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KIT8020CRD8FF1217P-1_UM Rev -
User Manual
Figure 6. Bench test setup of the EVL boards
7.2 Measurements
To maximize the accuracy of the measurements when using the EVL board, some
suggestions are listed below:
Use a highly accurate 0.0131ohm shunt (not provided in the kit) to measure
the low side current waveform as shown below in Figure 7. This can help to
shorten the current sense loop.
Figure 7. Low side current measurement
A BNC probe is connected to measure low-side Vgs waveform, a x100 HV
probe is used to measure low side Vds waveform, and a differential probe is
used to measure high-side Vgs waveform. All probes must be placed as close
as possible to reduce incorrect ringing due to probe placement.
Place the power inductor as close as possible to connect at CON3 to reduce
the switching node loop area, and a 1uF 1200V film capacitors is connected
between the output of inductor and ground connector CON5.
A 12W AC fan is used to cool the heatsink and inductor when measuring
waveforms and taking thermal measurements.
A RC snubber is added on the drain to source to damp high dv/dt ringing on
the switching node and slow the high dv/dt.
A capacitance (1nF) is added between gate to source terminal to shunt the
miller current from drain to gate. This external capacitor will introduce low
impedance path for Cdv/dt from miller capacitance effect and reduce the
ringing on the gate pins.
