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3-39.
Figure 3-4 illustrates the method by which a power
supply's constant voltage output can be programmed using
an external voltage with a voltage gain dependent upon the
ratio of Rp to Rg. Note that this method is no different
from the circuit normally used for constant voltage control
of the output except that an external reference (the pro-
gramming voltage source) has been substituted for the
internal reference.
On most supplies, external terminals
are available so that the connections shown ín Figure 3-4
can be accomplished without any internal wiring changes.
in all HP remotely programmable power supplies, the
summing point S is made available, and the configuration
of Figure 3-4 can always be accomplished using the external
programming voltage source Ep and external precision wire-
wound resistors Rp and Rp. (Rp should not exceed 10k;)
As indicated by the equation in Figure 3-4, Rp can be
selected so that the resulting voltage gain is either less or
greater than unity.
it is possible to use the front panel
controi on the supply as the voltage gain control Hp.
E
CHOOSE Er 2-1p NORMAL
SERIES
REGULATOR
COMPARISON
AMPL.
PE
E ia
out
Ep
EP
Figure 3-4. Voltage Programming with Variable Voltage Gain
3-5
3-41
As shown in Figure 3-5, the supply's internal
reference voltage (* Voce) and VOLTAGE control are
disconnected (dotted lines) and are replaced with the
59601B's
output voltage and POWER SUPPLY FULL
SCALE ADJUST.
Note that in the unipolar mode, 59501B
output terminal A1 is negative with respect to A2.
This
polarity must be complied with when making connections.
The connections shown in Figure 3-5 are typical for most
supplies.
3-42
Constant Current.
Figure 3-6 illustrates the
connections required for the 59501B to program the out-
put current of a typical HP power supply.
Programming
constant current consists of replacing the internal reference
with the output voltage from the 59501B and replacing
the internal CURRENT control with the POWER SUPPLY
FULL SCALE ADJUST controls on the 59501B... With
these connections, the voltage developed across POWER
SUPPLY FULL SCALE ADJUST (Rp) becomes the reference
against which the voltage drop across the output current
monitoring resistor (Rag) is compared.
The relationship
between. Ep and the supply's output current depends upon
the resistance ratio Rp/Rn and on the constant current pro-
gramming coefficient (Kp) of the particular supply. The
relationship between input voltage and output current is,
lout * (Ep x
Rp} * (Kp x Ra)
TYPICAL
HP
POWER
SUPPLY
[ZERO ADJUST]
(d
Figure 3-5. Typical Connections for CV Programming
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