When connecting a low-side FET gate-driver to a FET (N-channel MOSFET) that has a current sense resistor connected between its source and ground, where should I connect the ground of the gate driver?
I am of two minds on this. First, all of the data sheets that I have looked at do not show a current sense resistor on the FET's source. As a result, the gate-driver has its ground connected to the source. Because it is the capacitor between the gate and source that I am charging/discharging with the driver, I am inclined to connect the gate driver's source, as this way the sense resistor will not degrade di/dt into the gate. However, if I connect the gate driver's ground to high side of the sense resistor, that means that the reference for the input to the driver will move with source current. If the sense resistor is small, then I should not expect the driver's ground to move much and as long as I make sure my driving signals take this into account it should not be a problem.
Long story short, should I connect my low-side gate-driver's ground to the high side or low side of the current sense resistor that is between the FET's source and ground?
Edit: I was asked what this circuit does. This is an active dump load for a tether-operated remotely operated vehicle. In order to provide sufficient power to the vehicle, the operator side power supply will need to increase its output voltage at times to compensate for tether losses. This circuit monitors the voltage at the vehicle-end of the load and diverts power to a power resistor when the vehicle-side voltage exceeds a limit in order to keep the input voltage to the vehicle within an acceptable range. The circuit also measures current through the power resistor and communicates this (as well as vehicle input voltage) to the power supply's controller at the top end so that the power supply can be commanded to reduce its output voltage as necessary. Conversely, when vehicle input voltage drops too low, the power supply is commanded to increase output voltage. The FET controls current through the power resistor via PWM.