3
AN1386.1
December 23, 2009
Selecting Switches
Switch S1 selects PVCC bias supply from V
IN
or an
additional supply source. When S1 is pushed up, the
PVCC bias connects to the input power side. When S1 is
pushed down, the PVCC bias connects to the additional
power supply. For typical applications, the PVCC bias
voltage is +5V (+10%) or +12V (+20%). It can also
supply a wider range from +6.5V to +14.4V.
Switch S2 selects module Enable (On) or Disable (Off).
When S2 is pushed up, the COMP/EN pin of the module is
enabled and the module starts initialization and
operation. When S2 is pushed down, the COMP/EN pin of
the module connects to ground and the module will be
shut down.
Quick Start
The evaluation board can be evaluated simply, as shown
in Figure 2. The power connection of the evaluation
board supplies the input voltage from the DC Power
Supply, and the load connection of the evaluation board
delivers power to the Electronic Load. If the input voltage
is +5V or +12V, the PVCC bias does not require
additional supply and it can connect to the input side
directly by pushing switch S1 to the up state.
Figure 3 shows the ISL820xMEVAL1Z application
schematic for +5V or +12V input voltage. The PVCC pin
can connect to the input supply directly.
Typical Application Schematic
Typical Application with Separated Power
Supply
Figure 4 shows the ISL820xMEVAL1Z application
schematic for a wide input voltage from +1V to +20V.
The PVCC supply can 5V/+12V or +6.5V to
+14.4V.
SWITCH
UP
DOWN
S1
V
IN
+5V/+12V or +6.5V to +14.4V
SWITCH
UP
DOWN
S2
EN
Disable
VIN
S1
+5V/+12V
OR
+6.5V TO +14.4V
VIN
S1
+5V/+12V
OR
+6.5V TO +14.4V
EN
S2
ENABLE
EN
S2
DISABLE
FIGURE 2. QUICK START FOR EVALUATION BOARD
FIGURE 3. QUICK START SCHEMATIC
C
PVCC
VIN (+5V/+12V)
C
IN
C
OUT
R
SEN-EX
R
FB
VOUT
COMP/EN
FB
ISET
PGND
VOUT
PHASE
VIN
PVCC
FIGURE 4. WIDE INPUT RANGE SCHEMATIC
C
PVCC
VIN
C
IN
C
OUT
R
SEN-EX
R
FB
VOUT
COMP/EN
FB
ISET
PGND
VOUT
PHASE
VIN
PVCC
(+1V TO +20V)
P
VCC
(+5V/+12V OR +6.5V TO +14.4V)
Application Note 1386
