Dual power supply
Board contains switching power supply
that creates stable voltage and
current levels necessary for
powering each part of the
board. Power supply section
contains two power regulators:
ST1S10
,
which
generates
VCC-5V, and
MC33269DT3.3
which
creates VCC-3.3V power supply. The board
can be powered in three different ways: with
USB
power supply (CN1)
, using external adapters via adapter
connector
(CN24)
or additional screw terminals
(CN25)
. External
adapter voltage levels must be in range of
9-15V DC or 7-12V AC
. Use
jumper
J22
to specify which power source you are using and jumper
J5
to specify
whether you are using 5V or 3.3V power supply. Upon providing the power using either
external adapter or USB power source you can turn on power supply by using
SWITCH 1
(Figure
3-1)
. Power
LED (Green ON)
will indicate the presence of power supply.
Figure 3-2: Dual power supply unit schematic
Figure 3-1: Dual power supply unit of EasyAVR
™
v7
C3
0
10
0n
F
C3
1
10
0n
F
C3
2
10
0n
F
VCC-5V
POWER
R45
2K2
LD41
E1
1
22
0u
F/
35
V/
LE
SR
R54
100K
C28
1uF
L1
10uH
R56
20K
VCC-5V
J22
2
1
3
VCC-USB
D1
1N4007
D2
1N4007
D3
1N4007
D4
1N4007
CN24
CN25
R50
10K
1
2
3
5
4
6
7
8
GND
FB
INH
VINA
PGND
SW
VINSW
SYNC
E
U5
ST1S10
C34
22uF
C35
22uF
C29
22uF
R51
4K7
J5
VCC-5V
VCC-BRD
VCC-3.3V
C27
100nF
VCC-5V
2
1
3
GND
Vout
Vin
REG1
MC33269DT3.3
E8
10uF
3.3V VOLTAGE REGULATOR
VCC-3.3V
C26
100nF
E9
10uF
FP2
AVCC
VCC-BRD
AVCC
E6
10
uF
5V SWITCHING POWER SUPPLY
VCC-USB
FP1
C3
100nF
1
2
3
4
VCC
GND
CN1
USB
SWITCH1
po
w
er supply
page 6
Easy
AVR
v7
