Linear Hall circuit with high precision and wide application voltage
Through segmented calibration technology, the output signals of linear Hall circuits within a wide voltage range are accurately debugged and calibrated, which solves the problem that linear Hall circuits are difficult to maintain high accuracy within a wide voltage range, and achieves higher signal accuracy and more efficient calibration process.
Patent Information
- Application Number
- CN202421974195.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-15
- Publication Date
- 2025-05-30
- Estimated Expiration
- 2034-08-15
AI Technical Summary
Existing linear Hall circuits are difficult to maintain high accuracy over a wide voltage range, and the offset voltage affects the accuracy of the output signal.
The segmented calibration technology is used to divide the power supply voltage into several smaller ranges and accurately debug and calibrate within each range. The external adjustment method ensures that the output signal maintains high accuracy over the entire voltage range.
Significantly improve the accuracy of linear Hall circuit signals within a wide voltage range, reduce irregular voltage differences caused by offsets, and improve overall performance and calibration efficiency.
Smart Images
Figure CN222926217U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of microelectronic integration technology, and in particular to a linear Hall circuit with high precision and wide application voltage. Background Art
[0002] In the field of linear Hall sensors, accuracy is a key performance indicator and is crucial for ensuring the competitiveness of sensors. However, due to process asymmetry during the manufacturing process of Hall elements, offset voltages often occur, which can significantly affect the accuracy of measurement results. For example, under the conditions of a magnetic field intensity of 1 mT and a bias current of 1 mA, the output voltage of the Hall element may be only dozens or hundreds of microvolts, while the offset voltage can be as high as more than 1 millivolt, far exceeding the amplitude of the sensing signal.
[0003] To eliminate this offset voltage, some internal calibration techniques, such as rotating current technology and chopper modulation technology, are commonly used in the industry. Although these techniques can reduce the offset voltage to a certain extent, their implementation often requires complex circuit design, and when introducing high-frequency signals, additional filtering circuits are also required to maintain the linearity and low-noise characteristics of the output signal. This not only increases the product cost but also may introduce new uncertainties.
[0004] In addition, when the Hall element and its main amplifier are powered by an external voltage, their offset voltages may vary with the power supply voltage, resulting in differences in output accuracy at different supply voltages, limiting the application of the sensor in a wider voltage range.
[0005] Currently, there is an urgent need to design a linear Hall circuit with high precision and wide application voltage to meet the application requirements of linear Hall circuits for simultaneously achieving high precision and wide voltage range. Summary of the Utility Model
[0006] The purpose of the utility model is to overcome the deficiencies of the prior art and provide a linear Hall circuit with high precision and wide application voltage. By using an external trimming method with the proposed circuit structure, the supply voltage is divided into several smaller ranges, and precise debugging and calibration are performed within each range to ensure that the output signal can maintain high precision throughout the voltage range.
[0007] To achieve the above object, a linear Hall circuit with high precision and wide application voltage is designed, including: a Hall signal generator circuit, a first-stage dual-input and dual-output amplifier connected to the Hall signal generator circuit in series, and a rail-to-rail amplifier connected to the first-stage dual-input and dual-output amplifier in series. It further includes: an output voltage calibration module, the output end of the output voltage calibration module is connected to the circuit between the first-stage dual-input and dual-output amplifier and the rail-to-rail amplifier, and the output voltage calibration module includes a power supply detection module and a voltage calibration circuit. The power supply detection module is used to confirm the divided gear position corresponding to the power supply voltage and generate a corresponding enable signal to drive the DAC module corresponding to this gear position in the voltage calibration circuit.
[0008] Preferably, the linear Hall circuit with high precision and wide application voltage provided by the present utility model further includes other technical features. Among them, the output end of the output voltage calibration module is connected to the circuit between the first-stage dual-input and dual-output amplifier and the rail-to-rail amplifier through a buffer circuit, and the buffer circuit is used to enhance the driving ability of the Vref signal output by the output voltage calibration module.
[0009] Preferably, the linear Hall circuit with high precision and wide application voltage provided by the present utility model further includes other technical features. Among them, the power supply detection module includes a power supply voltage division input module, several comparators, an encoder, and a reference voltage VBG. The output end of the reference voltage VBG is several control voltages, each control voltage is connected to a comparator, these comparators are respectively connected to the positive power supply VCC through resistors, and the output ends of the comparators are connected to the encoder, and the encoder is used to output an enable control signal.
[0010] Preferably, the voltage calibration circuit of the voltage calibration module of the linear Hall circuit with high precision and wide application voltage provided by the present utility model includes several DAC modules. The input ends of the DAC modules are connected to external debugging signals and enable control signals, and the output ends are conductively connected to the buffer circuit.
[0011] Compared with the prior art, the present utility model has the following advantages:
[0012] Adopting a segmented calibration technique, the power supply voltage is divided into several smaller intervals, and each interval is adjusted independently and meticulously. This method can achieve more accurate signal output at different voltage levels, ensure the improvement of the signal accuracy of the linear Hall circuit within the entire power supply voltage range, and reduce the large and irregular differences in voltage caused by offset. Through targeted optimization, the overall performance is significantly improved, and the calibration process is more efficient and accurate. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 is a schematic diagram of the connection relationship of the present utility model;
[0014] Figure 2 is a schematic diagram of the power supply detection module of the present utility model;
[0015] Figure 3 is the circuit diagram of the power supply detection module of Embodiment 1;
[0016] Figure 4 is a schematic diagram of the voltage calibration module of the present utility model;
[0017] Figure 5 is the circuit diagram of the voltage calibration module of Embodiment 1;
[0018] Figure 6 is the circuit diagram of the dual-input and output amplifier of Embodiment 1;
[0019] Figure 7 is the circuit diagram of the rail-to-rail amplifier of Embodiment 1. Specific Embodiment
[0020] To make the purpose, principle and structure of the present utility model clearer, the following is further elaborated in conjunction with the accompanying drawings and specific embodiments.
[0021] Embodiment 1:
[0022] Refer to Figures 1-5 , this embodiment provides a linear Hall circuit with high precision and wide application voltage. Aiming at the deficiencies of the prior art, a linear Hall circuit structure that can still maintain high output precision under a relatively wide supply voltage is proposed. The specific implementation scheme includes: 1. Programming and debugging circuit: Read the adjustable voltage range, debugging bits and step size of typical values in each supply voltage range through the output end of the amplifier; and perform debugging and calibration through the method of external programming; 2. Power supply detection module: Monitor the change of the supply voltage of the power supply voltage after power-on, compare the given voltage threshold with the supply voltage of the power supply voltage, divide the voltage range into several smaller range intervals, and generate corresponding enable signals, so as to be transmitted to the subsequent calibration module; 3. Voltage calibration circuit: According to the enable signal sent by the above power supply detection module, and read all the data bit voltages of the DAC through external debugging, select the corresponding calibration module, read the voltage Vref closest to half of the supply voltage VCC in the DAC as the calibration signal, and then transmit the voltage Vref to the main amplifier circuit after enhancing the driving ability through a buffer amplifier, so as to perform the calibration work on the chip output voltage at the input end of the last-stage rail-to-rail amplifier.
[0023] It should be noted that in the prior art, in the case of normal voltage supply, the linear Hall circuit generates a differential Hall signal VHALL by the Hall signal generator circuit. The Hall signal VHALL passes through the first-stage dual-input and output amplifier (see Figure 6After signal amplification, an available differential linear Hall signal is formed. Finally, through a rail-to-rail amplifier (see Figure 7 ) for further amplification and increasing the output swing of the signal. These three modules constitute the main circuit of the linear Hall circuit. Before external modulation, the actual output signal of the main circuit of the linear Hall circuit formed by these three modules will have a large and irregular difference from the ideal 1 / 2*VCC due to the offset voltage of the Hall element itself and the offset of the subsequent amplifier. Moreover, at different supply voltages, this difference cannot be equivalently converted, seriously affecting the precision characteristics of the linear Hall circuit.
[0024] The technical solution proposed in this patent compares and grades the power supply voltage through voltage division conversion with the threshold voltage, and selects the voltage value close to the middle value as the typical voltage value in different grading levels. The potential of the DAC module in the voltage calibration circuit is selected through external debugging to achieve the purpose of output voltage calibration, ensuring that the output signal of the voltage in its own level has extremely high precision characteristics. Since the voltage range of each grading level is much smaller than the overall application voltage range, by first calibrating the typical voltage close to the middle value in each level, it can also ensure that the remaining voltages in the same level can show relatively high precision characteristics at the output end. After debugging and calibrating the typical voltage values of all levels, if power is re-supplied (power supply voltage) during subsequent work, different supply power voltage ranges will correspond to the typical voltages of each level after debugging and calibration, so as to improve the grading efficiency and calibration accuracy of the power supply voltage in subsequent work.
[0025] When the circuit is powered on again and connected to the power supply voltage after the first programming and debugging, the power detection module will immediately confirm the grading level corresponding to the powered-on power supply voltage and generate a corresponding enable signal to drive the DAC module corresponding to this level in the voltage calibration circuit. Since the corresponding programming bit signal has been burned into the module during the first debugging, the voltage calibration circuit can immediately determine the power level and send the calibration signal Vref to the main part of the Hall circuit for debugging after receiving the enable signal from the power detection end. During this process, the calibration signal Vref will calibrate the final output voltage at the non-inverting input terminal of the rail-to-rail amplifier.
[0026] Since the linear Hall circuit has a two-stage amplification structure, the offset voltage of the Hall element will be further amplified during both amplifications. The calibration voltage Vref is debugged and calibrated between the first stage and the second stage of the Hall circuit. Moreover, it is inevitable that there are offset signals in each of the two-stage amplifiers. Therefore, the main amplification functional stage of the linear Hall circuit should be the first stage, and the rail-to-rail amplifier in the second stage must have a very small amplification factor, and its main function should be to increase the signal output swing.
[0027] The linear Hall sensor adopts a two-stage amplification structure, and the offset voltage of the Hall element may increase during both amplification processes. The calibration signal Vref needs to be adjusted and calibrated between the first-stage and second-stage amplifiers. Since there may be inherent offset signals in each stage of the amplifier, the main amplification function of the linear Hall sensor should be concentrated in the first stage, that is, a dual-input and dual-output amplifier is set in the first stage, and the dual-input and dual-output amplifier is set before the calibration signal Vref. In the second-stage amplifier, in order to reduce the offset ratio when the calibrated voltage is amplified again, an amplifier with a lower amplification factor is used, that is, a rail-to-rail amplifier, and its main function is to expand the swing range of the signal output.
[0028] Finally, the linear Hall circuit adjusts and calibrates the output potential of the amplifier through the Vref signal generated by the voltage calibration circuit, so that the output static level has high-precision characteristics. It should be noted that the driving ability of the Vref signal terminal needs to be higher than that of the pre-stage amplifier. Therefore, a buffer circuit can be considered to be added in the middle of the Vref signal to enhance the driving ability of the Vref signal. Since the first-stage amplifier of the pre-stage needs to be responsible for the main Hall signal amplification function, an instrumentation amplifier with lower noise and higher precision can be selected as the circuit structure of the first-stage amplifier.
[0029] The above is only the specific implementation manner of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by this utility model, according to the technical solution and the concept of this utility model, makes equivalent replacements or changes, and all should be covered within the protection scope of this utility model.
Claims
1. A high-precision linear Hall circuit with wide applied voltage, comprising Hall signal generator circuit, The first stage dual input and output amplifier connected to the Hall signal generator circuit line, A rail-to-rail amplifier connected to the first stage dual input-output amplifier line, Features Also includes an output voltage calibration module, wherein the output end of the output voltage calibration module is connected to the line between the first-stage dual-input-output amplifier and the rail-to-rail amplifier, The output voltage calibration module includes a power detection module and a voltage calibration circuit. The power detection module is used to confirm the sub-gear position corresponding to the power supply voltage and generate an enable signal corresponding thereto to drive a DAC module corresponding to the gear position in the voltage calibration circuit.
2. A high-precision, wide-application-voltage linear Hall circuit as claimed in claim 1, characterized in that The output end of the output voltage calibration module is connected to the line between the first-stage dual-input and output amplifier and the rail-to-rail amplifier through a buffer circuit, and the buffer circuit is used to enhance the driving capability of the output voltage calibration module to output the Vref signal.
3. A high-precision, wide-application-voltage linear Hall circuit as claimed in claim 1, characterized in that The power detection module includes a power voltage division input module, several comparators, an encoder and a reference voltage VBG. The output end of the reference voltage VBG is several control voltages, each control voltage is connected to a comparator, and these comparators are respectively connected to a positive power supply VCC through resistors. The output end of the comparator is connected to the encoder, and the encoder is used to output an enable control signal.
4. A high-precision, wide-application-voltage linear Hall circuit as claimed in claim 1, characterized in that The voltage calibration circuit of the voltage calibration module includes a plurality of DAC modules, the input end of the DAC module is connected to an external debugging signal and an enable control signal, and the output end is conductively connected to a buffer circuit.