Referece datasheet : DDA002C Datasheet.

The DDA002C controller hosts a high performance circuitry dedicated to driving half−bridge topologies, such as lamp ballasts for backlighting applications or resonant converters like the LLC circuit. The controller includes everything needed to build a reliable and rugged converter, including a pre−heating period and various protections such as an adjustable brown−out, for instance. Both, minimum and maximum switching frequencies, are adjustable by single pull down resistor, offering the ability to operate between 30 kHz and 500 kHz.