Rabbit Smartcat, Руководство пользователя

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User’s Manual 73
A
PPENDIX
B. P
OWER
S
UPPLY
Appendix B describes the power circuitry provided on the
BL2100.
B.1 Power Supplies
Power is supplied to the BL2100 via header J5/J4. The BL2100 is protected against
reverse polarity by a diode at D1 as shown in Figure B-1.
Figure B-1. BL2100 Power Supply
The input voltage range is from 9 V to 36 V. A switching power regulator is used to pro-
vide a Vcc of +5 V for the BL2100 logic circuits. Vcc is not accessible to the user.
The digital ground and the analog ground share a single split ground plane on the board,
with the analog ground connected at a single point to the digital ground by a 0

resistor
(R29). This is done to minimize digital noise in the analog circuits and to eliminate the
possibility of ground loops. External connections to analog ground are made on header
J2/J1, and external connections to digital ground are made on headers J5/J4 and J11/J10.
B.1.1 Power for Analog Circuits
Power to the analog circuits is provided by way of a two-stage low-pass filter, which iso-
lates the analog section from digital noise generated by the other components. The analog
power vV powers the op-amp for the buffered A/D converter inputs, the A/D con-
verter, the D/A converter, and the 4.096 V reference circuit. The maximum current draw
on +V is less than 10 mA. +V is not accessible to the user.
POWER
IN
J5/J4
47 µF
330 µF
U4
+RAW
Vcc
L1
C66
C56
330 µH
D1
D1
1N5819
14
15
8
1
12
7
17
18
10
2
3
4
1
SWITCHING POWER REGULATOR
VIN
LM2575