ETAS ES1392.1, User Manual

Page: 14 / 36

Hardware 14
2.6 Battery Voltage at the "CTRL" Connector
-UBatt and +UBatt are available at the "CTRL" connector. Both voltages are
protected (see Section 2.12.2 on page 17).
2.7 MRC Signal
To keep the wiring harnesses as simple as possible, the main relay control sig-
nal (MRC signal) is routed from the "BATTERY NODES" connector to the
"CTRL" connector. The signal is protected (see section 2.12.3 on page 17).
It is not used for any other purpose on the ES1392.1 High Current Switch
Board.
2.8 Reverse-Connect Protection of the Battery Node Switches
The switches to +UBatt are protected against voltages at the battery node
which are above the battery voltage.
This may occur, for example, in a system with two battery voltages (12 V/42 V)
if a short occurs between battery nodes of the two different battery voltages.
Fig. 2-2 Reverse-Connect Protection
Without this protection, the MOS-FET switches would still conduct current
with this kind of error without being able to be switched off. This could result
in the lower battery voltage being increased and connected consumers being
destroyed; alternatively the switch itself could be destroyed because of an
overcurrent.
The protective circuit acts as a diode (as shown in Fig. 2-2 on page 14) without
actually causing the voltage drop of a diode. The low resistance values of the
switches (including reverse-connect protection) listed in the chapter "Technical
Data" on page 29 illustrate this.
ES1392
ES1392
+UBatt_A = +12 V
+UBatt_B = +42 V
Battery Node
Battery Node