CN111596236A - Magnetic field sensor with sensitivity correction and offset correction functions and implementation method - Google Patents
Magnetic field sensor with sensitivity correction and offset correction functions and implementation method Download PDFInfo
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- CN111596236A CN111596236A CN202010527313.8A CN202010527313A CN111596236A CN 111596236 A CN111596236 A CN 111596236A CN 202010527313 A CN202010527313 A CN 202010527313A CN 111596236 A CN111596236 A CN 111596236A
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Abstract
The invention discloses a magnetic field sensor with sensitivity correction and offset correction functions, which comprises: an analog signal path module, a correction module, a temperature detection module, an EEPROM memory module, and a segment processor module, gain correction coefficients and offset correction coefficients stored in digital form in the magnetic field sensor, are usable to generate analog control signals to control the sensitivity and offset of the analog signal path of the magnetic field sensor. The gain correction factor and the offset correction factor stored in digital form in the magnetic field sensor of the present invention can be used to generate an analog control signal to control the sensitivity and offset of the analog signal path of the magnetic field sensor. The invention has the advantages of not only simulating the quick response time of the channel, but also ensuring the sensitivity and the accuracy of the static output voltage at room temperature, changing the temperature compensation characteristic in the production and use processes, and simultaneously compensating the sensitivity drift and the static output voltage drift caused by mechanical stress and device aging.
Description
The technical field is as follows:
the invention relates to the technical field of magnetic field sensors, in particular to a magnetic field sensor with sensitivity correction and offset correction functions and an implementation method, which are suitable for a magnetic field sensor IC.
Background art:
magnetic field sensors are widely used in consumer electronics (e.g., washing machines, air conditioners, refrigerators, floor fans, etc.) and automotive (e.g., transmissions, automatic drop locks, seat belt buckles, brake light switches, automatic windows, etc.). Magnetic field sensors are an integral part of safety systems, EPS systems and body electronics systems. Modern automobiles have over 80 applications relying on magnetic sensors, with over 20 hundred million magnetic field sensors being used annually in the automotive field. In addition, the market capacity of the magnetic field sensor keeps 5 to 10 percent of the annual increase, and the development prospect is very good.
Magnetic field sensors tend to have a sensitivity and offset that varies with temperature. The reasons for the sensitivity temperature drift are mainly two: firstly, the inherent characteristics of the manufacturing material of the magnetic field sensing element are changed due to the temperature change; and secondly, the chip package and the bare chip are subjected to thermal expansion and cold contraction due to temperature change, so that mechanical stress is changed, and the magnetic field sensing element generates unequal potential. The offset (static output voltage) temperature drift is often related to the temperature-variable characteristics of the operational amplifiers used in the magnetic field sensors. Therefore, measures must be taken to compensate for the sensitivity of the magnetic field sensor and the temperature drift of the static output voltage to improve its detection accuracy.
Referring to fig. 1, a conventional magnetic field sensor includes a magnetic field sensing element, a supply current source supplying current to the magnetic field sensing element, a gain adjustable amplifier, a filter, and an output stage amplifier. The magnetic field sensing element converts an external magnetic field signal into a small signal voltage, the small signal voltage is amplified through the gain adjustable amplifier, the filter filters noise and offset voltage in a signal path, and finally a voltage signal which is in direct proportion to the size of the magnetic field is obtained through the output stage amplifier.
The conventional magnetic field sensor adjusts the sensitivity temperature drift of the magnetic field sensor by controlling the temperature coefficient of the supply current, wherein the reference voltage VREF is constant, the temperature coefficient of the compensation resistor R is γ, and the temperature coefficient of the sensitivity SI of the magnetic field sensing element is α. The supply current i (t) flowing through the magnetic field sensing element is:
if the temperature coefficient γ of the resistor R is equal to the temperature coefficient α of the sensitivity SI, the voltage VH output by the magnetic field sensing element is:
when γ is equal to α, the temperature coefficient of the generated supply current I will cancel out the temperature coefficient of sensitivity, so that the voltage VH output by the magnetic field sensing element does not vary with changes in temperature. The traditional magnetic field sensor is based on first-order temperature compensation, the principle is simple and easy to realize, but the high-order temperature coefficient cannot be compensated, the sensitivity drift caused by mechanical stress and device aging cannot be compensated, and the temperature drift of offset (static output voltage) is not compensated and corrected.
The temperature drift of the sensitivity and offset (static output voltage) of the magnetic field sensor can be eliminated using analog compensation techniques that use piezoresistors or the like to adjust the sensitivity and offset as a function of temperature. Such techniques can produce sensitivity and offset that are substantially constant with temperature, but often at the expense of accuracy of sensitivity or offset at room temperature. Furthermore, analog compensation techniques are fixed and not suitable for modifying the compensation characteristics during production or use. While magnetic field sensors using digital paths tend to be slower than magnetic field sensors using analog paths. In other words, hall sensors that employ digital paths do not respond well to rapidly changing magnetic fields (e.g., rapidly changing currents). It is therefore desirable to provide a magnetic field sensor that has the speed advantages of analog circuitry but uses different techniques for sensitivity and offset correction.
The invention content is as follows:
in response to the deficiencies of the prior art, the present invention provides a magnetic field sensor having an analog signal path that is corrected for sensitivity and offset by digital circuitry. The magnetic field sensor realizes the quick response time of an analog circuit, can modify the compensation characteristic in the production or use process, and realizes the nearly unchanged sensitivity and static output voltage in the whole temperature range.
In order to achieve the purpose, the invention provides the following technical scheme:
a magnetic field sensor having sensitivity correction and offset correction functions, comprising
An analog signal path module, a correction module, a temperature detection module, an EEPROM storage module and a segment processor module,
the analog signal path module is used for detecting an external magnetic field and outputting a voltage signal with a corresponding magnitude; the module responds to an external magnetic field, receives a gain control signal and an offset control signal output by the correction module, and finally generates a voltage signal which is in positive correlation with the magnitude of the magnetic field and serves as the output of the whole magnetic field sensor;
the correction module is used for sensitivity correction and offset correction; the module receives a gain correction signal and an offset correction signal output by the segment processor module, and generates a gain control signal and an offset control signal in response to the received signals, thereby controlling a sensitivity value (gain) and an offset value (static output voltage) of the analog signal path module;
the temperature detection module is used for detecting temperature information and outputting a digital signal representing a temperature value; the module monitors the temperature information of the environment where the magnetic field sensor is located in real time, converts the temperature information into a digital signal representing a temperature value through an internal analog-to-digital converter and transmits the signal to the segmented processor module;
the EEPROM storage module is used for storing data programmed by users and factories; the module realizes the writing and reading of serial data through a programming board and programming software, and transmits stored user gain correction values, user offset correction values, gain correction coefficients, offset correction coefficients and interpolation control signals to the segment processor module when the magnetic field sensor works normally;
the segment processor module processes various data according to a segment linear interpolation algorithm; the module receives digital signals representing temperature values, user gain correction values, user offset correction values, gain correction coefficients, offset correction coefficients, and interpolation control signals, and combines these digital signals to generate gain correction signals and offset correction signals.
As a further aspect of the present invention, the analog signal path module includes a current source, a magnetic field sensing element, a gain adjustable amplifier, a filter, and an output stage amplifier, wherein: a current source for generating a constant current as a supply current source for the magnetic field sensing element; a magnetic field sensing element for receiving an external magnetic field and generating a magnetic field small signal proportional to a magnitude of the external magnetic field; the gain adjustable amplifier is used for amplifying the small magnetic field signal and receiving a gain control signal, the gain of the gain adjustable amplifier is adjusted by the gain control signal, and finally a signal with the adjusted sensitivity is generated; the filter is used for receiving the signal after the sensitivity adjustment, filtering noise and offset voltage in the signal and generating a filtered signal; an output stage amplifier for receiving the filtered signal and finally generating an offset-adjusted signal, which is a voltage signal positively correlated with the magnitude of the magnetic field and is an output of the entire magnetic field sensor, in response to the offset control signal.
As a further aspect of the present invention, the correction module includes a gain adjustment circuit and an offset adjustment circuit, wherein: the gain adjusting circuit is used for receiving the gain correction signal and generating a gain control signal to adjust the gain value of the gain adjustable amplifier; and an offset adjusting circuit for receiving the offset correction signal and generating an offset control signal to adjust an offset (static output voltage) value of the output stage amplifier.
As a further aspect of the present invention, the temperature detection module includes a temperature sensor, an integrator, and a dual ramp ADC controller, wherein: the temperature sensor is used for detecting a real-time temperature value and outputting an analog voltage signal representing the temperature value; the integrator is used for integrating the analog voltage signal representing the temperature value to generate a PWM signal with the duty ratio related to the temperature; and the dual-slope ADC controller is used for converting the PWM signal into a digital signal related to the temperature, receiving the PWM signal of the integrator, generating an integration control signal and feeding the integration control signal back to the integrator so as to control the integration condition of the integrator.
As a further scheme of the invention, the EEPROM storage module comprises an interpolation control EEPROM, a correction coefficient EEPROM, a user gain EEPROM and a user offset EEPROM, wherein: the interpolation control EEPROM is used for storing interpolation control signals and transmitting the interpolation control signals to the segmentation processor in the working process of the sensor; the correction coefficient EEPROM is used for storing a plurality of gain correction coefficients and a plurality of offset correction coefficients and transmitting the correction coefficients to the segmentation processor in the working process of the sensor; the user gain EEPROM is used for storing a user gain correction value, a user can write the user gain correction value representing the sensitivity information into the EEPROM according to actual use requirements, and the user gain correction value is transmitted to the segmented processor in the working process of the sensor; and the user offset EEPROM is used for storing a user offset correction value, the user offset correction value representing the static output voltage information can be written into the EEPROM by a user according to actual use requirements, and the user offset correction value is transmitted to the segmented processor in the working process of the sensor.
As a further aspect of the present invention, the segment processor module comprises an interpolation processor, a combination processor, a gain adjustment register, and an offset adjustment register, wherein: an interpolation processor receiving a digital signal representing temperature information and identifying a temperature segment at which a temperature represented by the digital signal is located; receiving an interpolation control signal, and selecting a corresponding interpolation type from a plurality of preset interpolation types according to the interpolation control signal; receiving a pair of gain correction coefficients associated with the identified temperature segment and interpolating between the pair of gain correction coefficients based on the temperature signal to produce an interpolated gain correction value; receiving a pair of offset correction coefficients associated with the identified temperature segment and interpolating between the pair of offset correction coefficients as a function of the temperature signal to produce an interpolated offset correction value; a combining processor coupled to receive the user gain correction value and the interpolated gain correction value and to combine the user gain correction value and the interpolated gain correction value to generate a combined gain correction value, wherein the gain control signal is an analog signal related to the combined gain correction value; the combining processor is further coupled to receive the user offset correction value and the interpolated offset correction value and combine the user offset correction value with the interpolated offset correction value to produce a combined offset correction value, wherein the offset control signal is an analog signal related to the combined offset correction value. A gain adjustment register for receiving and storing the combined gain correction value and outputting a gain control signal to control the gain adjustment circuit; an offset adjustment register for receiving and storing the combined offset correction value and outputting an offset control signal to control the offset adjustment circuit.
The invention relates to a method for realizing a magnetic field sensor with sensitivity correction and offset correction, which comprises the following steps:
step S1: establishing a gain correction coefficient and an offset correction coefficient;
step S2: performing interpolation according to the measured temperature and in combination with the gain correction coefficient to establish an interpolated gain correction value;
step S3: combining the interpolated gain correction value and the user gain correction value to create a combined gain correction value;
step S4: applying a gain correction signal to a gain adjustment circuit to adjust a sensitivity value of the magnetic field sensor;
step S5: performing interpolation according to the measured temperature and in combination with the offset correction coefficient to establish an interpolated offset correction value;
step S6: combining the interpolated offset correction value and the user offset correction value to create a combined offset correction value;
step S7: the offset correction signal is applied to an offset adjustment circuit to adjust an offset voltage of the magnetic field sensor.
As a further aspect of the present invention, the process of establishing the gain correction coefficient includes: measuring a gain of the magnetic field sensor in the selected subset of the plurality of calibration temperatures during production of the magnetic field sensor; and establishing gain correction coefficients in a subset of the plurality of calibration temperatures from the measurements; and the gain correction coefficient is stored in the magnetic field sensor in advance.
As a further aspect of the present invention, the process of establishing the offset correction coefficient includes: measuring an offset of the magnetic field sensor in the selected subset of the plurality of calibration temperatures during production of the magnetic field sensor; and establishing offset correction coefficients in a subset of the plurality of calibration temperatures from the measurements; and the offset correction coefficient is stored in the magnetic field sensor in advance.
The operating principle of the invention is that the gain correction factor and the offset correction factor, which are stored in digital form in the magnetic field sensor, can be used to generate an analog control signal to control the sensitivity and the offset of the analog signal path of the magnetic field sensor. The invention has the advantages of not only simulating the quick response time of the channel, but also ensuring the sensitivity and the accuracy of the static output voltage at room temperature, changing the temperature compensation characteristic in the production and use processes, and simultaneously compensating the sensitivity drift and the static output voltage drift caused by mechanical stress and device aging.
In summary, according to the above technical solutions, compared with the prior art, the present invention has the following advantages:
1. the sensitivity and static output voltage are corrected by digital circuitry on the analog signal path. Therefore, the circuit has the advantages of not only having the quick response time of an analog path, but also ensuring the sensitivity and the accuracy of static output voltage at room temperature, and changing the temperature compensation characteristic in the production and use processes.
2. By adopting the piecewise linear interpolation temperature compensation technology, high-order temperature compensation can be simultaneously carried out on the sensitivity and the static output voltage, and compared with first-order temperature compensation, the compensation effect is better.
3. The method can compensate the influence of temperature change on the sensitivity and the static output voltage, and can also compensate the sensitivity drift and the static output voltage drift generated by mechanical stress and device aging.
4. The compensation accuracy can be improved by increasing the number of bits of the digital signal representing the temperature value, and the sensitivity and the correction range of the static output voltage can be expanded by increasing the number of bits of the gain compensation coefficient and the offset compensation coefficient.
To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
Description of the drawings:
fig. 1 is a schematic diagram of a conventional magnetic field sensor.
Fig. 2 is a schematic structural diagram of the present invention.
Fig. 3 is a block diagram of the structure of an embodiment of the present invention.
Fig. 4 is a sensitivity-temperature characteristic graph of the present invention, and shows a gain correction coefficient.
Fig. 5 is a graph of the offset-temperature characteristic of the present invention, and shows an offset correction coefficient.
Fig. 6 is a flowchart of the operation of the present invention for sensitivity correction and offset correction.
The specific implementation mode is as follows:
the invention will be described more fully and clearly in connection with the accompanying drawings and the accompanying knowledge, and it is to be understood that the circuit diagrams described are merely exemplary embodiments of the invention, and are not intended to represent all exemplary embodiments.
Before describing the present invention, some introductory concepts and terminology are explained. The term "magnetic field sensing element" is used to describe a variety of electronic elements that can sense a magnetic field. The magnetic field sensing element may be, but is not limited to, a hall effect element, a magnetoresistive element, or a magnetic transistor. The term "magnetic field sensor" is used to describe a circuit comprising a magnetic field sensing element. Magnetic field sensors may be used in a variety of applications, including but not limited to current sensors that sense a magnetic field generated by a current carried by a current carrying conductor, magnetic switches that sense the proximity of a ferromagnetic object, rotation detectors that detect the speed and angle of rotation of a ferromagnetic article, and magnetic field sensors that detect the magnetic field density of a magnetic field.
Although a magnetic field sensor having a hall effect element is shown and described in the following examples, the same techniques may be applied to a magnetic field sensor having any type of magnetic field sensing element.
Referring to fig. 2, a magnetic field sensor having sensitivity correction and offset correction functions solves the problems of sensitivity temperature drift and offset (static output voltage) temperature drift of the magnetic field sensor. The method specifically comprises the following steps: the analog signal path module 1, the correction module 2, the temperature detection module 3, the EEPROM memory module 4, and the segment processor module 5, the gain correction coefficients and the offset correction coefficients stored in digital form in the magnetic field sensor, may be used to generate analog control signals to control the sensitivity and offset of the analog signal path of the magnetic field sensor. The invention has the advantages of simulating the quick response time of the channel, ensuring the sensitivity at room temperature and the precision of the static output voltage, changing the temperature compensation characteristic in the production and use processes, and simultaneously compensating the sensitivity drift and the static output voltage drift caused by mechanical stress and device aging;
the analog signal path module 1 is used for detecting an external magnetic field and outputting a voltage signal in direct proportion to the magnitude of the magnetic field, and the gain and the offset of the module are respectively controlled by a gain control signal and an offset control signal; the correction module 2 is used for receiving the gain correction signal and the offset correction signal and correspondingly generating a gain control signal and an offset control signal; the temperature detection module 3 is used for detecting the ambient temperature in real time and outputting a digital signal representing a temperature value; the EEPROM storage module 4 is used for receiving serial data written in from the outside and storing a user gain correction value, a user offset correction value, a gain correction coefficient, an offset correction coefficient and an interpolation control signal; the segment processor module 5 is used for receiving the digital signal representing the temperature value, the user gain correction value, the user offset correction value, the gain correction coefficient, the offset correction coefficient and the interpolation control signal, and generating the gain correction signal and the offset correction signal through a segment linear interpolation algorithm by combining the received data.
Referring to fig. 3, the analog signal path module 1 includes a current source 301 for generating a constant current as a supply current source of the magnetic field sensing element, a magnetic field sensing element 302, a gain adjustable amplifier 303, a filter 304, and an output stage amplifier 305; a magnetic field sensing element for receiving an external magnetic field and generating a magnetic field small signal proportional to a magnitude of the external magnetic field; the gain adjustable amplifier is used for amplifying the small magnetic field signal, receiving a gain control signal and generating a signal after sensitivity adjustment; the filter is used for receiving the signal after the sensitivity adjustment, filtering noise and offset voltage in the signal and generating a filtered signal; an output stage amplifier for receiving the filtered signal and, in response to the offset control signal, generating an offset adjusted signal which is a voltage signal proportional to the magnitude of the magnetic field and which is the output of the entire magnetic field sensor; the method specifically comprises the following steps: the current source 301 generates a constant current and supplies it to the hall effect element 302. The hall effect element 302 generates a magnetic field small signal 302a in response to the external magnetic field 319. The external magnetic field 319 is a magnetic field to be measured, and for a current sensor, the external magnetic field 319 is generated by passing a current through a current-carrying conductor, which may be a part of the magnetic field sensor or external to the magnetic field sensor; the gain adjustable amplifier 303 receives the magnetic field small signal 302a and the gain control signal 306a and generates a sensitivity adjusted signal 303 a. The filter 304 is coupled to receive the sensitivity-adjusted signal 303a and is configured to generate a filtered signal 304 a. The output stage amplifier 305 receives the filtered signal 304a and the offset control signal 307a and generates an offset adjusted signal 305a, which is the output signal of the entire magnetic field sensor 300, with gain correction and offset correction.
Referring to fig. 3, the correction module includes a gain adjustment circuit 306 and an offset adjustment circuit 307, the gain adjustment circuit for receiving the gain correction signal and generating a gain control signal to adjust the gain value of the gain adjustable amplifier; an offset adjustment circuit for receiving the offset correction signal and generating an offset control signal to adjust an offset value of the output stage amplifier; further, gain adjustment circuit 306 is coupled to receive gain correction signal 317a and is configured to generate gain control signal 306 a. The offset adjustment circuit 307 is coupled to receive the offset correction signal 318a and is configured to generate an offset control signal 307 a;
referring to fig. 3, the temperature detection module 3 includes a temperature sensor 308 for detecting a real-time temperature value and outputting an analog voltage signal representing the temperature value, an integrator 309, and a dual ramp ADC controller 310; the integrator is used for integrating the analog voltage signal representing the temperature value to generate a PWM signal with the duty ratio related to the temperature; the dual-slope ADC controller is used for converting the PWM signal into a digital signal representing a temperature value, receiving the PWM signal of the integrator, generating an integral control signal and feeding the integral control signal back to the integrator so as to control the integral condition of the integrator; the method specifically comprises the following steps: the temperature sensor 308 detects a real-time temperature value 320 and generates an analog voltage signal 308a representative of the temperature value. An integrator (dual ramp ADC)309 is coupled to receive an analog voltage signal 308a representative of the temperature value and, by integration, generates a PWM signal 309a having a duty cycle dependent on temperature, the integration of which is controlled by an integration control signal 310 a. Dual ramp ADC controller 310 is coupled to receive the duty cycle temperature dependent PWM signal 309a and is configured to generate a digital signal 310b representative of a temperature value and an integral control signal 310 a.
Referring to fig. 3, the EEPROM memory module 4 includes an interpolation control EEPROM311 for transmitting an interpolation control signal to the segmentation processor, a correction coefficient EEPROM312, a user gain EEPROM313, and a user offset EEPROM 314; a correction coefficient EEPROM for storing a plurality of gain correction coefficients and a plurality of offset correction coefficients, the correction coefficients being transmitted to the segmented processor; the user gain EEPROM is used for storing a user gain correction value and transmitting the user gain correction value to the segment processor module 5; the user offset EEPROM is used for storing user offset correction values and transmitting the user offset correction values to the segment processor module 5; further, the interpolation control EEPROM311 provides an interpolation control signal 311a to the combination processor 316. Wherein the interpolation control signal 311a is transmitted to the interpolation control EEPROM311 through the communication link 321 a;
the correction coefficient EEPROM312 includes a plurality of gain correction coefficients 312a and a plurality of offset correction coefficients 312 b. Each gain correction coefficient 312a and each offset correction coefficient 312b is associated with a respective one of a plurality of selected temperatures. In some embodiments, there are five selected temperatures, each associated with a respective gain correction coefficient 312a (Sense _ n) and a respective offset correction coefficient 312b (VQ _ n). The gain correction factor 312a and the offset correction factor 312b are transmitted to the correction factor EEPROM312 via the communication link 321 b; an user gain EEPROM313 to provide a user gain correction value 313a to the combining processor 316, wherein the user gain correction value 313a is transmitted to the user gain EEPROM313 via a communication link 321 c. User offset EEPROM314 is operative to provide a user offset correction value 314a to combining processor 316, wherein user offset correction value 314a is communicated to user offset EEPROM314 via communication link 321 d.
Referring to FIG. 3, the segment handler module 5, comprises a receiver for receiving a digital signal 310b representative of a temperature value; specifically, the method comprises the following steps of; the segment handler module 5 performs several functions: the segment processor module 5 may identify the temperature segment in which the digital signal 310b representing the temperature value is located; the segment processor module 5 may also receive a pair of gain correction coefficients 312a and a pair of offset correction coefficients 312b associated with determining a temperature segment, the pair of gain correction coefficients 312a and the pair of offset correction coefficients 312b being associated with the identified temperature segment at the temperature; the segment processor module may interpolate between a pair of gain correction coefficients 312a based on the digital signal 310b representing the temperature value to produce a gain correction signal 317a, the gain control signal 306a being an analog signal determined by the gain correction signal 317 a; the segment processor module may interpolate between a pair of offset correction coefficients 312b based on the digital signal 310b representing the temperature value to produce an offset correction signal 318a, the offset control signal 307a being an analog signal determined by the offset correction signal 318 a. It will be appreciated that the segment processor module is a digital circuit that processes digital signals or values, and that the segment processor module controls the gain (sensitivity) and offset (static output voltage) of the analog signal path module described above.
The segment processor module includes, among other things, an interpolation processor 315 coupled to receive a digital signal 310b representative of a temperature value, coupled to receive a pair of gain correction coefficients 312a and a pair of offset correction coefficients 312 b. In some embodiments, interpolation processor 315 may also receive interpolation control signal 311a, which interpolation control signal 311a may determine the interpolation algorithm type for gain interpolation and offset interpolation. The type of interpolation is described further below. Interpolation processor 315 is configured to generate interpolation gain correction values 315a and interpolation offset correction values 315 b. To this end, the interpolation processor 315 identifies the temperature segment in which the digital signal 310b representing the temperature value is located to receive a pair of gain correction coefficients 312a and a pair of offset correction coefficients 312b for the respective temperature segment.
The segment processor module also includes a combining processor 316 coupled to receive the interpolated gain correction value 315a and the interpolated offset correction value 315b, and coupled to receive the user gain correction value 313a and the user offset correction value 314 a. The combining processor is configured to generate a combined gain correction value 316a and a combined offset correction value 316 b.
The segment processor module also includes a gain adjustment register 317 for storing the combined gain correction value 316a and outputting a gain correction signal 317a to the gain adjustment circuit 306. The segment processor module also includes an offset adjustment register 318 for storing the combined offset correction value 316b and outputting an offset correction signal 318a to the offset adjustment circuit 307.
In one embodiment of the present invention, the interpolation of the gain is performed by the interpolation processor 315. Interpolation processor 315 generates interpolated gain correction value 315a by the following linear interpolation formula:
here, DO [6:0] is a 7-bit digital signal 310b representing a temperature value, and CoeffB, CoeffA are a pair of gain correction coefficients 312a across the temperature segment determined by DO [6:5 ]. The interpolation processor 315 specifies a plurality of interpolation manners, and selects a corresponding gain interpolation type (i.e., in equation (3)) according to the interpolation control signal 311 a.
In one embodiment of the invention, the combining processor jointly interpolates the gain correction value 315a and one of the user gain correction values 313a to produce a combined gain correction value 316a according to the following equation:
here, SENSuserIs the user gain correction value 313 a; kDEVIs a magnetic field sensor specific constant representing the sensitivity of a particular type of magnetic field sensor (e.g., decimal 306).
If the sensitivity deviates from the ideal value by a factor of (1+ Δ SENS%) times the ideal value at a certain temperature T, the sensitivity value after the deviation is multiplied by (1- Δ SENS%) after the gain correction by equation (4) so that the actually obtained sensitivity value is equal to the ideal sensitivity value. In one particular embodiment, the sensitivity correction range is: -6.25% -6.054%. If the sensitivity correction range needs to be increased, the number of bits of the gain correction coefficient 312a may be increased, and the correction range is doubled every time one bit is increased.
In one embodiment of the present invention, interpolation of the offset is performed by the interpolation processor 315. Interpolation processor 315 generates interpolation offset correction value 315b by the following linear interpolation formula:
here, DO [6:0] is a 7-bit digital signal 310b representing a temperature value, and CoeffB, CoeffA are a pair of offset correction coefficients 312b across the temperature segment determined by DO [6:5 ].
In some embodiments, the interpolation processor 315 is specific to a plurality of interpolation modes, and selects a corresponding offset interpolation type according to the interpolation control signal 311 a. It is also possible to choose among the following linear interpolation types, each differing by a factor of two (one bit shift).
In a particular embodiment, the combining processor jointly interpolates the offset correction value 315b and one of the user offset correction values 314a to produce the combined offset correction value 316b according to the following equation:
here, VQuserIs the user offset correction value 314 a.
If the offset voltage deviates from the ideal value and is increased by n × lsb (where n is an integer and lsb is an offset voltage correction step) at a certain temperature T, the deviated offset voltage value is subtracted by n × lsb after the temperature compensation of equation (8) so that the actually obtained offset voltage value is equal to the ideal offset voltage value. In one particular embodiment, the offset voltage correction range is: -32 lsb-31 lsb. If the offset correction range needs to be increased, the number of bits of the offset correction coefficient 312b may be increased, and the correction range is doubled every time one bit is increased.
As can be appreciated from the above equation, the interpolated gain correction value 315a and the user gain correction value 313a are calculated in a multiplicative manner, and thus the combination processor 316 includes a multiplier; the interpolation offset correction value 315b and the user offset correction value 314a are calculated as an addition, and thus the combination processor 316 includes an adder, as expected.
Referring to fig. 4, a vertical axis 402 is a scale with sensitivity changes in percent, a first horizontal axis 403 is a temperature scale in degrees celsius, and a second horizontal axis 404 is a 7-bit digital signal DO <6:0> representing temperature values, represented in decimal 0 to 127.
Characteristic 401 represents the relative sensitivity of the magnetic field sensor without sensitivity correction. It can be seen that the relative sensitivity represented by characteristic curve 401 tends to decrease at low temperatures and tends to be higher at high temperatures.
At the first temperature point (-40 ℃), the gain correction factor 405(Sens _1) increases the sensitivity up to the same sensitivity as at room temperature. I.e. the sensitivity value at-40 c is the same as the sensitivity value at room temperature due to the application of the gain correction coefficient 405(Sens _ 1). Similarly, other gain correction coefficients 406, 407, 408, 409(Sens _2, Sens _3, Sens _4, Sens _5) may be applied at other temperatures associated therewith (10 deg.C, 60 deg.C, 110 deg.C, 160 deg.C, respectively) to keep the sensitivity of the magnetic field sensor constant at these temperatures.
The graph 400 has 4 temperature segments, which are-40 deg.C to 10 deg.C, 10 deg.C to 60 deg.C, 60 deg.C to 110 deg.C, and 110 deg.C to 160 deg.C. At any temperature segment, for example, 10 ℃ to 60 ℃, the interpolation processor can identify the temperature segment through the first two bits DO [6:5] of the digital signal DO [6:0], and perform interpolation operation by using gain correction coefficients (406, 407) associated with the boundary of the identified temperature segment to obtain an interpolation gain correction value, so that the sensitivity of the magnetic field sensor and the sensitivity at room temperature are basically kept unchanged.
As above, the gain interpolation may be a linear interpolation. However, in other embodiments, the gain interpolation may be another form, such as quadratic interpolation.
In one particular embodiment, there are 5 gain correction coefficients (405-409) and 4 associated temperature segments, while in other embodiments there may be more than 5 or less than 5 gain correction coefficients and associated temperature segments. In general, the greater the number of gain correction coefficients stored in the correction coefficient EEPROM, the more accurate the interpolated gain correction value, and the more accurate the correction relative sensitivity of the magnetic field sensor.
Although in the present embodiment, the temperature segments are uniform in degree, in other embodiments, the temperature segments may have unequal degrees. For example, in some embodiments, a temperature segment near room temperature 410 may have a greater (or lesser) temperature span than a temperature segment away from room temperature 410.
Referring to fig. 5, a vertical axis 502 is a relative variation of the offset voltage with a 9-bit digital value, a first horizontal axis 503 is a temperature scale in degrees celsius, and a second horizontal axis 504 is a 7-bit digital signal DO <6:0> representing a temperature value, represented in decimal 0 to 127.
Characteristic 501 represents the relative offset voltage of the magnetic field sensor without offset correction. It can be seen that the relative offset voltage represented by characteristic curve 501 tends to decrease at low temperatures and tends to be higher at high temperatures.
At the first temperature point (-40 ℃), the offset correction factor 505(VQ _1) increases the offset voltage up to the same value as the offset voltage at room temperature. That is, the offset voltage at-40 ℃ is the same as the offset voltage at room temperature due to the application of the offset correction coefficient 505(VQ _ 1). Similarly, other offset correction factors 506, 507, 508, 509(VQ _2, VQ _3, VQ _4, VQ _5) may be applied at other temperatures associated therewith (10 deg.C, 60 deg.C, 110 deg.C, 160 deg.C, respectively) so that the offset voltage (static output voltage) of the magnetic field sensor remains constant at these temperatures.
The graph 500 has a total of 4 temperature segments, which are-40 deg.C to 10 deg.C, 10 deg.C to 60 deg.C, 60 deg.C to 110 deg.C, and 110 deg.C to 160 deg.C. At any temperature segment, for example, 10 ℃ to 60 ℃, the interpolation processor can identify the temperature segment through the first two bits DO [6:5] of the digital signal DO [6:0], and perform interpolation operation by using offset correction coefficients (506, 507) associated with the boundary of the identified temperature segment to obtain an interpolation offset correction value, so that the offset voltage of the magnetic field sensor and the offset voltage at room temperature are basically kept unchanged.
As described above, the offset interpolation may be a linear interpolation. However, in other embodiments, the offset interpolation may be another form, such as quadratic interpolation.
In one particular embodiment, there are 5 offset correction factors (505-509) and 4 associated temperature segments, while in other embodiments there may be more than 5 or less than 5 offset correction factors and associated temperature segments. In general, the greater the number of offset correction coefficients stored in the correction coefficient EEPROM, the more accurate the interpolated offset correction value, and the more accurate the corrected relative offset of the magnetic field sensor.
Although in the present embodiment, the temperature segments are uniform in degree, in other embodiments, the temperature segments may have unequal degrees. For example, in some embodiments, a temperature segment near room temperature 510 may have a larger (or smaller) temperature span than a temperature segment away from room temperature 510.
Referring to fig. 6, in the generation process of the magnetic field sensor, a temperature point and a temperature segment corresponding to the temperature point are determined in advance according to actual requirements by a factory; then measuring the gain and offset at the selected calibration temperature subset results in the sensitivity-temperature profile shown in fig. 4 and the offset-temperature profile shown in fig. 5; establishing a gain correction coefficient and an offset correction coefficient according to the measured temperature characteristic curve; and finally, storing the plurality of gain correction coefficients and the plurality of offset correction coefficients into a correction coefficient EEPROM by a factory. Before the chip actually works, the interpolation control signal is stored in the interpolation control EEPROM by a factory, and the user gain correction value and the user offset correction value are written into the user gain EEPROM and the user offset EEPROM by a user through the pass link.
In the working process of the chip, a temperature detection module of the magnetic field sensor measures the ambient temperature and generates a digital signal representing a temperature value; then, an interpolation processor determines temperature segments and interpolates according to the measured temperature to establish an interpolation gain correction value; then the combined processor receives the user gain correction value and combines the interpolation gain correction value and the user gain correction value to establish a combined gain correction value; the generated combined gain correction value is stored in a gain adjustment register; and finally, the gain adjusting register applies the gain adjusting signal to the gain adjusting circuit so as to adjust the sensitivity value of the magnetic field sensor, thereby completing sensitivity correction. After the sensitivity correction is completed, the interpolation processor performs interpolation according to the measured temperature to establish an interpolation offset correction value; then the combined processor receives the user offset correction value and combines the interpolation offset correction value and the user offset correction value to establish a combined offset correction value; the generated combined offset correction value is stored in an offset adjustment register; finally, the offset adjustment register applies the offset adjustment signal to the offset adjustment circuit to adjust the offset voltage (static output voltage) of the magnetic field sensor, thereby completing the offset correction.
In summary, the present invention provides a magnetic field sensor having sensitivity correction and offset correction functions. The magnetic field sensor corrects the sensitivity and the static output voltage through a digital circuit on an analog signal path, has the quick response time of the analog path, ensures the precision of the sensitivity and the static output voltage at room temperature, and can change the temperature compensation characteristic in the production and use processes; by adopting a piecewise linear interpolation temperature compensation technology, high-order temperature compensation can be simultaneously carried out on the sensitivity and the static output voltage; the influence of temperature change on the sensitivity and the static output voltage can be compensated, and the sensitivity drift and the static output voltage drift generated by mechanical stress and device aging can be compensated; the compensation accuracy can be improved by increasing the number of bits of the digital signal representing the temperature value, and the sensitivity and the correction range of the static output voltage can be expanded by increasing the number of bits of the gain compensation coefficient and the offset compensation coefficient.
In the present invention, the magnetic field sensor achieves fast response time of the analog circuit, and also modifies the compensation characteristics during production or use, achieving nearly constant sensitivity and static output voltage over the full temperature range, but does not preclude achieving a single sensitivity correction or offset correction by redesign of the magnetic field sensor. The invention provides a single instance embodiment as follows.
The following provides specific examples of the invention
Example 1
A magnetic field sensor with sensitivity correction, comprising: analog signal path module 1, correction module 2, temperature detection module 3, EEPROM memory module 4 and segment processor module 5, wherein:
the analog signal path module 1 is used for detecting an external magnetic field and outputting a voltage signal with a corresponding magnitude; the module responds to an external magnetic field, receives a gain control signal output by the correction module 2, and finally generates a voltage signal which is in direct proportion to the magnitude of the magnetic field and serves as the output of the whole magnetic field sensor;
the correction module 2 is used for sensitivity correction; this module receives the gain correction signal output by the segment processor module 5 and generates a gain control signal in response to the received signal, thereby controlling the sensitivity value (gain) of the analog signal path module 1.
The temperature detection module 3 is used for detecting temperature information and outputting a digital signal representing a temperature value; the module monitors the temperature information of the environment where the magnetic field sensor is located in real time, converts the temperature information into a digital signal representing a temperature value through an internal analog-to-digital converter and transmits the signal to the segment processor module 5;
the EEPROM storage module 4 is used for storing data programmed by users and factories; the module realizes the writing and reading of serial data through a programming board and programming software, and transmits stored user gain correction values, gain correction coefficients and interpolation control signals to the segment processor module 5 when the magnetic field sensor works normally;
the segment processor module 5 processes various data according to a segment interpolation algorithm; the module receives digital signals representing temperature values, user gain correction values, gain correction coefficients, and interpolation control signals, and combines these digital signals to generate a gain correction signal.
Example 2
A magnetic field sensor with offset correction, comprising: analog signal path module 1, correction module 2, temperature detection module 3, EEPROM memory module 4 and segment processor module 5, wherein:
the analog signal path module 1 is used for detecting an external magnetic field and outputting a voltage signal with a corresponding magnitude; the module responds to an external magnetic field, receives an offset control signal output by the correction module 2, and finally generates a voltage signal which is in direct proportion to the magnitude of the magnetic field and serves as the output of the whole magnetic field sensor;
the correction module 2 is used for offset correction; this module receives the offset correction signal output by the segment processor module 5 and generates an offset control signal in response to the received signal, thereby controlling the offset value (static output voltage) of the analog signal path module 1.
The temperature detection module 3 is used for detecting temperature information and outputting a digital signal representing a temperature value; the module monitors the temperature information of the environment where the magnetic field sensor is located in real time, converts the temperature information into a digital signal representing a temperature value through an internal analog-to-digital converter and transmits the signal to the segment processor module 5;
the EEPROM storage module 4 is used for storing data programmed by users and factories; the module realizes the writing and reading of serial data through a programming board and programming software, and transmits stored user offset correction values, offset correction coefficients and interpolation control signals to the segment processor module 5 when the magnetic field sensor works normally;
the segment processor module 5 processes various data according to a segment interpolation algorithm; the module receives digital signals representing temperature values, user offset correction values, offset correction coefficients, and interpolation control signals, and combines these digital signals to generate gain correction signals and offset correction signals.
Example 3
A magnetic field sensor having sensitivity correction and offset correction functions, comprising: analog signal path module 1, correction module 2, temperature detection module 3, EEPROM memory module 4 and segment processor module 5, wherein:
the analog signal path module 1 is used for detecting an external magnetic field and outputting a voltage signal with a corresponding magnitude; the module responds to an external magnetic field, receives a gain control signal and an offset control signal output by the correction module 2, and finally generates a voltage signal which is in direct proportion to the magnitude of the magnetic field and serves as the output of the whole magnetic field sensor;
the correction module 2 is used for sensitivity correction and offset correction; this module receives the gain correction signal and the offset correction signal output by the segment processor module 5 and generates a gain control signal and an offset control signal in response to the received signals, thereby controlling the sensitivity value (gain) and the offset value (static output voltage) of the analog signal path module 1.
The temperature detection module 3 is used for detecting temperature information and outputting a digital signal representing a temperature value; the module monitors the temperature information of the environment where the magnetic field sensor is located in real time, converts the temperature information into a digital signal representing a temperature value through an internal analog-to-digital converter and transmits the signal to the segment processor module 5;
the EEPROM storage module 4 is used for storing data programmed by users and factories; the module realizes the writing and reading of serial data through a programming board and programming software, and transmits stored user gain correction values, user offset correction values, gain correction coefficients, offset correction coefficients and interpolation control signals to the segment processor module 5 when the magnetic field sensor works normally;
the segment processor module 5 processes various data according to a segment interpolation algorithm; the module receives digital signals representing temperature values, user gain correction values, user offset correction values, gain correction coefficients, offset correction coefficients, and interpolation control signals, and combines these digital signals to generate gain correction signals and offset correction signals.
In this embodiment, the analog signal path module 1 comprises a current source, a magnetic field sensing element, a gain adjustable amplifier, a filter and an output stage amplifier, wherein: a current source for generating a constant current as a supply current source for the magnetic field sensing element; a magnetic field sensing element for receiving an external magnetic field and generating a magnetic field small signal proportional to a magnitude of the external magnetic field; the gain adjustable amplifier is used for amplifying the small magnetic field signal and receiving a gain control signal, the gain of the gain adjustable amplifier is adjusted by the gain control signal, and finally a signal with the adjusted sensitivity is generated; the filter is used for receiving the signal after the sensitivity adjustment, filtering noise and offset voltage in the signal and generating a filtered signal; an output stage amplifier for receiving the filtered signal and, in response to the offset control signal, ultimately generating an offset adjusted signal that is a voltage signal proportional to the magnitude of the magnetic field and is the output of the entire magnetic field sensor.
In the present embodiment, the correction module 2 includes a gain adjustment circuit and an offset adjustment circuit, wherein: the gain adjusting circuit is used for receiving the gain correction signal and generating a gain control signal to adjust the gain value of the gain adjustable amplifier; and an offset adjusting circuit for receiving the offset correction signal and generating an offset control signal to adjust an offset (static output voltage) value of the output stage amplifier.
In this embodiment, the temperature detection module 3 includes a temperature sensor, an integrator, and a dual ramp ADC controller, wherein: the temperature sensor is used for detecting a real-time temperature value and outputting an analog voltage signal representing the temperature value; the integrator is used for integrating the analog voltage signal representing the temperature value to generate a PWM signal with the duty ratio related to the temperature; and the dual-slope ADC controller is used for converting the PWM signal into a digital signal representing the temperature value, receiving the PWM signal of the integrator, generating an integration control signal and feeding the integration control signal back to the integrator so as to control the integration condition of the integrator.
In the present embodiment, the EEPROM memory module 4 includes an interpolation control EEPROM, a correction coefficient EEPROM, a user gain EEPROM, and a user offset EEPROM, wherein: the interpolation control EEPROM is used for storing interpolation control signals and transmitting the interpolation control signals to the segmentation processor in the working process of the sensor; the correction coefficient EEPROM is used for storing a plurality of gain correction coefficients and a plurality of offset correction coefficients and transmitting the correction coefficients to the segmentation processor in the working process of the sensor; the user gain EEPROM is used for storing a user gain correction value, a user can write the user gain correction value representing the sensitivity information into the EEPROM according to actual use requirements, and the user gain correction value is transmitted to the segmented processor in the working process of the sensor; and the user offset EEPROM is used for storing a user offset correction value, the user offset correction value representing the static output voltage information can be written into the EEPROM by a user according to actual use requirements, and the user offset correction value is transmitted to the segmented processor in the working process of the sensor.
In this embodiment, the segment processor module 5 comprises an interpolation processor, a combination processor, a gain adjustment register, and an offset adjustment register, wherein: an interpolation processor receiving a digital signal representing temperature information and identifying a temperature segment at which a temperature represented by the digital signal is located; receiving an interpolation control signal, and selecting a corresponding interpolation type from a plurality of preset interpolation types according to the interpolation control signal; receiving a pair of gain correction coefficients associated with the identified temperature segment and interpolating between the pair of gain correction coefficients based on the temperature signal to produce an interpolated gain correction value; receiving a pair of offset correction coefficients associated with the identified temperature segment and interpolating between the pair of offset correction coefficients as a function of the temperature signal to produce an interpolated offset correction value; a combining processor coupled to receive the user gain correction value and the interpolated gain correction value and to combine the user gain correction value and the interpolated gain correction value to generate a combined gain correction value, wherein the gain control signal is an analog signal related to the combined gain correction value; the combining processor is further coupled to receive the user offset correction value and the interpolated offset correction value and combine the user offset correction value with the interpolated offset correction value to produce a combined offset correction value, wherein the offset control signal is an analog signal related to the combined offset correction value. A gain adjustment register for receiving and storing the combined gain correction value and outputting a gain control signal to control the gain adjustment circuit; an offset adjustment register for receiving and storing the combined offset correction value and outputting an offset control signal to control the offset adjustment circuit.
In this embodiment, during production of the magnetic field sensor, the gain of the magnetic field sensor is measured in the selected subset of the plurality of calibration temperatures; and establishing gain correction coefficients in a subset of the plurality of calibration temperatures from the measurements; and pre-storing the gain correction factor in the magnetic field sensor; and measuring an offset of the magnetic field sensor in the selected subset of the plurality of calibration temperatures; and establishing offset correction coefficients in a subset of the plurality of calibration temperatures from the measurements; and stores the offset correction coefficient in the magnetic field sensor in advance. The invention corrects sensitivity and static output voltage through digital circuits on the analog signal path. Therefore, the circuit has the advantages of not only having the quick response time of an analog path, but also ensuring the sensitivity and the accuracy of static output voltage at room temperature, and changing the temperature compensation characteristic in the production and use processes. By adopting the piecewise linear interpolation temperature compensation technology, high-order temperature compensation can be simultaneously carried out on the sensitivity and the static output voltage, and compared with first-order temperature compensation, the compensation effect is better. The method can compensate the influence of temperature change on the sensitivity and the static output voltage, and can also compensate the sensitivity drift and the static output voltage drift generated by mechanical stress and device aging. The compensation accuracy can be improved by increasing the number of bits of the digital signal representing the temperature value, and the sensitivity and the correction range of the static output voltage can be expanded by increasing the number of bits of the gain compensation coefficient and the offset compensation coefficient.
The technical principle of the present invention has been described above with reference to specific embodiments, which are merely preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. Other embodiments of the invention will occur to those skilled in the art without the exercise of inventive faculty, and such will fall within the scope of the invention.
Claims (8)
1. A magnetic field sensor having sensitivity correction and offset correction functions, comprising
The device comprises an analog signal path module (1), a correction module (2), a temperature detection module (3), an EEPROM storage module (4) and a segment processor module (5), wherein the analog signal path module (1) is used for detecting an external magnetic field and outputting a voltage signal with a corresponding magnitude, and is used for receiving a gain control signal and an offset control signal output by the correction module (2); the correction module (2) is used for receiving the gain correction signal and the offset correction signal output by the segment processor module (5); the temperature detection module (3) is used for detecting temperature information and outputting a digital signal representing a temperature value; the EEPROM storage module (4) is used for storing data programmed by users and factories; the segment processor module (5) is for receiving the digital signals representing temperature values, storing user and factory programmed data, and generating gain correction signals and offset correction signals.
2. The magnetic field sensor with sensitivity correction and offset correction functions of claim 1,
the temperature detection module (3) converts the temperature information into a digital signal representing the temperature value through an internal analog-to-digital converter and transmits the signal to the segment processor module (5); the EEPROM storage module (4) transmits the stored user gain correction value, user offset correction value, gain correction coefficient, offset correction coefficient and interpolation control signal to the segment processor module (5); the segment processor module (5) receives the digital signal representing the temperature value, the user gain correction value, the user offset correction value, the gain correction coefficient, the offset correction coefficient, and the interpolation control signal, and generates a gain correction signal and an offset correction signal.
3. The magnetic field sensor with sensitivity correction and offset correction functions of claim 2, characterized in that the analog signal path block (1) comprises a current source for generating a constant current as a supply current source for the magnetic field sensing element, a gain adjustable amplifier, a filter and an output stage amplifier; the magnetic field sensing element is used for receiving an external magnetic field and generating a magnetic field small signal which is in direct proportion to the size of the external magnetic field; the gain adjustable amplifier is used for amplifying the small magnetic field signal, receiving a gain control signal and generating a signal after sensitivity adjustment; the filter is used for receiving the signal after the sensitivity adjustment, filtering noise and offset voltage in the signal and generating a filtered signal; the output stage amplifier receives the filtered signal and, in response to the offset control signal, generates an offset adjusted signal, which is a voltage signal proportional to the magnitude of the magnetic field and is the output of the entire magnetic field sensor.
4. A magnetic field sensor with sensitivity correction and offset correction functions as claimed in claim 3, characterized in that the correction module (2) comprises a gain adjustment circuit and an offset adjustment circuit, the gain adjustment circuit being adapted to receive the gain correction signal and to generate a gain control signal for adjusting the gain value of the gain adjustable amplifier; the offset adjustment circuit is configured to receive the offset correction signal and generate an offset control signal to adjust an offset value of the output stage amplifier.
5. The magnetic field sensor with sensitivity correction and offset correction functions of claim 4, wherein the temperature detection module (3) includes a temperature sensor for detecting a real-time temperature value and outputting an analog voltage signal representative of the temperature value, an integrator, and a dual-ramp ADC controller; the integrator is used for integrating the analog voltage signal representing the temperature value to generate a PWM signal with the duty ratio related to the temperature; the dual-ramp ADC controller is used for converting the PWM signal into a digital signal representing the temperature value, receiving the PWM signal of the integrator, generating an integration control signal and feeding the integration control signal back to the integrator so as to control the integration condition of the integrator.
6. The magnetic field sensor with sensitivity correction and offset correction functions as claimed in claim 5, characterized in that the EEPROM memory module (4) contains an interpolation control EEPROM, a correction coefficient EEPROM, a user gain EEPROM and a user offset EEPROM, the interpolation control EEPROM being used to transmit interpolation control signals to the segmentation processor; the correction coefficient EEPROM is used for storing a plurality of gain correction coefficients and a plurality of offset correction coefficients and transmitting the correction coefficients to the segmentation processor; the user gain EEPROM is used for storing a user gain correction value and transmitting the user gain correction value to the segment processor module (5); and the user offset EEPROM is used for storing the user offset correction value and transmitting the user offset correction value to the segment processor module (5).
7. The magnetic field sensor with sensitivity correction and offset correction functions of claim 6, wherein the segment processor module (5) includes an interpolation processor, a combination processor, a gain adjustment register, and an offset adjustment register, the interpolation processor receiving the digital signals representing the temperature information and identifying the temperature segment at which the temperature represented by the digital signals is located; receiving an interpolation control signal, and selecting a corresponding interpolation type from a plurality of preset interpolation types according to the interpolation control signal; receiving a pair of gain correction coefficients associated with the identified temperature segment and interpolating between the pair of gain correction coefficients based on the temperature signal to produce an interpolated gain correction value; receiving a pair of offset correction coefficients associated with the identified temperature segment and interpolating between the pair of offset correction coefficients as a function of the temperature signal to produce an interpolated offset correction value;
the combining processor coupled to receive the user gain correction value and the interpolated gain correction value and to combine the user gain correction value and the interpolated gain correction value to generate a combined gain correction value, wherein the gain control signal is an analog signal related to the combined gain correction value; the combining processor is further coupled to receive the user offset correction value and the interpolated offset correction value and to combine the user offset correction value with the interpolated offset correction value to produce a combined offset correction value, wherein the offset control signal is an analog signal related to the combined offset correction value;
the gain adjusting register is used for receiving and storing the combined gain correction value and outputting a gain control signal to control the gain adjusting circuit;
the offset adjustment register is used for receiving and storing the combined offset correction value and outputting an offset control signal to control the offset adjustment circuit.
8. Method for implementing a magnetic field sensor with sensitivity correction and offset correction, characterized in that it comprises the following steps:
step S1: establishing a gain correction coefficient and an offset correction coefficient;
step S2: performing interpolation according to the measured temperature and in combination with the gain correction coefficient to establish an interpolated gain correction value;
step S3: combining the interpolated gain correction value and the user gain correction value to create a combined gain correction value;
step S4: applying a gain correction signal to a gain adjustment circuit to adjust a sensitivity value of the magnetic field sensor;
step S5: performing interpolation according to the measured temperature and in combination with the offset correction coefficient to establish an interpolated offset correction value;
step S6: combining the interpolated offset correction value and the user offset correction value to create a combined offset correction value;
step S7: the offset correction signal is applied to an offset adjustment circuit to adjust an offset voltage of the magnetic field sensor.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112946033A (en) * | 2021-02-05 | 2021-06-11 | 湖南汽车工程职业学院 | Method and device for measuring carbon dioxide refrigerant based on electrostatic capacity |
| CN113050014A (en) * | 2021-03-24 | 2021-06-29 | 中国工程物理研究院计量测试中心 | Method and system for calibrating sensitivity coefficient of low-frequency pulse magnetic field sensor |
| CN113175523A (en) * | 2021-04-20 | 2021-07-27 | 中国北方车辆研究所 | Oil level signal processing system and method for AT automatic transmission |
| CN113703512A (en) * | 2021-11-01 | 2021-11-26 | 宁波中车时代传感技术有限公司 | Hall sensor temperature compensation circuit and compensation method thereof |
| CN117031365A (en) * | 2023-08-02 | 2023-11-10 | 迈胜医疗设备有限公司 | Magnetic field measuring device, control method thereof, electronic equipment and related device |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101802555A (en) * | 2007-09-18 | 2010-08-11 | 弗劳恩霍夫应用研究促进协会 | Method for determining a parameter-dependent correction value approximation curve in sections and sensor arrangement |
| CN102762951A (en) * | 2010-01-08 | 2012-10-31 | 艾沃思宾技术公司 | Method and structure for testing and calibrating magnetic field sensing device |
| CN102881817A (en) * | 2011-07-14 | 2013-01-16 | 迈克纳斯公司 | Magnetic field sensor and method for determining the offset voltage of a magnetic field sensor |
| CN103140770A (en) * | 2010-06-30 | 2013-06-05 | 莱姆知识产权股份有限公司 | Autonomously calibrated magnetic field sensor |
| CN103308075A (en) * | 2013-05-07 | 2013-09-18 | 赛卓电子科技（上海）有限公司 | Current output-type linear hall-effect sensor |
| JP2014163825A (en) * | 2013-02-26 | 2014-09-08 | Asahi Kasei Electronics Co Ltd | Temperature characteristic correction circuit and method for magnetic sensor |
| EP2899560A1 (en) * | 2010-10-12 | 2015-07-29 | Allegro Microsystems, LLC | Magnetic field sensor and method used in a magnetic field sensor that adjusts a sensitivity and/or an offset over temperature |
| CN105705959A (en) * | 2013-10-30 | 2016-06-22 | 泰连德国有限公司 | Temperature compensation method of magnetic control fields in a hall sensor with OS adaption |
| CN107532900A (en) * | 2015-12-31 | 2018-01-02 | 华为技术有限公司 | One kind determines calibration parameter method and mobile device |
-
2020
- 2020-06-11 CN CN202010527313.8A patent/CN111596236A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101802555A (en) * | 2007-09-18 | 2010-08-11 | 弗劳恩霍夫应用研究促进协会 | Method for determining a parameter-dependent correction value approximation curve in sections and sensor arrangement |
| CN102762951A (en) * | 2010-01-08 | 2012-10-31 | 艾沃思宾技术公司 | Method and structure for testing and calibrating magnetic field sensing device |
| CN103140770A (en) * | 2010-06-30 | 2013-06-05 | 莱姆知识产权股份有限公司 | Autonomously calibrated magnetic field sensor |
| EP2899560A1 (en) * | 2010-10-12 | 2015-07-29 | Allegro Microsystems, LLC | Magnetic field sensor and method used in a magnetic field sensor that adjusts a sensitivity and/or an offset over temperature |
| CN102881817A (en) * | 2011-07-14 | 2013-01-16 | 迈克纳斯公司 | Magnetic field sensor and method for determining the offset voltage of a magnetic field sensor |
| JP2014163825A (en) * | 2013-02-26 | 2014-09-08 | Asahi Kasei Electronics Co Ltd | Temperature characteristic correction circuit and method for magnetic sensor |
| CN103308075A (en) * | 2013-05-07 | 2013-09-18 | 赛卓电子科技（上海）有限公司 | Current output-type linear hall-effect sensor |
| CN105705959A (en) * | 2013-10-30 | 2016-06-22 | 泰连德国有限公司 | Temperature compensation method of magnetic control fields in a hall sensor with OS adaption |
| CN107532900A (en) * | 2015-12-31 | 2018-01-02 | 华为技术有限公司 | One kind determines calibration parameter method and mobile device |
Non-Patent Citations (1)
| Title |
|---|
| 董健方 等: "GaAs基霍尔传感器的研究进展", 《半导体技术》 * |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112946033A (en) * | 2021-02-05 | 2021-06-11 | 湖南汽车工程职业学院 | Method and device for measuring carbon dioxide refrigerant based on electrostatic capacity |
| CN112946033B (en) * | 2021-02-05 | 2024-02-13 | 湖南汽车工程职业学院 | Method and device for measuring carbon dioxide refrigerant based on electrostatic capacity |
| CN113050014A (en) * | 2021-03-24 | 2021-06-29 | 中国工程物理研究院计量测试中心 | Method and system for calibrating sensitivity coefficient of low-frequency pulse magnetic field sensor |
| CN113175523A (en) * | 2021-04-20 | 2021-07-27 | 中国北方车辆研究所 | Oil level signal processing system and method for AT automatic transmission |
| CN113703512A (en) * | 2021-11-01 | 2021-11-26 | 宁波中车时代传感技术有限公司 | Hall sensor temperature compensation circuit and compensation method thereof |
| CN113703512B (en) * | 2021-11-01 | 2022-03-08 | 宁波中车时代传感技术有限公司 | Hall sensor temperature compensation circuit and compensation method thereof |
| WO2023071720A1 (en) * | 2021-11-01 | 2023-05-04 | 宁波中车时代传感技术有限公司 | Hall sensor temperature compensation circuit and hall sensor temperature compensation method |
| CN117031365A (en) * | 2023-08-02 | 2023-11-10 | 迈胜医疗设备有限公司 | Magnetic field measuring device, control method thereof, electronic equipment and related device |
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