Abstract: A high-frequency switching power conversion circuit is disclosed. The circuit is capable of operating either as an inverter or as a rectifier, by the use of an array of high-power, bidirectional switches. AC waveforms are produced by ROM-based pulse width modulation, the clocking of which may be phase-locked to an active AC load. Analog voltage sense circuitry detects high or low output voltage and alters the base address in ROM to a lower or higher duty cycle waveform, respectively, providing digital regulation of the output. Overcurrent protection circuitry, responsive to an inductive load, alters the pulse width modulation pattern to produce a dynamically clamped output dependent upon high-power, variable frequency loads. No-load detection circuitry drastically reduces the duty cycle on the switching elements, thus conserving energy when not needed.

Abstract: An inverter circuit is provided for use with a DC power supply and includes a transformer having a center-tapped primary coil and a secondary coil as well as a switch and a switch controller operating to maintain a constant RMS output voltage. Improvements in the inverter circuit include a switch formed of individual discrete and Darlington transistors connected in parallel so that the discrete transistors predominantly carry the load during low load operation and the Darlington transistor during high load operation.