Patent ID: 7936216
Filing Date: 2011-05-03
Classification: H03F

Abstract:
1. A method for current sensing and current limiting in a self-oscillating class D amplifier comprising a Pulse Width Modulator, a driver circuit, one or more output switching semiconductors and a global control system, the method comprising the steps of: a) current sensing directly across terminals of said one or more output switching semiconductors; b) current limiting by use of a local autonomously controlled self-oscillating loop, the loop comprising a comparator with a reference level and a detection level as inputs and an output for controlling said driver circuit; and c) creating, with an arrangement of current sources, diodes and detection circuitry, one current path divided into two equal current paths, whereof the first current path detects a voltage across the one or more output switching semiconductors and consequently a voltage across the second current path reflects the hereby detected voltage and is equal to the voltage across the one or more output switching semiconductors.