Datasheet

INA220

www.ti.com

SBOS459D –JUNE 2009–REVISED SEPTEMBER 2010

The Current Register (04h) is then calculated by this result by the power LSB that is 20 times the

multiplying the shunt voltage contents by the 1 × 10

-3

current LSB, or 20 × 10

-3

, results in a power

Calibration Register and then dividing by 4095. For calculation of 5991 × 20mW/bit, which equals

this example, the shunt voltage of 2000 is multiplied 119.82W. This result matches what is expected for

by the calibration register of 20480 and then divided this register. A manual calculation for the power being

by 4095 to yield a Current Register of 2712h. delivered to the load would use 11.98V (12VCM –

20mV shunt drop) multiplied by the load current of

The Power Register (03h) is then be calculated by

10A to give a 119.8W result.

multiplying the Current Register of 10002 by the Bus

Voltage Register of 2995 and then dividing by 5000. Table 2 shows the steps for configuring, measuring,

For this example, the Power Register contents are and calculating the values for current and power for

1767h, or a decimal equivalent of 5991. Multiplying this device.

Table 2. Configure/Measure/Calculate Example

(1)

STEP # REGISTER NAME ADDRESS CONTENTS ADJ DEC LSB VALUE

Step 1 Configuration 00h 019Fh

Step 2 Shunt 01h 07D0h 2000 10µV 20mV

Step 3 Bus 02h 5D98h 0BB3 2995 4mV 11.98V

Step 4 Calibration 05h 5000h 20480

Step 5 Current 04h 2712h 10002 1mA 10.002A

Step 6 Power 03h 1767h 5991 20mW 119.82W

(1) Conditions: load = 10A, V

= 12V, R

SHUNT

= 2mΩ, V

SHUNT

FSR = 40mV, and V

BUS

= 16V.

Product Folder Link(s): INA220