Chroma A620028 - Function Description; I;P (PFC) Stage

Theory of Operation
6-3
Figure 6-4 shows the digital stage structure.
Figure 6-4
6.2 Function Description
6.2.1 I/P (PFC) Stage
1. The input stage is a bridge rectifier that rectifies the 3-phase AC power source to DC.
2. The input stage inhibits inrush current by connecting the input circuit through a 40Ω
resistor in series during power-on to charge the input capacitor. It then turns on an SCR
after a few seconds and bypasses this current limit resistor.
FPGA
DSP Memory
Linear
Regulator
+1.26VD
+3.3VD
+5VD
DGND
Isolated APG
Keyboard
K Board U Board
RS232/RS485
USB,System BUS
G Board
GPIB
Ethernet
Z Board
Fan signal
A Board
AC_Fault signal
C Board
F Board
Driver signal
SCR driver signal
+1.2VD
D Board