9.2.1.2 Detailed Design Procedure

The INA241x is designed to measure current in a typical solenoid application. The INA241x measures current

across the 50-mΩ shunt that is placed at the output of the half-bridge. The INA241x measures the differential

voltage across the shunt resistor, and the signal is internally amplified with a gain of 50 V/V. The output of the

INA241x is connected to the analog-to-digital converter (ADC) of an MCU to digitize the current measurements.

Solenoid loads are highly inductive and are often prone to failure. Solenoids are often used for position control,

precise fluid control, and fluid regulation. Measuring real-time current on the solenoid continuously can indicate

premature failure of the solenoid, which can lead to a faulty control loop in the system. Measuring high-side

current also indicates if there are any ground faults on the solenoid or the FETs that can be damaged in an

application. The INA241x, with high bandwidth and slew rate, can be used to detect fast overcurrent conditions

to prevent the solenoid damage from short-to-ground faults.

10 Power Supply Recommendations

The INA241x makes accurate measurements beyond the connected power-supply voltage (VS) because the

inputs (IN+ and IN–) can operate anywhere between –4 V and 110 V independent of VS. For example, with the

VS power supply equal to 5 V, the common-mode voltage of the measured shunt can be as high as 110 V.

10.1 Power Supply Decoupling

Place the power-supply bypass capacitor as close to the supply and ground pins as possible. TI recommends a

bypass capacitor value of 0.1 μF. Additional decoupling capacitance can be added to compensate for noisy or

high-impedance power supplies.

INA241A, INA241B

SBOSA30 – MARCH 2022

www.ti.com

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