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TB9051FTG current sensing

#1

Good day, I am using a TB9051FTG with a brushed dc motor. For current sensing I have been using an ina219 between 24V power supply and the TB9051. Now I want to use the integrated current sensing of the TB. Going one direction, both INA and TB current measurements are almost the same. Going the other direction there is a difference of around 50mA between both measurements.

Any hint why that would be?

Thanks

#2

Hello.

Can you post a schematic diagram detailing where your external sensor is in your system? Can you also tell me how much current you are running through the motor?

-Tony

#3

Hey,
I use the ina219 as high side between the power supply and the TB.

The motor is drawing around 200mA. And the difference going one direction is around 20-30mA.

#4

Hello,

I suspect that both your sensors need calibration of some kind to be more accurate. You could try measuring the voltage on the OCM pin and the current reading on your INA219 with no current flowing to get a baseline for each. Could you also try measuring a range of currents and graphing the results from the driver and sensor?

-Tony