Description
●The IR21571 is a fully integrated, fully protected 600V ballast control IC designed to drive virtually all types of rapid start fluorescent lamp ballasts. Externally programmable features such as preheat time & frequency, ignition ramp characteris tics, and running mode operating frequency provide a high degree of flexibility for the ballast design engineer. Comprehensive protection features such as protection from failure of a lamp to strike, filament failures, low dc bus conditions, thermal
●overload, or lamp failure during normal operation, as well as an automatic restart function, have been included in the design. The heart of this control IC is a variable frequency oscillator with externally programmable deadtime. Precise control of a 50% duty cycle is accomplished using a T-flip-flop. The IR21571 is available in both 16 pin DIP and 16 pin narrow body SOIC packages.
●Features
●•Programmable preheat time & frequency
●•Programmable ignition ramp
●•Protection from failure-to-strike
●•Lamp filament sensing & protection
●•Protection from operation below resonance - 0.2V CS threshold sync’d to falling edge on LO
●•Protection from low-line condition
●•Automatic restart for lamp exchange
●•Thermal overload protection
●•Programmable deadtime
●•Integrated 600V level-shifting gate driver
●•Internal 15.6V zener clamp diode on VCC
●•Micropower startup (150uA)
●•Latch immunity protection on all leads
●•ESD protection on all leads
