SCALE™-2 1SC0450E2B0
Preliminary Description & Application Manual
www.power.com/igbt-driver
Page 17
T
CSHD
(refer to the chapter “Input for adjusting the turn-off delay in fault condition (CSHD)”). Note that
failure to respect the minimum hold time may lead to incorrect driver behavior.
The recommended circuitry for using the OUT terminal as an external fault input is shown in Fig. 7
(transistor connected to “External fault input”). The external effective capacitance (components and board
parasitic capacitances referred to VISO, VE and COM) must not exceed the value given in the driver data
sheet /3/ to avoid unexpected driver fault triggering in normal operation.
In normal operation, each edge of the control signal IN is acknowledged by the driver with a short pulse
(OUT is switched to low for a short period of time; refer to driver data sheet /3/ for details). As this can be
observed by the host controller, this method allows simple and continuous monitoring of all drivers and
fiber-optic links of the system (Fig. 8).
Fig. 8
Driver behavior and status feedback in normal operation (Refer to Fig. 7 for the recommended
command interface)
The driver can detect three different secondary-side faults:
V
CE
-desaturation detection in case of a short-circuit; refer to chapter “Collector sense (VCE)”
Secondary-side supply under-voltage; refer to chapter “Power-supply monitoring”
External fault (as described above)
The signal truth table of Table 6 shows the behavior of the OUT signal in normal operation as well as in a
fault condition. Only the pulse length of OUT differs between normal operation (acknowledge) and the
different fault conditions.