Super-efficient single-stage isolated switching power amplifier

A switching power amplifier for receiving an input signal and generating an amplified output signal across a load, the amplifier comprising:

• a power supply circuit configured to supply power, and store and recirculate return energy;
• a transformer circuit, the transformer circuit having a primary side including a primary winding having a set of terminals, the transformer circuit having a secondary side including a secondary winding having a set of terminals;
• a modulator circuit configured to receive an input signal, the modulator circuit configured to generate a periodic clock signal, the modulator circuit configured to modulate the input signal using the clock signal as a reference clock signal to output a set of modulated drive signals carrying information about the input signal, the modulator circuit configured to generate and output a set of periodic waveform drive signals and a set of clamping drive signals using the clock signal, with each clamping drive signal of the set of clamping drive signals having a timing relationship to one waveform drive signal of the set of waveform drive signals;
• a waveform generator circuit coupled to the power supply circuit to receive power and coupled to the set of terminals of the primary winding to drive the transformer circuit, the waveform generator circuit driven by the set of waveform drive signals and configured to generate a corresponding set of periodic waveform signals, the set of periodic waveform signals driving the set of terminals of primary winding to generate a corresponding set of periodic amplified waveform signals at the set of terminals of the secondary winding through the transformer circuit;
• a bidirectional active clamping circuit coupled to the set of terminals of the secondary winding to receive the set of amplified waveform signals, the bidirectional active clamping circuit driven by the set of clamping drive signals and configured to store excess energy associated with ringing and voltage spikes otherwise included in the set of amplified waveform signals and discharge stored excess energy during each of a series of time intervals derived from a corresponding series of cycles of one waveform drive signal of the set of waveform drive signals, at least one portion of said discharged energy returning back to the primary side from the secondary side through the transformer circuit;
• a bidirectional switching circuit comprising a set of bidirectional power switches driven by the set of modulated drive signals and coupled to the bidirectional active clamping circuit on the secondary side to receive the set of amplified waveform signals, the bidirectional switching circuit configured to use the driven set of bidirectional power switches to generate a set of one or more amplified modulated signals carrying information about the input signal and amplified through the set of amplified waveform signals;
• and
• a converter circuit coupled to the bidirectional switching circuit to receive the set of one or more amplified modulated signals, the converter circuit configured to convert the received set of one or more amplified modulated signals to an amplified output signal across a load, with the amplified output signal being an amplified substantial replica of the input signal.