ICB2FL02G Datasheet, PDF (15/55 Pages) Infineon Technologies AG – Smart Ballast Control IC for Fluorescent Lamp Ballasts

2^nd Generation FL-Controller for FL-Ballasts
Functional Description
2.2.2 Operating Levels from Soft Start to Run Mode
This chapter describes the operating flow from phase 5 (Preheating mode) until phase 8 (Run mode)
in detail. In order to extend the life time of the filaments, the controller enters - after the Soft Start
Phase - the Preheating mode (phase 5 Figure 6). The preheating frequency is set by resistors R22
PIN RFPH to GND in combination with R21 (Figure 3) typ. 100 kHz e.g. R22 = 8.2 kΩ in parallel to
R21 = 11.0 kΩ see Figure 3 at the R_FRUN - PIN). The preheating time can be selected by the
programming resistor (R23 in Figure 3) at PIN RTPH from 0 ms up to 2500 ms (phase 5 Figure 6).
Figure 6 Typical Variation of Operating Frequency during Start Up
During Ignition (phase 6 Figure 6), the operating frequency of the inverter is shifted downward in t_typ =
40 ms (t_max = 237 ms) to the run frequency set by a resistor (R21 in Figure 3) at PIN RFRUN to GND
(typical 45 kHz with 11.0 kΩ resistor). During this frequency shifting, the voltage and current in the
resonant circuit will rise when the operation is close to the resonant frequency with increasing voltage
across the lamp. The ignition control is activated if the sensed slope at the LSCS pin reaches typically
205 mV/µs ± 25 mV/µs and exceeds the 0.8V threshold. This stops the decreasing of the frequency
and waits for ignition. The ignition control is now continuously monitored by the LSCS PIN. The
maximum duration of the Ignition procedure is limited to 237 ms. Is there no Ignition within this time
frame, the ignition control is disabled and the IC changes over into the latched fault mode.
Furthermore, in order to reduce the lamp choke, the ignition control is designed to operate with a lamp
choke in magnetic saturation during ignition. For an operation in magnetic saturation during ignition;
the voltage at the shunt at the LSCS pin 1 has to be V_LSCS = 0.75V when ingition voltage is reached. If
the ignition is successful, the IC enters the Pre – Run mode (phase 7 Figure 6). The Pre Run mode is
a safety mode in order to prevent a malfunction of the IC due to an instable system e.g. the lamp
parameters are not in a steady state condition. After 625 ms Pre Run mode, the IC changes into the
Run Mode (phase 8 Figure 6). The Run mode monitors the complete system regarding bus over- and
under voltage, open loop, over current of PFC and / or Inverter, lamp over voltage (EOL1) and rectifier
effect (EOL2) (see chapter 2.5) and capacitive load 2 (see chapter 2.6).
Preliminary Datasheet
Page 15 of 55
ICB2FL02G
V1.2