WO2023071720A1 - Hall sensor temperature compensation circuit and hall sensor temperature compensation method - Google Patents

Abstract

A Hall sensor temperature compensation circuit, comprising a Hall sensing module, which generates an analog voltage signal according to an external magnetic field and a current; an analog compensation module, which is connected to the Hall sensing module, and is used for performing analog compensation on the generated analog voltage signal; and a digital compensation module, which comprises a compensation calculation unit, wherein the compensation calculation unit obtains compensation codewords according to external environment temperature information, and then performs gain compensation on an analog compensation process and performs offset compensation on an analog-to-digital conversion process by means of the compensation codewords. Temperature compensation is performed by means of combining digital compensation with analog compensation, such that the dependence on a process is low, the precision of a Hall sensor is higher, the circuit consistency is better, a storage space required is small, the response speed of an output signal is faster, and a compensation range is wider.

Description

A Hall sensor temperature compensation circuit and its compensation method technical field

The invention belongs to the technical field of sensors, and relates to a Hall sensor, in particular to a Hall sensor temperature compensation circuit and a compensation method thereof.

Background technique

In the field of magnetic field sensors, a Hall sensor is a semiconductor device designed using the Hall effect. Its characteristic is that it can convert an external magnetic field signal into a voltage signal, and the magnitude of the signal is proportional to the magnitude of the external magnetic field signal. As a semiconductor device, it has obvious disadvantages, that is, the output voltage signal will drift with the change of the external environment temperature. This kind of temperature drift is not obvious at normal temperature, but the temperature drift may affect the working performance of the magnetic sensor system at high and low temperatures, so the purpose of the temperature compensation circuit is to eliminate the temperature drift of semiconductor devices in a targeted manner.

The traditional temperature compensation is divided into analog compensation and digital compensation. The analog mainly realizes the compensation of temperature drift by adjusting the capacitance/resistance, and the digital mainly realizes the compensation of temperature drift through the look-up table or the temperature characteristic of eradicating the temperature drift through the first-order or second-order calculation of the compensation value. compensate. At present, most Hall sensor chips use analog compensation technology, such as piezoresistors, etc., which can adjust the sensitivity and the offset of the output zero point with temperature, but this is often at the expense of the sensitivity and the accuracy of the output zero point. In addition, the analog compensation technique is fixed, not suitable for production or field-changed compensation and calibration.

Contents of the invention

The object of the present invention is to solve the above-mentioned problems in the existing technology, and propose a Hall sensor temperature compensation circuit and compensation method with high precision, large compensation range, small storage space and fast response speed.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A Hall sensor temperature compensation circuit, comprising:

Hall sensor module, which generates analog voltage signal according to external magnetic field and current;

The analog compensation module is connected with the Hall sensing module, and is used for analog compensation to the generated analog voltage signal;

The temperature sensor module is used to obtain the current external environment temperature information;

An output module, configured to convert the analog voltage signal after analog compensation to output a digital voltage signal;

A digital compensation module, which includes a compensation calculation unit, the compensation calculation unit generates a corresponding compensation codeword according to the external environment temperature information, and the compensation codeword includes a gain codeword and a drift codeword, and then the gain codeword is used to gain the analog compensation process Compensate, and perform drift compensation on the analog-to-digital conversion process through the drift codeword.

In the aforementioned Hall sensor temperature compensation circuit, the steps for the compensation calculation unit to obtain the compensation codeword include:

A1: Judging the appropriate inflection point temperature according to the initial state of the Hall sensor;

A2: Configure the temperature inflection point for the compensation calculation unit;

A3: Divide the temperature range into multiple temperature segments according to the temperature inflection point, and select the gain temperature coefficient and drift temperature coefficient of each temperature segment;

A4: Generate compensation codewords according to the preset calculation formula according to the gain temperature coefficient and the drift temperature coefficient.

In the aforementioned temperature compensation circuit for a Hall sensor, the digital compensation module further includes:

The temperature calculation unit is connected with the temperature sensor, and is used to convert the external environment temperature information into a real-time temperature signal T1, and calculate the temperature difference T through a preset algorithm according to the preset inflection point temperature T0 and the real-time temperature signal T1.

In the aforementioned Hall sensor temperature compensation circuit, the temperature calculation unit includes a DEM module, an LPF module, and an AVG module, wherein the specific work of the temperature calculation unit includes steps:

B1: Extract the obtained external environment temperature information through the DEM module, and perform cumulative calculations to obtain the accumulated environmental temperature information;

B2: Perform discrete convolution on the accumulated ambient temperature information through the LPF module;

B3: Calculate the average value of the output result of the LPF module through the AVG module to obtain the real-time temperature signal T1;

B4: Calculate the difference between the real-time temperature signal T1 and the preset inflection point temperature T0 to obtain the temperature difference T.

In the aforementioned Hall sensor temperature compensation circuit, the calculation formula for generating the compensation codeword is specifically as follows:

Gain code word: GAIN_TRIM=(gain0+1)*TC_g*T+gain0;

Drift codeword: OFFSET_TRIM=K0*(TC_f*T+1)–K1;

Among them, gain0 is the gain coefficient of the zero point, TC_g is the configured gain temperature coefficient, K0 is the voltage coefficient converted according to the reference voltage value, K1 is the coefficient used to adjust the zero offset; TC_f is the configured drift temperature coefficient, and T is the temperature Difference.

In the aforementioned Hall sensor temperature compensation circuit, the analog compensation module includes a signal amplification unit, which is used to perform multi-stage amplification of the analog voltage signal generated by the Hall sensor module, wherein the first stage of amplification is based on the output of the compensation calculation unit The gain code word adjusts the gain of the analog voltage signal by adjusting the resistance coefficient of the signal amplifying unit.

In the aforementioned Hall sensor temperature compensation circuit, the analog compensation module further includes a filter unit connected to the signal amplifying unit, and the filter unit includes an operational amplifier, a resistor, and a capacitor, wherein the operational amplifier is used to process the input signal Amplification, resistors are used for feedback regulation of the circuit, and capacitors are used for signal filtering and regulation.

In the above-mentioned Hall sensor temperature compensation circuit, the Hall sensor module includes a power supply, two Hall elements connected in series and a chopper unit, the input ends of the two Hall elements are connected to the power supply, and the two Hall elements The output terminals of the components are all connected to the chopping unit, and the output terminals of the chopping unit are connected to the analog compensation module.

The purpose of the present invention is also to provide a Hall sensor temperature compensation control method, according to the above compensation circuit, measure the external temperature and perform temperature compensation on the Hall sensor.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention uses a combination of digital and analog compensation for temperature compensation. Compared with conventional analog compensation methods, this design is less dependent on the process, which makes the Hall sensor have higher precision and better circuit consistency. Compared with the implementation of digital look-up table, the required storage space is small, and the response speed of the output signal is faster. Compared with the second-order compensation calculation method, it is simpler, and it is convenient for design and implementation and customer application. Compared with the first-order compensation calculation, the calculation accuracy is higher. High, the compensation range is larger.

2. The built-in temperature sensor is used, and the external temperature information is converted into a bit data stream through the analog-to-digital converter, which is used for the temperature calculation unit to restore the temperature information, so that the obtained temperature information is fast and accurate, and no additional external temperature acquisition device is required. The circuit design is reasonable and efficient.

3. The present invention selects the temperature inflection point and configures the temperature coefficient according to the initial output result of the Hall sensor chip, and then calculates the corresponding compensation code word in combination with the temperature difference, and performs gain adjustment and drift adjustment through the compensation code word. The temperature compensation method has higher accuracy High, practical, small storage space, greatly improving the integration of the Hall sensor chip.

Description of drawings

Fig. 1 is a block diagram of the circuit structure in the present invention.

Fig. 2 is a structural block diagram of the digital compensation module in the present invention.

FIG. 3 is a schematic diagram of gain compensation coefficients and inflection points in the present invention.

Detailed ways

The following are specific embodiments of the present invention and in conjunction with the accompanying drawings, the technical solutions of the present invention are further described, but the present invention is not limited to these embodiments.

It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relationship between the components in a certain posture (as shown in the accompanying drawings). Relative positional relationship, movement conditions, etc., if the specific posture changes, the directional indication also changes accordingly.

Embodiment one

As shown in Figures 1 to 3, the present invention provides a Hall sensor temperature compensation circuit, including:

Hall sensor module, which generates analog voltage signal according to external magnetic field and current;

The analog compensation module is connected with the Hall sensing module, and is used for analog compensation to the generated analog voltage signal;

The temperature sensor module is used to obtain the current external environment temperature information;

An output module, configured to convert the analog voltage signal after analog compensation to output a digital voltage signal;

A digital compensation module, which includes a compensation calculation unit, the compensation calculation unit generates a corresponding compensation codeword according to the external environment temperature information, and the compensation codeword includes a gain codeword and a drift codeword, and then the gain codeword is used to gain the analog compensation process Compensate, and perform drift compensation on the analog-to-digital conversion process through the drift codeword.

A Hall sensor temperature compensation circuit provided by the present invention uses digital and analog compensation to perform temperature compensation on the voltage signal drift of the Hall sensor chip caused by changes in the external environment temperature, through the Hall sensor module and the analog compensation module Perform analog compensation on the Hall sensor, and perform digital compensation on the Hall sensor through the digital compensation module. Compared with the conventional analog compensation method, this design is less dependent on the process, which makes the Hall sensor have higher precision and circuit consistency. Well, compared with the implementation of digital look-up table, the required storage space is small, the response speed of the output signal is faster, and the calculation method of the second-order compensation is simpler, and it is convenient for design and implementation and customer application. Compared with the first-order compensation The calculation accuracy is higher and the compensation range is larger.

Preferably, as shown in Figures 1 to 3, the digital compensation module further includes:

The temperature calculation unit is connected with the temperature sensor, and is used to convert the external environment temperature information into a real-time temperature signal T1, and calculate the temperature difference T through a preset algorithm according to the preset inflection point temperature T0 and the real-time temperature signal T1.

Further preferably, the temperature sensor is used to obtain the current external environment temperature information, and convert the real-time temperature analog signal into a real-time temperature data signal through a built-in digital-to-analog converter.

In this embodiment, the temperature sensor collects the temperature information of the external environment in real time, and converts the real-time temperature analog signal into a voltage value. For comparison, the voltage signal is converted into a real-time temperature data signal, that is, the voltage signal is converted into a data stream and output to the temperature calculation unit. The temperature calculation unit restores the code stream information output by the temperature sensor to the ambient temperature, that is, converts the real-time temperature data signal into a real-time temperature signal T1, and calculates the temperature difference T according to T1 and the preset high and low temperature inflection point temperature T0, and the preset high and low temperature inflection point temperature T0 generally takes the normal temperature of 25 degrees Celsius. In this embodiment, a built-in temperature sensor is used, and the external temperature information is converted into a bit data stream through an analog-to-digital converter, which is used for the temperature calculation unit to restore the temperature information, so that the obtained temperature information is fast and accurate, and no additional external temperature information is required. The acquisition device, the entire circuit design is reasonable and efficient.

Preferably, as shown in Figures 1 to 3, the step of generating a corresponding compensation codeword by the compensation calculation unit includes:

A1: Judging the appropriate inflection point temperature according to the initial state of the Hall sensor;

A2: Configure the temperature inflection point for the compensation calculation unit;

A3: Divide the temperature range into multiple temperature segments according to the temperature inflection point, and select the gain temperature coefficient and drift temperature coefficient of each temperature segment;

A4: Generate compensation codewords according to the preset calculation formula according to the gain temperature coefficient and the drift temperature coefficient.

Further preferably, the calculation formula for generating the compensation codeword is specifically as follows:

Gain code word: GAIN_TRIM=(gain0+1)*TC_g*T+gain0;

Drift codeword: OFFSET_TRIM=K0*(TC_f*T+1)–K1;

Among them, gain0 is the gain coefficient of the zero point, TC_g is the configured gain temperature coefficient, K0 is the voltage coefficient converted according to the reference voltage value, K1 is the coefficient used to adjust the zero offset; TC_f is the configured drift temperature coefficient, and T is the temperature Difference.

In this embodiment, the gain codeword and the drift codeword are obtained through the compensation calculation unit, and the gain codeword is used to adjust the gain of the signal amplification unit (AMP). The working principle of the compensation calculation unit is: first, according to the initial output of the sensor chip The state judges the appropriate inflection point temperature, and then configures the inflection point for the port I_inf_pt_c and port I_inf_pt_h of the compensation calculation unit through the external software, divides the temperature range into multiple temperature segments according to the temperature inflection point, and then selects the temperature coefficient of each temperature segment (TC_g /TC_f), and finally combined with the calculation result T of the temperature difference, the compensation codeword is obtained according to the calculation formula. Example: The temperature range of the Hall sensor is -40 degrees to 125 degrees. According to the initial state of the Hall sensor chip output, select the appropriate inflection point temperature. For example, as shown in Figure 3, divide the temperature into 4 segments, then you need to set 3 inflection point temperatures, such as -20 degrees, 25 degrees, 85 degrees (the temperature point is mainly determined according to the change curve of the chip output results), after selecting the appropriate inflection point temperature, and then through the external software to compensate the calculation unit port I_inf_pt_c and port I_inf_pt_h configures the inflection point, and then further configures the temperature coefficient (TC_g/TC_f) of each temperature segment, and finally combines the temperature difference T to calculate the corresponding gain codeword and drift codeword. When the accuracy of temperature compensation needs to be improved, more inflection point temperatures can be selected according to the initial state curve output by the Hall sensor chip, and more segments can be made on the entire temperature range to meet the required compensation accuracy. The temperature compensation method provided by this embodiment has higher precision, strong practicability, and small storage space, which greatly improves the integration degree of the Hall sensor chip.

Preferably, as shown in Figure 2, the temperature calculation unit includes a DEM module, an LPF module and an AVG module, wherein the specific work of the temperature calculation unit includes steps:

B1: Extract the obtained external environment temperature information through the DEM module, and perform cumulative calculations to obtain the accumulated environmental temperature information;

B2: Perform discrete convolution on the accumulated ambient temperature information through the LPF module;

B3: Calculate the average value of the output result of the LPF module through the AVG module to obtain the real-time temperature signal T1;

B4: Calculate the difference between the real-time temperature signal T1 and the preset inflection point temperature T0 to obtain the temperature difference T.

In this embodiment, the temperature calculation unit restores the code stream information output by the temperature sensor to the ambient temperature, that is, converts the real-time temperature data signal into a real-time temperature signal T1, and calculates the temperature difference T according to T1 and the preset high and low temperature inflection point temperature T0, The specific working process of the temperature calculation unit is as follows: first, the temperature sensor inputs the real-time temperature data signal into the DEM module (extraction module), which extracts the input real-time temperature data signal and performs cumulative calculation, and the cumulative calculation result is input into the LPF module (Digital low-pass filter) followed by discrete convolution, that is, multiplying the corresponding coefficients on consecutive N temperature points and summing them, and then summing and averaging the output results of the LPF module through the AVG module (average module) The real-time temperature signal T1 is obtained, and finally the difference between the real-time temperature signal T1 and the preset high and low temperature inflection point temperature T0 is calculated to obtain the temperature difference T. In addition, in order to ensure the linearity and accuracy of the temperature calculation, the temperature calculation unit can adjust the gain and offset of the temperature calculation result through the port I_temp_offset_trim and the port I_temp_co_trim through the external software. In particular, the port I_tsr_en can turn off the calculation function of the module. The port I_tsr_out_force can output a fixed temperature value to the subsequent module.

Preferably, as shown in Figure 1, the analog compensation module includes a signal amplification unit, which is used for multi-stage amplification of the analog voltage signal generated by the Hall sensor module, wherein the first-stage amplification is based on the gain code word output by the compensation calculation unit By adjusting the resistance coefficient of the signal amplifying unit, the gain trimming of the analog voltage signal is carried out.

Further preferably, the analog compensation module also includes a filter unit (LPF) connected to the signal amplification unit, the filter unit includes an operational amplifier, a resistor, and a capacitor, wherein the operational amplifier is used to amplify the input signal, and the resistor is used to amplify the input signal. The circuit performs feedback regulation, and the capacitor is used for signal filtering and regulation.

In this embodiment, the analog compensation module includes a signal amplifying unit and a filtering unit, and the signal amplifying unit performs gain trimming on the input voltage signal according to the gain codeword output by the compensation calculation unit, specifically, the signal amplifying unit performs gain adjustment on the input voltage signal Multi-stage amplification is performed, wherein the first-stage amplification adjusts the resistance coefficient according to the gain code word of the compensation calculation unit, and then realizes the gain adjustment of the input analog voltage signal. Example: If the amplification factor of the signal amplification unit is GAIN_TRIM and the trimming factor is set to 50%-150%, then the relationship between the input voltage v_in and the output voltage v_out is v_out=v_in*GAIN_TRIM, and the range of the output result v_out is 0.5v_in ~1.5v_in. The filter unit, that is, the active second-order low-pass filter, mainly includes an operational amplifier, resistors, and capacitors. The operational amplifier is used to amplify the input voltage signal, the resistor plays a role of feedback adjustment to the circuit, and the capacitor is used to filter and adjust the signal, and the frequency of the passing signal can be adjusted by changing the capacitance of the capacitor.

Preferably, as shown in Figure 1, the Hall sensing module includes a power supply, two Hall elements connected in series and a chopping unit (chop), the input terminals of the two Hall elements are connected to the power supply, and the output of the two Hall elements Both terminals are connected to the chopper unit, and the output terminal of the chopper unit is connected to the analog compensation module.

In this embodiment, through the driving of two Hall elements, the differential voltage is output, and then the differential voltage is filtered by the chopper unit, and the analog temperature drift compensation of Hall is realized by combining the amplification and low-pass filtering in the analog compensation module , and then combined with digital temperature compensation to realize the final temperature compensation. Compared with the traditional analog compensation, the temperature compensation method provided by this embodiment is less dependent on the process, so that the circuit has better consistency and higher precision.

Preferably, as shown in Figure 1, the Hall sensor temperature compensation circuit provided by this embodiment further includes an output module, the output module is respectively connected to the filtering unit and the compensation calculation unit, and the output module is based on the digital compensation module The calculation result adjusts Vref (reference voltage), thereby changing Vout (output voltage signal), and the voltage signal after analog compensation and digital compensation minimizes the output voltage drift and ensures the accuracy of the output voltage.

Embodiment two

The present invention also provides a Hall sensor temperature compensation control method. According to the compensation circuit according to the first embodiment, the external temperature is measured and the Hall sensor is temperature compensated.

It should be noted that, in the present invention, descriptions involving "first", "second", "one" and so on are only for description purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating The number of technical characteristics. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined. The terms "connection" and "fixation" should be interpreted in a broad sense, for example, "fixation" can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical connection or an electrical connection; it can be a direct connection , can also be indirectly connected through an intermediary, and can be an internal communication between two elements or an interaction relationship between two elements, unless otherwise clearly defined. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

In addition, the technical solutions of the various embodiments of the present invention can be combined with each other, but it must be based on the realization of those skilled in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered as a combination of technical solutions. Does not exist, nor is it within the scope of protection required by the present invention.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which the present invention belongs can make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, but they will not deviate from the spirit of the present invention or go beyond the definition of the appended claims range.

Claims (9)

1. A Hall sensor temperature compensation circuit, characterized in that it comprises:

   Hall sensor module, which generates analog voltage signal according to external magnetic field and current;

   The analog compensation module is connected with the Hall sensing module, and is used for analog compensation to the generated analog voltage signal;

   The temperature sensor module is used to obtain the current external environment temperature information;

   An output module, configured to convert the analog voltage signal after analog compensation to output a digital voltage signal;

   A digital compensation module, which includes a compensation calculation unit, the compensation calculation unit generates a corresponding compensation codeword according to the external environment temperature information, and the compensation codeword includes a gain codeword and a drift codeword, and then the gain codeword is used to gain the analog compensation process Compensate, and perform drift compensation on the analog-to-digital conversion process through the drift codeword.
2. A Hall sensor temperature compensation circuit according to claim 1, wherein the step of generating a corresponding compensation codeword by the compensation calculation unit comprises:

   A1: Judging the appropriate inflection point temperature according to the initial state of the Hall sensor;

   A2: Configure the temperature inflection point for the compensation calculation unit;

   A3: Divide the temperature range into multiple temperature segments according to the temperature inflection point, and select the gain temperature coefficient and drift temperature coefficient of each temperature segment;

   A4: Generate compensation codewords according to the preset calculation formula according to the gain temperature coefficient and the drift temperature coefficient.
3. A kind of Hall sensor temperature compensation circuit according to claim 2, is characterized in that, digital compensation module also comprises:

   The temperature calculation unit is connected with the temperature sensor, and is used to convert the external environment temperature information into a real-time temperature signal T1, and calculate the temperature difference T through a preset algorithm according to the preset inflection point temperature T0 and the real-time temperature signal T1.
4. The temperature compensation circuit for a Hall sensor according to claim 3, wherein the temperature calculation unit includes a DEM module, an LPF module, and an AVG module, wherein the specific work of the temperature calculation unit includes steps:

   B1: Extract the obtained external environment temperature information through the DEM module, and perform cumulative calculations to obtain the accumulated environmental temperature information;

   B2: Perform discrete convolution on the accumulated ambient temperature information through the LPF module;

   B3: Calculate the average value of the output result of the LPF module through the AVG module to obtain the real-time temperature signal T1;

   B4: Calculate the difference between the real-time temperature signal T1 and the preset inflection point temperature T0 to obtain the temperature difference T.
5. A kind of Hall sensor temperature compensation circuit according to claim 4, is characterized in that, the calculation formula that generates compensation code word is specifically as follows:

   Gain code word: GAIN_TRIM=(gain0+1)*TC_g*T+gain0;

   Drift codeword: OFFSET_TRIM=K0*(TC_f*T+1)–K1;

   Among them, gain0 is the gain coefficient of the zero point, TC_g is the configured gain temperature coefficient, K0 is the voltage coefficient converted according to the reference voltage value, K1 is the coefficient used to adjust the zero offset; TC_f is the configured drift temperature coefficient, and T is the temperature Difference.
6. A Hall sensor temperature compensation circuit according to claim 1, characterized in that the analog compensation module includes a signal amplification unit, which is used for multi-stage amplification of the analog voltage signal generated by the Hall sensor module, wherein one stage The amplification is to adjust the gain of the analog voltage signal by adjusting the resistance coefficient of the signal amplification unit according to the gain code word output by the compensation calculation unit.
7. A Hall sensor temperature compensation circuit according to claim 6, wherein the analog compensation module further includes a filter unit connected to the signal amplifying unit, and the filter unit includes an operational amplifier, a resistor and a capacitor, wherein the operation The amplifier is used to amplify the input signal, the resistor is used to adjust the feedback of the circuit, and the capacitor is used to filter and adjust the signal.
8. The temperature compensation circuit for a Hall sensor according to claim 1, wherein the Hall sensor module includes a power supply, two Hall elements connected in series and a chopping unit, and the input ends of the two Hall elements are The power supply is connected, and the output terminals of the two Hall elements are connected to the chopping unit, and the output terminals of the chopping unit are connected to the analog compensation module.
9. A Hall sensor temperature compensation method, characterized in that, according to the compensation circuit according to any one of claim 1, the external temperature is measured and the Hall sensor is temperature compensated.

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