
© by SEMIKRON / 2019-07-23 / Technical Explanation / SKYPER
®
42 LJ R
PROMGT.1026/ Rev.7/ Template Technical Explanation
Page 17/35
4.8
Error mode selection | Primary side
The behaviour of the SKYPER
42 LJ R driver core on an error event can be selected via the configuration
pin CFG_ERR.
Connecting the CFG_ERR pin to the PWR_GND pin forces the driver to set its outputs to off-state
immediately when an error is detected. As long as the driver has not been reset the error event is reported
at the corresponding terminal and the driver’s outputs are kept locked. Whereby, depending on whether an
error is detected on the primary or on the secondary side the driver switches off the connected
semiconductors via the standard turn-off or the soft-off path. If an error occurs on the primary side the
driver will activate the standard turn-off paths of both channels. If an error occurs on the secondary side,
the driver will activate the soft-off path of the affected secondary side. The semiconductor connected to the
other secondary side will be switched off with the standard turn-off procedure.
If the CFG_ERR pin is connected to the PWR_VS pin, the driver locks its outputs in case of any error event
and, hence, reports the error event at the terminal nERR_OUT, but the driver will not be set the outputs to
off-state, immediately. The outputs will be set to off-state, when the driver has received a turn-off
command at the corresponding signal input TOP_OFF/BOT_OFF. Depending on whether an error is detected
on the primary or secondary side the driver activates the standard turn-off or the soft-off path, as
described above.
Further information related to the primary and secondary error events, as well as on the error reset
conditions can be found in chapter 5.1.
Parameter
Min
Typ
Max
Threshold high
-
-
11 V
Threshold low
7.5 V
-
-
4.9
External error input | Secondary side
Each secondary side of the driver provides an error input (nERR_IN_TOP/nERR_IN_BOT) to handle an
external error event. These inputs are low active. Pulling one input to low-level forces the driver into error
state. The behaviour of the driver in case of an external error event depends on the configuration done via
the configuration pin CFG_ERR, as described in chapter 4.8.
The external error input is typically used to monitor temperature, current or voltage of modules, phase legs
or systems. The error input of the secondary TOP side can be disabled by connecting it to the
PWR_VS_P_TOP pin the error input of the secondary BOT side by connecting it to the PWR_VS_P_BOT pin.
Figure 13 shows a recommended circuitry of an over temperature detection by NTC resistor monitoring. If
the voltage at the positive input of the comparator falls below the voltage level at the comparator’s
negative input the comparator will set the nERR_IN input to low-level and will generate an external error
event. Assuming that resistor R
3
and R
4
have the same value the comparator’s trip level is reached when
the value of the NTC falls below the value of R
CGF(temp)
. Please note that the negative supply pin of the
comparator is connected to PWR_VS_N which has to be taken into account, in case the NTC thermistor is
monitored by an external application circuit as well.