INA240: Bidirectional Current sense -26V to +26V

Tom Van Gaever

Part Number: INA240
Other Parts Discussed in Thread: LMP8481

Tool/software:

Hi,

I have a bidirectional motor which is simulated with a 2,7mH coil and a 2 Ohm resistor.The motor is controlled with a H-bridge with 26V high side and -26V low side.

I need to measure the current going through the resistor in both directions. Could I do this with the INA240 IC? Are there better IC I could use?

Sould I just measure it with an opamp circuit?

Thanks

6 months ago

0 Clemens Ladisch 6 months ago

Guru 317280 points

What power supplies do you have available? The LMP8481 would require ±30 V (because of its minimum 4 V input voltage).

0 Guang Zhou 6 months ago

TI__Mastermind 34240 points

Hi Tom,

If you’re using a single supply, such as 5V, many of our current sense amplifiers will be able to support high side (26V) measurements.

If the system has a more complex level-shifting scheme, like Clemens suggested, then the options open up for the low side (-26V) as well.

Regards

Guang

0 Tom Van Gaever 6 months ago in reply to Guang Zhou

Prodigy 10 points

Hi thanks for the replies, I made a mistake, with the pulse width modulation only 2.5 amps go through the resistor max. So it's only aproximalty +5 and -5V over the resistor that I want to measure with a 3.3 V ADC. What would be the appropriate IC?

0 Guang Zhou 6 months ago in reply to Tom Van Gaever

TI__Mastermind 34240 points

Hi Tom,

The -5V still limits the selection of parts. However we have some that can withstand this voltage. Here is a complete list.

It sounds like the common mode voltage will be switching between 5 and -5V, ie, a PWM signal. If so, the INA241 is probably the best fit.

Another option is Hall current sensors. With these you won’t even need the shunt resistor. Here is a list what’s available

Regards

Guang

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INA240: Bidirectional Current sense -26V to +26V