Quick Start Procedure - Linear Technology DC2215A Demo Manual

Quick start proceDure

Using short twisted pair leads for any power connections
and with all loads and power supplies off, refer to Figure 6
for the proper measurement and equipment setup. The
power supplies 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.
The indicators for PRIORITY, VALID1 and VALID2 are
negative logic while the indicator for PGOOD is positive
logic. PGOOD indicates the output voltage is good if it is
pulled to V and VALID1 and VALID2 indicate that the
CC
input voltage on the respective sources are good if the
pins are pulled to ground. With the unit enabled (JP4,
(ENA = ON) and JP2 (DIODE = PRIORITY)) the unit is
operating in PRIORITY mode. This means that if there is
enough voltage on V then V
IN1
to the converter independent of the voltage on V
VALID1 will be low.
If JP2 (DIODE) is connected to IDEAL DIODE the unit is
operating in IDEAL DIODE mode and power will be drawn
from whichever source has enough voltage to be enabled
and is the higher voltage. Both VALID1 and VALID2 will be
low if V and V are above their operating thresholds.
IN1 IN2
Turrets
Left side of board:
V : 4.3V to 42V supply input: do not exceed +42V.
IN1
GND: Ground connection for input supply.
V : 6V to 8.4V supply input: operational to +42V.
IN2
Right side of board:
GND: Ground connection for LOAD.
V : 3.3V/2.5A first of two terminals in parallel.
OUT
V : 3.3V/2.5A second of two terminals in parallel.
OUT
GND: Ground connection for LOAD.
will be supplying power
IN1
and
IN2
DEMO MANUAL DC2215A
Jumpers
JP1/PWM/SYNCH: Selects PMW or Burst Mode opera-
tion. Leaving the jumper open and applying a square
wave signal to the SYNC pin allows the converter to
be synchronized. Default position is PWM which puts
the unit in fixed frequency PWM operation.
JP2/DIODE: Selects PRIORITY or DIODE-OR mode.
JP3/EXTV : connects EXTV
CC
diode or leaves EXTV
LTC3126 derives bias from V
is V .
OUT
JP4/ENA: Selects ENA = ON/OFF . The default position
is "ON".
1. JP1 through JP4 settings to start:
JP1 PWM/SYNC = PWM
JP2 DIODE = PRIORITY
JP3 EXTVcc = VOUT
JP4 ENA = ON
2. With the power supplies (V
as shown in Figure 6. If accurate current measurements
are desired (for efficiency calculations for example)
then connect the ammeters in series with the supplies
as shown. The ammeters, however, are not required.
3. Connect the load, set at 5Ω, (660mA) to V
in Figure 6. Again, connect an ammeter if accurate
current measurement or monitoring is desired.
4. Turn on the Power Supply, V
age. The converter will start at approximately 4.3V.
5. Verify V is ~3.3V.
OUT
6. V can now be varied between 4.3V and 42V. V
IN1
will remain in regulation for load currents up to 2.5A.
7. Set V to 0V and turn off V
IN1
to V through a
CC OUT
open. If EXTV is open, the
CC CC
. The default position
IN
, V ) OFF connect them
IN1 IN2
as shown
OUT
, and increase the volt-
IN1
.
IN1
OUT
dc2215af
5