Is that any best way to measure High side mosfet drain current?

Question

To be specific, I am using 6 MosFETs (for ex. PSMN030-60YS) to drive an inductive load. I want to measure drain current of High-Side MosFETs. The way I am doing right now is by lifting the MosFET mounting base (drain pad) and attaching a small loop as possible (I know it does add some extra inductance and have small voltage drop) across the mounting base of MosFET itself and drain landing of PCB (a crude image is attached below).

I don't know any best way to measure drain current of high side MosFET apart from this.

Is there any proper way to do so without adding extra L or R component by adding a wire like I displayed?

Answer 1

The problem with the above setup is heat dissipation will be reduced and could overheat the part.

The source current is also the drain current for a mosfet. The way this is typically done is by cutting traces and inserting a series current resistor. If you need to know the swtiching current this is likely the best solution.

It really depends on how accurate you need the measurement to be. One way without cutting traces is to estimate the power of all the circuitry by using a benchtop supply with a current meter and then switching loads on and off to determine how much power they are using. The power of the local circuits can be estimated from the total. The current can be determined if you know the voltage of the local circuit.