Datasheet

© 2008 Microchip Technology Inc. DS01208A-page 7
AN1208
FIGURE 5: STATE FLOW DIAGRAM OF DIGITAL PFC
Update
PWM2 Duty
Cycle
Current PI
Control
Calculate
Reference
Current
Voltage PI
Control
Power-on
delay
Calculate
∑ V
AC
and
Sample
Count 'N'
Calculate
Feed-forward
Compensate
E
n
d
o
f
P
o
w
e
r
-
o
n
D
e
l
a
y
S
t
a
r
t
o
f
P
o
w
e
r
-
o
n
D
e
l
a
y
Measured V
AC
Measured V
DC
Calculate
Sample
Count 'N'
A/D Interrupt
Service
Routine
Measured I
AC
Wait for ADC
Interrupt
Measured V
AC
V
AVG
and
I
ACREF
Voltage
PFC Switch
Pressed
Read
I
A
and I
B
∑ V
AC
and