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
GND
A0
A1
Current
Shunt
V =V V-
SHUNT IN+ IN-
Typically<50mV
Supply Load
-
+
3Vto5.5V
V
S
TPS2480
TPS2481
SLUS939B –APRIL 2010–REVISED DECEMBER 2010 www.ti.com
ADC Operation
The two analog inputs to the TPS2480/81, VINP and VINM, connect to a shunt resistor in the bus of interest. The
TPS2480/81 is typically powered by a separate supply from 3 V to 5 .5V. The bus being sensed can vary from 0
V to 26 V. There are no special considerations for power-supply sequencing (for example, a bus voltage can be
present with the supply voltage off, and vice-versa). The TPS2480/81 senses the small drop across the shunt for
shunt voltage, and senses the voltage with respect to ground from VIN– for the bus voltage. Figure 25 illustrates
this operation.
Figure 25. TPS2480/81 Configured For Current and Voltage Measurement
When the TPS2480/81 is in the normal operating mode (that is, MODE bits of the Configuration Register are set
to '111'), it continuously converts the shunt voltage up to the number set in the shunt voltage averaging function
(Configuration Register, SADC bits). The device then converts the bus voltage up to the number set in the bus
voltage averaging (Configuration Register, BADC bits). The Mode control in the Configuration Register also
permits selecting modes to convert only voltage or current, either continuously or in response to an event
(triggered).
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