Patent ID: 8013678
Filing Date: 2011-09-06
Classification: H03F

Abstract:
1. A self-oscillating amplifier system, comprising: a pulse modulator to modulate an input signal to form a pulse modulated signal; a switching power amplification stage to amplify the pulse modulated signal; a passive filter to demodulate a switching output signal; a first feedback path applied from a switching stage output; a second feedback path applied from the filter output; means for forming an error signal by subtracting signals from said first and second feedback paths from the input signal; and a forward path connecting said means for forming an error signal to said pulse modulator, thereby forming a closed loop, said first and second feedback paths and said forward path having transfer functions so as to ensure self-oscillating conditions of said closed loop, wherein self-oscillation occurs at an oscillation frequency, at which a total phase lad of the first feedback path, the second feedback path, the forward path and any propagation delay is 180 degrees.