Current sense resistors play an important role in the circuit. Our familiar battery management system and power management system use a large number of current sense resistors to feed back the current signal, so that other controllers can further control the circuit. In this process, the current sense resistor precision is extremely important. The battery management system on new energy vehicles has a very large impact on the safety of the entire vehicle, and all of them attach great importance to current sensing resistors.

We know that switch mode power supplies usually use current mode control. Because of the high reliability, simple loop compensation design, and simple and reliable load distribution function, many switching power supplies are currently using this solution. The current sense signal is an important part of the current mode switching power supply design. It is used to regulate the output and provide overcurrent protection. The current sense resistor is usually used to monitor the current during this process.
 
The switching power supply current sense resistor is typically set at the peak inductor current by the selected inductor value, the power switch on-time, the circuit's input and output voltages, and the load current. When the circuit is shorted, the inductor current rises rapidly until the current limit is reached, reaching the maximum current sense voltage to protect the device and downstream circuitry. The built-in current foldback limit then further reduces the inductor current to minimize thermal stress. 

Current sense resistors are used in multiphase power supply designs to achieve accurate current sharing. For light-load power supply designs, it prevents reverse current flow and increases efficiency. In addition, when the load of the multiphase application is small, the current sense resistor can be used to reduce the number of phases required, thereby increasing circuit efficiency. For loads that require a current source, the current sense resistor converts the power supply to a constant current source that can be used for applications such as LED driving, battery charging, and laser driving.
 
As more and more technologies are put into the development of current-sense resistors, future current-sense resistors will have great improvements in materials and production processes, and in the application of battery management systems and power management systems more and more.