Datasheet

R
2
R
1
V
SIG
OPA454
V+
V-
R
4
R
5
R
2
OPA454
V-
V+
R
6
R
7
OPA454
V+
V-
V
OUT
V
OUT 2 1 2 1
=(1+2R /R )(V V )-
V
1
V
2
V
CM
A
1
A
2
A
3
(1)
R
2
R
1
OPA454
V+
V-
R
4
R
5
R
SHUNT
R
2
OPA454
V-
V+
R
6
R
7
OPA454
V+
V-
V
OUT
V
SUPPLY
Plus
Minus
or
Load
V =(1+2R /R
OUT 2 1 2 1
)(V V )-
V
1
V
2
A
1
(1)
A
2
(1)
A
3
(2)
OPA454
www.ti.com ....................................................................................................................................... SBOS391A – DECEMBER 2007 – REVISED DECEMBER 2008
Figure 74 uses three OPA454s to create a
high-voltage instrumentation amplifier. V
CM
± V
SIG
must be between (V – ) + 2.5V and (V+) – 2.5V. The
maximum supply voltage equals ± 50V or 100V total.
Figure 75 uses three OPA454s to measure current in
a high-side shunt application. V
SUPPLY
must be
greater than V
CM
. V
CM
must be between (V – ) + 2.5V
and (V+) – 2.5V. Adhering to these restrictions keeps
V
1
and V
2
within the voltage range required for linear
operation of the OPA454. For example, if V+ = 50V
and V – = 50V, then V
1
= +47.5V (maximum) and
V
2
= – 47.5V (minimum). The maximum supply
voltage equals ± 50V, or 100V total.
See Figure 76 and Figure 79 for example circuits that
use the OPA454 in an output voltage boost
configurations in three and six op amp output stages,
respectively.
(1) The linear input range is limited by the output swing on the
input amplifiers, A
1
and A
2
.
Figure 74. High-Voltage Instrumentation Amplifier
(1) To increase the linear input voltage range, configure A
1
and A
2
as unity-gain followers.
(2) The linear input range is limited by the output swing on the input amplifiers, A
1
and A
2
.
Figure 75. High-Voltage Instrumentation Amplifier for Measuring High-Side Shunt
Copyright © 2007 – 2008, Texas Instruments Incorporated Submit Documentation Feedback 25
Product Folder Link(s): OPA454