Z-World eDisplay OP7200, Руководство пользователя

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User’s Manual 123
A
PPENDIX
B. P
OWER
S
UPPLY
Appendix B describes the power circuitry provided on the
OP7200.
B.1 Power Supplies
Power is supplied to the OP7200 via pins 1 and 2 of screw-terminal header J3. The OP7200
is protected against reverse polarity by a full-wave bridge rectifier as shown in Figure B-1.
The full-wave bridge rectifier also allows the OP7200 to be powered from 24 V AC.
Figure B-1. OP7200 Power Supply
The input voltage range is from 9 V to 40 V DC. A switching power regulator is used to
provide a Vcc of +5 V for the OP7200 logic circuits. Vcc is can be made accessible to the
user by installing a 0
Ω
resistor at R71. Vcc will then be available instead of digital input
IN15 on pin 4 of screw-terminal header J10.
The OP7200 can alternatively be powered by 24 V AC. In this case the full-wave bridge
rectifier produces approximately 30 V DC at the input of the switching regulator.
Although a significant drop will be measured at the input to the switching regulator, the
voltage will never drop below +9 V DC. As long as the minimum input level is maintained
at the input to the regulator, Vcc will be held at +5 V DC.
There is provision on the printed-circuit board for a transorb to be installed at TVS1 in
parallel with C49 to provide suppression for positive noise pulses above 51 V. This part is
only needed when the OP7200 will be used in industrial environments where a clean
source of power cannot be guaranteed, and is not part of the normal factory build.
POWER IN
J3
47 µF
330 µF
U8
Vcc
L9
C39
C49
330 µH
D24
1N5819
14
15
8
1
12
7
17
18
10
2
3
4
1
SWITCHING POWER REGULATOR
VIN
LM2575
+PWR
–PWR
TVS1