User’s Manual
67
APPENDIX C. POWER MANAGEMENT
Appendix C describes the power circuitry distributed on the
Intellicom.
C.1 Power Supplies
Power is supplied to the Intellicom board from an external source either through header J7
or from another Intellicom through header J5, the RJ-12 jack.
The Intellicom board itself is protected against reverse polarity by Shottky diodes at D6
and D7 as shown in
Figure C-1. The Shottky diode has a low forward voltage drop, 0.3 V,
which keeps the minimum DCIN required to power the Intellicom lower than a normal sil-
icon diode would allow.
Figure C-1. Intellicom Power Supply Schematic
Capacitor C28 provides surge current protection for the voltage regulator, and allows the
external power supply to be located some distance away from the Intellicom board. A
switching power regulator is used. The input voltage range is from 9 V to 40 V.
POWER
IN
J7
47 F
330 F
LM2575
U2
+RAW
Vcc
L1
C22
C28
330 H
1
2
D7
D5
1N5819
14
15
8
1
12
7
17
18
10
2
3
4
1
SWITCHING POWER REGULATOR
TVS1
DCIN
+RAW_RS485
D6