IRPLLNR2U International Rectifier, IRPLLNR2U Datasheet - Page 14

• 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

14
At the completion of the Ignition Ramp mode (beginning of the Run mode) the near/below resonance
(under-current) detection is also enabled. Near/below resonance detection is performed by synchro-
nously sensing the voltage across resistor RCS, which relates to the current flowing in the low side
MOSFET (M3), just prior to the turn off of M3. If this voltage is lower than the near/below resonance
threshold (CS- = 0.2V) of the CS pin of IC2, a lamp fault condition is signaled and the ballast goes
into Fault mode. This could occur if the frequency of oscillation becomes too close to the resonant
Figure 15: Failure of lamp to ignite condition (lamp
Figure 17: Hard-switching condition (upper filament
filaments good): Upper trace: voltage across
open): Upper trace: voltage across RCS,
Lower trace: IC2 HO-VS pin voltage
Middle trace: IC2 LO pin voltage,
RCS, Lower trace: lamp voltage
Figure 18: Hard-switching condition (upper filament open):
Lamp voltage during Preheat mode and beginning of
Figure 16: Failure of lamp to ignite condition (lamp
Ignition Ramp mode when lamp fault is detected
filaments good): Lamp voltage during the end
of Preheat and Ignition Ramp modes
www.irf.com