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, thus making
the board capable of supporting both 5V and 3.3V
microcontrollers. Power supply unit can be powered in
two different ways: with
USB power supply
, and 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 microcontroller. Upon providing the power using either
external adapter, or USB power source, you can turn the board on using
SWITCH 1
(Figure 3-1)
.
Figure 3-2: Dual power supply unit schematics
Figure 3-1: Dual power supply unit of EasyPIC
™
v7
VCC-5V
E4
10uF
VCC-3.3
E7
10uF
C14
100nF
MC33269DT3.3
REG1
VOUT
GND
VIN
3
1
2
R66
2K2
LD37
VCC-5V
POWER
CN30
CON2
CN31
CON2
D12
1N4007
1N4007
1N4007
1N4007
D13
D15
D14
-
+
E1
220uF/35V
U3
SWC
SWE
CT
GND
DRVC
IPK
VIN
CMPR
MC34063A
R34
3K
R35
1K
VCC-SW
R65
0.22
L2
220uH
D1
MBRS140T3
E2
220uF/35V
E6
220uF/35V
VCC-SW
J6
M1X3
VCC-5V
VCC-USB
SWITCH1
1
2
3
4
8
7
6
5
C8
220pF
1
2
3
J5
M1X3
VCC-3.3
VCC-BRD
VCC-5V
VCC-EXT
po
w
er supply
page 6
