User Connections and Considerations
50
Figure 4-9. External Voltage Programming
If you cannot avoid capacitive coupling, it may help to place capacitors from the unused programming inputs to ground.
Especially with auto-parallel operation, connecting a capacitor (
≥
4,000 pF) from
VP
to
P Common
on the master supply
will ensure proper operation. Also with auto-parallel operation, do not allow more than about 500 pF capacitive loading
between
IM
and
Common
P.
Programming Considerations.
When voltage programming the output, the frequency of the programming source is limited by the slew rate of the power
supply. To keep the power supply from slewing its output (going into nonlinear operation), the maximum programming rate
is 3750 V/s. The maximum downprogramming rate (when the power supply is sinking current) is 750 V/s. These restrictions
can be expressed as the maximum programming frequency that can be applied without causing distortion at the output. The
following formula can be used to determine this frequency:
F
=
50 (voltage rating of supply)
p - p amplitude of desired output sine wave
MAX
At frequencies >6 kHz, voltage programming is subject to a 3 dB bandwidth limitation.