ICB2FL03G Datasheet, PDF (18/60 Pages) Infineon Technologies AG – 2nd Generation FL Controller for Fluorescent Lamp Ballasts

ICB2FL03G
Controller for Fluorescent Lamp Ballasts
Functional Description
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 (typically 45 kHz
with an 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 0.8 V
threshold. This stops the decrease 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. If there is 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 size of the lamp choke, the ignition control is designed to operate with a lamp
choke in magnetic saturation during ignition. For operation in magnetic saturation during ignition; the voltage at
the shunt at the LSCS pin 2 has to be V_LSCS = 0.75 V when the ignition voltage is reached. If 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 unstable system – e.g., the lamp parameters are not in a steady state condition.
After 625 ms pre-run mode, the IC changes to the run mode (phase 8, Figure 6). The run mode monitors the
complete system regarding bus over- and undervoltage, open loop, overcurrent of PFC and / or inverter, lamp
overvoltage (EOL1) and rectifier effect (EOL2) (see Section 2.5) and capacitive loads 1 and 2 (see Section 2.6).
Figure 8 shows the lamp voltage versus the frequency during the different phases from preheating to the run
mode. The lamp voltage rises by the end of the preheating phase with decreasing frequency (e.g., 100 kHz to
50 kHz) up to, for example, 700 V during ignition. After ignition, the lamp voltage drops down to its working level
with continuous decreasing of the frequency (Figure 8) down to its working level e.g. 45 kHz (set by a resistor at
the RFRUN pin to ground). After decreasing of the frequency stops, the IC enters the pre-run mode.
Lamp Voltage vs Frequency @ different Modes
1000
900
800
700
600
Operation without Load
500
IGNITION
400
300
200
Operation with Load
100
0
10000
PRE Run
and
RUN Mode
After
IGNITION
Frequency [Hz]
After Ignition Before Ignition
1000
900
800
700
600
500
400
300
200
100
Pre Heating
0
100000
Figure 7 Lamp Voltage versus Frequency during the different Startup Phases
Final Data Sheet
18
V1.1, 2013-08-14