ICB1FL02G_08 Datasheet, PDF (32/37 Pages) Infineon Technologies AG – Smart Ballast Control IC for Fluorescent Lamp Ballasts

ICB1FL02G
Application Examples
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_-1--0_-5---,_-µ--5_--A-V_---
=
1165 k Ω
Selected values: R31= 390k; R32= 390k; R33= 390k (=1170k).
Current source resistors R34, R35 for detection of high-side filament:
R34 + R35
=
-----------^V-----^I--^N-----^M------^I--^N--------------
ILVSSINKMAX
–
( R31
+
R32
+
R33 )
=
2^-2--6^-0---µ^0---V-A^{--- – (1170k)}
=
6522 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_{-----R-----E----S---C-----1---M------I---N--}
IRES3MIN
=
--¹---^,---⁵---⁵----^V-----
27, 0µA
=
57, 4kΩ
R36 _A
≥
-^V----^R-----^E----^S---^C-----¹---^M------^A-----^X---
IRES3MAX
=
1^--1-5^--,-,^--6-1^--5--µ^--V--A^---
=
109, 3kΩ
Selected values in a topology with 2 lamps in parallel: R36A= 110k; R36B= 110k.
Low pass filter capacitor C19:
Capacitor C19 provides a low pass filter together with resistor R36 in order to suppress AC voltage drop at the
low-side filament. When we estimate an AC voltage of 10V peak-to-peak at low-side filament during run mode at
f_RUN= 40kHz, we need a suppression of at least a factor F_LP= 100 (-40dB).
C19 =
----------------^F---^L2-----^P----–-----¹----------------- =
(2 ⋅ π ⋅ fRUN ⋅ R36)
2
----------------¹---⁰---⁰-------–-----¹---------------- = 7, 1nF
(2 ⋅ π ⋅ 40kHz ⋅ 56k)
Selected value for better ripple suppression: C19= 22nF.
Datasheet Version 2.1
32
September 2008