Sifos Technologies PowerSync PSA100, Technical Reference Manual, Page: 32 / 147

PowerSync Analyzer Reference Manual
March 9, 2010 Sifos Technologies page 32
waveform transition occurs assuming Trigger 1 (
see Section 3.1.5
) is armed. Similarly,
Event
trigger mode means that
Initiate Transient
will configure the load transient and the next Event (or External) Trigger will then cause the load
transient to start. The
Initiate Transient
button will annunciate via red text that a change has been selected and must be
applied.
The
Suppress Foldback
control is disabled with the PSA-1200 and is reserved for use with future PSA hardware.
The
Copy Settings
control will open the Port Replication menu and copy all Static and Transient Load configuration
settings to the selected test ports.
3.1.7. PD Power-Up Emulation with Load Configuration
The PowerSync Analyzer performs 802.3af PD Power-Up Emulation utilizing both the static and transient load
resources along with the waveform trigger. This has two advantages from a testing point of view:
•
Load transients can be utilized to simulate in-rush load currents.
•
802.3af classification and power-up can be performed in the presence of independent legacy detection pulses
(
see Section 2.2.4
).
A startup classification emulation is performed by setting the static load current to the desired value for a classification
signature current and then configuring the load transient to trigger on power-up (e.g. 35 volts, rising edge) and provide a
two-step current load starting with an inrush current for a small time interval followed by a steady state current
appropriate to the PD classification emulated
(see Figure 3.9)
.
The
Emulate PD
sub-menu offers a simple means to
construct all of the configurations necessary for a PD
connection emulation. Users may select the class
signature they choose to emulate (
Class 0
,
Class 1
,
Class 2
,
Class 3
, or
Class 4
). Each PD Class offers
a default steady state power load. Users may
override this with a user-entered power target (watts)
that will take effect after the PSE port powers up.
The
ARM PD Emul.
button loads the appropriate
values of classification current into the static current
configuration and similarly configures the load
current transient to create an inrush and steady state
current that is appropriate for the PD being emulated.
It performs necessary trigger configuration and
transient initiation (equivalent to pressing
Initiate
Transient
), and it arms the internal trigger all in a single button press. As soon as the test port is connected and a
successful detection occurs, the process of classification emulation will be fully armed and ready to emulate PD startup
behaviors.
The classification signature settings utilized for each PD class are:
•
Class 0:
2.5 mA
•
Class 1:
10.5 mA
•
Class 2:
18.5 mA
•
Class 3:
28 mA
•
Class 4:
40 mA
If a non-default
PD Target Power
is entered prior to selecting
ARM PD Emul
., PSA Interactive will attempt to measure the
actual PSE port voltage on the presently selected
slot,port so that a steady state load current can be
computed and loaded into the
Transient Step 2
value. In this case, the user will be alerted that
PSA Interactive needs to make the voltage
measurement meaning that the Port settings for
Figure 3.9
PD Startup Emulation with a PSA Test Port
802.3 PD Emulation
20
50
Detection
Vol
ts
D
C
Static Load
Appears
10
Classification
Power-Up
Internal Trigger Level
Transient
Step 1
Transient
Step 2
In-Rush
Load Current
Steady State
Load Current
802.3 PD Emulation
20
50
Detection
Vol
ts
D
C
Static Load
Appears
10
Classification
Power-Up
Internal Trigger Level
Transient
Step 1
Transient
Step 2
In-Rush
Load Current
Steady State
Load Current
Figure 3.10
PD Startup Emulation – PD Class 2
Seeking 6.4 Watts of Power
Figure 3.10
PD Startup Emulation for
a 6.4Watt, Class 2 PD.