ina219 datasheet

INA219
www.ti.com SBOS448G –AUGUST 2008–REVISED DECEMBER 2015
8.6.3.2 Bus Voltage Register (address = 02h)
The Bus Voltage register stores the most recent bus voltage reading, V
BUS
.
At full-scale range = 32 V (decimal = 8000, hex = 1F40), and LSB = 4 mV.
Figure 24. Bus Voltage Register
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
BD12 BD11 BD10 BD9 BD8 BD7 BD6 BD5 BD4 BD3 BD2 BD1 BD0 — CNVR OVF
At full-scale range = 16 V (decimal = 4000, hex = 0FA0), and LSB = 4 mV.
CNVR: Conversion Ready
Bit 1 Although the data from the last conversion can be read at any time, the INA219 Conversion Ready bit (CNVR)
indicates when data from a conversion is available in the data output registers. The CNVR bit is set after all
conversions, averaging, and multiplications are complete. CNVR will clear under the following conditions:
1.) Writing a new mode into the Operating Mode bits in the Configuration Register (except for Power-Down or
Disable)
2.) Reading the Power Register
OVF: Math Overflow Flag
Bit 0 The Math Overflow Flag (OVF) is set when the Power or Current calculations are out of range. It indicates that
current and power data may be meaningless.
8.6.3.3 Power Register (address = 03h) [reset = 00h]
Full-scale range and LSB are set by the Calibration register. See the Programming the Calibration Register .
Figure 25. Power Register
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
PD15 PD14 PD13 PD12 PD11 PD10 PD9 PD8 PD7 PD6 PD5 PD4 PD3 PD2 PD1 PD0
R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
The Power register records power in watts by multiplying the values of the current with the value of the bus
voltage according to the equation Equation 5:
8.6.3.4 Current Register (address = 04h) [reset = 00h]
Full-scale range and LSB depend on the value entered in the Calibration register. See Programming the
Calibration Register for more information. Negative values are stored in 2's complement format.
Figure 26. Current Register
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
CSIGN CD14 CD13 CD12 CD11 CD10 CD9 CD8 CD7 CD6 CD5 CD4 CD3 CD2 CD1 CD0
R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
The value of the Current register is calculated by multiplying the value in the Shunt Voltage register with the
value in the Calibration register according to the Equation 4:
8.6.4 Calibration Register
8.6.4.1 Calibration Register (address = 05h) [reset = 00h]
Current and power calibration are set by bits FS15 to FS1 of the Calibration register. Note that bit FS0 is not
used in the calculation. This register sets the current that corresponds to a full-scale drop across the shunt. Full-
scale range and the LSB of the current and power measurement depend on the value entered in this register.
See the Programming the Calibration Register. This register is suitable for use in overall system calibration. Note
that the 0 POR values are all default.
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