Comparison of charge pump circuits for half-bridge inverters

Charge pumps can be used to generate floating voltage supplies owing to the ir low input to output voltage drop and circuit simplicity. When used to po wer the high-side circuitry of half-bridges, the charge pump circuit can be simplified significantly by replacing the function of the dedicated pump o scillator with the switching action of the half-bridge output voltage. Thre e classes of the auto charge pump are identified, and a model is derived fo r each of the circuits. Using the model, auto charge pump circuits are desi gned for use in a half-bridge inverter and tested. The tests show a good ma tch between the models and the experimental results. Finally, a comparison of the the various auto charge pump circuits is made.