To replace magnetic ballast control systems in fluorescent lamps, International Rectifier has introduced a control IC that uses a novel control method to eliminate the need for a power factor correction (PFC) stage. The single-chip SO8 device achieves high power factor with ultra-low total harmonic distortion (THD). No electrolytic capacitor is needed at the input.
The IRS2538DS integrates a 600-V half-bridge control circuit, bootstrap MOSFET, and comprehensive set of protection features to further reduce component count and printed-circuit board (PCB) area, as well as to increase reliability. Features include preheat, ignition and running lamp modes, closed-loop lamp current control, fixed pre-heat time (2 s typical), adaptive deadtime (0.5 µs to 1.5 µs typical), lamp insert auto-restart, micropower startup (125 µA), and an internal 15.6-V Zener diode clamp on Vcc.