HP 6038A - Page 40

3-204 Constant Voltage Output, Voltage Control. The
setup shown in Figure 3-10 allows the output voltage to be
varied by using an externa! voltage source to program the sup¬
ply. A voltage source variable from 0 to -f 5 volts produces a
proportional output voltage from zero to full scale. The static
load on the programming voltage source is less than 5/iA. A
source resistance of less than 10 k is necessary to avoid degrada¬
tion of offset and drift specifications.
NOTE
If external resistors are used to limit the remote-
programming voltage to 5 Vdc, the resulting high
programming-source resistance can degrade the
power supply's programming speed, offset and
drift performance. Limit the equivalent source
resistance to 10 k ohm maximum. Figure 3-11
shows a convenient way to calculate suitable
voltage-divider resistance values for a 5 k ohm
source resistance.
3-2(B Constant Current Output, Resistance Control.
The setup shown in Figure 3-12 allows the output current to
be varied by using an external resistor to program the supply.
The discussion in Paragraph 3-203 for constant voltage opera¬
tion also applies for constant current operation.
CAUTION
If the programming terminals UP to ^ P) become
open circuited during resistance programming, the
output current will tend to rise above rating. The
power supply will not be damaged if this occurs,
but the user's load may be damaged. If there is a
possibility that the programming leads may be
opened, it is suggested that the optional resistor
be connected directly across terminals IP and
^P, as shown in Figure 3-12. The value of this
resistor should be selected to limit the output cur¬
rent to the maximum that the had can handle
without damage. For example, if the had can han¬
dle half the full current rating of the power supp¬
ly, a 20(X) ohm resistor should be connected from
IP to ^ P. Of course, if this resistor is used, the
resistance value actually programming the supply
Is the parallel combination of the programming
resistor and the optional resistor.
3-206 Constant Current Output, Voltage Control. The
setup shown in Figure 3-13 allows the output current to be
varied by using an external voltage current to program the sup¬
ply, The discussions in paragraphs 3-201 through 3-203 also
apply for constant current operation. The note following
paragraph 3-204 applies also to programming output current.
3-207 MULTIPLE-SUPPLY OPERATION
3-208 The power supply can be operated in combination
with other power supplies to provide increased output capability.
Connecting the outputs of two or more power supplies in series
can provide an output voltage of up to 240 volts. Auto-paraliel
operation of two power supplies can provide output current of
up to 20 amps. Other configurations are possible, contact
Hewlett-Packard, New Jersey Division for specific application
assistance.
3-209 Auto-Parallel Operation
3-210 Two units can be connected in an auto-parallel com¬
bination to provide twice the output current capability. One of
the power supplies, the master, is programmed normally via
the HP-IB. The other power supply, the slave. Is analog pro¬
grammed by the master. The slave may be connected to the
HP-IB for readback, status, etc., but the MODE switches of
the slave must be set so that the slave is analog programmed
by the master.
NOTE
Proportional currents from auto-paralleled units
require equal load-lead voltage drops. Connect
each unit to the had using separate pairs of wire
with length and gauge chosen to provide equal
voltage drops from pair to pair. If this is not feasi¬
ble, connect each unit to a pair of distribution
terminals using equal-voltage-drop wire pairs, and
then connect the distribution terminals to the had
with a single pair of leads.
3-27