IR2166S International Rectifier, IR2166S Datasheet - Page 26

• Manufacturer Part Number: IR2166S
• Description: IC PFC/BALLAST CONTROL 16-SOIC
• Manufacturer: International Rectifier
• Type: PFC/Ballast Controllerr

Specifications of IR2166S

• Frequency: 39 ~ 50 kHz
• Current - Supply: 10mA
• Current - Output: 400mA
• Voltage - Supply: 11.5 V ~ 15.6 V
• Operating Temperature: -25°C ~ 125°C
• Package / Case: 16-SOIC (3.9mm Width)
• Package: 16-lead SOIC Narrow
• Circuit: Fluorescent Ballast IC
• Offset Voltage (v): 600
• Output Source Current Min (ma): 250
• Output Sink Current Min (ma): 400
• Vcc Range (v): 10-25V with UVLO
• Output Voltage Min (v): 10
• Output Voltage Max (v): 25
• Pbf: PbF Option Available
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *IR2166S

to increase in order to keep the DC bus constant.
Should the on-time increase too far, the resulting
peak currents in LPFC can exceed the saturation
current limit of LPFC. LPFC will then saturate
and very high peak currents and di/dt levels will
occur. To prevent this, the maximum on-time is
limited by limiting the maximum voltage on the
COMP pin with an external zener diode DCOMP
(Figure 8). As the line input voltage decreases,
the COMP pin voltage and therefore the on-time
will eventually limit. The PFC can no longer
supply enough current to keep the DC bus fixed
for the given load power and the DC bus will
begin to drop. Decreasing the line input voltage
further will cause the VBUS pin to eventually
decrease below the internal 3V threshold (Figure
9). When this occurs, VCC is discharged
internally to UVLO-, the IR2166 enters UVLO
mode and both the PFC and ballast sections
are disabled (see State Diagram). The start-up
supply resistor to VCC, together with the micro-
power start-up current of the IR2166, determine
the line input turn-on voltage. This should be
set such that the ballast turns on at a line voltage
level above the under-voltage turn-off level. It
is the correct selection of the value of the supply
resistor to VCC and the zener diode on the
COMP pin that correctly program the on and off
line input voltage thresholds for the ballast. With
these thresholds correctly set, the ballast will
turn off due to the 3V under-voltage threshold
on the VBUS pin, and on again at a higher line
input voltage (hysterisis) due to the supply
resistor to VCC. This hysterisis will result in a
proper reset of the ballast without flickering of
the lamp, bouncing of the DC bus or re-ignition
of the lamp when the DC bus is too low.
IR2166 & (PbF)
26
PFC Over-Current Protection (optional)
In case of fast on/off interruptions of the mains input
voltage or during normal lamp ignition, the DC bus
voltage level can decrease below the instantaneous
rectified line voltage. Should this occur, the PFC
inductor current and PFC MOSFET current can
increase to high levels causing the PFC inductor to
saturate and/or the PFC MOSFET to become
damaged. During fast on/off interruptions of the input
mains voltage, the DC bus can drop during the time
when the mains voltage is interrupted (off). Since
VCC is still above UVLO-, the IC will continue to
operate and will increase the COMP pin voltage to
increase the PFC MOSFET on-time due to the
dropping of the DC bus. When the mains voltage
returns again quickly, (before VCC reaches UVLO-
), the on-time of the PFC MOSFET is too long for
the given mains voltage level resulting in high PFC
inductor and MOSFET currents that can saturate
the inductor and/or damage the PFC MOSFET
(Figure 12).
Figure 12, High PFC inductor current during fast mains
on/off (upper trace: DC Bus, 100V/div; middle trace:
AC line input voltage, 100V/div; lower trace: PFC
inductor current 1A/div).
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