International Rectifier (El Segundo, CA) introduced the new IR1110 Soft Start Controller IC, a soft start solution for ac converters. The device is claimed to provide increased system reliability and safety to ac motor drive, welding, induction heating, UPS, power supply and other applications that run off the ac line.The IR1110's protection features are claimed to prolong dc bus capacitor lifetime by preventing serious damage from dc bus short circuits. The device provides an array of status feedback signals for versatile system control. The IC is designed to promote up-time by eliminating idling during power dip ride-through. "For some time, power conversion system advances have been focused on the high-frequency output or inverter stages of line driven systems," stated David Tam, IR vice president for control IC products. "In fact, the input or ac converter stage is often the weak link in the entire power conversion system, with the dc bus capacitor the most bulky and problematic component in any high-power system. Our new Soft Start Controller IC is the first highly integrated solution available to control an ac converter and protect the dc bus capacitor from damage and catastrophic failure."The IR1110 is based on a single IC that drives three SCRs in a half-control, 3-phase input bridge. With low power consumption, the IC is able to run off the SCR snubber derived power supply. Charging, protection and supervisory functions include soft dc bus capacitor charging; current limit protection against dc bus short circuit; fast ramp-back recovery from a transient line loss; dynamic dc bus voltage regulation; and versatile line diagnostics. Available in a MQFP64 package, the IR1110 Soft Start Controller IC is priced from $20 in quantities of 1,000.