V

= V

- GND

BUS

IN-

Range of 0V to 26V

Typical Application 12V

Data (SDA)

3.3V Supply

Clock (SCL)

´

Power Register

Current Register

I C-/SMBUS-

Compatible

Interface

2

Voltage Register

V

IN+

V

IN-

ADC

PGA

INA219

GND

A0

A1

V

= V

- V

SHUNT

IN+

IN-

Typically < 50mV

Supply

Load

-

+

INA219 Power-Supply Voltage

3V to 5.5V

V

S

R

SHUNT

INA219

SBOS448G – AUGUST 2008 – REVISED DECEMBER 2015

www.ti.com

Feature Description (continued)

Figure 13. INA219 Configured for Shunt and Bus Voltage Measurement

Although the INA219 can be read at any time, and the data from the last conversion remain available, the

conversion ready bit (Status register, CNVR bit) is provided to help coordinate one-shot or triggered conversions.

The conversion ready bit is set after all conversions, averaging, and multiplication operations are complete.

The conversion ready bit clears under any of these conditions:

•

Writing to the Configuration register, except when configuring the MODE bits for power down or ADC off

(disable) modes

•

Reading the Status register

•

Triggering a single-shot conversion with the convert pin

8.3.1.1 Power Measurement

Current and bus voltage are converted at different points in time, depending on the resolution and averaging

mode settings. For instance, when configured for 12-bit and 128 sample averaging, up to 68 ms in time between

sampling these two values is possible. Again, these calculations are performed in the background and do not add

to the overall conversion time.

8.3.1.2 PGA Function

If larger full-scale shunt voltages are desired, the INA219 provides a PGA function that increases the full-scale

range up to 2, 4, or 8 times (320 mV). Additionally, the bus voltage measurement has two full-scale ranges: 16 or

32 V.

8.3.1.3 Compatibility With TI Hot Swap Controllers

The INA219 is designed for compatibility with hot swap controllers such the TI TPS2490. The TPS2490 uses a

high-side shunt with a limit at 50 mV; the INA219 full-scale range of 40 mV enables the use of the same shunt for

current sensing below this limit. When sensing is required at (or through) the 50-mV sense point of the TPS2490,

the PGA of the INA219 can be set to /2 to provide an 80-mV full-scale range.

10

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