KEPCO BHK-MG Series, Operator'S Manual

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BHK-1/2-MG 030916
3-49
3.9 OPERATING MODES
This section describes the following operating modes for the BHK-MG 40W Power Supply
• Slow/Fast Mode
• Series Operation
• Automatic Series Operation
• Master-Slave Series Operation
• Parallel Operation
• Automatic Parallel Operation
• Master-Slave Parallel Operation
3.9.1 SLOW/FAST MODE OF OPERATION
In slow mode of operation the internal output capacitor C
OUT
is connected across the sensing
terminals via TB1, terminal 1 (-OUT.C) and terminal 2 (-OUT). This effectively increases the
main feedback capacitance by adding the internal feedback capacitor for slow mode C
FS
. to the
fast mode capacitor C
FF
(see Figure 3-19). When internal output capacitor C
OUT
is across the
output, output noise is reduced, and, in voltage mode, the amplitude of transients caused by
dynamic load changes is also reduced. The disadvantage of slow mode is that programming
time is increased. Therefore, slow mode is recommended for voltage mode applications where
low noise and low amplitude recovery transients due to dynamic load changes are important.
In fast mode of operation the internal output capacitor is disconnected from the sensing termi-
nals, by removing the link between TB1, terminal 1 (-OUT.C) and terminal 2 (-OUT). This also
effectively reduces the main feedback capacitance by removing the internal capacitor for slow
mode, C
FS
from the circuit. This configuration reduces the programming time in voltage mode
and, in current mode, reduces the duration of transients caused by dynamic load changes; the
disadvantage is that output noise is increased. Therefore, the fast mode of operation is recom-
mended for voltage mode applications when a quick response to programming is important
(e.g., when the power supply is effectively operating as a power amplifier), and for current mode
applications when quick recovery time at load changes is desired.
If desired, an external output capacitor can also to be used; the following instructions apply
when using an external output capacitor:
a. Use a capacitor rated to more than the maximum output voltage of the power supply. If
a series combination of polarized type capacitors is used, potential equalizer resistors
in parallel with each capacitor should be installed and attention should be paid to the
polarity of the capacitors: the “plus” terminal of each capacitor is connected to the
“minus” terminal of the next capacitor, if present, or to +OUT terminal of the power sup-
ply (see Figure 3-19).