AN2123 STMicroelectronics, AN2123 Datasheet - Page 6

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

Active Miller clamp
The right-hand waveform shows the results of the test in the same conditions but without any additional
capacitors and with the active Miller clamp.
Figure 9. Active Miller clamp: test waveforms related to above schematic
For high-power applications, buffers can be used to increase the output current capability.
shows a schematic principle with external buffers for both the driver output and the clamp function.
Figure 10. Using external buffer to increase the current capability of the driver and clamp outputs
6/15
Vce (100V/div)
Vge (1V/div)
TD351
without Miller clamp
Vgs spike up to 6V!
8
7
6
5
VH
OUT
VL
CLAMP
VH
T1
T2
the Vgs spike is reduced to about 3V
Vce (100V/div)
Miller clamp implemented
Vge (1V/div)
T3
in the same conditions,
Figure 10
AN2123