Application Note
23 of 28
V 1.0
2019-01-23
ILD8150 80 V high side buck LED driver IC with hybrid dimming
Application with flyback converter XDPL8218
5
Application with flyback converter XDPL8218
The ILD8150 IC operates as the secondary stage along with a primary-stage flyback or LLC converter. For
example, it may be used together with a PFC flyback based on XDPL8218. XDPL8218 is a digitally configurable
Secondary-Side Regulated (SSR) controller suitable for PFC flyback operating in Constant Voltage (CV) mode.
The XDPL8218 board operates with a universal AC input of 90 V
rms
to 305 V
rms
and provides a constant voltage of
54 V. So the ILD8150 hysteretic buck converter operates with a fixed input voltage of 54 V and has constant
output current. ILD8150 can provide a wide dimming range from 0.5 to 100 percent, with high accuracy across
all conditions. It dumps 100 or 120 Hz ripples from the primary side, so the output current is pure DC, which
eliminates flicker. The efficiency of such a system is shown in Figure 26.
Figure 26
Efficiency of combined stages vs number of LEDs
86,1
87
87,8
88,3
88,8
89,4
84
85
86
87
88
89
90
33/11
36/12
39/13
42/14
45/15
48/16
Ef
fici
en
cy
%
Output voltage
[V]/
LED number
Efficiency vs LED number
