CPWR-AN08 CREE [Cree, Inc], CPWR-AN08 Datasheet - Page 5

• Manufacturer Part Number: CPWR-AN08
• Description: Application Considerations for Silicon Carbide MOSFETs
• Manufacturer: CREE [Cree, Inc]

5
CPWR-AN08, REV -
Application Considerations for SiC MOSFETs -
January 2011
The inductive turn-off losses versus temperature of the
IGBTs are shown in Figure 6. The freewheeling diode
Schottky diode. The turn-off losses of the IGBTs are significantl
strongly increase with temperature. This is due to the tail loss inherent with IGBTs. The NPT IGBT is
strongly increase with temperature. This is due to the tail loss inherent with IGBTs. The NPT IGBT is
strongly increase with temperature. This is due to the tail loss inherent with IGBTs. The NPT IGBT is
significantly better than the TFS IGBT. However, the NPT IGBT conduction losses are much higher than
significantly better than the TFS IGBT. However, the NPT IGBT conduction losses are much higher than
significantly better than the TFS IGBT. However, the NPT IGBT conduction losses are much higher than
the CMF20102D. The TFS IGBT conduction loss is lower than the
the highest of the three.
To achieve fast switching time, the gate drive interconnections need to have minimum parasitics,
To achieve fast switching time, the gate drive interconnections need to have minimum parasitics,
To achieve fast switching time, the gate drive interconnections need to have minimum parasitics,
especially inductance. This requires the gate driver to be located as close as possible to the
especially inductance. This requires the gate driver to be located as close as possible to the
especially inductance. This requires the gate driver to be located as close as possible to the
CMF20120D. Care should be exercised to minimize or eliminate r
be achieved by selecting an appropriate external gate resistor.
be achieved by selecting an appropriate external gate resistor. The silicon IGBT current
certain amount of turn-off snubbing that reduces voltage overshoot and ringing. As with any majority
carrier device, the CMF20120D has no tail, so the amount of drain voltage overshoot and parasitic
ringing is noticeably higher. The higher ringing is of concern because the lower transconductance and
ringing is noticeably higher. The higher ringing is of concern because the lower transconductance and
ringing is noticeably higher. The higher ringing is of concern because the lower transconductance and
low threshold voltage of the CMF20120D
di/dt can couple back to the gate circuit through any common gate/source inductance.
di/dt can couple back to the gate circuit through any common gate/source inductance. A Kelvin
connection for the gate drive is recommended, especially if the gate driver cannot be located clos
CMF20120D. Ferrite beads (nickel-
are helpful to minimize ringing while maintaining fast switching time
are helpful to minimize ringing while maintaining fast switching time. It is also recommended to connect a
high value resistor (10kΩ) between gate and source in order to prevent excessive floating of the gate
during system power up propagation delays.
Like any other power MOSFET, the
that has a 2.5 – 2.7 V built-in voltage, but a
to a Si SJMOSFET. Use of this diode is not recommended due to its high forward drop. An exte
to a Si SJMOSFET. Use of this diode is not recommended due to its high forward drop. An exte
to a Si SJMOSFET. Use of this diode is not recommended due to its high forward drop. An external SiC
Schottky diode is suggested. Cree’s C2D10120A is the recommended device until such time that a
247 single co-packaged part is released.
Conclusions:
Figure 6: Switching loss vs. temperature comparison (V
: Switching loss vs. temperature comparison (V
. Care should be exercised to minimize or eliminate ringing in the gate drive circuit. This can
power MOSFET, the CMF20102D has a body diode. The body diode is a SiC PN
Turn-off Loss
off losses versus temperature of the CMF20120D compared with the TFS and NPT
The TFS IGBT conduction loss is lower than the NPT IGBT, but the switching loss is
ed part is released.
of the CMF20120D reduces gate noise immunity. The high level of drain current
off snubbing that reduces voltage overshoot and ringing. As with any majority
off snubbing that reduces voltage overshoot and ringing. As with any majority
off losses of the IGBTs are significantly higher than the CMF20120D
in voltage, but a substantially lower reverse recovery charge when compared
Figure
Cree’s C2D10120A is the recommended device until such time that a
Cree’s C2D10120A is the recommended device until such time that a TO-
gation delays.
The freewheeling diode used with all devices was a 1.2 kV, 10A SiC
recommended, especially if the gate driver cannot be located clos
recommended, especially if the gate driver cannot be located close to the
en gate and source in order to prevent excessive floating of the gate
en gate and source in order to prevent excessive floating of the gate
has no tail, so the amount of drain voltage overshoot and parasitic
has no tail, so the amount of drain voltage overshoot and parasitic
-zinc recommended) in lieu of or in addition to an external gate resistor
5: Qg*R
zinc recommended) in lieu of or in addition to an external gate resistor
This document is provided for informational purposes only and is not a warranty or a specification.
For product specifications, please see the data sheets available at www.cree.com/power. For warranty
information, please contact Cree Sales at [e-mail].
reduces gate noise immunity. The high level of drain current
substantially lower reverse recovery charge when compared
DS(on)
Application Considerations for SiC MOSFETs
January 2011
Figure of Merit Comparison
6
used with all devices was a 1.2 kV, 10A SiC
DD
= V
inging in the gate drive circuit. This can
CC
It is also recommended to connect a
= 800V, I
compared with the TFS and NPT
Turn-on Loss
, but the switching loss is
D
= I
current tail provides a
CMF20120D and
C
= 20A,
= 20A, R
is a SiC PN diode
A Kelvin
G
= 10)