Abstract: A power conversion system comprising at least one Pulse Modulated Amplifier (1), including a pulse modulator for generating a pulse modulated signal based on a reference input (vi), a switching power stage arranged to amplify the pulse modulated signal, and a control system arranged to compensate for power supply voltage variations, and a voltage supply (2) providing drive voltage (Vs) to each amplifier, wherein said voltage supply (2) is provided with said input reference (vi), and arranged to provide a first drive voltage component (Vs) tracking an amplified absolute value of the input reference (vi). Pulse area modulation according to the invention will result in improved efficiency and at the same time ensure lower levels of EMI, as the mean amplitude of the PAM signal is lowered.

Abstract: A pulse modulation power converter comprising a forward path including a forward block (15), a switching stage (11) for amplifying an output from the forward block, and an output filter (12) for low pass filtering an output signal from the switching stage, a global feedback path (13), connected to the low pass filtered output signal, comprising a global feedback block (18, 19) for generating a feedback signal, and means (14) for subtracting said feedback signal from an input signal, and feeding the result to said forward path. The global feedback block and/or forward block includes means for compensating at least a portion of a phase lag of said output filter, and means for obtaining a 180 degrees phase lag at a switching frequency, thereby achieving conditions for a controlled oscillation at said switching frequency. The control system combines the advantages of the self-oscillation technology with a high gain, wide-band control loop for suppressing non-linearities.