有足够的DC分量时，其控制桥式磁电阻传感器TMR[A]24A和TMR[C]24C的偏置电压的高电平占空比。
桥式磁电阻传感器TMR[A]24A，TMR[B]42B和TMR[C]24C是半桥，全桥，推挽桥，或它们的任意的结合。
TMR近场磁通信系统11可能包括另一个数字信号输入端，用于TMR近场磁通信系统11在听力回路模式，T-coil模式和待机模式之间手动切换，其中待机模式中TMR T-coil不工作。
TMR T-Coil近场磁通信系统可以封装成柔性板上芯片封装(COF)、多芯片封装(single semiconductor package)或板上芯片封装(COB)。
实施例5
图12为实施例5。为了扩展AC磁场检测中DC磁场阈值范围，TMR近场磁通信系统11还包括若干个检测相同方向磁场分量的额外磁电阻传感器TMR[A1]，TMR[A2]，…，TMR[Ai](i为正整数)，且这些额外磁电阻传感器TMR[A1]，TMR[A2]，…，TMR[Ai](i 为正整数)的敏感方向与磁电阻传感器TMR[A]相同。由电源电路19提供电力，每个传感器的输出与带有缓冲输入的模拟信号电路37的输入相连。这些磁电阻传感器具有不同的Hsat，并且Hsat分布如图13所示。这种设计使得在很宽的DC磁场范围内，AC磁场可以得到平滑的测量。电源电路19包括可以提高磁电阻传感器灵敏度的倍压器28和降低电耗的占空比控制器36。每一个磁电阻传感器的输出经缓冲器，输出到高通滤波器18，滤波器18的每路输出与放大器12电相连，放大器12将来自于磁电阻传感器的AC电信号放大，并经模拟输出端14将经过处理后的AC电信号传给音频电声装置。
以上仅为本发明的实施例而已，并不用于限制本发明，对于本领域的技术人员来说，本发明可以有各种更改和变化。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (20)

  1. TMR近场磁通信系统，用于检测近场磁通信系统产生的AC和DC磁场，并将磁信号转换成被音频电声装置接收的电信号，所述TMR近场磁通信系统包括
    检测磁场的桥式磁电阻传感器TMR[A]；
    与桥式磁电阻传感器TMR[A]的输出相连接的模拟信号电路，所述模拟信号电路包括滤波器和放大器，所述滤波器将所述桥式磁电阻传感器TMR[A]输出的AC和DC电信号分离，所述放大器放大所述AC电信号，模拟信号输出端将放大后的所述AC电信号传给所述音频电声装置；
    与所述桥式磁电阻传感器TMR[A]及所述模拟信号电路相连的电源电路和为所述电源电路提供电力供应的电源输入端；
    所述桥式磁电阻传感器TMR[A]是低灵敏度线性TMR磁电阻传感器，高灵敏度线性TMR磁电阻传感器或非线性TMR磁电阻传感器。
  2. 根据权利要求1所述的TMR近场磁通信系统，包括：
    与所述桥式磁电阻传感器TMR[A]连接的数字信号电路，所述数字信号电路处理所述磁电阻传感器TMR[A]输出的电信号的直流分量；
    数字信号输出端，将所述桥式磁电阻传感器TMR[A]输出的直流分量的信息传给所述音频电声装置。
  3. 根据权利要求2所述的TMR近场磁通信系统，所述电源电路包括占空比控制器，用于控制所述桥式磁电阻传感器TMR[A]的高平占空比；所述数字信号电路包括检测所述桥式磁电阻传感器TMR[A]输出信号中的大的所述DC电信号的存在的比较器；当所述比较器在TMR桥式磁电阻传感器[A]的输出中检测到大的所述DC电信号时，所述占空比控制器停止工作，其输出仍为直流偏置电压。
  4. 根据权利要求3所述的TMR近场磁通信系统，所述电源电路包括倍压器，当所述比较器在桥式磁电阻传感器TMR[A]的输出中检测到大的所述DC电信号时，所述倍压器开启，增加所述桥式磁电阻传感器TMR[A]的偏置电压。
  5. 根据权利要求1所述的TMR近场磁通信系统，包括与所述电源电路相连的桥式磁电阻 传感器TMR[B]。
  6. 根据权利要求5所述的TMR近场磁通信系统，包括：
    与所述桥式磁电阻传感器TMR[B]连接的数字信号电路处理来自于所述桥式磁电阻传感器TMR[B]的DC电信号，所述数字信号电路包括一个用于检测所述桥式磁电阻传感器TMR[B]的输出中较大直流分量的比较器，当所述比较器在所述桥式磁电阻传感器TMR[B]的输出信号中的检测到所述DC电信号时，所述比较器发出信号，使所述桥式磁电阻传感器TMR[A]的偏置电压开启；
    数字输出端，将所述桥式磁电阻传感器TMR[B]输出的直流分量的信息传给所述音频电声装置；
    桥式磁电阻传感器TMR[B]的电阻比所述桥式磁电阻传感器TMR[A]的电阻大。
  7. 根据权利要求6所述TMR近场磁通信系统，所述电源电路包括倍压器，当所述比较器在所述桥式磁电阻传感器TMR[B]的输出中检测到DC电信号时，所述倍压器就会开启，以增加桥式磁电阻传感器TMR[A]的偏置电压。
  8. 根据权利要求5-7的任一项所述的TMR近场磁通信系统，包括桥式磁电阻传感器TMR[C]，所述桥式磁电阻传感器TMR[C]和所述磁电阻传感器TMR[B]分别检测两个沿互相垂直方向的磁场分量，所述磁电阻传感器TMR[C]是高灵敏度线性TMR磁电阻传感器，用来检测所述AC磁场。
  9. 根据权利要求8所述的TMR近场磁通信系统，所述模拟信号电路连接到所述桥式磁电阻传感器TMR[C]的输出端，所述模拟信号电路分离和放大所述桥式磁电阻传感器TMR[C]输出的AC电信号，并将经过处理的所述AC电信号传给所述TMR近场磁通信系统的模拟信号输出端。
  10. 根据权利要求1或5的任一项所述TMR近场磁通信系统，所述桥式磁电阻传感器TMR[A]和所述桥式磁电阻传感器TMR[B]是半桥，全桥，推挽桥，或它们的任意的结合；所述TMR近场磁通信系统封装成薄膜覆晶封装，多芯片封装，或板上芯片封装；桥式磁电阻传感器TMR[A]和所述桥式磁电阻传感器TMR[B]用晶粒翻转工艺制作。
  11. 根据权利要求8所述TMR近场磁通信系统，所述桥式磁电阻传感器是半桥，全桥， 推挽桥，或它们的任意的结合；所述TMR近场磁通信系统封装成薄膜覆晶封装，多芯片封装，或板上芯片封装；桥式磁电阻传感器用晶粒翻转工艺制作。
  12. 根据权利要求10所述的TMR近场磁通信系统，所述桥式磁电阻传感器TMR[A]是采用晶粒翻转工艺制作的非线性TMR传感器，每一个桥臂的偏移磁场大于其饱和磁场，所述偏移磁场与所述饱和磁场之和等于所述桥式磁电阻传感器TMR[A]的运行的最大DC磁场。
  13. 根据权利要求11所述的TMR近场磁通信系统，所述桥式磁电阻传感器TMR[A]是采用晶粒翻转工艺制作的非线性TMR传感器，每一个桥臂的偏移磁场大于其饱和磁场，所述偏移磁场与所述饱和磁场之和等于所述桥式磁电阻传感器TMR[A]的运行的最大DC磁场。
  14. 根据权利要求1，5的任一项所述的TMR近场磁通信，包括一个数字输入端，用于TMR近场磁通信系统在听力回路模式，T-coil模式和待机模式之间手动切换，其中待机模式中桥式磁电阻传感器TMR[A]不工作。
  15. 根据权利要求8所述的TMR近场磁通信系统，包括一个数字输入端，用于TMR近场磁通信系统在听力回路模式，T-coil模式和待机模式之间手动切换，其中待机模式中桥式磁电阻传感器TMR[A]不工作。
  16. 根据权利要求1所述的TMR近场磁通信系统，包括桥式磁电阻传感器TMR[C]，所述桥式磁电阻传感器TMR[C]和所述桥式磁电阻传感器TMR[A]分别检测两个相互垂直的磁场的分量，所述磁电阻传感器TMR[C]是高灵敏度线性TMR传感器，用于检测AC磁场，所述桥式磁电阻传感器TMR[C]的输出被缓冲并且与所述模拟信号电路中的所述音频放大器AC耦合。
  17. 根据权利要求16所述的TMR近场磁通信系统，包括数字信号电路，所述数字信号电路包括比较器，所述的比较器从所述桥式磁电阻传感器TMR[C]和所述桥式磁电阻传感器TMR[A]的输出端接收DC电信号，所述比较器的输出端连接到所述数字信号输出端，并通过数字信号输出端将所述的桥式磁电阻传感器TMR[A]输出信号的DC分量信息传输到所述音频电声装置。
  18. 根据权利要求1所述的TMR近场磁通信系统，包括一个或多个额外的桥式磁电阻传感器TMR[A1]，TMR[A2]，…，TMR[Ai]；所有所述磁电阻传感器TMR[Ai]具有不同的Hsat；所 有所述桥式磁电阻传感器TMR[Ai]与所述桥式磁电阻传感器TMR[A]检测相同方向的磁场分量；所述的桥式磁电阻传感器TMR[Ai]是高灵敏度线性TMR磁电阻传感器，低灵敏度TMR磁电阻传感器或非线性TMR磁电阻传感器；所述桥式磁电阻传感器TMR[A]和所述桥式磁电阻传感器TMR[Ai]的输出经过缓冲，与所述模拟信号电路中的所述音频放大器AC耦合，所述i为正整数。
  19. 根据权利要求16或18任一项所述的TMR近场磁通信系统，至少一个桥式磁电阻传感器的偏移场大于其饱和场，并使其在位于10～100G的磁场范围内运行，以取得最佳信噪比。
  20. 根据权利要求16或18所述TMR近场磁通信系统，所述TMR近场磁通信系统封装成薄膜覆晶封装，多芯片封装，或板上芯片封装；所述桥式磁电阻传感器TMR[A]和所述桥式磁电阻传感器TMR[Ai]用晶粒翻转工艺制作。
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