Datasheet

Ballast section L6585DE
20/33
The oscillator characteristic curves represent the half bridge frequency versus the
resistance R placed between RF pin and ground. During preheating R is equal to R
RUN
in
parallel with
R
PRE
whereas during Run mode R is equal to R
RUN
. Each curve is related to a
value of the
C
OSC
capacitor and are depicted in Figure 10.
The value of
C
OSC
is measured between pin 1 (OSC) and 15 (GND); for other capacitor
values please refer to AN2870.
The right value of R during preheating and run mode can be found graphically considering
the curve related with the chosen capacitor and respectively
F
PRE
and F
RUN
“
Figure 10. Oscillator characteristics
Some useful equations are given:
IGNPREIGN
ddd
CH
TchPRE
CR3T
5.1
63.4
lnCRC
I
63.4
TT
⋅⋅≅
⎟
⎠
⎞
⎜
⎝
⎛
⋅+==