A feed-forward (FF) BiNMOS driver that combines a multi-stage CMOS inverter and a bipolar emitter-follower transistor is proposed as a low-voltage BiCMOS driver. High-speed and low-voltage operation is made possible by a multi-stage inverter and feed-forward control from the pre-stage inverters to the bipolar emitter-follower. Two key factors determining the driver delay time, output load capacitance and wiring resistance, are described and analyzed in detail. Experiments with a gate-chains test chip fabricated with 0.5-µm BiCMOS technology confirm the low-voltage operation of the FF-BiNMOS driver. Applications of the new driver to a BiCMOS SRAM are also described.

This paper describes configuration and operation of a high-frequency link resonant inverter using cycloconverter techniques. In this inverter, a resonant link high-frequency voltage generated in a primary resonant inverter is isolated by a high-frequency transformer, then directly converted into a resonant link low-frequency voltage in a cycloconverter. The switching losses and surge voltage levels can be reduced by making all switches in the primary inverter and the cycloconverter operate at zero voltage. The relationship between characteristic impedance of the resonant circuit and the conversion efficiency, and the distortion factor characteristics of the output voltage waveforms are discussed by comparing of analytical and experimental results.

This paper describes a new configuration and control method for an uninterruptible power supply (UPS) with a bidirectional cycloconverter. When commercial AC power is operating normally, the load is supplied by commercial AC power and the bidirectional cycloconverter operates as a battery charger. During interruptions of commercial AC power, the bidirectional cycloconverter operates as an inverter and supplies AC power to the load. Unlike a conventional UPS, this new configuration does not require a battery charger, so it can be small, light-weight, cost-effective, and highly efficient. The output voltage characteristics and the transient voltage drop in the output when commercial AC power fails are also discussed by numerical analysis and experiments.