71M6521 Demo Board User’s Manual
Revision 2.18
© 2005-2009 TERIDIAN Semiconductor Corporation
Page: 57 of 111
Figure 2-5: Calibration Spreadsheet for Fast Calibration
2.2.6 COMPENSATING FOR NON-LINEARITIES
Nonlinearity is most noticeable at low currents, as shown in Figure 2-6, and can result from input noise and
truncation. Nonlinearities can be eliminated using the
QUANT
variable.
Figure 2-6: Non-Linearity Caused by Quantification Noise
The error can be seen as the presence of a virtual constant noise current. While 10mA hardly contribute any
error at currents of 10A and above, the noise becomes dominant at small currents.
The value to be used for
QUANT
can be determined by the following formula:
LSB
IMAX
VMAX
I
V
error
QUANT
⋅
⋅
⋅
−
=
100
Where error = observed error at a given voltage (V) and current (I),
VMAX = voltage scaling factor, as described in section 1.8.2,
IMAX = current scaling factor, as described in section 1.8.2,
0
2
4
6
8
10
12
0.1
1
10
100
I [A]
e
rr
o
r [
%
]
error
