I will be using the DRV8353F and its shunt amplifier functionality. However, I am concerned about the location of the shunts; the datasheet recommends placing the shunts between the MOSFET source and the power GND (see image).
My concern is as follows: I want to power all low-side transistor gates with the same isolated supply. This means that the supply reference would be at the lower side of the shunts. Consequently, the gate current will flow through the shunt amplifiers. This worries me for two reasons:
The gate current loops would increase substantially in size to include the shunts.
The gate current will have an impact on the current measured. Although the average current is low, it reaches peaks of several amps to properly drive the high-power MOSFETs (I achieve this by placing a push-pull circuit at the gate).
My questions are:
Is it possible to change the location of the shunts and place them on the other side of the MOSFET? This would involve connecting the shunts in series with the transistors but at the drain side instead of the source.
If this solution is not possible, is there another way to prevent these issues while using only one supply for the low-side MOSFETs?"
