LOG114EVM Datasheet, PDF (5/21 Pages) Texas Instruments – LOG114EVM User Guide

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LOG114EVM
The high-current linearity correction circuit (refer to Figure 4) creates an error signal that is proportional to
input current I₁ by using R2, R3 and R4, and amplifier A5. Resistor R1 is used to properly level-shift the
resulting output signal. The signal at the output from amplifier A5 is then coupled to the input of amplifier
A4 in a manner that subtracts the error signal from the output of the EVM, V_OUT.
VBIAS
(from the Level Shifter)
R2
I_PHOTO
3W
A1
V+
VREF
A4
VERR
A3
A2
A5
V-
R3
1 kW
Figure 4. High-Current Linearity Correction Circuit
R4
5 kW
R2
21.5 kW
SBOU110 – September 2011
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LOG114EVM User Guide
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