EVAL6569 Datasheet, PDF (8/14 Pages) Panasonic Semiconductor – THE L6569 A NEW HIGH VOLTAGE IC DRIVER FOR ELECTRONIC LAMP BALLAST

AN880 APPLICATION NOTE
as a transformer supplying the voltage to the fila-
ments. Only few components are added around
the L6569 (see figure 18), and the control of the
preheat energy is less sensitive to the preheat du-
ration and the inverter frequency (see figure 17b).
The start up initialization
The initial conditions of the power switching start
up requires care; especially if the resonant and
switching frequencies are close to each other.
The resonant network is not loaded and the full
Figure 17: Basic preheat voltage control diagram (a); preheat filament energy curve (b)
(A)
VCTL
LAMP
E
Vf
VCTL
(B)
E=V²/R
t
Figure 18: Double frequency control for the L6569 with programmed frequency and duration.
1_Vs
RF
R
CF
2_RF
3_CF
L6569
C
CF_ST
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