Dual Power Supply - mikroElektronika EasyAVR v7 User Manual

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.
VCC-USB
FP1
VCC
C3
GND
100nF
CN25
page 6

Dual power supply

Board contains switching power supply
that creates stable voltage and
current
ST1S10,
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
VCC-BRD
FP2
CN1
1
2
3
4 AVCC
USB
D1 D2
1N4007 1N4007
D3 D4
CN24
1N4007 1N4007
5V SWITCHING POWER SUPPLY
Figure 3-2: Dual power supply unit schematic
levels necessary for
powering each part of the
board. Power supply section
contains two power regulators:
which generates
VCC-5V
POWER
AVCC VCC-5V
LD41
E9
R45
10uF
2K2
3.3V VOLTAGE REGULATOR
VCC-BRD
VCC-5V VCC-3.3V
J5
R50 U5 ST1S10
10K 1 8
VINA PGND
2 7
INH SW
3 6
FB VINSW
4 5
GND SYNC
C29
22uF
C28
1uF
Figure 3-1: Dual power supply unit of EasyAVR
REG1
1
GND
2
Vout VCC-3.3V
3
Vin
C26
E8
MC33269DT3.3
100nF
10uF
C27
100nF
SWITCH1
VCC-5V
VCC-USB
L1 10uH
J22
R51
4K7
R54
100K
C34 C35
22uF 22uF
R56
20K
v7
™
EasyAVR
v7