ICB1FL01G Datasheet, PDF (13/38 Pages) Infineon Technologies AG – Smart Ballast Control IC for Fluorescent Lamp Ballasts

ICB1FL01G
Functional Description
3.3 Typical operating levels during start-up
Within 10ms after start-up the inverter shifts operating frequency from 120kHz to the preheating frequency set by
resistor at pin RFPH. Preheating time can be selected by programming resistor at RFPH pin in steps of 17ms from
0ms to 2000ms.
After preheating the operating frequency of the inverter is shifted downwards in 40ms typically to the run
frequency. During this frequency shifting the voltage and current in the resonant circuit will rise when operating
close to the resonant frequency with increasing voltage across the lamp. As soon as the lower current sense level
(0,8V) is reached, the frequency shift downwards is stopped and increased by a couple of frequency steps in order
to limit the current and the ignition voltage also. The procedure of shifting the operating frequency up and down
in order to stay within the max ignition level is limited to a time frame of 235ms. If there is no ignition within this
time the control is disabled and the status is latched as a fault mode.
Typical variation of operating frequency during start-up
120kHz
f,V
65kHz
50kHz
40kHz
Frequency
Lamp Voltage
Figure 9
10ms
Softstart
0-2000ms
Preheating
40-235ms 250ms
t
Ignition Pre-Run Normal Operation
Softstart proceeds in 15 steps à 650µs according ∆f_PH = (120kHz - f _PH)/ 15steps.
Ignition proceeds in 127 steps à 324µs according ∆f_IGN = (f_PH - f_RUN)/ 127steps.
Typical variation of operating frequency and lamp voltage during start-up.
1000
900
800
700
Ignition
600
500
Without
400
Load
300
200
100
0
10000
With
Load
Run
After
Ignition
Operating Frequency
Preheating
100000
Figure 10 Typical lamp voltage versus operating frequency due to load change of the resonant circuit.
Preliminary Datasheet Version 1.5
13
June 2005