VICOR PI33 EVAL1 Series, User Manual

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UG:309 Page 6
The following information is intended to provide the user with a description of the various “soft”
buttons and user menus available in the Buck GUI.
The “File” menu provides “Exit” as the only option available when left clicking on it. If the user chooses
“Exit”, a dialog box will pop up to allow the user to confirm their selection. If “Yes” is chosen, the GUI
will close and Buck GUI will terminate. If “No” is selected, the user will be returned to the main program
without exiting the GUI.
The “Help” menu provides the current revision of the Buck GUI. There is no interactive user help or
search utility provided at this time, although there may be expanded help facilities in the future build
releases of the software.
The “Address” menu will produce a drop down dialog box for the user to be able to select the
decimal address of the PI33xx‑xx determined by the ADR0 and ADR1 decodes in Table 1. For example,
if the PI33xx‑xx unit has both ADR0 and ADR1 floating or not connected, the child address will be
76 decimal or 4C. Configuring ADRO and ADR1 allow for eight addressable locations from 72d to
79d or 48h to 4Fh.
The “FAULT” button allows the user to read the PI33xx‑xx fault telemetry information. The fault register
is 8 bits wide with the most significant bit set to logic 0 always. The gray indicator panels for each fault
on the Buck GUI display will illuminate bright red to indicate the decoded fault(s) for the user, so they
don’t have to refer to Table 4 for the decoded value. In addition, the binary value of the register will be
displayed in the “FAULT” window.
The PI33xx‑xx fault logging only occurs when the controller is in normal operation mode. After a fault
is detected and assessed, the fault is latched into the register so long as the controller V
CC
is active and
above the minimum threshold. The controller will take the appropriate action to protect the PI33xx‑xx
and system based on the type of fault. If for example, the input voltage is high enough to power the
controller but below the minimum under voltage lock out threshold, the controller will prevent the unit
from enabling and remain in a low‑power state. Since it has not entered operate mode, the UVLO fault
will not be logged. If the input voltage is higher than the undervoltage lockout threshold but drops to
zero, the fault will remain latched as long as there is V
CC
to the controller. Once the controller V
CC
dips
below the minimum value, the fault data will not remain valid. The fault register will be cleared upon
power on reset. If V
CC
remains after a logged fault, the fault register must be cleared in order to log any
new events. A description of the logged faults is as follows:
FLT[0] – VCC_UV: if this bit is set, it indicates that the internal power supply for the PI33xx‑xx has gone
into undervoltage.
FLT[1] – UVLO: if this bit is set, the indication is that the input voltage decreased below the
undervoltage lock outthreshold (UVLO) at some point while the unit was in operate mode. The UVLO
threshold is defined as the minimum value required for a PI33xx‑xx to be able to meet all specified
parameters of operation.
FLT[2] – OVLO: if set indicates that the input voltage exceeded the over voltage lockout threshold
(OVLO) at some point while the unit was in operate mode. The OVLO threshold is that value where the
input voltage is too high for a PI33xx‑xx to be able to meet all specified parameters of operation.
FLT[3] – VOUT_HI: if this bit is set, it indicates that the error amplifier input was higher than it should
be for the programmed output voltage during operate mode, indicating that the output voltage
may be too high.
FLT[4] – SLOW_IL: if this bit is set, it indicates that the error amplifier output was at the positive rail for
more than 1 ms during operate mode. This means that the load current demand was higher than the
maximum output current available from the PI33xx‑xx.
FLT[5] – FAST_IL: if this bit is set, it indicates that the peak current in the output inductor was higher
than the maximum peak current allowed during operate mode. It is an indicator of output short circuit
or inductor failure.
FLT[6] – OTP: if this bit is set, it indicates that the PI33xx‑xx internal temperature exceeded the
maximum temperature for safe operation during operate mode and that the PI33xx‑xx shut down to
prevent damage.
Table 4
Fault register assignments
FLT[7] FLT[6] FLT[5] FLT[4] FLT[3] FLT[2] FLT[1] FLT[0]
0 OTP FAST_IL SLOW_IL VOUT_HI OVLO UVLO VCC_UV