
© by SEMIKRON / 2019-07-23 / Technical Explanation / SKYPER
®
42 LJ R
PROMGT.1026/ Rev.7/ Template Technical Explanation
Page 23/35
5.2
Dead time and Interlock
The internal dead time generation of the SKYPER
42 LJ R as well as the interlock feature can be selected
via the configuration pin CFG_IDT. The following modes could be selected:
•
Interlock enabled, 2µs dead time
•
Interlock disabled, no dead time
Interlock enabled
To enable the interlock feature the CFG_IDT pin has to be connected to PWR_GND. The interlock feature is
typically used when driving power semiconductor modules in half bridge configuration. The feature
prevents the two outputs from being activated simultaneously which would lead to shorted DC-link (bridge
shoot through). The interlock feature allows controlling a power semiconductor module with one switching
signal and its inverted signal at the driver’s inputs TOP_IN/BOT_IN.
The internal timer which generates the dead time, starts with each turn-off command at the inputs
TOP_IN/BOT_IN. As long as the dead time of 2µs has not been elapsed the driver locks the other output. If
the pulse pattern generated by the customer’s controller also includes a dead time, the resulting system
dead time will be determined by either the controller or the driver, depending on whichever dead time is
longer. The SKYPER
42 LJ R does not add the internal generated dead time to the dead time of the pulse
pattern of the controller.
Interlock disabled
When the interlock feature is disabled by connecting the configuration pin CFG_IDT to the PWR_VS pin
both outputs of the driver can be switched independently from each other. Both output channels could be
switched-on at the same time.
Table 8 shows the resulting system dead time depending on the configuration via the CFG_IDT pin.
Table 8: SKYPER
®
42 LJ R | Resulting system dead time
CFG_IDT
Interlock
Controller dead time
SKYPER dead time Resulting dead time
LOW
Enabled
No dead time
2µs
2µs
LOW
Enabled
< 2µs
2µs
2µs
LOW
Enabled
> 2µs
2µs
>2µs
HIGH
Disabled
2µs
No dead time
2µs
HIGH
Disabled
No dead time
No dead time
No dead time
Important Note
When the interlock function is disabled a bridge shoot through has to be prevented by the customer’s
control unit.