INSTRUCTION
MANUAL
-
MODEL
DLP
400-5-7
50A
20
As current
flows
through
the
pass
transistors,
the top
of SH101
(+) becomes
more
and more
positive,
until
the
voltage
at
Pin 4
becomes
equal
to
that
of
Pin
5,
causing
Ul
to
regulate
the
current
through
the
pass
transistors.
As
the
input
voltage
rises,
the
voltage
at
Pin
5
rises
proportionally,
causing
more
current
to
flow,
until
the
voltage
drop
across SH101
is
high
enough
to
create
an
equilibrium
between
the
inverting
and
non-inverting
inputs
of Ul,
giving the
effect
of
a
resistive
load.
The
maximum
voltage
that
can
be
applied
to
the
non-inverting
input
is
limited
by
R24
and
R54,
so
that
approximately only
10
millamperes
of
current
can
be
drawn
for
each volt
at
the
input.
5.3
0-.03A/V
MODE
In
this
position,
the
circuit
operates the same
as
in
the
0-.01A/V
mode,
with
the
exception
that the
input
voltage
is
now
divided
by
R23,
R30, and
R125.
This
new
divider
allows
more
voltage to
be
applied
to
the
non-inverting
input
of
Ul
(Pin
5),
requiring
a
much
higher
current
to
flow
through
SH101
before
the
voltage
at
the
inverting
input
is
sufficient
to
cause
Ul
to
regulate
the pass
structure.
R23
and R30
are
set
so
that
about .03A
of
current
can
be
drawn
for each
volt
at the input.
OTI400-5-75QA]
