User Guide
16 of 46
Rev. 1.0
2022-03-09
48V Battery Switch Reference Design
R 48V BATT Switch10
System and functional description
The fast overcurrent detection output OCD of the current sensor can be connected to the SAFESTATEN pin of
the gate driver in order to provide a second switch off path for overcurrent events. To enable this functionality
the solder jumper on the adaptor board has to be bridged as shown in Figure 15.
Figure 15
Solder jumper on adaptor board to connect OCD1 to SAFESTATEN
Note:
For calibration of the current sensor the solder jumper needs to be open, because the OCD1 may
be pulled low during calibration, which would cause an unintended switch off via the SAFESTATEN
signal.
2.2.7
Freewheeling
When the MOSFETs are switched off, the sudden drop in current flow will induce a large voltage in the output
inductance which pulls the output (LD+) below ground potential (LD-). To protect the switch MOSFETs against
overvoltage a freewheeling MOSFET (Q13) is placed between LD+ and LD-.
Figure 16
Freewheeling MOSFET
Due to its intrinsic body diode, the MOSFET allows freewheeling without beeing switched on. Nevertheless, the
gate signal is routed to the interface connector to provide the option to add an active control circuit.
