PEB3265 Infineon Technologies Corporation, PEB3265 Datasheet - Page 124

• Manufacturer Part Number: PEB3265
• Description: (PEB326x / PEB426x) Dual Channel Slicofi-2 / Slic Duslic
• Manufacturer: Infineon Technologies Corporation

Preliminary
Assumption:
• Loop resistance R
• Ring offset RO2 = 60 V (CRAM coefficient set accordingly). Ring offset RO2 is
• Select Active High (ACTH) mode by setting the line mode command CIDD/CIOP bits
Sequence to determine the loop resistance R
• Select DC levelmeter by setting bits LM-SEL[3:0] in register LMCR2 to 0101.
• Read levelmeter result registers LMRES1, LMRES2.
• Switch into reverse polarity mode by setting bit REVPOL in register BCR1 to 1.
• Read levelmeter result registers LMRES1, LMRES2.
If the loop resistor connected between Ring and Tip is 1000
the expected current will be 30 mA, because the actual voltage applied to Ring and Tip
is 30 V. Considering the fact, that the current measurement in reverse polarity mode will
also become inverted, the read results have to be added. The sum of both levelmeter
results (normal- and reverse polarity) should therefore be 60 mA current difference.
Figure 50
Figure 50
The following calculation shows the elimination of the voltage and current offset caused
by output stage and current sensor. This differential measurement method both
Data Sheet
selected by setting bits RNG-OFFSET[1:0] in register LMCR3 to 10.
The exact value for the Ring offset voltage can be determined from the *.res result file
generated by DuSLICOS during the calculation of the appropriate coefficients.
M2, M1, M0 to 010. In ACTH mode half of the ring offset voltage RO2 of e.g. 60 V will
be present and applied to Ring and Tip.
shows the differential measurement method and the elimination of the offsets.
Differential Resistance Measurement
Reverse Polarity
loop
= 1000
Offsets
U
offset
I
; R
TIP/RING
I
offset
loop
= R
expected values
124
LINE
dU
loop
Normal Polarity
+ 2*R
differentially:
PROT
dI
measured
values
+ 2*R
(R
Operational Description
V
duslic_0008_differentially.emf
LINE
TIP/RING
STAB
+ R
PROT
2000-07-14
+ R
DuSLIC
STAB
),