Datasheet

AD8219
Rev. A | Page 11 of 12
APPLICATIONS INFORMATION
HIGH-SIDE CURRENT SENSING
In this configuration, the shunt resistor is referenced to the
battery (see Figure 28). High voltage is present at the inputs
of the current sense amplifier. When the shunt is battery
referenced, the AD8219 produces a linear ground referenced
analog output.
+IN
I
LOAD
SHUNT
GND
–IN
4V
TO
8
0V
AD8219
OUTV
S
09415-026
LOAD
Figure 28. Battery Referenced Shunt Resistor
Figure 28 shows the supply pin, V
S
, connected directly to the
positive input (+IN) pin. In this mode, the internal LDO powers
the AD8219 as long as the common-mode voltage at the input
pins is 4 V to 80 V. Additionally, V
S
can also be connected to a
standalone supply that can vary from 4 V to 80 V as shown in
Figure 29.
+IN
I
LOAD
SHUNT
GND
–IN
AD8219
OUTV
S
4V
TO
8
0V
4V
TO
8
0V
09415-029
LOAD
Figure 29. Standalone Supply Operation
MOTOR CONTROL CURRENT SENSING
The AD8219 is a practical, accurate solution for high-side
current sensing in motor control applications. In cases where
the shunt resistor is referenced to a battery and the current
flowing is unidirectional (as shown in Figure 30), the AD8219
monitors the current with no additional supply pin necessary
provided the battery voltage in the following circuit is in the 4 V
to 80 V range.
+IN
GND
–IN
BATTERY
MOTOR
I
MOTOR
AD8219
OUTV
S
09415-027
Figure 30. High-Side Current Sensing in Motor Control