Dialog Semiconductor Gmbh

Lars Lennartson

Horst Knoedgen

Johan Nilsson

A method for compensating for the pulse area error of a Class-D power amplifier is achieved; especially it compensates the variations in the supply voltage and similar dependencies. A Class-D Amplifier typically gets pulse coded digital input (PCM) and may comprise a Sigma Delta Modulator to generate the signals driving the power output stage, typically an H-Bridge. A fundamental idea of this invention is to measure the real area of the output pulses, where the area is defined as the pulse duration multiplied by the pulse voltage amplitude, and to compare it with the ideal nominal pulse area. The pulse area error is calculated and then subtracted from said amplifier's input data. Key element of this invention is the &ldquo;Pulse Area Compensation Function&rdquo;, which calculates said real pulse area (voltage amplitude multiplied by time), compares said real pulse area with said ideal pulse area and feeds the difference into the input of said Sigma Delta Modulator.

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Veberod, Sweden

Lars Lennartson