The PT5613 is a ballast control IC, with the Power Factor Correction (PFC) control and the 650V half-bridge driver, designed to drive all types of fluorescent lamps. In the Ballast Control section, the features such as programmable preheat time and frequency, programmable and precise run frequency, self-adapting ignition time regulator and auto-restart for lamp replacement, provide a high degree of flexibility for the ballast design engineers. The protection features include the filaments detection, ignition failure, rectifier effect and end-of-life protection for lamp and the over-current protection for half bridge. It is easy to support full protection in multi-lamp design. In the PFC control section, there are two control modes: Critical Conduction Mode for nominal load and Discontinuous Conduction Mode for light load. The PFC features include internal fixed maximum on-time, programmable current limitation, over voltage and open loop protections. The PFC control, with the controlled on-time and internal THD optimization, provides the quality of high PF and low THD.