AMC1200_15 Datasheet, PDF (17/31 Pages) Texas Instruments – AMC1200/B Fully-Differential Isolation Amplifier

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AMC1200, AMC1200B
SBAS542D – APRIL 2011 – REVISED JULY 2015
Typical Applications (continued)
8.2.1.3 Application Curve
In frequency inverter applications the power switches must be protected in case of an overcurrent condition. To
allow fast powering off of the system, low delay caused by the isolation amplifier is required. Figure 34 shows the
typical full-scale step response of the AMC1200.
500 mV/div
200 mV/div
500 mV/div
Time (2 ms/div)
Figure 34. Typical Step Response of the AMC1200
8.2.2 Isolated Voltage Measurement
The AMC1200 and AMC1200B can also be used for isolated voltage measurement applications, as shown in a
simplified way in Figure 35. In such applications, usually a resistor divider (R₁ and R₂ in Figure 35) is used to
match the relatively small input voltage range of the AMC device. R₂ and the input resistance R_IN of the
AMC1200 also create a resistance divider that results in additional gain error. With the assumption that R₁ and
R_IN have a considerably higher value than R₂, the resulting total gain error can be estimated using Equation 1:
G_ERRTOT
=
G_ERR
+
R₂
R_IN
where
• G_ERR = the gain error of AMC device.
(1)
L1
R₁
R₂
R_IN
L2
Figure 35. Voltage Measurement Application
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