ICB1FL02G Datasheet, PDF (31/37 Pages) Infineon Technologies AG – Smart Ballast Control IC for Fluorescent Lamp Ballasts

ICB1FL02G
Set resistor R21 for run frequency, at a projected run frequency of 45kHz:
Application Examples
R21
=
RFRUN
=
5-----⋅_{---1---0---8-----}⋅_---Ω_{-----H-----z-}
fRUN
=
5-----⋅_{---1---0---8-----}⋅_---Ω_{-----H-----z-}
45 k H z
=
11, 1kΩ
Selected value: R21= 11,0k
Set resistor R22 for preheating frequency, at a projected preheating frequency of 105kHz:
R22
=
RFPH
=
-f-----P-------H-----------_â‹-R-----R----F------F-R------R---U------U----N------N--------–----1--
5 ⋅ 108 ⋅ ΩHz
=
-1------0------5-------k-------H--------1-z-----1----_⋅--^,_{----1--0----1---k---,------0-------k------–----1--}
5
⋅
8
10
⋅
Ω
H
z
=
8, 4kΩ
Selected value: R22= 8,2k
Set resistor R23 for preheating time, at a projected preheating time of 900ms:
R23 = RTPH = -₍--1---1-T--2--P-m---H--s---^[)--m--_⁄--₍-s--k-^]--_Ω-----₎- = -₍--1---1---2--9-m--0---0-s--₎-m---_⁄--s₍---k---_Ω------₎ = 8, 93kΩ
Selected value: R23= 8,2k
Gate drive resistors R16, R26, R27 are recommended to be equal or higher than 10Ohm.
Shunt resistors R24, R25:
The selected lamp type 54W-T5 requires an ignition voltage of V_IGN= 800V peak. In our application example the
resonant inductor is evaluated to L2= 1,46mH and the resonant capacitor C20= 4,7nF. With this inputs we can
calculate the ignition frequency f_IGN :
fIGN =
---1-----^±-----V-^π--------B--^â‹------V-U--------I--S---G-------^{⋅--N----2------} =
4 ⋅ π² ⋅ L2 ⋅ C20
----------------1----^±-----^{π-4------1---⋅---0---8----V--0------0---â‹}----V--2------------------- = 69759Hz
4 ⋅ π² ⋅ 1, 46mH ⋅ 4, 7nF
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.
Datasheet Version 1.2
31
February 2006