The Hall effect is a kind of magnetoelectric effect, which was discovered by Hall (A.H. Hall, 1855-1938) in 1879 when studying the conductive mechanism of metals. It was later discovered that semiconductors, conductive fluids, etc. also have this effect, and the Hall effect of semiconductors is much stronger than that of metals. Various Hall devices fabricated using this phenomenon are widely used in industrial automation technology, detection technology, and information processing. aspect. Hall devices are divided into two categories: Hall element and Hall IC. The former is a simple Hall plate, which is often used to amplify the obtained Hall voltage. The latter integrates the Hall chip and its signal processing circuitry on the same chip. Hall IC is a product that has appeared in the semiconductor integrated circuit industry for nearly 20 years, but because of its small size, light weight, long life, easy installation, low power consumption, high frequency, vibration resistance, not afraid of dust and oil. The advantages of pollution and low cost make it extremely widely used. Hall ICs have many other names, such as: Hall Effect IC, Hall Effect Sensor IC, Hall Sensor, Hall circuit, Hall IC . Hall is sometimes translated into Hall, so it can also be called Hall IC. Hereinafter referred to as Hall IC. Hall ICs are usually classified into digital Hall ICs and linear Hall ICs according to the type of output signals. The digital Hall IC controls the output to be turned on or off by the strength of the external magnetic field, similar to the role of a switch, and is therefore often referred to as a switching Hall IC. The linear Hall IC output is an analog signal, and the output voltage is usually linear with the strength of the external magnetic field. Switching Hall ICs are often divided into four types: single-pole Hall IC (Unipolar), locked Hall IC (Latch), two-stage Hall IC (Bipolar), and full-level Hall IC (Omnipolar). For convenience of explanation, according to the usual convention, when the south pole (S pole) of the applied magnetic field is close to the marked side of the Hall IC, the direction of the magnetic field acting on the Hall IC is positive, and when the north pole (N pole) is close to the marking surface The magnetic field is negative.

Single-stage Hall IC: Often referred to as a switch Hall IC, a Hall switch, and a Hall Effect Switch. Responding only to a single pole (often the S pole). Most unipolar Hall ICs, when the S pole faces the marking surface and the applied magnetic induction B exceeds the operating point (BOP) (ie B>BOP>0), the output is turned on and the output goes from high to low. When the magnetic induction weakens below the release point (BRP) (ie, 0 < B < BRP) or the removal (B = 0), the output is turned off and the output goes from low to high. If the external magnetic field is larger than the BOP during the power-on process of the single-stage Hall IC, the initial state of the output will be turned on. Conversely, if the external magnetic field is less than the BOP during the above electrical process, the initial state of the output will be off.

Locked Hall IC: The S and N poles must be alternately applied to the Hall IC. Most latched Hall ICs, when the S pole faces the marking surface and the applied magnetic induction exceeds the operating point (BOP) (ie, B>BOP>0), the output turns on and the output goes from high to low. When the magnetic induction is weakened until it is removed (B = 0), the output remains on. When the N pole faces the marking surface and the applied magnetic induction exceeds the release point (BRP) (ie, B < BRP < 0), the output is turned off and the output is turned from low to high. During the power-on of the locked Hall IC, if the external magnetic field is between BOP and BRP, the initial state of the output will be uncertain.

Full-Level Hall IC: A newer type that treats the S and N poles equally. In general, any one of the magnetic poles faces the marking surface, and the applied magnetic induction B exceeds the operating point (BOP) (ie, |B|>BOP), the output is turned on, and the output changes from high to low. When the magnetic induction weakens below the release point (BRP) (ie |B|<BRP) or the removal (B=0), the output is turned off and the output goes from low to high. There are also some full-level Hall ICs that are opposite to the above output states. The full-scale Hall IC is similar to the characteristics of the reed switch, and is used in many to replace the reed switch to improve reliability.

Two-stage Hall IC: It is a relatively early type. Initially due to semiconductor process limitations, the Hall sensor has a large sensitivity range and poor consistency. The same type of Hall, part of the latch type (middle curve), part of the S pole unipolar type (right curve), part of the N pole unipolar type (left curve), is a mixture of three. Often the indicator only gives the maximum BOP (>0) and the minimum BRP (<0). Any two-stage Hall IC cannot be determined to be a single-stage Hall IC, a locked Hall IC, or a negative unipolar Hall. IC. At present, there are few double-stage Hall ICs in the new models. Note that many users will mistake (or call) a two-stage Hall IC as a locked-type Hall IC, and mistakenly believe (or call) an all-pole Hall IC.

Linear Hall IC: The output is an analog signal. The output level is linear in a certain range and is called a linear magnetic field. The applied magnetic field is outside the linear magnetic field range and will no longer be linear until the output is saturated, with the lowest output saturation voltage and the highest output saturation voltage.

These are simple and commonly used Hall ICs. In addition to these, in recent years there have been some highly integrated and complex dedicated Hall ICs such as differential Hall ICs (Double Hall ICs) with integrated ADC, DAC and signal processing. The rotary position sensor of the circuit, the three-axis position sensor, and the brushless motor drive chip integrated with the motor control and drive circuit. In addition, current sensor ICs designed using the Hall principle are also a large category of Hall ICs.

With the popularity of portable devices such as mobile phones, notebook computers, and DVs, the power consumption of Hall ICs has been demanded, resulting in a new class of Hall IC-micropower Hall ICs. It is a type of digital Hall IC that is separately separated by power consumption. It uses a sleep mechanism to reduce power consumption, and the average power consumption can reach uA level. It can also be divided into single-stage Hall IC, locked-type Hall IC, and full-level Hall IC according to functions. A system generally used for long-term battery power supply.