HP 6235A - Page 12

load protection provided by the current limiting circuit. A
high-current output pulse may damage load components
before the average output current is large enough to cause
the current limiting circuit to operate.
3-31 Reverse Current Loading. An active load connec¬
ted to the power supply may actually deliver a reverse cur¬
rent to the supply during a portion of its operating cycle.
An external source cannot be allowed to pump current
into the supply without risking loss of regulation and poss¬
ible damage to the output capacitor. To avoid these effects,
it is necessary to preload the supply with a dummy load
resistor so that the power supply delivers current through
the entire operating cycle of the load device.
3-32 Reverse Voltage Protection. Internal diodes con¬
nected with reverse polarity across the output terminals
protect the output electrolytic capacitors and the driver
transistors from the effects of a reverse voltage applied
across a supply output. Since series regulator transistors
cannot withstand reverse voltage either, diodes are also
connected across them. When operating supplies in parallel,
these diodes protect an unenergized supply that is in parallel
with an energized supply.
3-33 Output Voltage Overshoot. During turn-on or
turn-off of ac power, output plus overshoot will not exceed
1V if the output is set for less than IV. If the control is set
for 1V or higher, there is no overshoot.
3-4