Power Distribution (Prodigy Ii Systems Df+1200 And Greater) - GE Medical Systems PRODIGY Service Manual

2.6 Power Distribution (PRODIGY II Systems
DF+1200 and greater)
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2-64 System Overview
The PRODIGY II system reduces scanner cost by using a single switching DC
power supply which provides +5,+/-12, and +24VDC. The supply is connected
directly to the cSBC via J14. J13 is provided as a power out connector to run
power to the DMB for Prodigy II. 0R0 bypass resistor are provided to allow
flexibility in grounding and filtering schemes. The PWB is divided into 4
ground plane regions - DGND for +5V digital returns, AGND for +/-12V analog
returns, SCNGND for +24V returns, and ISO_GND for the host I/O island.
Large zeners and rectifiers are provided for over-voltage and reverse-voltage
protection. Standard capacitor filter banks are provided. For EMC all cable
exits other than host and DMB I/O are located over the 24V planes. The 24V
plane is separated from the 5V plane via optical isolation to prevent 5V noise
from reaching cables (radiated EMC) and to prevent motor noise and ESD
pulses from reaching the digital and analog IC's. The 24V plane contains
primarily power FET switches and power resistors used to control scanner
motors, X-ray source, LED, etc. The +/-12V planes contain analog electronics
used for detector and HVPS control. A +12V regulator is used to produce
12VDC for the Centent drives of off +24VDC, maintaining isolation from the
+12V plane. An additional +5V regulator is used to make 5V for the OMI's of
off +12V motors. 4 opto channels are used to sense the presence of the 4 DC
input voltages. The opto outputs are used to drive 4 green power on indicator
LED's and to allow the CPU to detect power outs.
PRODIGY Service Manual (Rev C - 2000)