SEMIKRON SKiiP 4 - Overcurrent and Short Circuit Protection

© by SEMIKRON / 2017-09-07 / Technical Explanation / SKiiP
®
4 Page 37/73
If the overlap time is longer than 3µs both IGBT’s will be switched off and the HALT-signal is activated to
indicate an error condition. This is shown in the Figure 5.22.
Please note: Before continuing with the switching operation both switching input signals HB_TOP and
HB_BOT must be set to LOW.
Figure 5.22: Timing diagram for the HB_TOP/HB_BOT overlapping error processing (t>3µs)
5.3.7.5 Over current Protection (OCP)
The over current protection (OCP) is a protection that is based on the integrated current sensor
measurement and, hence, it protects based on a load imposed current. The application shall be selected to
ensure that the peak load current stays safely below the over current protection level. For further details
please refer to the corresponding datasheet of the SKiiP 4.
5.3.7.6 Short Circuit Protection (SCP)
The short circuit protection (SCP) circuit is protecting against short circuit situations by initiating a safe
turn-off of the IGBTs. The protection circuit monitors the collector-emitter voltage VCE of the IGBT during
the on-state of the device and derives a suitable threshold from this value to turn-off the IGBT in case of a
short circuit. Once the threshold level is exceeded the blanking time delay starts and ignores the high
current for this period to increase the noise immunity of this circuit. The activated SCP will result in ERROR
state and an error signal will be issued correspondingly.
The threshold voltage (V
CEstat
) and the blanking time (t
bl
) are listed in the SKiiP
®
4 data sheet.