INSTRUCTION
MANUAL
-
MODEL
DLP
400-5-750A
—
21
5.4
0-1A
MODE
An
internal
voltage
reference
(6V)
is
generated
by
series-dropping
R14 and
zener diode
VR8,
which
in
turn
is
reduced
by the voltage
divider
network
of
R56,
R21,
R125A,
and
R125B.
A
portion
of
this
voltage determined
by
the
DC
load
adjust
control
is
fed
into
the
non-inverting
input of
U1
(Pin
5)
.
The
inverting
input
(Pin
4) is
connected
to
the
top (+)
of
shunt
SH101.
The
pass
structure
is
turned
on by
U1
until
the
voltage
drop
across
the
shunt
is
sufficient
to
equalize
the
voltage
on
the
inverting
and
non-inverting inputs
of
U1.
These two
points
are
controlled
only
by
the
voltage
reference supplied
to
Pin
5
and
the
current
through
the
shunt,
which
means
a
constant
amount
of
current will
flow
through
the
Dynaload
regardless
of
the
input
voltage
change.
The
maximum voltage
that
can
be
applied
to
the
non-inverting input,
determined
by
divider
R56 and
R21,
is
limited
so
that a
current
of
approximately
1
amp
provides a
sufficient
voltage
drop
across the
shunt to
cause
U1
to
regulate
the
current
in
the pass
structure.
5.5
0-5
A
MODE
*
This
range
operates the
same way
as the
0-1A mode,
except
that
the
reference
is
divided
by
R19
and
R20,
allowing
more
voltage
to be
applied
to
the
non-inverting
IJTP400-5-75QA]
