101-1017 Rabbit Semiconductor, 101-1017 Datasheet - Page 212

• Manufacturer Part Number: 101-1017
• Description: KIT DEV POWERCORE 3800 INT'L
• Manufacturer: Rabbit Semiconductor
• Series: PowerCore FLEXr
• Type: MPU Moduler

Specifications of 101-1017

• Contents: RabbitCore Module, Dev. Board, AC Adapter, Cable and Dynamic C® CD-Rom
• Processor To Be Evaluated: PowerCore 38xx
• Interface Type: Ethernet
• For Use With/related Products: RCM3800
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Thus, as an example, if the user's 5 V circuitry consumes 2.5 W and the user's 3.45 V cir-
cuitry consumes 0.5 W, then total power needed from the power supply is (2.5 W × 1.33 +
0.5 W × 1.92 + (PowerCore consumption as optionally configured)) = 5.3 W to 7.0 W. If
that external power supply is a 24 V center-tapped AC supply (giving 12 V on each side of
the center tap), then it will need to source I = (Power/Voltage) current. Bear in mind that
voltage presented to the regulators has a 0.7 V diode drop. Thus the voltage in this formula
must be reduced by 0.7 V, so current = Power/11.3 V current (in amps). 5.3 W /11.3 V =
469 mA; 7.0 W/11.3 V = 619 mA. This is the maximum current the AC power supply will
need to deliver. An AC supply may not need to deliver that much current since the filter
capacitor may raise the DC voltage input into the regulator, allowing less current to be
consumed. If a DC supply were used, this is the current the power supply would have to
deliver.
The input power circuit configuration is shown below for Option 4.
A full-wave center-tapped rectifier has a third connection on the secondary side of the AC
transformer for ground. Both sides of the windings go separately through diodes as shown
above. This is essentially two half-wave rectifier circuits with one inverted from the other.
This configuration combines the advantages of full-wave and half-wave rectifiers.
204
The output from this full-
wave center-tapped rectifier
is shown at right.
W
PowerCore FLEX