9.2.1.2 Detailed Design Procedure

For this application, the INA241x measures current in the drive circuitry of a 48 V, 4000 RPM motor.

To demonstrate the performance of the device, the INA241A2 with a gain of 20 V/V was selected for this design

and powered from a 5 V supply.

Using the information in the Section 8.4.3.2 section, the reference point is set to mid-scale by splitting the supply

with REF1 connected to supply and REF2 connected to ground. This configuration allows for bipolar current

measurements. Alternatively, the reference pins can be tied together and driven with an external precision

reference.

The current-sensing resistor is sized so that the output of the INA241x is not saturated. A value of 100 mΩ was

selected to maintain the analog input within the device limits.

9.2.1.3 Application Curve

Time (20

s/div)

-10

0.25

0

0.5

10

0.75

20

1

30

1.25

40

1.5

50

1.75

60

2

70

2.25

80

2.5

90

2.75

100

3

110

3.25

Motor Inline PWM Input Signal

VOUT

Figure 9-2. INA241A2 Inline Motor Current-Sense Input and Output Signals

INA241A, INA241B

SBOSA30A – MARCH 2022 – REVISED AUGUST 2022

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