What is the best way to connect a current sensor in an h bridge circuit?

Thread Starter

rfengineer28

Joined Apr 28, 2021
71
Hello, I am putting together an h bridge PCB where I will be using a current sensor the ACS72981 but I am confused as to what the protocol for using these sensors is in terms of connecting them on the PCB. I am using a 4-layer board where I have signal on the 1st layer, ground on the second, power on the 3rd, and signal on the 4th. the sensor is SMD so I have to drop it down to the 3rd layer through a via but can I do that? any advice would be appreciated.
 

ronsimpson

Joined Oct 7, 2019
2,261
What is the purpose of the current sensor? If you are measuring the current ramp in the MOSFETs it might be a little slow, phase shift. It is good to 250khz but that is slow if you are monitoring the current ramp.

I would connect the power supply capacitor very close to pins 1& 2, then drop down to power and ground.
 

Thread Starter

rfengineer28

Joined Apr 28, 2021
71
What is the purpose of the current sensor? If you are measuring the current ramp in the MOSFETs it might be a little slow, phase shift. It is good to 250khz but that is slow if you are monitoring the current ramp.

I would connect the power supply capacitor very close to pins 1& 2, then drop down to power and ground.
The purpose of the current sensor is for me to be able to monitor the current on the board and eventually construct a current feedback loop
 

crutschow

Joined Mar 14, 2008
30,463
Why not connect the sense resistor in series with the bottom of the bridge to ground?
That will give you a ground based signal.
 
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