Datasheet

Output Voltage
(1 V/div)
Time (500 µs/div)
VOUT
VREF
C002
0V
-
-
+
Reference
Voltage
C
BYPASS
0.1µF
5V Supply
Load
Output
-
+
IN-
IN+
GND
V+
OUT
REF
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Typical Applications (continued)
9.2.2 Bidirectional Operation
Figure 32. Bidirectional Application Schematic
9.2.2.1 Design Requirements
The device is a bidirectional, current-sense amplifier capable of measuring currents through a resistive shunt in
two directions. This bidirectional monitoring is common in applications that include charging and discharging
operations where the current flow-through resistor can change directions.
9.2.2.2 Detailed Design Procedure
The ability to measure this current flowing in both directions is enabled by applying a voltage to the REF pin, as
shown in Figure 32. The voltage applied to REF (V
REF
) sets the output state that corresponds to the zero-input
level state. The output then responds by increasing above V
REF
for positive differential signals (relative to the IN–
pin) and responds by decreasing below V
REF
for negative differential signals. This reference voltage applied to
the REF pin can be set anywhere between 0 V to V+. For bidirectional applications, V
REF
is typically set at mid-
scale for equal signal range in both current directions. In some cases, however, V
REF
is set at a voltage other
than mid-scale when the bidirectional current and corresponding output signal do not need to be symmetrical.
9.2.2.3 Application Curve
An example output response of a bidirectional configuration is shown in Figure 33. With the REF pin connected
to a reference voltage, 2.5 V in this case, the output voltage is biased upwards by this reference level. The
output rises above the reference voltage for positive differential input signals and falls below the reference
voltage for negative differential input signals.
Figure 33. Bidirectional Application Output Response
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