SCALE™-2 1SC0450E2B0
Preliminary Description & Application Manual
www.power.com/igbt-driver
Page 11
DC/DC output (VISO), emitter (VE) and COM terminals
The driver is equipped with blocking capacitors on the secondary side of the DC/DC converter (for values
refer to the data sheet /3/). IGBTs with a gate charge of up to 4.7µC can be driven without additional
external capacitors (C
1
and C
2
in Fig. 6 are not assembled). Eq. 1 and Eq. 2 give the recommended
capacitance value of C
1
and C
2
for gate charges above this value:
C
1
[μF]≥(Q
G
[μC]-4.7)∙4
C
1
in Fig. 6; 4µF blocking capacitance
per 1µC gate charge between VISO
and VE
Eq. 1
C
2
=
C
1
2
C
2
in in Fig. 6; blocking capacitance
between VE and COM, half of the C
1
value
Eq. 2
Example: IGBT modules with a gate charge of up to 42µC can be driven with external capacitances of
149.2µF between the VISO and VE terminals and 74.6µF between the VE and COM terminals (C
1
and C
2
of Fig. 6).
If the capacitance C
1
(or C
2
) exceeds 200µF (or 100µF), please contact the Power Integrations support
service.
The blocking capacitors must be connected as close as possible to the driver’s terminal pins with minimum
inductance. Ceramic capacitors with a dielectric strength ≥25V are recommended.
No static load must be applied between VISO and VE, or between VE and COM. A static load can be applied
between VISO and COM if necessary.
Reference terminal (REF)
The reference terminal REF allows the threshold to be set for short-circuit protection with a resistor placed
between REF and VE (R
th
of Fig. 6). An internal resistor of 68kΩ sets the default threshold value to 10.2V. It
can be reduced with the use of an external resistor R
th
according to the following Eq. 3:
R
th
[
kΩ
]
=
68∙V
th
[V]
10.2-V
th
[V]
with V
th
<10.2V
Eq. 3
It is recommended to keep the reference voltage at its maximum default value of 10.2V (without using an
external resistor R
th
).
Collector sense (VCE)
The collector sense must be connected to the IGBT collector with the circuit shown in Fig. 6 in order to
detect a short circuit condition.
General information and recommendations:
The overall value R
tot
of the resistors R
vcei
is calculated with equation Eq. 4:
R
tot
=
∑
R
vcei
=
n
i=1
R
vce1
+...+R
vcen
Eq. 4
It is recommended to dimension the overall value R
tot
of the resistors in order for a current I
Vce
of
about 0.6…0.8mA to flow through them at the maximum DC-link voltage (Eq. 5). This current must
not exceed 0.8mA. It is recommended to use series-connected resistors; the minimum creepage and
clearance distances required for the application must be considered and the maximum voltage,