ICB2FL03G Datasheet, PDF (17/60 Pages) Infineon Technologies AG – 2nd Generation FL Controller for Fluorescent Lamp Ballasts

ICB2FL03G
Controller for Fluorescent Lamp Ballasts
Functional Description
If V_CC exceeds the 10.6 V level and stays below 14.0 V (start-up hysteresis – phase 2, Figure 5), the IC checks
whether the lamps are assembled by detecting a current across the filaments.
The low side filaments are checked from a source current of typical I_RES3 = - 21.3 μA flowing out of pin 13 RES
(Figure 5 I_RES). This current produces a voltage drop of V_RES < 1.6 V (filament is ok) at the low side filament sense
resistor (R 36 in Figure 3), connected to GND (via low side filament). An open low side filament is detected (see
Section 2.3.2), when the voltage at the RES pin exceeds the V_RES > 1.6 V threshold (Figure 5 V_RES).
The high side filaments are checked by a current of I_LVS > 12 μA typically via resistors R41, R42, R43 and R44
(Figure 3) into the LVS pin 12 (for a single lamp operation). An unused LVS pin has to be disabled via connection
to GND. An open high side filament is detected (see Section 2.3.3) when there is no sink current into the LVS pin.
This causes a higher source current out of the RES pin (typically 42.6 μA / 35.4 μA) in order to exceed V_RES >
1.6 V. In the case of defective filaments, the IC keeps monitoring until an adequate current from the RES or the
LVS pin is present (e.g. in case of removal of a defective lamp).
When V_CC exceeds the 14.0 V threshold – by the end of the start-up hysteresis in phase 2 , Figure 5 – the IC waits
for 130 μs and senses the bus voltage. If the rated bus voltage is in the corridor of 12.5 % < V_BUSrated < 105 %, the
IC powers up the system and enters phase 3 (Figure 5 V_BUSrated > 95 % sensing); if not, the IC initiates a UVLO
until the chip supply voltage falls below V_CC < 10.6 V. As soon as the condition for a power-up is fulfilled, the IC
starts the inverter gate operation with an internal fixed start-up frequency of 135 kHz. The PFC gate drive starts
with a delay of approx. 300 μs. Next, the bus voltage will be checked for a rated level above 95 % for a duration
of 80 ms (phase 3, Figure 5). When leaving phase 3, the IC enters the soft start phase and shifts the frequency
from the internal fixed start-up frequency of 135 kHz down to the set preheating frequency – e.g. f_RFPH = 100 kHz.
2.2.2 Operating Levels from Soft Start to Run Mode
This section describes the operating flow from phase 5 (preheating mode) to phase 8 (run mode) in detail. In order
to extend the lifetime 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 R_FPH 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, RFRUN 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).
135kHz
f,V
65kHz
50kHz
3
4
40kHz
10ms
Start-Up Softstart
VLSCS
0.8 V
Frequency
5
Lamp Voltage
0-2500ms
Preheating
6
7
8
40-237ms 625ms
Ignition Pre-Run
t
Normal Operation
Run
Figure 6
Softstart proceeds in 15 steps à 650µs according Δf_PH = (135kHz - f_PH)/ 15steps.
Ignition proceeds in 127 steps à 324µs according ΔfIGN = (fPH - fRUN)/ 127steps.
Preheating Frequency with 8.7 kΩ Resistor from PIN RFPH to GND
RUN Frequency with a 12.0 kΩ Resistor from PIN RFRUN to GND
Typical Variation of Operating Frequency during Startup
Final Data Sheet
17
V1.1, 2013-08-14