Method and circuit for using sensefet for battery protection module

A device for resistor lossless current sensing comprising:

• a first power transistor, wherein a drain of the first power transistor is conductively coupled to a current input to the device;
• a first sense transistor, wherein the gate of the sense transistor is conductively coupled with a gate of the first power transistor and a drain of the sense transistor is conductively coupled with the drain of the first power transistor;
• a current sense conversion circuit configured to convert a current output from the first sense transistor to an output voltage wherein the current output from the first sense resistor and output voltage are proportional to the current from the current input to the device and wherein the current sense conversion circuit generates the output voltage which is not in a current path through the first power transistor.