Active Miller clamp

AN2123

6/15

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.

For high-power applications, buffers can be used to increase the output current capability. Figure 10

shows a schematic principle with external buffers for both the driver output and the clamp function.

Figure 9. Active Miller clamp: test waveforms related to above schematic

Figure 10. Using external buffer to increase the current capability of the driver and clamp outputs

Vce (100V/div)

Vge (1V/div)

Vce (100V/div)

Vge (1V/div)

without Miller clamp

Vgs spike up to 6V!

Miller clamp implemented

in the same conditions,

the Vgs spike is reduced to about 3V

7

6

OUT

VL

8

VH

5

CLAMP

TD351

VH

T1

T2

T3