APPENDIX C. POWER MANAGEMENT
C.1 Power Supplies
Power is supplied to the Jackrabbit board from an external source through either header J1 or header J4. J1 is a
ground on pins 1 and 3. The symmetry allows for a
The Jackrabbit board itself is protected against reverse polarity by a Shottky diode at D2 as shown in Figure
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| LINEAR POWER SUPPLY | |||||
J1 |
| +RAW DCIN |
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| Vcc |
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POWER IN | 1 | D2 |
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| 7805 |
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2 |
| 1 | U1 | 3 |
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3 | 1N5819 | C1 |
| 2 |
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| C2 |
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| 10 µF |
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| 100 nF |
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| SWITCHING POWER SUPPLY | Vcc | |||||
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| 14 | LM2575 | 7 |
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| U2 |
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| 15 | 17 |
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| C3 | |
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| 2 |
| 4 | |||
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| 8 |
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| 330 µF | ||
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| 18 | 1 | 330 µH | ||
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| L1 | 3 |
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| 10 | D1 |
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| 12 |
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| 1N5819 |
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Figure C-1. Jackrabbit Power Supply Schematic
The external power, +RAW, is provided to any daughterboard connected to the Jackrabbit via pin 38 of header J4. +RAW is not protected against reversed polarity, such as could happen if the cable was connected to header J1 offset by one pin. This absence of protec- tion is intentional so as to provide the maximum possible voltage to any daughterboard connected to the Jackrabbit.
Capacitor C1 provides surge current protection for the voltage regulator, and allows the external power supply to be located some distance away from the Jackrabbit board. A switching power supply or a linear power supply option is provided, depending on the Jackrabbit model.
User’s Manual | 79 |
