Effective method to eliminate Hall sensor error - Database & Sql Blog Articles

inductance

Hall sensor has been widely used in electrical measurement, automatic control and computing devices due to its advantages of no contact, small size and simple structure. Since Hall sensors generate many errors, although various compensation measures have been taken at present, it is difficult to effectively compensate various errors with only one compensation circuit. To this end, this paper designs a circuit that can effectively compensate for various errors without using a compensation circuit.
Main error and cause
1. The zero error zero error is caused by the unequal potential. The main reason for generating the unequal potential is that the two Hall electrodes are not mounted on the same equipotential surface; the uneven distribution of materials causes uneven distribution of resistance, poor contact of the control electrodes, and uneven current distribution.
2. The main cause of parasitic DC potential error is parasitic DC potential: the contact between the control electrode and the Hall element is poor, forming a non-ohmic contact; the two Hall electrodes are asymmetrical in size, so that the heat capacity of the two electrodes is different, the heat dissipation state is different, and the two poles The temperature difference potential occurs between the Hall elements to cause temperature drift.
3. Inductive Zero Potential Error When the Hall element is operating in an AC or pulsating magnetic field, even if the control current is not applied, the Hall terminal has a certain output due to the asymmetrical distribution of the Hall pole, and its magnitude is proportional to the pulsation frequency and magnetic induction of the magnetic field. The amplitude and the sensing area of ​​the two Hall electrode leads.
4. Self-excited magnetic field zero potential error When the Hall element is connected to the control current, this current also generates a magnetic field, called the self-excitation magnetic field. When the electrode leads are asymmetrical, the magnetic induction strengths on both sides of the element are not equal, and the zero potential of the self-excited field will be output.
5. Temperature error

At present, in order to eliminate the above error, in addition to the attention in the process, the resistance compensation circuit is generally used for compensation, but the effect is still not satisfactory in the more precise measurement.
Method of eliminating various errors

The potential drawn by the voltage follower composed of the operational amplifier A4 drives the shielding layer of the cable, so that the interference of the AC common mode voltage is well suppressed. The circuit shown in Figure 3 is suitable for various sensor circuits.