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