Teledyne LeCroy Power Analyzer Package - Manual (Page 6)

Power Analysis Software
Deskew Signal Source
To assist with eliminating propagation delay differences among voltage and current probes used for
device testing, the DCS015 dekew calibrated source is recommended. This source has time-coincident
voltage and current signals used to adjust deskew values within the oscilloscope channel controls and
Power Analyzer software.
Method of Operation
The general process for using the software to conduct power analysis is:
1. Set up DUT test circuit, consider isolation requirements, attach probes, and setup oscilloscope trig-
ger
This includes all physical circuit setup and oscilloscope setup for timebase and acquisition triggers. We
show recommended connections, probing points, and trigger events for each type of analysis in the pre-
liminary setup topics.
2. Set up voltage and current source channels
Make all Vertical settings on the channels to be used for a test and perform all necessary preliminary
adjustments to ensure measurement accuracy.
Because signals associated with power devices are relatively fast, it is important to determine whether
the propagation time for the current and voltage signal paths are the same. Signal delay characteristics of
the voltage and current probes, as well as the distance the signals must travel from the probe tips to the
input of the oscilloscope, can cause time-coincident points on the voltage and current signals to be
sampled by the oscilloscope at different times. Even a small time difference can cause significant errors to
occur in the measurements. Therefore, we recommend performing a preliminary deskew procedure and
repeating it whenever you change to the physical characteristics of the probes or the bandwidth/filter set-
tings of the input channels.
Likewise, Fine DC Adjust voltage channels to remove any residual charge that may be in the probes.
3. Select analysis type, tests to be performed, and measurements to be displayed
This step comprises most of the work you will do in the Power Analyzer Software. Once the source chan-
nels are set up, various tests can be performed on the same inputs. The software automatically cal-
culates your selected power measurements and displays them on screen, with test-appropriate trace
annotations and overlays to help you see significant portions of the input waveforms.
Power Analysis Software Dialogs
The Power Analysis Software presents a series of dialogs for setting up measurements specific to testing
switched-mode power supplies ad devices. Generally, the order of the tabs presents the order in which
you proceed to use the software, working from left to right.
Power Analysis Dialog
The first tab is the Power Analysis dialog. This is the main set of controls where you select the Voltage
and Current Source input channels, the Analysis Type, and the specific Tests to run.
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