Magnetoresistance Relaxation Oscillator Magnetometer

Abstract

To rapidly measure the magnitude of an external magnetic field.SOLUTION: A magnetoresistive relaxation oscillator magnetometer (1) includes: a capacitor (2); a charge resistor (3); a discharge resistor (4); a charge / discharge switch (5); a high voltage source terminal (6); a grounding terminal (7); and a signal output terminal (Vout). The charge resistor (3) comprises at least one charge magnetoresistive unit, and the discharge resistor (4) comprises at least one discharge magnetoresistive unit. The charge / discharge switch (5) is connected to the high voltage source terminal (6) and the high voltage source terminal (6) charges the capacitor (2) via the charge resistor (3) in a charge state, and the charge / discharge switch (5) is connected to the grounding terminal (7) and the capacitor (2) discharges electricity via the grounding terminal (7) by the discharge resistor (4) during a discharge stage.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to the technical field of magnetic sensors, and more particularly to magnetoresistive relaxation oscillator magnetometers. [Background technology]

[0002] Magnetoresistive sensors typically have 1 / f noise when used, and the noise of the magnetoresistive sensor Developing low-noise magnetoresistive sensors will improve the accuracy of magnetic signal measurement. It is extremely important.

[0003] Generally, magnetoresistive sensors have high 1 / f noise at low frequencies and mainly thermal noise at high frequencies. Furthermore, its noise energy density is considerably lower than that of noise energy density at low frequencies. Therefore, currently, the magnetic signal is modulated into a high-frequency magnetic field, and then the magnetic resistance sensor is used to measure the frequency. The frequency magnetic field is measured and a high-frequency voltage signal is output, then demodulation is performed to extract the low-frequency zone. The purpose is to move the measurement of the magnetic signal to the high-frequency zone and reduce the 1 / f noise energy density. Making it happen is the most common option.

[0004] However, existing high-frequency magnetic signal measurement devices typically have complex structures and low frequencies. It has a wavenumber response. [Overview of the project] [Means for solving the problem]

[0005] One embodiment of the present disclosure relates to a magnetoresistive relaxation oscillator for rapid measurement of an external magnetic field. We provide force meters.

[0006] One embodiment of the present disclosure comprises a capacitor, a charging resistor, a discharging resistor, and a charge / discharge switch. The magnetoresistive relaxation oscillator magnetometer includes a high-voltage source terminal, a ground terminal, and a signal output terminal. Provided. The charging resistor consists of at least one charging magnetoresistance unit, and the discharge resistor is It consists of at least one discharge magnetoresistance unit.

[0007] The first end of the capacitor is connected to the ground terminal, and the second end of the capacitor is connected to the charge / discharge terminal. The charging resistor, discharging resistor, and signal output terminal are connected via a switch, respectively. The discharge switch is further connected to the high-voltage source terminal.

[0008] During the charging phase, the charge / discharge switch is switched to the high voltage source terminal, and the high voltage source terminal is used for charging. The capacitor is charged via a resistor, while during the discharge phase, the charge / discharge switch is connected to the ground terminal. The switch is activated, and as a result, the capacitor discharges to the ground terminal via the discharge resistor.

[0009] When an external magnetic field causes a change in resistance in the charging resistor and the discharging resistor, The charge and discharge time of the capacitor changes, and the pulse signal output by the signal output terminal is the charge. The signal processing circuit includes one or more harmonics of a resistor or discharge resistor, and the external magnetic field To measure, we measure the pulse signal.

[0010] According to the magnetoresistive relaxation oscillator magnetometer provided in this embodiment, periodic charging Discharge is performed by employing a capacitor, a charging resistor, and a discharging resistor. The charge / discharge cycle is directly proportional to the product of capacitance and charge / discharge resistance, and as a result, charge / discharge Resistance is converted into charge pulse voltage and discharge pulse voltage as a function of time within the charge / discharge cycle. Therefore, measurement time can be shortened, the signal-to-noise ratio is reduced, and the structure is simple. It is as follows.

[0011] To more clearly explain the technical solutions in the embodiments of the present disclosure or the prior art, the attached drawings used in the description of the embodiments or the prior art are briefly introduced below, and the attached drawings in the following description are some specific embodiments of the present disclosure, but various basic concepts of the device structure, driving method, and manufacturing method disclosed and suggested by the embodiments of the present disclosure can be extended and expanded to other structures and drawings, which is obvious to those skilled in the art, and there is no doubt that they are within the scope of the claims of the present disclosure.

Brief Description of the Drawings

[0012] [Figure 1] It is a schematic diagram of a magnetoresistive relaxation oscillator magnetometer provided by an embodiment of the present disclosure. [Figure 2] It is a schematic diagram of the charging in FIG. 1. [Figure 3] It is a schematic diagram of the discharging in FIG. 1. [Figure 4] It is a schematic diagram of a magnetoresistive relaxation oscillator magnetometer provided by an embodiment of the present disclosure. [Figure 5] It is a schematic graph of the voltage Vc(t) applied to the capacitor in FIG. 1 and the voltage VR2(t) applied to the discharge resistor. [Figure 6] It is a schematic diagram of a magnetoresistive relaxation oscillator magnetometer provided by an embodiment of the present disclosure. [Figure 7] It is a schematic diagram of the charging in FIG. 6. [Figure 8] It is a schematic diagram of the discharging in FIG. 6. [Figure 9] It is a schematic graph of the voltage Vc(t) applied to the capacitor in FIG. 6. [Figure 10] It is a schematic diagram of a magnetoresistive relaxation oscillator magnetometer provided by an embodiment of the present disclosure. [Figure 11] It is a schematic diagram of the charging in FIG. 10. [Figure 12] Figure 10 is a schematic diagram of the discharge. [Figure 13] Figure 10 is a circuit diagram of the equivalent trigger. [Figure 14] Figure 10 shows schematic graphs of the voltage Vc(t) and voltage Vout(t) across the capacitor at the trigger output terminal. [Figure 15] This is a schematic diagram of a magnetoresistive relaxation oscillator magnetometer provided by one embodiment of the present disclosure. [Figure 16] Figure 15 is a schematic diagram of the charging process. [Figure 17] Figure 15 is a schematic diagram of the discharge. [Figure 18] Figure 15 is a circuit diagram of the equivalent trigger. [Figure 19] Figure 15 shows schematic graphs of the voltage Vc(t) and voltage Vout(t) across the capacitor at the trigger output terminal. [Figure 20] This is a schematic diagram of a magnetoresistive relaxation oscillator magnetometer provided by one embodiment of the present disclosure. [Figure 21] This is a schematic diagram of a magnetoresistive relaxation oscillator magnetometer provided by one embodiment of the present disclosure. [Figure 22] This is a schematic diagram of a magnetoresistive relaxation oscillator magnetometer provided by one embodiment of the present disclosure. [Figure 23] These are graphs of four typical signal outputs from a relaxation oscillator magnetometer. [Modes for carrying out the invention]

[0013] To further clarify the purpose, technical solutions, and benefits of this disclosure, the technical solutions of this disclosure are described below. The decision is as clearly and clearly demonstrated by implementation, with reference to the accompanying drawings in the embodiments of this disclosure. The embodiments fully described and described are part of the embodiments of this disclosure, and all implementations It is clear that this is not a form. The embodiments disclosed and implied in this disclosure All other embodiments that can be obtained by those skilled in the art based on the basic concepts fall within the scope of the present invention.

[0014] One embodiment of the present disclosure comprises a capacitor, a charging resistor, a discharging resistor, and a charge / discharge switch. The magnetoresistive relaxation oscillator magnetometer includes a high-voltage source terminal, a ground terminal, and a signal output terminal. Provided. The charging resistor consists of at least one charging magnetoresistance unit, and the discharge resistor is It consists of at least one discharge magnetoresistance unit. The first end of the capacitor is the ground terminal. The second end of the capacitor is connected to the charge resistor and discharge resistor via a charge / discharge switch. The resistor and signal output terminals are connected respectively, and the charge / discharge switch is further connected to the high voltage source terminal. It is connected to the high voltage source terminal. During the charging phase, the charge / discharge switch is switched to the high voltage source terminal. The terminals charge the capacitor via the charging resistor, while during the discharge phase, the charge / discharge switch The circuit is switched to the ground terminal, and as a result, the capacitor discharges to the ground terminal via the discharge resistor. To charge. An external magnetic field causes a change in resistance in the charging resistor and the discharging resistor. At that time, the charge and discharge time of the capacitor changes, and the pulse signal output by the signal output terminal is , including one or more harmonics of a charging resistor or a discharging resistor, the signal processing circuit is external A pulse signal is measured to measure the magnetic field.

[0015] As appropriate, the charging magnetoresistance unit and the discharging magnetoresistance unit are anisotropic magnetoresistance units. It is a giant magnetoresistive unit, or tunnel magnetoresistive unit.

[0016] According to the magnetoresistive relaxation oscillator magnetometer provided in this embodiment, periodic charging Discharge is performed by employing a capacitor, a charging resistor, and a discharging resistor. The charge / discharge cycle is directly proportional to the product of the capacitor's capacitance and the resistance of the charge / discharge resistor, Therefore, the charge / discharge resistance value is time-dependent on the charge pulse voltage and time within the charge / discharge cycle. It is converted into a discharge pulse voltage. Therefore, the measurement time can be shortened, and the signal-to-noise ratio is reduced. The ratio decreases, and the structure becomes simpler.

[0017] The above constitutes the core concepts of this disclosure, and the technical solutions in the embodiments of this disclosure are: The embodiments of this disclosure will be clearly and completely described below in combination with the accompanying drawings. All other embodiments that a person skilled in the art can obtain based on the embodiments of this disclosure without any creative effort are, This falls within the scope of protection of the present invention.

[0018] Referring to Figure 1, a schematic diagram of one embodiment of the magnetoresistive relaxation oscillator magnetometer of the present disclosure is given. The magnetoresistive relaxation oscillator magnetometer 1 consists of a capacitor 2, a charging resistor 3, and a discharge resistor 4. And the charge / discharge switch 5, the high voltage source terminal 6, the ground terminal 7, and the signal output terminal Vout Includes. The charging resistor 3 consists of at least one charging magnetoresistance unit and the discharge resistor 4 It consists of at least one discharge magnetoresistance unit. The first end of capacitor 2 is connected It is connected to the ground terminal 7. The charge / discharge switch 5 is used as appropriate for metal oxide semiconductor field-effect transients. It is a MOSFET, and the second terminal of capacitor 2 and the second terminal of charging resistor 3 are Both are connected to the gate of MOSFET 5, and the discharge resistor 4 is connected to the drain of MOSFET 5. The high voltage source terminal 6 is located between the ground terminal 7 and the first end of the charging resistor 3. It is connected to the source of MOSFET 5. The two ends of capacitor 2 are signal output terminals. This is Vout.

[0019] In this embodiment, the capacitor 2 is located between the gate of the MOSFET 5 and the ground terminal 7. The charging resistor 3 is located between the high-voltage source terminal 6 and the gate of the MOSFET 5. Figure 2 As shown, during the charging phase, the charge / discharge switch 5 is switched to the high voltage source terminal 6, In other words, MOSFET 5 is turned off, and charge / discharge switch 5 cuts off the high voltage source terminal 6. The high-voltage source terminal 6 is connected to the charging resistor 3 in a charging branch path as indicated by the arrow. The capacitor 2 is charged via the charge / discharge switch, as shown in Figure 3. Terminal 5 is switched to the ground terminal 7, meaning MOSFET 5 is turned on, and the charge / discharge switch Terminal 5 is connected to the ground terminal 7, and capacitor 2 has a discharge branch as indicated by the arrow. The discharge occurs through the discharge resistor 4 to the ground terminal 7.

[0020] An external magnetic field is applied to the magnetometer 1, and during the charging phase, the external magnetic field causes the resistance of the charging resistor 3 to A resistance change is triggered, and during the discharge phase, the resistance change in the discharge resistor 4 is caused by the external magnetic field. This is triggered, and therefore the charge / discharge time of the capacitor changes. During the charging phase, the signal output terminal... The child outputs a charging pulse voltage signal, and the charging pulse voltage signal is transmitted to one or more charging resistors. It contains several harmonics, and during the discharge stage, the signal output terminal outputs a discharge pulse voltage signal, and the discharge pulse The discharge voltage signal includes one or more harmonics of the discharge resistor. The signal processing circuit uses an external magnetic field. To measure the magnitude of the field, the pulse signal at the signal output terminal is measured.

[0021] In other embodiments, the charge / discharge switch 5 shown in Figure 4 is a triode, and the capacitor The second end of the capacitor 2 and the second end of the charging resistor 3 are both connected to the base of the triode 5. The discharge resistor 4 is located between the emitter of the triode 5 and the ground terminal 7, and the high voltage source terminal 6 These are connected to the first end of the charging resistor 3 and the collector of the triode 5, respectively.

[0022] As appropriate, charging resistors and discharging resistors are opposite in the direction of magnetic field sensing, and sensitivity is They are the same, and the resistance is the same when no external magnetic field is applied, and the push. A pull-type magnetoresistive resistor is formed. The charging resistor is, as appropriate, a magnetic field sensing magnetoresistive unit.

[0023] Figure 5 shows the voltage Vc(t) across the capacitor and the voltage across the discharge resistor in magnetometer 1. Voltage V R2 This is a schematic graph of (t), where the voltage signal Vc(t) across the capacitor is, This is a pulse signal output by the output terminal.

[0024] Charging characteristic curve 1, which is produced by the voltage Vc(t) applied to the capacitor during the charging phase. 1 is an exponentially increasing function, and the formula for the charging characteristic curve 11 is equation (1), during the discharge phase. The discharge characteristic curve 12, which is brought about by the voltage Vc(t) applied to the capacitor, is exponential. It is a decreasing function, and as can be seen from Figure 5, the equation for the discharge characteristic curve 12 is equation (2). ru.

number

[0025] V0 is the charging end voltage or discharging start voltage, t1 is the charging time, and t2 is... This is the discharge time, where R1 is the resistance value of the charging resistor and R2 is the resistance value of the discharging resistor. C is the capacitance value of the capacitor.

[0026] Therefore, the charging time t1 of the voltage Vc(t) applied to the capacitor during the charging phase is R2 *Determined by the time constant of C, while the voltage Vc(t) across the capacitor during the discharge phase It can be understood that the discharge time t2 is determined by the time constant R1*C.

[0027] V P V is the peak voltage of the capacitor during the charging and discharging process. V Charging and This is the valley voltage of the capacitor during the discharge process, and the voltage across the discharge resistor during the charging phase. R The current and voltage in 2(t) are both 0, and the voltage across the discharge resistor is V R2 (t) is discharge Figure 5 shows that it is the only one that exists among them. Therefore, the electricity applied to the discharge resistor Pressure V R2 The pulse period of (t) is T = t1 + t2.

[0028] Referring to Figure 6, Figure 6 shows a magnetoresistive relaxation oscillator provided by one embodiment of the present disclosure. This is a schematic diagram of a magnetometer. The magnetoresistive relaxation oscillator magnetometer 1 consists of a capacitor 2 and a charging resistor 3. And, a discharge resistor 4, a charge / discharge switch 5, a high voltage source terminal 6, a ground terminal 7, and a signal output The charging resistor 3 includes terminal Vout. The charging resistor 3 consists of at least one charging magnetoresistance unit. The discharge resistor 4 consists of at least one discharge magnetoresistance unit. The first end is connected to the grounding terminal 7. The charge / discharge switch 5 is connected to the ON end 5a as appropriate. It is a triode bidirectional switch including an off end 5b and a connecting end 5c, and the high voltage source end 6 is The on terminal 5a is connected via the charging resistor 3, and the ground terminal 7 is connected via the discharge resistor 4. The second end of capacitor 2 is connected to the connected end 5c, and the off end 5b is connected to the connected end 5c. During the energizing phase, the ON end 5a is connected to the connecting end 5c, and during the discharging phase, the OFF end 5b is connected to the connecting end 5c. The terminal end 5c is electrically connected.

[0029] As appropriate, charging resistors and discharging resistors are opposite in the direction of magnetic field sensing, and sensitivity is They are the same, and the resistance is the same when no external magnetic field is applied, and the push. A pull-type magnetoresistive resistor is formed. The charging resistor is, as appropriate, a magnetic field sensing magnetoresistive unit.

[0030] In this embodiment, the capacitor 2 is connected to the connection terminal 5c of the charge / discharge switch 5 and the ground terminal 7. The charging resistor 3 is located between the high-voltage source terminal 6 and the ON terminal 5a of the charge / discharge switch 5. The discharge resistor 4 is located between the ground terminal 7 and the off end 5b of the charge / discharge switch 5. As shown in Figure 7, during the charging phase, the charge / discharge switch 5 switches to the high voltage source terminal 6. It is replaced, that is, the ON end 5a is connected to the connection end 5c of the charge / discharge switch 5, The voltage source terminal (+Vdd) 6 is connected to the charging resistor in the charging branch path as indicated by the arrow. Charge capacitor 2 via 3. As shown in Figure 8, during the discharge phase, the charge / discharge switch Terminal 5 is switched to the ground terminal 7, that is, the off terminal 5b is connected to the charge / discharge switch 5. The terminal end 5c is conductive, and capacitor 2 is discharged through the path of the branching as indicated by the arrow. The discharge is directed to the ground terminal 7 via the discharge resistor 4.

[0031] An external magnetic field is applied to the magnetometer 1, and during the charging phase, the external magnetic field causes the charging resistor 3 to... A resistance change is induced, and during the discharge phase, the resistance change in the discharge resistor 4 is caused by the external magnetic field. This is caused, and therefore the charge / discharge time of the capacitor changes. During the charging phase, the signal output The terminal outputs a charging pulse voltage signal, and the charging pulse voltage signal is transmitted to one of the charging resistors or It contains multiple harmonics, and during the discharge phase, the signal output terminal outputs a discharge pulse voltage signal, and discharge The pulse voltage signal includes one or more harmonics of the discharge resistor. The signal processing circuit is external. To measure the magnitude of the magnetic field, the pulse signal at the signal output terminal is measured.

[0032] Figure 9 is a schematic graph of the voltage Vc(t) across the capacitor in magnetometer 1, The voltage signal Vc(t) applied to the capacitor is a pulse signal output by the signal output terminal. be.

[0033] Charging characteristic curve 1, which is produced by the voltage Vc(t) applied to the capacitor during the charging phase. 1 is an exponentially increasing function, and during the discharge stage, the voltage Vc(t) across the capacitor is determined by 1. Figure 9 shows that the resulting charging characteristic curve 12 is an exponentially decreasing function. The charging time t1 of the voltage Vc(t) applied to the capacitor during the charging phase is equal to the time constant R1*C. Therefore, the voltage Vc(t) applied to the capacitor during the discharge phase is determined by the discharge time t2. This is determined by the time constant R²*C.

[0034] Referring to Figure 10, Figure 10 shows a magnetoresistive relaxation generator provided by one embodiment of the present disclosure. This is a schematic diagram of a vibrator magnetometer. The magnetoresistive relaxation oscillator magnetometer 1 consists of a capacitor 2 and a charging resistor. Device 3, discharge resistor 4, charge / discharge switch 5, high voltage source terminal 6, ground terminal 7, signal Includes output terminal Vout. The charging resistor 3 has at least one charging magnetoresistance unit or Therefore, the discharge resistor 4 consists of at least one discharge magnetoresistance unit. The first end of 2 is connected to the ground terminal 7. The charge / discharge switch 5 is connected to the ON end 5a as appropriate. It is a triode bidirectional switch including an off terminal 5b and a connecting terminal 5c, and a charging resistor The discharge resistor is the same common resistor 3 & 4, and the second terminal of capacitor 2 is Common resistors 3 and 4 are connected in series to form an RC series, and the RC series is connected at the terminals. The high-voltage source terminal 6 is connected to the ON terminal 5a, and the ground terminal 7 is connected to the OFF terminal. It is connected to part 5b. During the charging phase, the ON end 5a is conductive to the connecting end 5c, and during the discharging phase In the middle, the off end 5b is electrically connected to the connecting end 5c.

[0035] In this embodiment, common resistors 3 and 4 are provided, and common resistors 3 and 4 are charging resistors and The discharge resistors are multiplexed, and the common resistors 3 & 4 and the second terminal of capacitor 2 are connected. They are electrically connected to form an RC series, which consists of a ground terminal 7 and a charge / discharge switch. It is located between the connection end 5c of 5. As shown in Figure 11, during the charging phase, the charge / discharge switch Switch 5 is switched to the high voltage source terminal 6, that is, the ON terminal 5a is the charge / discharge switch. The connection end 5c of 5 is conductive, and the high voltage source terminal (+Vdd) 6 is indicated by the arrow. The capacitor 2 is charged via common resistors 3 and 4 in the charging branch path. As shown in Figure 12. To enable this, during the discharge phase, the charge / discharge switch 5 is switched to the ground terminal 7, that is, The off end 5b is conductive to the connection end 5c of the charge / discharge switch 5, and the capacitor 2 is connected to the arrow. Therefore, the discharge proceeds to the ground terminal 7 via common resistors 3 and 4 through the discharge branch path shown. .

[0036] An external magnetic field is applied to magnetometer 1, and during the charging phase, the common resistors 3 and 4 are affected by the external magnetic field. A resistance change is caused, and during the discharge phase, the resistance in common resistors 3 and 4 is affected by the external magnetic field. This causes a change in the capacitor's charge and discharge time. During the charging phase, The signal output terminal outputs a charging pulse voltage signal, and the charging pulse voltage signal is connected to a common resistor 3& The discharge pulse voltage signal includes one or more harmonics of 4, and during the discharge stage, the signal output terminal is connected to the discharge pulse voltage signal. The output is a discharge pulse voltage signal which includes one or more harmonics of common resistors 3 and 4. The signal processing circuit measures the pulse signal at the signal output terminal to measure the magnitude of the external magnetic field. The number of resistors is reduced in this embodiment.

[0037] Figure 13 is a circuit diagram of the equivalent trigger in Figure 10. The magnetometer 1 further includes a low voltage source terminal. The charge / discharge switch is a trigger, and the input and output terminals of the trigger are high It is a voltage source terminal or low voltage source terminal, and the charging resistor and discharge resistor are the same one common It is a resistor, and the second end of the capacitor is connected to the trigger input terminal, and the common resistor The two ends are connected to the trigger's input and output terminals, respectively, and the signal output terminal is, It is located at the output or input terminal of the trigger. The charge / discharge switch 5 is located at input terminal 6(2) The Schi has output terminals 8(2) as a high-voltage source terminal and a low-voltage source terminal, respectively. This is a MIT trigger (Schmitt trigger). Capacitor 2 is connected to the ground terminal 7 and input terminal 6. 2) is connected between the two ends of the common resistors 3 and 4, and the input terminal 6(2) of trigger 5. These are connected between the output terminal 8(2) and the output terminal 8(2).

[0038] During the charging phase, output terminal 8(2) is a high-voltage source terminal, and input terminal 6(2) is a low-voltage source terminal. The power terminal is the output terminal 8(2), which charges capacitor 2 via common resistors 3 and 4. The voltage across capacitor 2 increases. If not, the voltage applied to trigger 5 is switched, that is, input terminal 6(2) is high voltage The voltage source terminal is the output terminal 8(2), which is a low voltage source terminal, and then it is the discharge stage. Enter.

[0039] During the discharge phase, capacitor 2 begins to discharge, and the voltage at input terminal 6(2) decreases. If the voltage across capacitor 2 is less than the threshold Vp1, the voltage inversion will occur again at input terminal 6. (2) and at output terminal 8(2), capacitor 2 enters the charging process. The charging branch 9(2) and the discharging branch 10(2) are connected to the Schimit trigger 5, and This is carried out by charging and discharging capacitor 2.

[0040] Figure 14 shows the voltage Vc(t) across the capacitor at the trigger output terminal in Figure 10 and the current This is a schematic graph of pressure Vout(t). off This is the capacitor charging and discharging process This is the peak voltage at the point, V on This is in the charging and discharging process of a capacitor. This is the trough voltage, and the charge brought about by the voltage Vc(t) across the capacitor during the charging phase. The electrical characteristic curve 11(2) is an exponentially increasing function, and the voltage across the capacitor during the discharge stage The charging characteristic curve 12(2) resulting from Vc(t) is an exponentially decreasing function. out(t) is a high / low level pulse voltage, the charging time is t1, and the discharging time is t2. Therefore, the charging time t1 is equal to the discharging time t2.

[0041] Referring to Figure 15, Figure 15 shows a magnetoresistive relaxation generator provided by one embodiment of the present disclosure. This is a schematic diagram of a vibrator magnetometer. The magnetoresistive relaxation oscillator magnetometer 1 consists of a capacitor 2 and a charging resistor. Device 3, discharge resistor 4, charge / discharge switch 5, high voltage source terminal 6, ground terminal 7, signal Includes output terminal Vout. The charging resistor 3 has at least one charging magnetoresistance unit or Therefore, the discharge resistor 4 consists of at least one discharge magnetoresistance unit. The first end of 2 is connected to the ground terminal 7. The charge / discharge switch 5 is connected to the ON end 5a as appropriate. It is a triode bidirectional switch including an off terminal 5b and a connecting terminal 5c, and a charging resistor 3 a is connected in series with diode 3b in the charging direction, which is turned on to form an RD charging sequence. Next, the discharge resistor 4a is turned on in the discharge direction to form an RD discharge sequence. Connected in series with Od 4b, the RD charging series and RD discharging series form the RD series. Connected in parallel in this manner, the second end of capacitor 2 and the RD series form an RC series. They are connected in series as shown, and the RC series is connected to the connection end 5c, and the high voltage source terminal 6 is O The ON terminal 5a is connected to the ON terminal, and the ground terminal 7 is connected to the OFF terminal 5b. During the charging phase, the ON terminal 5a is connected to the connecting end 5c, and during the discharge phase, the off end 5b is connected to the connecting end 5c. It can be done.

[0042] As appropriate, charging resistors and discharging resistors are opposite in the direction of magnetic field sensing, and sensitivity is They are the same, and the resistance is the same when no external magnetic field is applied, and the push. A pull-type magnetoresistive resistor is formed. The charging resistor is, as appropriate, a magnetic field sensing magnetoresistive unit.

[0043] In this embodiment, the RC series is formed by connecting capacitor 2 and the RD series in series. The RD series is formed by connecting the RD charging series and the RD discharging series in parallel. The RC series is formed as such, and is located between the grounding terminal 7 and the connection end 5c of the charge / discharge switch 5. As shown in Figure 16, during the charging phase, the charge / discharge switch 5 is switched off the high voltage source terminal 6. The ON end 5a is replaced, that is, the ON end 5a is connected to the connecting end 5c of the charge / discharge switch 5. The high voltage source terminal (+Vdd) 6 is in the RD series in the charging branch path as indicated by the arrow. The capacitor 2 is charged via the following. As shown in Figure 17, during the discharge phase, the charge / discharge switch Terminal 5 is switched to the ground terminal 7, that is, the off terminal 5b is connected to the charge / discharge switch 5. The terminal end 5c is conductive, and capacitor 2 is discharged through the path of the branching as indicated by the arrow. Discharge is directed to the grounding terminal 7 via the RD series.

[0044] An external magnetic field is applied to the magnetometer 1, and during the charging phase, the resistance in the RD series is affected by the external magnetic field. A change is triggered, and during the discharge phase, an external magnetic field causes a change in resistance in the RD series. Therefore, the charge and discharge time of the capacitor changes. During the charging phase, the signal output terminal is It outputs a charging pulse voltage signal, and the charging pulse voltage signal is one or more RD series frequencies. During the discharge phase, the signal output terminal outputs a discharge pulse voltage signal, and the discharge pulse voltage The signal contains one or more harmonics of the RD series. The signal processing circuit takes into account the magnitude of the external magnetic field. To measure this, the pulse signal at the signal output terminal is measured. The number of resistors in this embodiment is It decreases.

[0045] Figure 18 is a circuit diagram of the equivalent trigger of Figure 15. The magnetometer 1 further includes a low voltage source terminal. The charge / discharge switch is a trigger, and the input and output terminals of the trigger are high A voltage source terminal or low voltage source terminal, the charging resistor is configured to form an RD charging sequence. A diode with a charging direction is connected in series with a discharge resistor, and the RD discharge series A diode having a discharge direction that is turned on to form a capacitor is connected in series with a diode. The second end of the RD is connected to the trigger input terminal, and the RD charging sequence and RD discharging sequence are connected. The two ends of the parallel-connected RD charging and RD discharging series are connected in parallel. The input and output terminals are connected respectively, and the signal output terminal is connected to the trigger output terminal. It is located at the input terminal.

[0046] The charge / discharge switch 5 connects the input terminal 6(4) and output terminal 8(4) to the high-voltage source terminals, respectively. It is a Schimit trigger having a child and low voltage source terminal. Capacitor 2 is grounded. It is connected between terminal 7 and input terminal 6(4), and the two ends of the RD series are connected to the input of trigger 5. It is connected between terminal 6(4) and output terminal 8(4), respectively. The charging branch 9(4) is directly The discharge branch 10(4) includes a charging resistor 3a and a charging diode 3b connected in a row. , including a discharge resistor 4a and a discharge diode 4b connected in series, and a charging branch 9(4) The discharge branch 10(5) is connected in parallel.

[0047] During the charging phase, output terminal 8(4) is a high-voltage source terminal, and input terminal 6(4) is a low-voltage terminal. The power terminal is the output terminal 8(4), which charges the capacitor 2 via the charging resistor 3a. The voltage across capacitor 2 increases. When the voltage is higher than the threshold Vph, the trigger is activated. Voltage switching occurs, meaning that input terminal 6(4) is a high-voltage source terminal, and output terminal 8(4) is a low-voltage source terminal, which then enters the discharge phase.

[0048] During the discharge phase, capacitor 2 begins to discharge via discharge resistor 4a, and input terminal 6(4 When the voltage at ) decreases and the voltage is less than the threshold Vp1, voltage inversion occurs at input terminal 6( 4) and again occurs at output terminal 8(4), and the charging process begins. Therefore, the charging Branch 9(4) and discharge branch 10(4) are connected to Schimit trigger 5, and capacitor This is carried out by charging and discharging in two ways.

[0049] Figure 19 shows the voltage Vc(t) across the capacitor at the trigger output terminal in Figure 15 and the current This is a schematic graph of the voltage Vout(t). During the charging phase, the voltage across the capacitor Vc(t) The resulting charging characteristic curve 11(4) is an exponentially increasing function, and during the discharge phase, The charging characteristic curve 12(4) resulting from the voltage Vc(t) applied to the capacitor is, It is a numerically decreasing function. Vout(t) is a high / low level pulse voltage, and the charging time is t. The value is 1, and the discharge time is t2.

[0050] Regarding the charge-discharge function of an RC series, what is the formula for its frequency f, as well as the charging time t1 and discharge time? The power supply time t2 is as follows: f = 0.8 / (RC) t1∝R1C t2∝R2C That is the case.

[0051] The charging time t1 is directly proportional to the charging resistor R1, and the discharge time t2 is directly proportional to the discharge resistor R2. It is understandable to use examples.

[0052] The above solutions include the following three cases:

[0053] In case 1, t1 = t2, that is, R and C form a series combination, and then Charging and discharging are performed, and the charging resistor R1 and the discharging resistor R2 are the same or the same 1 These are two common resistors.

[0054] In case 2, t1 changes and t2 is constant, that is, the discharge resistor R2 does not change. It remains as is, that is, it is a magnetic shield magnetoresistive unit, and only the charging resistor R1 is external. The magnetic field H changes, i.e., R2 and R1 constitute a sensing reference magnetoresistor pair. do.

[0055] In case 3, t1 + t2 = constant, that is, the charging branch R1 and the discharging branch R2 are... This is a pair of shup-pull type magnetoresistors.

[0056] The output pulse function of the signal output terminal is a piecewise periodic function, with a period T = t1 + t2, and its base The basic formula is,

number

number

number

number

number

[0057] For a magnetometer 1 containing a single resistor R, t1=t2, t1+t2=T=2t1, Therefore, a signal processing circuit may be used, as shown in Figure 20. Relaxation oscillator 1( 2) The output terminal of the Schmit trigger is connected directly to the frequency f / voltage V converter 21 and externally It is connected to the V-1 / V converter 22, and finally the output voltage is connected to the external magnetic This is the voltage at the charge / discharge time period T, which is directly proportional to the field H. The signal output terminal Vout is set as appropriate. It is connected to an FV converter, which converts the pulse signal into a voltage signal, and then, The voltage signal is converted into a voltage signal that is directly proportional to the external magnetic field by a V-1 / V converter.

[0058] As shown in Figure 21, the signal output terminal Vout is appropriately connected to the RC low-pass filter 2 Connected to 2, the first end of the first capacitor 24 in the RC low-pass filter 25 It is connected to the ground terminal, and the first resistor 23 in the RC low-pass filter 25 is It is located between the output terminal Vout and the second end of the first capacitor 24, and the first capacitor The two ends of the 24 output DC and the first harmonic, and the signal processing circuit is used during the charging period. The signal across the first capacitor 24 is converted in order to obtain the discharge period value.

[0059] As described above, the output terminal of the Schimit trigger of the relaxation oscillator 1(4) is one R One Clpf capacitor 24 is connected to the LPF resistor 23 and to ground. Connected in between, the Rlpf resistor 23 and the Clpf resistor 24 form an RC low-pass filter. A signal 25 is formed, and then the signal is output to Vout. The low-pass filter 25 filters the frequency It can be understood that the formula V0 can be directly obtained by removing a portion of the wavenumber. In the vibration circuit of the flux-pull coupled magnetoresistor pair, t1 + t2 is constant. The increase in t1 is proportional to R, and the decrease in t2 is proportional to R. Therefore, V0 is proportional to the external magnetic field H. For example. Another way is that two or more harmonics can be removed by the low-pass filter 25 to obtain V0 + V. Therefore, the value of t1 + t2 can be obtained by using the frequency f of V1(t). And (t1 + t2) * V0 is proportional to H.

[0060] Another way is that two or more harmonics can be removed by the low-pass filter 25 to obtain V0 + V. 1(t) In order to obtain As shown in FIG. 22, appropriately, the signal output terminal of the magnetoresistive relaxation oscillator magnetometer is connected to the analog-to-digital converter 31. The pulse signal is converted by the analog-to-digital converter 31. Then, the converted signal is processed and output by the microcontroller 32. The signal processing circuit directly measures the signal output by the microprocessor 32 to obtain the charging period and the discharging period. Appropriately, the analog-to-digital converter 31 may convert the analog signal into a digital signal. The microprocessor 32 is a DSP or an MCU, and directly outputs a digital signal related to the external magnetic field H according to a certain algorithm. The trigger output terminal of the relaxation oscillator 1(2) is connected to the AD converter 31, converts the analog signal into a digital signal, then inputs the digital signal to the MCU / DSP 32, and directly counts the time of the rising edge or the falling edge, and outputs the values of t1 and t2, which is proportional to H. ) and (t1 + t2) * V0 is proportional to H. is proportional to H.

[0061] As shown in FIG. 22, appropriately, the signal output terminal of the magnetoresistive relaxation oscillator magnetometer is connected to the analog-to-digital converter 31. The pulse signal is converted by the analog-to-digital converter 31. Then, the converted signal is processed and output by the microcontroller 32. The signal processing circuit directly measures the signal output by the microprocessor 32 to obtain the charging period and the discharging period. Appropriately, the analog-to-digital converter 31 may convert the analog signal into a digital signal. The microprocessor 32 is a DSP or an MCU, and directly outputs a digital signal related to the external magnetic field H according to a certain algorithm. The trigger output terminal of the relaxation oscillator 1(2) is connected to the AD converter 31, converts the analog signal into a digital signal, then inputs the digital signal to the MCU / DSP 32, and directly counts the time of the rising edge or the falling edge, and outputs the values of t1 and t2, which is proportional to H. is connected to the analog-to-digital converter 31, and the pulse signal is converted by the analog-to-digital converter 31. Then, the converted signal is processed and output by the microcontroller 32. The signal processing circuit directly measures the signal output by the microprocessor 32 to obtain the charging period and the discharging period. Appropriately, the analog-to-digital converter 31 may convert the analog signal into a digital signal. The microprocessor 32 is a DSP or an MCU, and directly outputs a digital signal related to the external magnetic field H according to a certain algorithm. The trigger output terminal of the relaxation oscillator 1(2) is connected to the AD converter 31, converts the analog signal into a digital signal, then inputs the digital signal to the MCU / DSP 32, and directly counts the time of the rising edge or the falling edge, and outputs the values of t1 and t2, which is proportional to H. The trigger output terminal of the relaxation oscillator 1(2) is connected to the AD converter 31, converts the analog signal into a digital signal, then inputs the digital signal to the MCU / DSP 32, and directly counts the time of the rising edge or the falling edge, and outputs the values of t1 and t2, which is proportional to H. converts the analog signal into a digital signal, then inputs the digital signal to the MCU / DSP 32, and directly counts the time of the rising edge or the falling edge, and outputs the values of t1 and t2, which is proportional to H. The rising edge or the falling edge time is directly counted, and the values of t1 and t2 are output, which is proportional to H. is output, which is proportional to H.

[0062] For any of the above embodiments, FIG. 23 shows four typical signal outputs of the relaxation oscillator magnetometer. This is a graph of forces. The corresponding charging resistor and discharging resistor in Figure (a) are common resistors. When charging time t1 is equal to discharging time t2, the value of H is similarly equal to time t1 This can be obtained by measuring the corresponding charging resistor and discharge resistor in Figure (b). When the resistor is a common resistor, the period T = t1 + t2 or the pulse frequency f can be directly measured. Then, 1 / f is calculated, and the value of H can be measured, as shown in Figure (c) in push-pull. It is a pair of type magnetoresistors, t1+t2=constant, and (t1-t2) / (t1+t2) is , is directly proportional to the external magnetic field H, and Figure (d) shows a pair of sensing reference magnetoresistors, where t2 = constant. Yes, t1 / t2 is directly proportional to the external magnetic field H.

[0063] The foregoing represents only preferred embodiments and applied technical principles of this disclosure. Please note that this disclosure is not limited to the specific embodiments described herein. Without deviating from the scope of protection, various obvious changes, readjustments, combinations, and placements may be made. Those skilled in the art will understand that the exchange may be made by those skilled in the art. Therefore, The disclosure has been described in more detail by the embodiments described above, but this disclosure is not limited to the above embodiments. This disclosure is not limited to any particular form. It includes a wider range of equivalent embodiments without departing from the concepts of this disclosure. It is also possible to do so, and the scope of this disclosure is determined by the attached claims.

Claims

1. A magnetoresistive relaxation oscillator magnetometer comprising a capacitor, a charging resistor, a discharging resistor, a charge / discharge switch, a high-voltage source terminal, a ground terminal, and a signal output terminal, wherein the charging resistor consists of at least one charging magnetoresistive unit, and the discharging resistor consists of at least one discharging magnetoresistive unit, The first end of the capacitor is connected to the ground terminal, the second end of the capacitor is connected to the signal output terminal, and the second end of the capacitor is connected to the charging resistor during the charging phase and to the discharging resistor during the discharging phase via the charge / discharge switch. During the charging phase, the high-voltage source terminal charges the capacitor via the charging resistor through the switching action of the charge / discharge switch, while during the discharging phase, the capacitor discharges to the ground terminal via the discharge resistor through the switching action of the charge / discharge switch. A magnetoresistive relaxation oscillator magnetometer is provided, wherein when an external magnetic field causes a change in resistance in the charging resistor and the discharging resistor, the charging and discharging time of the capacitor changes, and the pulse signal output by the signal output terminal includes one or more harmonics of the charging resistor or the discharging resistor, and a signal processing circuit is connected to the signal output terminal and measures the pulse signal to measure the external magnetic field.

2. The magnetoresistive relaxation oscillator magnetometer according to claim 1, wherein the charging magnetoresistive unit and the discharging magnetoresistive unit are anisotropic magnetoresistive units, giant magnetoresistive units, or tunnel magnetoresistive units.

3. The charge / discharge switch is a metal oxide semiconductor field-effect transistor (MOSFET), the second end of the capacitor and the second end of the charging resistor are both connected to the gate of the metal oxide semiconductor field-effect transistor (MOSFET), the discharge resistor is located between the drain of the metal oxide semiconductor field-effect transistor (MOSFET) and the ground terminal, and the high-voltage source terminal is connected to the first end of the charging resistor and the source of the metal oxide semiconductor field-effect transistor (MOSFET), respectively, or The magnetoresistive relaxation oscillator magnetometer according to claim 1, wherein the charge / discharge switch is a triode, the second end of the capacitor and the second end of the charging resistor are both connected to the base of the triode, the discharge resistor is located between the emitter of the triode and the ground terminal, and the high voltage source terminal is connected to the first end of the charging resistor and the collector of the triode, respectively.

4. The charge / discharge switch is a triode bidirectional switch having an ON end, an OFF end, and a connecting end, wherein the high-voltage source end is connected to the ON end via the charging resistor, the ground terminal is connected to the OFF end via the discharge resistor, and the second end of the capacitor is connected to the connecting end. The magnetoresistive relaxation oscillator magnetometer according to claim 1, wherein during the charging phase, the ON end is conductive to the connecting end, and during the discharging phase, the OFF end is conductive to the connecting end.

5. The magnetoresistive relaxation oscillator magnetometer according to claim 3 or 4, wherein the charging resistor and the discharging resistor are opposite in the direction of magnetic field sensing, have the same sensitivity, and have the same resistance when no external magnetic field is applied, forming a push-pull type magnetoresistive magnetometer.

6. The magnetoresistive relaxation oscillator magnetometer according to claim 3 or 4, wherein the charging resistor is a magnetic field sensing magnetoresistive unit.

7. A magnetoresistive relaxation oscillator magnetometer comprising a capacitor, a charging resistor, a discharging resistor, a charge / discharge switch, a high voltage source terminal, a ground terminal, and a signal output terminal, wherein the charging resistor consists of at least one charging magnetoresistive unit, and the discharging resistor consists of at least one discharging magnetoresistive unit, The first end of the capacitor is connected to the ground terminal. The charge / discharge switch is a triode bidirectional switch having an on end, an off end, and a connection end; the charge resistor is connected in series with a diode having a charging direction that is turned on to form an RD charge series; the discharge resistor is connected in series with a diode having a discharge direction that is turned on to form an RD discharge series; the RD charge series and the RD discharge series are connected in parallel to form an RD series; the second end of the capacitor and the RD series are connected in series to form an RC series; the RC series is connected to the connection end; the high voltage source terminal is connected to the on end; and the ground terminal is connected to the off end. During the charging phase, the ON end is connected to the connecting end, and during the discharging phase, the OFF end is connected to the connecting end. A magnetoresistive relaxation oscillator magnetometer, wherein when an external magnetic field causes a change in resistance in the charging resistor and the discharging resistor, the charging and discharging time of the capacitor changes, and the pulse signal output by the signal output terminal includes one or more harmonics of the charging resistor or the discharging resistor, the signal output terminal is connected between the RC series and the connecting end of the triode bidirectional switch, and a signal processing circuit is connected to the signal output terminal and measures the pulse signal to measure the external magnetic field.

8. It also has a low-voltage source terminal, The magnetoresistive relaxation oscillator magnetometer according to claim 7, wherein the charge / discharge switch is a trigger, the input and output terminals of the trigger are the high-voltage source terminal or the low-voltage source terminal, the charge resistor is connected in series with a diode having a charge direction that is turned on to form an RD charge sequence, the discharge resistor is connected in series with a diode having a discharge direction that is turned on to form an RD discharge sequence, the second end of the capacitor is connected to the input terminal of the trigger, the RD charge sequence and the RD discharge sequence are connected in parallel, the two ends of the parallel-connected RD charge sequence and the RD discharge sequence are connected to the input and output terminals of the trigger, respectively, and the signal output terminal is located at the output terminal or the input terminal of the trigger.

9. The magnetoresistive relaxation oscillator magnetometer according to claim 1 or 7, wherein the signal output terminal is connected to an RC low-pass filter, the first end of a first capacitor in the RC low-pass filter is connected to the ground terminal, a first resistor in the RC low-pass filter is located between the signal output terminal and a second end of the first capacitor, the two ends of the first capacitor output DC and a first harmonic, and the signal processing circuit converts the signal across the first capacitor to obtain a charge period value and a discharge period value.

10. The magnetoresistive relaxation oscillator magnetometer according to claim 1 or 7, wherein the signal output terminal is connected to an analog-to-digital converter, the pulse signal is converted by the analog-to-digital converter, the converted signal is then processed and output by a microprocessor, and the signal processing circuit directly measures the signal output by the microprocessor to obtain the charging and discharging periods.

11. A magnetoresistive relaxation oscillator magnetometer comprising a capacitor, a common resistor, a charge / discharge switch, a high-voltage source terminal, a ground terminal, and a signal output terminal, wherein the common resistor consists of at least one magnetoresistive unit, The first end of the capacitor is connected to the ground terminal, and the second end of the capacitor is connected to the common resistor, which, via the charge / discharge switch, functions as a charging resistor during the charging phase and as a discharging resistor during the discharging phase. During the charging phase, the high-voltage source terminal charges the capacitor via the common resistor due to the switching action of the charge / discharge switch, while during the discharging phase, the capacitor discharges to the ground terminal via the common resistor due to the switching action of the charge / discharge switch. A magnetoresistive relaxation oscillator magnetometer wherein, when an external magnetic field causes a change in resistance in the common resistor, the charge-discharge time of the capacitor changes, and the pulse signal output by the signal output terminal includes one or more harmonics of the common resistor, the signal output terminal is connected between the common resistor and the charge-discharge switch, and a signal processing circuit is connected to the signal output terminal and measures the pulse signal to measure the external magnetic field.

12. The charge / discharge switch is a triode bidirectional switch having an on end, an off end, and a connection end, the second end of the capacitor and the common resistor are connected in series to form an RC series, the RC series is connected to the connection end, the high voltage source terminal is connected to the on end, and the ground terminal is connected to the off end. During the charging phase, the ON terminal is connected to the connecting terminal, and the common resistor functions as the charging resistor. The magnetoresistive relaxation oscillator magnetometer according to claim 11, wherein during the discharge stage, the off-end is connected to the connected end, and the common resistor functions as the discharge resistor.

13. It also has a low-voltage source terminal, The charge / discharge switch is a trigger, and the input and output terminals of the trigger are the high-voltage source terminal or the low-voltage source terminal, respectively, and the common resistor functions as the charging resistor during the charging phase and as the discharging resistor during the discharging phase. The magnetoresistive relaxation oscillator magnetometer according to claim 11, wherein the second end of the capacitor is connected to the input terminal of the trigger, the two ends of the common resistor are connected to the input terminal and the output terminal of the trigger, respectively, and the signal output terminal is located at the output terminal or the input terminal of the trigger.

14. The magnetoresistive relaxation oscillator magnetometer according to claim 12 or 13, wherein the signal output terminal is connected to an F-V converter, the F-V converter converts the pulse signal into a voltage signal, and the voltage signal is then converted by a V-1 / V converter into a voltage signal directly proportional to the external magnetic field.

Images