4.3 FPS Theory of Operation
Section 4: Theory of Operation
CV-6SLX User Manual
0101-8242-0, Rev. C
4-8
4.3.3 Filament Supply PCB
Figure 4-8 is a top-level block diagram for the Filament Supply PCB, whose circuits are described
in detail below.
Figure 4-8 Filament Supply PCB Overview Block Diagram
Filament DC Voltage Supply for Switch Mode Converter
A single-phase bridge rectifier circuit provides the raw dc power for the high-frequency switches.
The DC voltage is filtered and a + (positive) rail voltage and a - (negative) rail voltage is
established. The single-phase 220-V power for the filament and positions circuits enters on J104
Pin 1 and 4. The circuit is protected by fuses F-1 and F-2. The ac power is rectified by DB-10
and filtered by inductors L-10 and L-11 in combination with rail capacitors C-11 and C-12.
Low-Voltage DC Supplies
Low DC voltages of +24 V, +12 V, +5 V and –12V are supplied by T-102 via bridge rectifiers DB-
14 and DB-14. +12 V and +5V are down-regulated from +24 V by VR-101 and VR-103. -12 V is
down-regulated from –24 V by VR-102. These supplies provide power for the logic and control
circuits on the board.
Filament
DC Voltage
Supply
Filament
Current
Control
Circuit s
Low
Volt age
DC Supplies
Filament
Swit ch Mode
Supply
FILAMENT BIAS SET IN
EMISSION REQUEST IN
+ 24 V
208 -220
VAC
GUN GO O N IN
AUTO - BIAS ACTIVATE IN
AB IAS _RESET _IN
- 12 V
+ 5 V
+ 12 V
Current
Sense
Gun
Control
Monit or
Out puts
FILAMENT CURRENT MONITOR
EMISSION MONITOR OUT
GUN IS READY OUT
GUN IS ON OUT
AUT O -BIAS INDICATOR HI
AUT O -BIAS INDICATOR LO
HVPS
Status
EM MON
FIL I MON
HV INTERL OCK OUT
FIL PWR OK
FIL OK /OPEN
H VIS ON IN
HV INTERLOCK IN
HV IN REGULATION IN
PRIMARY FILAMENT VOLTAGE
