Infineon XDPL8218, Design Manual

Page: 3 / 48

Design Guide 3 of 48 V 1.0
2018-06-06
XDPL8218 design guide
For high power factor flyback converter with constant voltage output
Introduction
1 Introduction
XDPL8218 regulates Constant Voltage (CV) output of a HPF flyback converter, according to its feedback (FB) pin
voltage signal, which is controlled by the secondary-side regulation FB circuit via an isolated optocoupler, as
shown in
Figure 1 .
CoolMOS™
XDPL8218
Feedback
Circuit
VCC
CS
GD
ZCD
CV Output
HV
FB GND UART
AC Input
voltage
Figure 1 XDPL8218 flyback converter simplified circuitry with secondary-side regulated CV output
For LED lighting applications, XDPL8218 flyback CV output usually is converted to a CC output by a second-
stage DC-DC switching or linear regulator.
XDPL8218 comes in a PG-DSO-8 package with eight pins, as shown in the datasheet [1]. The main functions of
each pin are shown in
Table 1 .
Table 1 XDPL8218 pins assignment
Pin Symbol Type Pin name and main functions
1 ZCD Input Zero Crossing Detection pin:

Transformer auxiliary winding ZCD via external resistor/divider

Sensing of the reflected input and output voltage signals from auxiliary winding
via external resistors divider
2 FB Input Feedback pin:

Feedback voltage sensing for secondary-side output regulation
3 CS Input Current Sense pin:

Flyback MOSFET current sensing via external shunt resistor
4 GD Output Gate Drive pin:

Flyback MOSFET gate-drive control via external series resistor
5 HV Input High Voltage pin:

V
CC
charging via its internal 600 V start-up cell during start-up and protection

Rectified AC input voltage sensing via external series resistor for line
synchronization