Table 8-3. Design Parameters (continued)

DESIGN PARAMETERS

EXAMPLE VALUE

Common-mode voltage range

0 V to 24 V

Maximum sense current

1.5 A

RSENSE resistor

50 mΩ

Gain option

50 V/V

8.2.2 Detailed Design Procedure

The INA293 is designed to measure current in a typical solenoid application. The INA293 measures current

across the 50-mΩ shunt that is placed at the output of the half-bridge. The INA293 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

INA293 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 INA293, with high bandwidth and slew rate, can be used to detect fast overcurrent conditions to

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

8.2.2.1 Overload Recovery With Negative VSENSE

The INA293 is a unidirectional current sense amplifier that is meant to operate with a positive differential input

voltage (VSENSE). If negative VSENSE is applied, the device is placed in an overload condition and requires time

to recover once VSENSE returns positive. The required overload recovery time increases with more negative

VSENSE.

8.2.3 Application Curve

Figure 8-3 shows the output response of a solenoid.

0

10

20

30

40

0

2

4

6

Time (50 ms/div)

VCM

VOUT

Figure 8-3. Solenoid Control Current Response

8.3 Power Supply Recommendations

The INA293 power supply can be 5 V, whereas the input common-mode voltage can vary between –4 V to 110

V. The output voltage range of the OUT pin, however, is limited by the voltage on the power-supply pin.

8.4 Layout

8.4.1 Layout Guidelines

Attention to good layout practices is always recommended.

• Connect the input pins to the sensing resistor using a Kelvin or 4-wire connection. This connection technique

makes sure that only the current-sensing resistor impedance is detected between the input pins. Poor routing

of the current-sensing resistor commonly results in additional resistance present between the input pins.

Given the very low ohmic value of the current resistor, any additional high-current carrying impedance can

cause significant measurement errors.

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INA293

SBOS470B – DECEMBER 2019 – REVISED AUGUST 2022

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