AN2123 STMicroelectronics, AN2123 Datasheet - Page 7

• Manufacturer Part Number: AN2123
• Description: TD351 Advanced IGBT Driver Principles of operation and application
• Manufacturer: STMicroelectronics

AN2123
For very high-power applications, the active clamp function cannot replace the negative gate drive, due to
the effect of the parasitic inductance of the active clamp path. In these cases, the application can benefit
from the CLAMP output as an secondary gate discharge path (see
Figure 11. High power application: negative gate drive and secondary gate discharge path
With the above schematic, when the gate voltage goes close to VL+2 V (i.e. the IGBT is already driven
off), the CLAMP pin is activated. Again, the benefit is to lower the resistance between gate and emitter
when the IGBT is in the OFF state without affecting the IGBT turn-off characteristics.
Tip:
-10V
16V
What should one do with the CLAMP pin when not used in application?
Connect CLAMP to VL.
VH
1
2
3
4
IN
VREF
CD
LVOFF
TD351
CLAMP
OUT
VH
VL
8
7
6
5
Figure 11
below).
T1
T2
Active Miller clamp
T3
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