E981.08

Four Channel Sensor Interface PSI5

ADVANCE PRODUCT INFORMATION - JUL 26, 2011

5.1.5 Current Limitation

The circuit provides an over current protection of the RSU interfaces. When the current measured by the current

comparator exceeds typically 100 mA, the voltage will be turned off and an error flag is set.

5.1.6 Over Voltage Protection

The RSU interfaces are voltage protected against 40V. When the output voltage increases to 0.5V above the

nominal voltage, a pull down current is activated ( see 4. 1.12.3) and the channel will be switched off after 512µs

(see table in chapter 5.2.5.5).

5.1.7 Synchronous Parallel Bus Mode (PSI5-P10P-500/3L)

In parallel bus mode application, the sensors are connected in parallel to the bus line like shown in Figure 5.1-4.

It is possible to connect up to three sensor to each channel of the 981.08. The sync cycle time is 500μs with a

data transmission rate of 125kbit/s. The synchronisation pulse for the satellite channel feeds SATFD1-SATFD4

can be activated by MCU via the SAT_SYNC pin of the device. When a rising edge is detected, the 981.08

outputs sync pulses on channels SATFD1-SATFD4 in sequence to reduce the average current inrush to the

satellites as shown in Figure 5.1-5. The satellites can transmit from one to three messages per sync pulse

received. The Figure 5.1-6 shows the timing for one channel.

Figure 5.1-4 Synchronous Parallel Bus Mode Configuration (PSI5-P10P-500/3L)

In order to avoid EMC problems, the synchronisations pulses of the satellites will not be performed at the same

ELMOS Semiconductor AG

Data Sheet 21 / 46

QM-No.: 25DS0051E.00

This document contains information on a new product. ELMOS Semiconductor AG reserves the right to change specifications and information herein without notice.

V

SAT_OUT_OP

t

GND

S2

S1

S3

MCU

981.08

SPI

V

SAT_OUT_X

S3

V

SAT_OUT_SYNC

V

SAT_OUT_X

T

SYNC

S1

S2

SAT_SYNC