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3-41
SERIES OPERATION
3-42
Normal Series Connections (Figure..3-SK Two
or more power supplies can be operated in seiies to
obtain a higher voltage than that available from a
single supply.
When this connection is used, the
output voltage is the sum of the voltages of the in¬
dividual supplies.
Each of the individual supplies
must be adjusted in order to obtain the total output
voltage.
The power supply contains a protective
diode connected internally across the output which
protects the supply if one power supply is turned
off while its series partner(s) is on.
Figure 3-8.
Normal Series
3-43
AUTO-SERIES OPERATION (Figure 3-9)
3-44
Two or more power supplies can be operated
in Auto-Series to obtain a higher voltage than that
available from a single supply.
When this con¬
nection is used, the output voltage of each slave
supply varies in accordance with that of the master
supply; thus the total output voltage of the com¬
bination is determined by the setting of the front
panel VOLTAGE controls on the master.
The master
supply must be the most positive supply of the
series.
The output CURRENT controls of all series
units are operative and the current limit is equal
to the lowest control setting.
If any of the output
CURRENT controls are set too low, automatic
crossover to constant current operation will occur
and the output voltage will drop.
Remote sensing
and programming can be used, though the strapping
arrangements shown in Figure 3—9 show local sens¬
ing and programming.
Notice that the overvoltage
crowbar terminals (A13 and A14) are connected in
parallel which means that if any supply crowbars,
all supplies will be tripped.
3-45
In order to maintain the temperature coeffic¬
ient and stability specifications of the power supply,
the external resistors (Rx) shown in Figure 3-9
should be stable, low noise, low temperature coef¬
ficient (less than 5ppm per degree Centigrade) re¬
sistors.
The value of Ry is the maximum voltage
rating of the master supply divided by the voltage
programming current of the slave supply (1/Kp
where Kp is the voltage programming coefficient).
The power rating of R^ should be at least 10 times
the actual power dissipated in the resistor.
The
voltage contribution of the slave is determined by
its voltage control setting.
Figure 3-9.
Auto-Series Operation,
Two and Three Units
3-7
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