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DENOTES CONSTANT VOLTAGE FEEDBACK PATH
DENOTES CONSTANT CURRENT FEEDBACK PATH
Figure 4-1.
Overall Block Diagram
4-1
OVERALL BLOCK DIAGRAM DISCUSSION
4-2
The major circuits of the power supply are
shown on the overall block diagram, Figure 4-1.
The ac line voltage is first applied to the power
transformer, after which it is rectified and filtered.
The resulting raw dc is then fed to the series reg¬
ulator, which varies its conduction to obtain the
proper output voltage or current.
The series regu¬
lator includes a current limit circuit that automati¬
cally places the supply in the low voltage range
depending'upon the output voltage and current set¬
tings that have been selected and the output cur¬
rent of the supply.
For instance, if the supply is
set for high voltage output and high current output
and the load attempts to draw current above the
high voltage range current specification (that is,
above 1A for the 6104A/6114A supplies or above
0.4A fox the 6105A/6115A supplies), the series
regulator limits the output current and then de¬
creases the output voltage to the low range.
When
in the low range, the output current is then allowed
to reach the CURRENT setting up to the maximum
rating of the supply.
Notice, further, that dual
rectifier-filter circuits are employed to provide a
low value of raw dc voltage to the series regulator
in order to minimize internal power consumption
during low voltage (high current) operation.
Each
rectifier-filter furnishes most of the raw dc voltage
to the regulator during one of the two output voltage/
current ranges of the supply.
4-3
The series regulator is part of a feedback
loop consisting of the driver and the constant vol¬
tage/constant current comparators.
When operated
within the specified ranges, during constant voltage
4-1
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