Infineon XDPL8218, Design Manual

Page: 5 / 48

Design Guide 5 of 48 V 1.0
2018-06-06
XDPL8218 design guide
For high power factor flyback converter with constant voltage output
Design specifications
2 Design specifications
A front-stage HPF flyback converter with CV output set-point V
out,setpoint
of 54 V (54 V/0.8 A) has been selected as a
design example. The design specifications are shown in Table 2 .
Table 2 Design specifications
Specification Symbol Value Unit
Normal operational minimum AC input voltage V
AC,min
90 V
rms
Normal operational maximum AC input voltage V
AC,max
305 V
rms
Normal operational AC input frequency F
line
47 ~ 63 Hz
Secondary-side regulated CV output set-point V
out,setpoint
54 V
Steady-state output load current I
out
0 ~ 800 mA
Steady-state full-load output power P
out,full
43.2 W
Minimum efficiency at P
out,full
ƞ
min,at,P,out,full
90 %
Target minimum switching frequency at P
out,full
f
sw,min,at,P,out,full
52 kHz
Note: P
out,full
of 43.2 W is defined in this design example, to be able to supply a second-stage CC converter
which has minimum efficiency of 93 percent (or maximum 3.2 W loss) at full load, for a 40 W LED
driver design.
Note: The recommended f
sw,min,at,P,out,full
is between 50 kHz and 65 kHz. In general, higher f
sw,min,at,P,out,full
value would result in a smaller flyback transformer with lower efficiency, while lower f
sw,min,at,P,out,full
value would result in a larger flyback transformer with higher efficiency.