IRPLLNR2U International Rectifier, IRPLLNR2U Datasheet - Page 15

• Manufacturer Part Number: IRPLLNR2U
• Description: BALLAST 32W/T8 120V AC IR21571
• Manufacturer: International Rectifier

Specifications of IRPLLNR2U

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *IRPLLNR2U

frequency of the load circuit and the current in the load circuit commutates to close to zero. Figure 19
shows a near/below resonance condition where the voltage on resistor RCS falls below the 0.2V
threshold on the CS pin of IC2.
Resistors R17, R18 and capacitor
C13 form a divider/filter network
which is used to detect an open lower
lamp filament and/or lamp replace-
ment. Under normal conditions, the
voltage across C8 is approximately
zero volts. However, if the lower fila-
ment becomes open or the lamp is
removed, the voltage across C13 in-
creases above the 2V threshold for
the SD pin of IC2 and signals a lamp
fault condition which in turn puts the
ballast into Fault mode. The ballast
remains in the Fault mode until the
line voltage is cycled or a lamp re-
placement is performed. If the lamp
is replaced with a lamp with a good
lower filament, the voltage on the SD
Figure 19: Near/Below Resonance conditions
pin of IC2 is pulled back below the
Upper trace: voltage across RCS
2V threshold and the ballast will go
Lower trace: half-bridge output voltage
through a restart. Line voltage cycling
is also used to restart the ballast for all lamp fault conditions. The ballast will go through a full
Preheat, Ignition Ramp and Run modes any time a restart is performed. Note that the SD pin of IC2
is active during all modes of operation.
Another way that the ballast can go into Fault mode is if the AC line voltage falls below approximately
170Vrms. Resistors R11, R12 and capacitor C9 form a voltage divider/filter network which is con-
nected to the VDC pin of IC2 and is used to determine if the line voltage falls below permissible
levels. This happens when the line voltage is cycled or possibly a brownout condition occurs. The
VDC pin of IC2 senses a fault if the voltage at the pin falls below 3 volts and shutdown of the ballast
occurs. The ballast remains shutdown until the voltage at the VDC pin rises above 5.1 volts. At this
time if there are no other fault conditions the ballast will go through a full Preheat, Ignition Ramp and
Run mode. As in the case of the SD pin of IC2, the VDC pin of IC2 is active during all modes of
operation of the ballast.
IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245 Tel: [phone]
Data and specifications subject to change without notice.
10/28/2000
www.irf.com
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