Function Description; I/P (Pfc) Stage - Chroma 62020H-150S Operating & Programming Manual

Figure 6-4 shows the digital stage structure.
K Board
Keyboard
Isolated APG
+5VD
DGND
DSP
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.
U Board
RS232/RS485
USB,System BUS
D Board
+1.26VD
Linear
+1.2VD
Regulator
+3.3VD
FPGA
Memory
Figure 6-4
Theory of Operation
G Board
GPIB
Ethernet
Z Board
Fan signal
A Board
AC_Fault signal
C Board
Driver signal
F Board
SCR driver signal
6-3