Electronic lamp ballast with voltage source power feedback to AC-side

A low frequency to high frequency power converter comprising:

• a capacitive source impedance source of low frequency line voltage, having source connection points between which the low frequency line voltage is maintained,
• a DC supply circuit having at least two diodes and four terminals, and an energy storage capacitor, two of said terminals being AC-side terminals connected to said source connection points, and two of said terminals being DC-side terminals, one of said diodes being connected between one of the AC-side terminals and one of the DC-side terminals,
• a half-bridge inverter connected to receive DC voltage from said DC-side terminals, said inverter comprising two switching transistors connected in series and having an output node between said transistors for providing a high frequency output voltage,
• a load circuit carrying a first high frequency current, connected between said output node and one of said DC-side terminals, said load circuit comprising a plurality of load circuit elements including a resonance inductor, at least one resonance capacitor forming part of a resonant circuit with said resonance inductor, and two load connection points for a non-linear load which is at least substantially resistive in an operating condition, and
• a high frequency capacitor providing a path for a second high frequency current, said high frequency capacitor being connected between one of said AC-side terminals and a location along said load circuit at which there is a voltage at said high frequency, said high frequency capacitor having a value selected such that said high frequency capacitor receives energy from one of said AC-side terminals during a first portion of every cycle of said high frequency voltage, and said high frequency capacitor transfers energy directly to said energy storage capacitor during a different portion of every cycle of said high frequency voltage, via a capacitive and non-inductive energy transfer.