Patent ID: 8643436
Filing Date: 2014-02-04
Classification: H03F

Abstract:
1. A multi-level class D amplifier, comprising: a hybrid H-bridge circuit, having a pair of output terminals, comprising: a quantizer to compare an input signal to a plurality of threshold voltages, and a controller, coupled to the quantizer, to generate a pulse density modulated (PDM) control signal to the H bridge circuit, the control signal activating, during at least one operational phase of the PDM signal, one of the first and second pairs of transistors connected to one of the output terminals and one of the third pair of transistors connected to an other one of the output terminals, wherein an output voltage between the pair of output terminals comprises a plurality of pulses, wherein a maximum voltage and a minimum voltage of each of the plurality of the pulses are two adjacent voltage levels of more than three distinct voltage levels, and the plurality of the pulses has more than two distinct combination of the maximum voltage and the minimum voltage as two adjacent voltage levels of more than three distinct voltage levels.