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DEMO MANUAL DC1922A
Quick start proceDure
Using short twisted pair leads for any power connections
and with all loads and power supplies off, refer to Figure 3
for the proper measurement and equipment setup. The
power supply (PS1) should not be connected to the circuit
until told to do so in the procedure below.
When measuring the input or output voltage ripple, care
must be taken to avoid a long ground lead on the oscil-
loscope probe. Measure the input or output voltage ripple
by touching the probe tip directly across the V
IN
or V
OUT
and GND terminals (see Figure 4), or by using an oscil-
loscope probe tip jack.
1. Jumper, PS1 and LOAD settings to start:
PS1 = OFF
JP1 (RUN) = ON
JP2 (MPPC) = OFF
JP3 (PWM) = BURST MODE OPERATION
JP4 (DUST PWR) = NC
2. With power OFF connect the power supply (PS1) as
shown in Figure 3. If accurate current measurements
are desired (for efficiency calculations for example)
then connect an ammeter (AM1) in series with the sup-
ply as shown. The ammeter is not required however.
3. Connect a 50mA load to V
OUT
as shown in Figure 3
(100Ω for V
OUT
= 5V). Connect an ammeter (AM2) if
accurate current measurement or monitoring is desired.
4. Turn on PS1 and slowly increase voltage until the
voltage at V
IN
is 4.0V.
5. Verify V
OUT
is ~5.0V.
6. V
IN
can now be varied between 2.42V and 15.0V.
V
OUT
should remain in regulation.
7. Load current (I
OUT
) can also be varied. The maximum
I
OUT
is a function of V
IN
and the current limit. Consult
the data sheet for more information on I
OUT
vs V
IN
.
In general for V
IN
> V
OUT
I
OUT
can be increased to
200mA. For V
IN
< V
OUT
I
OUT
capability will be reduced.
8. For operation in fixed frequency (PWM) mode move
Jumper JP3 to FIXED FREQ. See the data sheet for
more information on Burst Mode operation.
9. NOTE: If V
OUT
drops out of regulation, check to be
sure that V
IN
is not below the minimum value for
regulation (see data sheet).
For USE with a Solar Cells/MPPC:
10. With power OFF move jumper MPPC (JP2) to ON.
11. If using a power supply as the source, place a mini-
mum of 10Ω, 10W resistor in series with the input to
simulate the source resistance. If using a solar cell (s)
or high impedance source, no additional resistance
should be needed.
12. Set resistor R9 to a value which will set the MPPC
pin to the desired voltage. See the data sheet section
“Programming the MPPC Voltage” for more informa-
tion.
13. With no load and the MPPC voltage set, increase the
source voltage above the MPPC set point. V
OUT
should
be in regulation. As the load is increased V
IN
will drop
until it reaches the MPPC set voltage. As the load is
increased further, V
OUT
will drop out of regulation,
but V
IN
will be regulated to the set point voltage. This
is to prevent the input source from collapsing and to
allow the maximum power to be extracted from the
source.
14. Consult the data sheet for more information on
maximum power point control (MPPC) operation.
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