EasyManuals Logo

HP Lab Series User Manual

HP Lab Series
60 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Page #25 background imageLoading...
Page #25 background image
SECTION
IV
PRINCIPLES
OF
OPERATION
..
REFERENCE
REFERENCE
-
CIRCUIT
VOLTAGES
CONSTAN.T
-
T
CURRENT
-
BIAS
BIAS
,...
INPUT
.
-
SUPPLY
~
VOLTAGES
CIRCUIT
.
I+
AC
POWER
I
XFMR
RECTIFIER,
SERIES
+
-
FILTER,
..
REG.
-
PREREG.
CURRENT
SAMPLING
RESISTOR
-
/\IVER
-
..
~-
OR
'ii
CONSTANT
..,
GATE
-
DC
4-
VOLTAGE
INPUT
OUTPUT
ERROR
----
-
CIRCUIT
AllPL.
-
r..-
PRE
REG.
-
CONTROL
CIRCUIT
....
I
f
METER
CIRCUIT
,
,,
-
NOTE•
-
-----
DENOTES
VOL
TA6E
FEEDBACK
PATH
-----
DENOTES CURRENT FEEDBACK PATH
Figure
4-1.
Overall
Block Diagram
4-1
OVERALL
BLOCK
DIAGRAM
DISCUSSION
4-2
The major
circuits
of
the
power
supply
are
shown
on
the
overall
block
diagram
of
Figure
4-1.
The
ac
input
voltage
is
first
rectified
and
applied
to
the
preregulator
SCR
which
operates
in
conjunc-
tion
with
the
SCR
control
circuit
to
fonn a
feedback
loop.
This·
preregulator
feedback loop
minimizes
the
power
dissipated
by
the
series
re.gulator
by
keeping
the
voltage
drop
across
the
regulator
at
a
low
and
constant
level.
4-3
To
accomplish
this,
the
SCR
control
circuit
issues
a
phase
adjusted
firing
pulse
to
the
SCR
once
during
each
half
cycle
of
the
input
ac.
The
control
circuit
continuously
samples
the
output
voltage,
the
input
line
voltage
(from
T3),
and
the
voltage
across
the
series
regulator
and,
on
the
basis
of
these
inputs,
determines
at
what
time
each
fll:ing
pulse
is
generated.
4-1
4
...
4 The
phase
adjusted
output
of
the
SCR
is
ap-
plied
to
the
series
regulator
which
varies
its
con-
duction
to
provide a
regulated
voltage
or
current
at
the
output
terminals.
4-5
The
series
regulator
is
part
of
another
feed-
back
loop
which
consists
of
the
error
and
driver
amplifiers
and
the
Constant
Voltage/Constant
Cur-
rent
comparators.
The
series
regulator
feedback
loop
provides
fine
and
"fast"
regulation
of
the
out-
put
while
the
preregulator
feedback
loop
handles
large,
relatively
slow,
regulation
demands.
·
4-6
The
feedback
signals
that
control
the
conduc-
tion
of
the
series
regulator
are
originated
within
the
constant
voltage
or
constant
current
comparator.
During
constant
voltage
operation
the
constant
volt-
age
comparator
continuously
compares
the
output
voltage
of
the
supply
with
the
drop
across
the
VOLT-
AGE
controls.
If
these
voltages
are
not
equal,
the

Questions and Answers:

Question and Answer IconNeed help?

Do you have a question about the HP Lab Series and is the answer not in the manual?

HP Lab Series Specifications

General IconGeneral
BrandHP
ModelLab Series
CategoryPower Supply
LanguageEnglish

Related product manuals