IRPLLNR4 International Rectifier, IRPLLNR4 Datasheet - Page 10

• Manufacturer Part Number: IRPLLNR4
• Description: BALLAST UNIV INP FLUOR IR2166
• Manufacturer: International Rectifier

Specifications of IRPLLNR4

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *IRPLLNR4

The ballast control section oscillator of the IR2166 is similar to oscillators found in many popular
PWM voltage regulator ICs and consists of a timing capacitor and resistor connected to ground.
Resistors RT and RPH program a current which determines the ramp up time of capacitor CT. The
downward ramping time of CT is the dead time between the switching off of the LO (HO) and the
switching on of the HO (LO) pins on the IR2166. The Preheat mode frequency of oscillation is
determined from the parallel between RT and RPH. It is selected such that the voltage appearing
across the lamp is below the minimum lamp ignition voltage while supplying enough current to preheat
the lamp filaments to the correct emission temperature within the Preheat mode period. The preheat-
ing of the lamp filaments is performed with a constant voltage during the Preheat mode. The wave-
form in Figure 1 shows the lamp filament current while Figure 2 shows lamp filament voltage during
the normal Startup, Preheat and Ignition Ramp modes of the ballast.
Figure 2: Lamp filament voltage during preheat and Ignition Ramp
(crossed lamps)
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RD-0602
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