Z-World Wildcat BL2000 User Manual - Ppendix

User’s Manual

71

A

PPENDIX

 C.  P

OWER

 S

UPPLY

Appendix C describes the power circuitry distributed on the

BL2000.

C.1  Power Supplies

Power is supplied to the BL2000 via a mini phone jack located at J7 or through the screw 

terminal strip, header J2. The BL2000 itself is protected against reverse polarity by a 

diode at D1 as shown in Figure C-1.

Figure C-1.  BL2000 Power Supply

Capacitor C28 provides surge current protection for the voltage regulator, and allows the 

external power supply to be located some distance away from the BL2000. A switching 

power regulator is used. The input voltage range is from 9 V to 40 V.

The BL2000 can alternatively be powered by 24 V AC. In this case D1 and C28 act as a 

half-wave rectifier to produce approximately 40 V DC at the input of the switching regula-

tor, U12. Although a significant drop will be measured at DCIN, 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.

Pin 12 on header J9 can be configured to either supply Vcc (0 

Ω

 surface-mounted resistor 

installed at R160) or GND (0 

Ω

 surface-mounted resistor installed at R161). When using 

pin 12 on header J9 to supply Vcc, take care not to draw more than 25 mA current from 

this pin, especially if you are using 24 V AC as your +RAW input power supply. The R160 

and R161 locations are shown in Figure A-4. 

POWER

IN

J2 orJ7

47 µF

330 µF

U12

+RAW

Vcc

L1

C29

C28

330 µH

D1

D2

1N5819

14

15

8

1

12

7

17

18

10

2

3

4

1

SWITCHING POWER REGULATOR

TVS1

DCIN

LM2575