8.2 Typical Applications

8.2.1 Current Shunt Monitoring in Battery Testing Systems

Figure 8-3 shows a current shunt monitoring design for the INA630. This exemplary circuit is designed to monitor

charging and discharging currents through a battery cell of ±100A. The INA630 is configured in a gain of 125V/V

and optimized to enable accuracy of 0.05% over a temperature range of 40°C. The output is a bipolar-ended

voltage of ±2.5V to feed into a bipolar ADC.

INA630

ADC

10 V

BATTERY

CELL

VS+

VS

VREF

OUT

10 V

R2

R1

GND

2.5 V

2.5 V

Charge

Current

ISENSE

5 V

FB

Figure 8-3. Battery Testing Current Shunt Monitor Circuit

8.2.1.1 Design Requirements

For this application, the design requirements are as follows:

• Charging and discharging current for single-cell battery of up to ±100A

• Sense resistor RSENSE of 200μΩ, equal to VSENSE of ±20mV

• Maximum common-mode voltage of VBAT at 4.2V

• Bipolar output voltage of ±2.5V

8.2.1.2 Detailed Design Procedure

This chapter details the procedure to lay out the gain resistor network, containing R1 and R2. Additional

guidance is provided to verify that the given input voltage lies within the allowed operating range.

The selection of the current shunt resistor is an important step for an accurate battery test system. A large shunt

resistor increases power dissipation which degrades the drift performance. A small resistor on the other side

requires a high-performance front end. For this design, the given charging current ICHARGE is ±100A, so RSENSE

is selected to be 200μΩ for best trade-off.

In charging mode, Equation 3 show the sense voltage to the input of the INA630:

VSENSE = ICHARGE × RSENSE = ±20mV

(3)

The full-scale range for the selected ADC is at 5V. The reference pin is grounded. Equation 4 shows the gain:

G = VOUT / VSENSE = 125V/V

(4)

• G represents the gain of the instrumentation amplifier.

• VSENSE represents the differential voltage at the INA630 inputs which is within the maximum allowed

differential input voltage of ±125mV.

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INA630

SBOSAI8A – MARCH 2025 – REVISED JULY 2025

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