E981.07 Datasheet, PDF (19/46 Pages) ELMOS Semiconductor AG – Two independent operating channels

Two Channel Sensor Interface PSI5
ADVANCE PRODUCT INFORMATION JUL 26, 2011
5.1.3 Current Comparator
E981.07
The satellite sensors modulate the current through the RSU line, in order to realise a Manchester coded data
transmission.
The “low” level of the current is represented by the quiescent current ISAT_Q_range of the sensors, while a “high”
level is created by switching on a current sink to the line, which increases the current to ISAT_OP (see Figure 5.1-
2).
A current transition in the middle of the bit time represents the logical value of the transferred data. A “high
current-low current” transition stand for a logical '1', a “low current-high current” transition for a logical '0'.
This current can be detected by measuring the voltage drop via an internal shunt. The current threshold is
automatically adapted to the quiescent current of the sensors in each RSU line.
I
SAT
I
SAT_OP
I
SAT_TH
BIT1
“0”
BIT2
“1”
BIT3
“1”
ΔI
I
SAT_Q_range
T
Bit
t
Figure 5.1-2 Current During Operation
ELMOS Semiconductor AG
Data Sheet 19 / 45
QM-No.: 25DS0050E.00
This document contains information on a new product. ELMOS Semiconductor AG reserves the right to change specifications and information herein without notice.