Type SCM, Single/Dual IGBT Snubber Capacitor Modules
Applications
Use style SCM as a discharge restrictive de-cou-
pling to protect dual IGBT modules from over volt-
age, Figure 1. Style SCM may also be used as an
“N”or “P”type snubber component for a clamp
snubber where single IGBT modules are used,
Figure 2.
Highlights
• Mount directly to the IGBT module
• Low inductance
• Low Loss
• Hyperfast diodes integrated into package
•
1 or 2 wire taps for connecting exter nal resistor
•
Flame resistant case and epoxy, meets UL 94VO
•
Other ter minal pitches and capacitance values
available.
Dischar ge Restrictive De-coupling
The circuit in Figure 1 operates on the same prin-
ciples as the de-coupling capacitor, but only dur-
ing tur n-off switching. As the IGBT tur ns off, ener-
gy trapped in the loop inductance is transferred to
the capacitor. The diode blocks oscillations from
occurring and excess charge on the capacitor is
discharged through the exter nal resistor.
RCD Clamp
The function of this snubber is similar to a clamp,
Figure 2. At turn-off, the snubber diode is forward
biased and the snubber is activated. The energy
trapped in the stray inductance is absorbed by the
snubber capacitor.During turn-on the snub ber caps
that were fully charged to bus voltage have a dis-
charge path through the forward biased free-wheel
diode, the IGBT, and the snubber resistors. This
reduces the reverse recover y voltage transient.