Power Supply Testing Example - Keysight Technologies N3301A Programming Manual

Power Supply Testing Example

A typical use for electronic loads when testing power supplies involves power supply burn-in. One of the
problems associated with burn-in is what to do if the power supply fails before the test is over. One
solution involves continuously monitoring the supply and removing the load if the supply fails during the
test (see figure 3-7).
In this example, the electronic load is used to burn-in a power supply at its rated output current. Because
the electronic load is operating in CC mode, if the power supply's output current drops below the rated
output current during the test, the UNR (unregulated) condition will be set on the electronic load. This can
be used to indicate that a failure has occurred on the power supply. If the unregulated condition persists
for a specified time, the inputs of the electronic load are turned off.
The purpose of this example is not to illustrate power supply testing, but to explain how to program and
use the status registers on the electronic load. The part of the program that runs the test simply monitors
the supply at the rated output current for one hour and stops the test. You can replace this portion of the
program with your own routine to test the power supply. Although SRQ (service request) is enabled to
interrupt only on the UNR bit in this example, you can modify the program to interrupt on other conditions.
l0 ! Power Supply Test Example Program
20 !
30 Current=10
40 Burn_in_time=36000
50 !
60 ON INTR 7 GOSUB Srq_service
70 ENABLE INTR 7;2
80 !
"CHAN 1;:
90 OUTPUT 705;
l00 OUTPUT 705;"*SRE 4"
110 OUTPUT 705;"STAT:CSUM:ENAB 2"
120 OUTPUT 705;"STAT:CHAN:ENAB l024"
130 OUTPUT 705;"FUNCTION CURRENT"
140 OUTPUT 705;"CURRENT:LEVEL";Current
l50 OUTPUT 705;"INPUT ON"
160 !
170 PRINT "Burn-in test started at ";TIME$(TIMEDATE)
180 !
190 FOR I=1 TO Burn_in_time
200 WAIT .1
210 NEXT I
220 !
Figure 3-7. Typical Burn-In Test
Power Supply Test Example Program
INPUT OFF"
Programming Examples - 3
! Load current in amperes
! One hour burn-in time
! Set up interrupt linkage
! Enable interrupts for SRQs
! Selects Chan 1; Disables input
! Enable SRQ (SRQ enable for CSUM)
! Enable Chan 1 (channel summary)
! Enable UNR bit (channel status)
! Sets CC mode
! Sets the CC level
! Enables the input
! Loop on wait You can write your
! own power supply test routine and
! insert it in this section
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