HP Lab Series User Manual

ulation
at
the
load
and
reduce
the
degradation
of
regulation
which
would
occur
due
to
the
voltage
drop
in
the
leads
between
the
power
supply
and
the
load.
Remote
.sensing
is
accomplished
by
utilizing
the
strapping
pattern
shown
in
Figure
3-7.
The
power
supply
should
be
turned
off
before
changing
strapping
patterns.
The
leads
from
the
+S
terminals
to
the
load
will
cany
less
than
10
milliamperes
of
current,
and
it
is
not
reguired
that
these
leads
be
as
heavy
as
the
load
leads.
However, they
must
be
twisted
or
shielded
to
minimize
noise
pick-up.
Figure
3-'?.
Remote
Sensing
------1CAUTIOt••-----
Observe
polarity
~hen
coMecting
the
sensing
leads
to
the
load.
3-33
For
reasonable
load
lead
lengths,
remote
sen.;.
.sing
greatly:
iinproves
the
performance
of
the
s~pply.
However,
·if
the
load
is
located
a
considerable
dis-
tance
from
the
supply,
added
precautions
must
be
observed
to
obtain
satisfactory
operation
•.
Notice
that
the
voltage
drop
in
the
load
leads
subtracts
directly
from
the
.available
output
voltage
and
also
reduces
the
amplitude
of
the
feedback
error
signals
that
are
developed
within
the
unit.
Because
of
these
factors
it
is
recommended
that
the
drop
in
eaph
load
lead
not
exceed
1
Volt.
If a
larger
drop
must
be
tolerate¢,
please
consult· a
Eiewlett-Packara
Sales
Engineer.
NOT~
Due
to
the
voltage
drop
in
the
load
leads,
i~
:may
be
necessary
to
readjust
the
current
limit
in
the
remote
sensing
mode.
3.-34
Another
factor
that
must
be
considered
is
the
inductance
of
long
load
leads
which
could
affect
.
the
stability
of
the
feedback
loop
and
cause
os·cil-
3-4
lation.
In
these
cases,
it
is
recommended.
that
the
output
capacitor
(C20)
be
physically
removed
from
the
power
supply
and
placed
across
the
load
tenni:-
nals.
3-35
Although
the
strapping
patterns
shown
in
Figures
3-3
through
3-6
employ
local
sensing,
note
that
it
is
possible
to
operate
a
power
supply
simul-
taneously
in
the
remote
sensing
and
Constant
Volt-
.
age/Constant
Current
remote
programming
modes.
3·_35
SERIES
OPERATION
3-3
7 Nonnal
Series
Connections
(Figure
3-8). Two
or
more
power
supplies
can
be
operated
in
series
to
obtain
a
higher
voltage
than
that
available
from
a
single
supply.
When
this
connection
is
used,
the
output
voltage
is
the
sum
of
the
voltages
of
the
in-
dividual
supplies.
Each of
the
individual
supplies
must
be
adjusted
in
order
to
obtain
the
total
outPut
voltage.
The
power
supply
contains
a
protective
diode
connected
internally
across
the
output
which
protects
the
supply
1f
one
power
supply
is
turned
off
while
its
series
partner(s)
is
on.
00
00
Al
A2 A3
A4
A5
A6
A7 A8
A9
-S
-
GN.D
+
Figure
3-8.
Normal
Serles
3-38
Auto-Ser1e·s
Connections
(Figure
3-9).
The
Auto-Series
configuration
is
used
when
it
is
desir-
able
to
have
the
-output
voitage
of
each
of
the
series
connected
supplies
vary
in
accordance
with
the
set-
ting
of
a
control
unit.
The
control
unit
is
called
the
master;
the
controlled
units
are
called
slaves.
At
maximum
output
voltage,
the
voltage
of
the
slaves
is
detennine4
by
the
setting
of
the
front
panel
VOLT-
AGE
coi.ltrol
on
the
master.
The
master
supply
must
be
the
~ost
positive
supply
of
the
series.
The
out-
put
CURRENT
controls
of
all
series
units
are
opera-
tive
and
the
CWTent
limit
is
equal
to
the
lowest
con-
trol
setting.
If
any
output
CURRENT
controls
are
set
too
low,
automatic
crossover
to
constant
current
operation
will
occur
and
the
outputvoftagewill"drop.
Remote.
sensing
and
programming
can
be
used;
how-
ever,
the
Strapping
arrangements
shown
in
the
appli-
cable
figures
show
local
sensing
and
programming •
•
•
~
.,,

HP Lab Series Specifications

General

Brand	HP
Model	Lab Series
Category	Power Supply
Language	English