The operating frequency of the system is determined by the inductance of
the primary and the bulk capacitor across the primary at resonance.
Coiltronics
®
Transformer Features:
1. Supply high voltage.
2. Operation frequency range from 40 to 80kHz.
3. Deliver output power from 2.5 to 14 watts.
4. Slim or low profile type easily built into your design.
5. Available in through-hole and SMT recess or gull wing type.
6. Operate in Royer and direct IC drive.
7. 1500 volt primary to secondary isolation.
8. Ferrite core material.
9. Designed for floating and non-floating applications.
10. Transformer secondary is machine wound on sections to increase
leakage inductance and reduce voltage gradient between layers.
F
Re
s
1
=
2
×
π
L
Pr
i
×
C
Bulk
Fres = Resonance Frequency
Determine the ballast capacitor value using the equation below.
C
ballast
=
I
lamp
2
×
π
×
F
res
(
V
run
−
V
sec
)
2
Layout and Circuit Considerations
Vsec = Transformer secondary voltage
Vrun = Lamp running voltage
Ilamp = Lamp current
Fres = Resonance frequency
Cballast = Ballast capacitor
The capacitor voltage is 90 degrees out of phase with the lamp running
voltage.
From this equation, determine the value of the ballast capacitor.
• The high voltage traces must be separated from low voltage traces.
• The ballast capacitor must be placed closer to the transformer secondary
pin.
• Avoid long wire connections from the transformer to the lamp. Stray
capacitance between wire and ground will reduce efficiency.
• Incorporate open lamp and overload protection in the circuit design. Open
lamp will cause full voltage in the transformer output and will burn the
transformer. Most of the CCFL IC has protection built in the circuit for
open and overload condition.
Schematic Relation to Part Number
Schematic A
CTX110652-R
CTX210652-R
Schematic B
CTX110655-R
CTX110657-R
CTX110659-R
CTX210655-R
CTX210657-R
CTX210659-R
Schematic C
CTX210403-R CTX110603-R
CTX210407-R CTX110605-R
CTX210409-R CTX110607-R
CTX210411-R CTX110609-R
CTX310403-R CTX110611-R
CTX310405-R CTX210603-R
CTX310407-R CTX210605-R
CTX310409-R CTX210607-R
CTX310411-R CTX210609-R
CTX210611-R
Schematic D
CTX110600-R
CTX210600-R
Schematic E
CTX410805-R
CTX410807-R
CTX410809-R
COOPER [ COOPER BUSSMANN, INC. ]
