Agilent Technologies E3646A, User Manual, Page: 157 / 211

Chapter 7 Tutorial
Extending the Voltage and Current Range
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7
Extending the Voltage and Current Range
The power supply may be able to provide voltages and currents greater than its rated
maximum outputs if the power-line voltage is at or above its nominal value. Operation
can be extended up to 3% over the rated output without damage to the power supply,
but performance can not be guaranteed to meet specifications in this region. If the
power-line voltage is maintained in the upper end of the input voltage range, the power
supply will probably operate within its specifications. The power supply is more likely
to stay within specifications if only one of the voltage or current outputs is exceeded.
Series Connections
Series operation of two or more power supplies can be accomplished up to the output
isolation rating of any one supply to obtain a higher voltage than that available from
a single supply. Series connected power supplies can be operated with one load across
both power supplies or with a separate load for each power supply. The power supply
has a reverse polarity diode connected across the output terminals so that if operated
in series with other power supplies, damage will not occur if the load is short-circuited
or if one power supply is turned on separately from its series partners.
When series connection is used, the output voltage is the sum of the voltages of the
individual power supplies. The current is the current of any one power supply. Each
of the individual power supplies must be adjusted in order to obtain the total output
voltage.
Parallel Connections
Two or more power supplies being capable of CV/CC automatic cross over operation
can be connected in parallel to obtain a total output current greater than that available
from one power supply. The total output current is the sum of the output currents of
the individual power supplies. The output of each power supply can be set separately.
The output voltage controls of one power supply should be set to the desired output
voltage; the other power supply should be set for a slightly higher output voltage. The
supply with the higher output voltage setting will deliver its constant current output,
and drop its output voltage until it equals the output of the other supply, and the other
supply will remain in constant voltage operation and only deliver that fraction of its
rated output current which is necessary to fulfill the total load demand.