Comparing Two Stage Ct And Shunt Results - Wolfspeed SPEEDVAL KIT HALF-BRIDGE MOD-MB-HB-0900V-40A User Manual

5.3. COMPARING TWO STAGE CT AND SHUNT RESULTS

Figure 25 shows switching energy measured on a 1200 V, 32 mΩ TO-263-7L MOSFET using the two
methods. The dashed lines are the measurements taken with the double CT method and the
solid lines are the measurements taken with the shunt method (1 Ω resistors). Both methods
yield very similar results
F
Figure 26 shows the measured turn-on waveforms using the two methods. The solid lines are the
measurements taken using the high-resistance shunt and the dashed lines are the measurements
taken using the CT. The blue waveforms are V
through the lower switch. The shunt method has lower insertion inductance into the power loop
than the CT method. The lower insertion inductance results in slightly higher peak currents due
to a slightly increased reverse recovery current (Figure 26). The lower insertion inductance also
results in lower peak V
PRD-06829 REV. 1, December 2022
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.
25: CT S S
IGURE VS HUNT WITCHING
overshoot at turn-off (Figure 27)
DS
SpeedVal Kit™ Half-Bridge User Guide
Solid lines: SMD shunt
Dashed lines: Double CT
E M
NERGY EASUREMENTS
on the lower switch. The red waveforms are I
DS
.
DS
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