Modeling and Operation of Resonant Switched-Capacitor DC-DC Converters Regulated by Switch Conductance under Overdamped Conditions

Switch conductance regulation is used in favor over dynamic off-time modulation in resonant SC DC-DC converters due to its smaller output voltage ripple and operation at a constant frequency. However, at light load the resonant oscillations are significantly damped because of the increased on resistance R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dson</inf> of the power switches. A modeling approach is presented and experimentally verified showing that under these conditions it is beneficial to scale both R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dson</inf> and the switching frequency f<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">switch</inf> to further reduce switching losses while still maintaining a reasonably small output voltage ripple.