First, the Hall sampling method of current detection.
Generally speaking, the voltage signal output from the Hall current sensor is input to the MCU detection method after processing. In many cases, Hall sampling has the advantage of measuring large current and low power dissipation. However, Hall sampling has many disadvantages. When measuring the current in a small range, it requires the use of a large offset voltage, which will cause errors and be easily affected by external magnetic fields. Hall sampling is very sensitive to ESD, which has high cost and large volume.
Second, the resistance sampling method of current detection
It uses high power precision resistor to carry on the current sampling, through the operation amplifier circuit input to the MCU. We also call it resistor sampling. Compared with Hall sampling, resistive sampling has the advantages of low cost and good applicability. The circuit can be designed according to different conditions to achieve the best results. In addition, the surge resistance of metal alloy less than 1m Ω is very good. Resistance sampling also has its own shortcomings. The high power precision resistor temperature drift is very serious and is not applicable in some specific applications, and the use of resistance sampling has a certain power loss.
Resistive sampling and Hall sampling have their own advantages and disadvantages, which method can be used depending on the circuit design. But in automobile current detection, resistance sampling methods will be more and more popular. In order to control the output of the total current of the battery, the total current must be monitored from time to time. With the development of high precision resistance, the temperature drift becomes smaller and smaller, and the resistance sampling method is used more and more in the battery management system.
