A brief discussion on the implementation process of current detection in automotive electronic systems

Here we mainly introduce the current detection method and discover some factors that are easily overlooked in the design. First consider two different methods, the shunt-based detection method and the magnetic field-based detection method.
Shunt method High-precision low-resistance resistors currently have the characteristics of high power and small size. This method has lower cost and higher accuracy. It is widely used in automotive electronics.
Detection methods based on magnetic fields, represented by current transformers and Hall sensors, have many advantages, such as good isolation and low power loss, which make them widely used in power drive technology and large current fields, but It also has shortcomings, such as large size, linear compensation characteristics and unsatisfactory temperature characteristics.
To realize the anti-pinch function, two detection methods are usually used at the same time. The following is an introduction using car window control as an example.
The working current of the body electronic control system we face is generally between 1 and 2, but we need to pay attention to the fact that most loads have r current. What needs to be covered today is the shunt method. This is the principle of our detection. The method of such a shunt is to insert a low-value detection resistor in series in the current path. This will form a small voltage drop, which can be amplified and thus treated as a proportional signal to the current. Of course, there are two most basic topologies
Low-side current detection
Place the detection resistor between the load and the circuit ground, then you can use an op amp to amplify the voltage drop formed on the resistor.
High-side sensing
Place the sense resistor between the power supply and the load.
Operational amplifier circuit for high-end detection
If you want to subdivide it more, you can take the position of the switch into consideration because we are facing an inductive load
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