101-1017 Rabbit Semiconductor, 101-1017 Datasheet - Page 215

• 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

The input power circuit configuration is shown below for Option 5.
Half wave rectification allows a common ground between the power-supply ground and
the circuit ground. Half-wave rectification only requires one diode, and so is less expensive
than the other power-supply options.
A half-wave rectifier experiences only one diode voltage drop (0.7 V) during the rectification.
Because current flows only during half the cycle, twice as much current will be required
(albeit for only half of the wave cycle) compared to a full-wave rectifier. Since all the cur-
rent going through the rectifier must go through a single diode drop, the power dissipated
is 0.7 V × current. A larger, more expensive AC transformer will be needed to provide the
current for a half-wave rectifier because twice the current is required during the positive
half-cycle to fill the gaps.
Because there is a common AC ground between the AC power transformer and the circuit,
AC zero-crossing detection is possible. Zero-crossing detection allows accurate triac tim-
ing control. Thus, the zero-crossing detection circuit is stuffed and triac control is sup-
ported with this option.
User’s Manual
The output from this half-
wave rectifier is shown at
right.
After the rectifier, the AC
voltage is filtered with a
large (1000 µF) capacitor.
The final filtered voltage is
shown by the solid line in the
diagram at right.
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