Power Factor Regulator (Pfr) Substitution Board; Duty Cycle Regulator; H-Bridge Board; Interface Connections - Hologic QDR 4500 Technical Manual

Power Factor Regulator (PFR) Substitution Board

The PFR Substitution Board is an interface adapter that rectifies the 240VAC power voltage
from the Low Voltage Power Supply and applies it to an energy storage capacitor. This board
may be replaced in future XRC designs by an active filter (Power Factor Regulator) designed to
control the crest factor and wave shape of the current drawn by the XRC from the power source.

Duty Cycle Regulator

The Duty Cycle Regulator generates power pulses of controlled amplitude for application,
through the H-Bridge, to the high voltage transformer in the X-ray source unit. These power
pulses are generated by a switching regulator transferring charge from the energy storage
capacitor to the load through a transfer inductor. The pulse amplitude determines the peak
energy of the X-rays generated by the X-ray Source Unit.

H-Bridge Board

The H-Bridge alternately connects the output pulses from the Duty Cycle Regulator to the high
voltage transformer in the X-Ray source unit with forward and reverse polarity.

Interface Connections

Figure 2-9 shows the high-level interconnections of the five X-Ray Controller Assembly boards.
Figure 2-10 through Figure 2-14 show the interface connections between the five boards. Table
2-11 through Table 2-19 describe the interface signals and identify the interconnection
connector and pin assignments among the five boards.
To/From
C-Arm
Interface
Relay Control
LOW
VOLTAGE
POWER
AC Power
SUPPLY
From
Power
Module
240 VAC

Figure 2-9. X-Ray Controller Assembly High-Level Interconnection Diagram

Section 2 - Functional Description
I/O
and
LOGIC
BOARD
Power
Timing
Reference
Isolated Power
PFR
340 VDC
SUBSTITUTION
BOARD
Filament Drive
Beam Current Sense
Bridge Control
H-BRIDGE
BOARD
DUTY
Sense
CYCLE
DRIVER
BOARD
X_RAY
SOURCE
2-21