User`s guide

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:
MC34063A, which generates
VCC-5V, and MC33269DT3.3 which
creates VCC-3.3V power supply. The board
can be powered in three dierent ways: with USB
power supply (CN2), using external adapters via adapter
connector (CN31) or additional screw terminals (CN30). External
adapter voltage levels must be in range of 9-32V DC or 7-23V AC. Use
jumper J6 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 EasyPIC
™
v7
1
2
3
4
8
7
6
5
SWC
SWE
CT
GND
DRVC
IPK
VIN
CMPR
U3
MC34063A
R65
0.22
R34
3K
VCC-SW
C8
220pF
D1
MBRS140T3
L2 220uH
E1
220uF/35V LESR
VCC-EXT
R35
1K
VCC-5V
J6
2
1 3
SWITCH1
VCC-USB
VCC-SW
D12
1N4007
D13
1N4007
D15
1N4007
D14
1N4007
J5
VCC-5V
VCC-BRD
VCC-3.3
C14
100nF
VCC-5V
2
1
3
GND
Vout
Vin
REG1
MC33269DT3.3
E7
10uF
VCC-3.3
CN31
CN30
VCC-5V
R66
2K2
LD37
E2
220uF/35V LESR
E4
10uF
VCC-USB
L4
FERRITE
C19
100nF
1
2
3
4
VCC
GND
CN2
USB
3.3V VOLTAGE REGULATOR
5V SWITCHING POWER SUPPLY
E6
220uF/35V LESR
VCC-5V
power supply
page 6