ICL5101_16 Datasheet, PDF (21/44 Pages) Infineon Technologies AG – Resonant controller IC with PFC for LED driver

ICL5101
Functional Description
2.3.2
PFC Bus Overvoltage and Open Loop
The bus voltage loop control is completely integrated (Figure 15) and provided by an 8-bit sigma-delta A/D
converter with a typical sampling rate of 280 µs and a resolution of 4 mV/bit. After leaving monitoring, the IC
starts to power up (VCC > 14.0 V). After power-up, the IC senses the bus voltage below 12.5 % (open loop) or
above 105 % (bus overvoltage) for 80 µs – 130 µs. In the case of bus overvoltage (V_BUSrated > 109 %) or open
loop (V_BUSrated < 12.5 %), the IC shuts off the gate drives of the PFC within 5 µs or 1 µs respectively. In this case,
the PFC restarts automatically when the bus voltage is within the corridor (12.5 % < V_BUSrated < 105 %) again. If
the bus voltage is valid after the 130 µs, the bus voltage sensing is set to 12.5 % < V_BUSrated < 109 %. If these
thresholds are departed from for longer than 1 µs (open loop) or 5 µs (overvoltage), the PFC gate drive stops
working until the voltage drops below 105 % or exceeds the 12.5 % level. If the bus overvoltage (> 109 %) lasts
for longer than 625 ms in run mode, the inverter gates also shut off and a power-down with complete restart is
attempted (Figure 15).
Figure 15 PFC Bus Voltage Operating and Error Levels
2.3.3
PFC Bus Voltage Levels 95 % and 75 %
When the rated bus voltage is in the corridor of 12.5 % < V_BUSrated < 109 %, the IC will check whether the bus
voltage exceeds the 95 % threshold (Figure 15) within 80 ms before entering soft start phase. Another threshold
is activated when the IC enters the run mode. If the rated bus voltage drops below 75 % for longer than 84 µs, a
power-down with a complete restart is attempted if a counter exceeds 800 ms. In the case of short-term bus
under voltage (the bus voltage reaches its working level in run mode before exceeding typically 800 ms - min.
500 ms) the IC skips phases and starts up directly in saturation control. The internal reference level of the bus
voltage sense V_PFCVS is 2.5 V (100 % of the rated bus voltage) with a high accuracy. Surge protection is
activated in the case of a rated bus voltage of V_BUS > 109 % and a low-side current sense voltage of V_LSCS >
1.6 V in extended saturation mode or of V_LSCS > 0.8 V in run mode for longer than 500 ns in RUN Mode.
Datasheet
21
Rev. 1.3, 2016-01-15