Teledyne LeCroy Power Analyzer Package - Manual (Page 15)

Operator's Manual
Device Losses Test
This test measures switching device power losses as:
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Mean power—Watts
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Peak power—instantaneous peaks in Watts
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Energy—Watts/seconds in Joules
1. Select the source channels and identify the switching zone .
2. On the Power Analysis tab choose Analysis Type Device and Test Losses.
3. Select the Measurements to calculate. Options are:
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Switching losses – losses from switch between states
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Conduction loss—loss from internal resistance
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Offstate losses—losses during the off state due to instrumentation as noted below
NOTE: Offstate loss in discontinuous power devices is typically zero, and any value is probably
due to residual DC in the current probe. Therefore, this measurement is useful for fine adjust-
ing the current probe. Adjust the Fine DC Offset field of current probe input settings until the
measured Offstate loss value is as close to zero as possible (ideally in Nano Joules).
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Sum—total measured losses over entire switching cycle
4. Choose to display the measured Mean Power, Peak Power, or Energy (Joules).
NOTE: Selecting "Measure Over All Selected Zones" uses all of the zones selected as the region for the
measurements. It will not sum each of the zones individually to give a final result. This is especially
true with displays of Mean Power and Peak Power.
5. If you have selected to calculate Conduction Loss, choose the conduction Calculation Method.
Options are:
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Std. Probe Inputs—Select if you are using only the standard two probes.
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2nd Voltage Probe—Select if you are using a differential amplifier (or 2nd voltage probe) to
measure saturation voltage at the event site. Select the Voltage Source channel where the
amplifier is connected.
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MOSFET Rds(on) Value—Best if your circuit is a MOSFET and you know the Resistance of the
conductor. Enter the value in Ω.
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IGBT Vce(sat) Value—Best if your circuit is an IGBT and you know the Saturation Voltage.
Enter the value in V.
Readouts for the selected measurements appear in a table below the grid area.
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