The Hall Effect occurs when a current-carrying metal or semiconductor material is placed perpendicular to a magnetic field, resulting in a voltage difference across the material’s width. This phenomenon is known as the Hall effect. The generated voltage, referred to as the Hall voltage (UH), can be expressed by the formula:
**UH = K · Ia · B / d**,
where **K** is the Hall coefficient, **Ia** is the current passing through the material, **B** is the magnetic induction (Lorentz force), and **d** is the thickness of the material. As a result, the sensitivity of the Hall effect increases with the strength of the applied magnetic field. While metals have relatively low Hall coefficients, semiconductors such as silicon, germanium, indium arsenide, and indium antimonide exhibit much higher values, making them more suitable for use in Hall sensors.
Hall effect sensors are widely used in modern applications due to their reliability and simplicity. In particular, they are popular in automotive systems where contactless sensing is preferred. These sensors offer advantages like a simple circuit design and low cost. However, they also have some limitations, including lower accuracy, poor linearity, slower response time, and significant temperature drift. To address these issues, this paper focuses on methods to reduce nonlinearity in Hall current sensors.
As an example, we examine the **S-5711ANDL-I4T1G** Hall sensor, which is designed for high sensitivity and operates over a wide temperature range (-40°C to +85°C). Its output voltage is nonlinearly related to the magnetic field strength, with an absolute linearity of about 29%. Additionally, it has an unbalanced voltage (**UHe**) that can affect measurement accuracy if not properly addressed. The internal circuit of the S-5711ANDL-I4T1G includes components that help reduce this imbalance and improve linearity.
The output voltage of the sensor is governed by the equation:
**UH = KH · IH · B · cosθ + Ke · IH**,
where **KH** is the Hall sensitivity, **IH** is the drive current, **B** is the magnetic induction, **cosθ** represents the angle between the normal of the component plane and the magnetic field, and **Ke** is the imbalance factor. The term **Ke · IH = UHe** is called the unbalanced voltage, and its ratio to the total Hall voltage defines the imbalance rate (**Re**), typically around ±10%.
To improve performance, a correction circuit is introduced. This circuit helps eliminate the unbalanced voltage and enhances the linearity of the sensor. The effectiveness of this correction is demonstrated through test curves. For instance, without correction (curve 1), the linearity is 29%, but after calibration (curve 3), it improves significantly to 7.6%. Curve 2 shows that while eliminating the unbalanced voltage improves linearity, it also reduces sensitivity, which can be compensated using an amplifier.
In conclusion, the nonlinear correction method applied to the Hall current sensor significantly improves its precision and linearity. Experimental results confirm that the proposed circuit can optimize the sensor’s working state, reduce errors, and enhance overall performance. This makes the Hall sensor a reliable and practical choice for various applications, especially in environments requiring accurate and stable magnetic field detection.
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