ICB1FL01G Datasheet, PDF (32/38 Pages) Infineon Technologies AG – Smart Ballast Control IC for Fluorescent Lamp Ballasts

ICB1FL01G
Application Examples
The second solution of this equation (with the minus sign) leads to a result of 50163Hz, which is on the capacitive
side of the resonant rise. This value is no solution, because the operating frequency approaches from the higher
frequency level.
In the next step we can calculate the current through the resonant capacitor C20 when reaching a voltage level
of 800V peak.
IC20 = VIGN ⋅ 2 ⋅ π ⋅ fIGN ⋅ C20 = 800V ⋅ 2 ⋅ π ⋅ 69759Hz ⋅ 4, 7nF = 1, 65A
Finally the resistors R24, R25 can be calculated from IC20 and the current limitation threshold during ignition
mode.
-R-----2---4----^â‹---R----2---5---
R24 + R25
=
V-----L----S----C----S----L----I---M------I--T--
I _{C 20}
=
1--0-,^{--,-6--8-5--V--A---}
=
0, 485Ω
Selected values are R24= 0,82Ohm; R25= 0,82Ohm.
Lamp voltage sense resistors R31, R32, R33
The selected lamp type 54W-T5 has a typical run voltage of 167V peak. We decide to set the EOL-thresholds at
a level of 1,5 times the run voltage level (= 250,5V peak).
R31 + R32 + R33
=
----V----L----E----O-----L-----
ILVSEOL
=
-2-2--5-3-0--0--^,-_µ-5---A-V---
=
1089 k Ω
Selected values: R31= 330k; R32= 390k; R33= 390k
Current source resistors R34, R35 for detection of high-side filament
R34 + R35
=
-----------V-----I--N-----M------I--N--------------
ILVSSINKMAX
–
(R31
+
R32
+
R33)
=
-22--2-0---0_µ---V-A--- – (1110k)
=
7980 k Ω
Selected values: R34= 2,2M; R35= 2,2M;
Current limitation resistor R30 for floating bootstrap capacitor C14
A factor of 2 is provided in order to keep current level significant below LSCS turn-off threshold.
R30
≥
---2----^â‹---V-----C----C-----O----N-----
VLSCSOVC
⋅
-R-----2---4----^â‹---R----2---5---
R24 + R25
=
2---1--⋅_{-,--1-6--4-V--V--- ⋅ 0-0--,-},_{--8-8--2-2----+-}⋅_---0-0--,_{-,--8-8--2-2-}
=
7, 18Ω
Selected value: R30= 10Ohm.
Low-side filament sense resistor R36
For a single lamp ballast
Selected value: R36= 56k
R36 ≤ ^{V----I-R-R---E--E---S-S--C-3----1M---M---I--N-I---N--} = -2-1-7--^,-_,--5-6--5--_µ--V--A--- = 56, 16kΩ
Preliminary Datasheet Version 1.5
32
June 2005