INA253: Current sensing using INA253.

Venkata Rao M

Part Number: INA253
Other Parts Discussed in Thread: INA240

Hi TI,

I have a requirement for low side current sensing design for the current range of -10A to +10A , with differential output. The current sense circuit should be able to measure to a minimum of 5mA resolution with high precision. For this i have chosen INA253A2 as my current sense amplifier.

Please let me know whether my selection can be used to achieve my design requirement.

If not can you suggest any current sense amplifier which can measure a resolution of 5mA change with high accuracy ?

Thanks & Regards,

M Venkata Rao.

11 months ago

0 Angel Rodriguez de San Miguel Bermudez 11 months ago

TI__Expert 4130 points

Hello Venkata,

I will take a look and get back to you by tomorrow.

Best Regards,

Angel

0 Angel Rodriguez de San Miguel Bermudez 11 months ago

TI__Expert 4130 points

Hello Venkata,

The INA253 should be able to satisfy your design requirements. Feel free to use our parametric search tool to filter out our products if there are additional specifications you are looking for: Current-sense amplifiers product selection | TI.com

Best Regards,

Angel

0 Venkata Rao M 11 months ago in reply to Angel Rodriguez de San Miguel Bermudez

Prodigy 60 points

Hi Angel,

I want to go with INA253 for current sensing. Can you provide a reference schematics for the same ? As i didn't find any.

Regards,

Venkat.

0 Angel Rodriguez de San Miguel Bermudez 11 months ago in reply to Venkata Rao M

TI__Expert 4130 points

Hi Venkata,

Feel free to take a look at or purchase our evaluation module for this part: INA253EVM Evaluation board | TI.com, it is intended for easy and quick evaluation of the device, and it will help you get familiar with current sensing. The schematic for the EVM is available in the EVM's user guide: INA253EVM User's Guide (ti.com).

Also feel free to take a look at our Precision Lab's series on current sensing to find some useful current sensing topics: Precision labs series: Current sense amplifiers | TI.com

Best Regards,

Angel

0 Venkata Rao M 11 months ago in reply to Angel Rodriguez de San Miguel Bermudez

Prodigy 60 points

Hi Angel,

Is there any equations available for the exact current consumption of INA253A2 for a particular VCC and VREF voltages because i have to use 16 INA253A2s in my design and i have to do power budgeting of each rail.
My inputs will be :

Input : -/+ 10A

VREF : +2.5V

VCC : +5V respectively.

Can you please guide me in calculating current consumption of INA253A2 on each voltage rail as per the above inputs (as this information is not mentioned in Datasheet) :

Regards,

Venkat.

0 Angel Rodriguez de San Miguel Bermudez 11 months ago in reply to Venkata Rao M

TI__Expert 4130 points

Hi Venkata,

Here are the internal resistor networks for INA240/INA253

			First Stage			Second Stage
Device	Gain (mV/A)	Resistor Variation	R_BIAS (kΩ)	Rint (kΩ)	RFB (kΩ)	NonInv Gain	Rint (kΩ)	RFB (kΩ)	Vbias for 2nd stage
INA253A1	100	+/-25%	6.7	25	500	2.5	50	125	Vs/2
INA253A2	200					5	50	250
INA253A3	400					10	50	500

These can be used to theoretically calculate current into REF pin.

For example, with Vs=5V and setting Vref to 2.5V by setting REF1 to Vs and REF2 to GND (or vice versa), you are essentially driving 5V across two 50kOhm resistors in-series, which is 50µA into REF1 and out of REF2. There will be some small current leakage into device's internal bias voltage (Vs/2), but since you are setting Vref to 2.5V, this leakage current will be negligible. Here is the equivalent DC circuit of INA253A2 below.

Best Regards,

Angel

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INA253: Current sensing using INA253.