AN_UBA2024T_15 Datasheet, PDF (12/18 Pages) NXP Semiconductors – CFL applications

Philips Semiconductors
CFL applications with the UBA2024T
APPLICATION NOTE
6.2 EXAMPLE 2: a 14W lamp (12W/150mA burner, suited for cold ignition)
Determining component values for 115V/60Hz mains
1) From table 2: Voltage doubler configuration, CBUF1=CBUF2=22µF, RFUS=6.8Ω
2) Vlamp≈12/0.150=80V. From table 3: Effective lamp coil voltage VLla_eff ≈ 122V. For LLA=3.1mH the output
frequency must be fout=122/(0.150⋅3.1⋅10^-3⋅2⋅π)=41.8kHz.
3) We choose COSC=180pF, then ROSC=1/(1.09⋅41.8⋅10³â‹…180⋅10^-12)=122kΩ. To stay within E24-range we choose
120kΩ, so fout=1/(1.09⋅120⋅10³â‹…180⋅10^-12)=42.5kHz.
4) The only E6-range value of CLA resulting in fign/fout between 1.6 and 1.8 is 1.5nF (fign/fout ≈1.74).
5) This burner is suited for cold ignition: CSW=100nF (see paragraph 5.3)
6) D1=D2=1N4007, CFS=10nF, CVDD=10nF and CDV=220pF (see section 6.4).
7) CHB1=CHB2=47nF (see section 6.4). LFILT is choosen 2.7mH.
Determining component values for 230V/50Hz mains
1) From table 2: Standard configuration, CBUF=6.8µF, RFUS=27Ω
2) Vlamp≈12/0.150=80V. From table 3: Effective lamp coil voltage VLla_eff ≈ 122V. For LLA=3.1mH the output
frequency must be fout=122/(0.150⋅3.1⋅10^-3⋅2⋅π)=41.8kHz.
3) We choose COSC=180pF, then ROSC=1/(1.09⋅41.8⋅10³â‹…180⋅10^-12)=122kΩ. To stay within E24-range we choose
120kΩ, so fout=1/(1.09⋅120⋅10³â‹…180⋅10^-12)=42.5kHz.
4) The only E6-range value of CLA resulting in fign/fout between 1.6 and 1.8 is 1.5nF (fign/fout ≈1.74).
5) For cold ignition CSW=33nF (see paragraph 5.3)
6) D1..D4=1N4007, CFS=10nF, CVDD=10nF and CDV=220pF (see section 6.4).
7) CHB1=CHB2=47nF (see section 6.4). LFILT is choosen 2.7mH.
REF
RFUS
D1, D2
D1..D4
CBUF1, CBUF2
CBUF
LFILT
CHB1, CHB2
CLA
DESCRIPTION
Fusible inrush current limiter resistor
Voltage doubler diodes
Bridge rectifier diodes
Buffer capacitors
Buffer capacitor
Filter inductor
Half bridge capacitors
Lamp capacitor
LLA
CDV
CFS
CVDD
COSC
ROSC
CSW
Lamp inductor
dV/dt limiting capacitor
Floating Supply buffer capacitor
low voltage supply buffer capacitor
Oscillator capacitor
Oscillator resistor
Sweep time capacitor
REMARKS
Special type, fusible, high peak power
High temperature electrolytic type
High temperature electrolytic type
Axial type
Foil type, capable of withstanding peak
voltages of twice it’s dc rating
E-16-Core
115V/60HZ
6.8Ω
1N4007
22µF/200V
2.7mH
47nF/200V dc
1.5nF/400V dc
230V/50Hz
27Ω
1N4007
6.8µF/400V
2.7mH
47nF/200V dc
1.5nF/400V dc
3.1mH
220pF/500V dc
10nF/50V
10nF/50V
180pF/50V
120kΩ/1/8W
100nF/25V
3.1mH
220pF/500V dc
10nF/50V
10nF/50V
180pF/50V
120kΩ/1/8W
33nF/50V
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