Datasheet

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
Interface
2
VoltageRegister
V
IN+
V
IN-
ADC
PGA
INA219
GND
A0
A1
Current
Shunt
V =V V-
SHUNT IN+ IN-
Typically<50mV
Supply Load
-
+
INA219Power-SupplyVoltage
3Vto5.5V
V
S
INA219
SBOS448F –AUGUST 2008– REVISED SEPTEMBER 2011 www.ti.com
Power-Up Conditions
(Configuration Register, BADC bits). The Mode
control in the Configuration Register also permits
Power-up conditions apply to a software reset via the
selecting modes to convert only voltage or current,
RST bit (bit 15) in the Configuration Register, or the
either continuously or in response to an event
I
2
C bus General Call Reset.
(triggered).
BASIC ADC FUNCTIONS All current and power calculations are performed in
the background and do not contribute to conversion
The two analog inputs to the INA219, V
IN+
and V
IN–
,
time; conversion times shown in the Electrical
connect to a shunt resistor in the bus of interest. The
Characteristics table can be used to determine the
INA219 is typically powered by a separate supply
actual conversion time.
from +3V to +5.5V. The bus being sensed can vary
from 0V to 26V. There are no special considerations Power-Down mode reduces the quiescent current
for power-supply sequencing (for example, a bus and turns off current into the INA219 inputs, avoiding
voltage can be present with the supply voltage off, any supply drain. Full recovery from Power-Down
and vice-versa). The INA219 senses the small drop requires 40μs. ADC Off mode (set by the
across the shunt for shunt voltage, and senses the Configuration Register, MODE bits) stops all
voltage with respect to ground from V
IN–
for the bus conversions.
voltage. Figure 19 illustrates this operation.
Writing any of the triggered convert modes into the
When the INA219 is in the normal operating mode Configuration Register (even if the desired mode is
(that is, MODE bits of the Configuration Register are already programmed into the register) triggers a
set to '111'), it continuously converts the shunt single-shot conversion. Table 7 lists the triggered
voltage up to the number set in the shunt voltage convert mode settings.
averaging function (Configuration Register, SADC
bits). The device then converts the bus voltage up to
the number set in the bus voltage averaging
Figure 19. INA219 Configured for Shunt and Bus Voltage Measurement
14 Submit Documentation Feedback Copyright © 2008–2011, Texas Instruments Incorporated
Product Folder Link(s): INA219