Patent ID: 7183818
Filing Date: 2007-02-27
Classification: H03F,H03K

Abstract:
1. A triangular wave generating circuit adapted to a class-D amplifier in which an input signal is subjected to pulse-width modulation and is then subjected to switched amplification, said triangular wave generating circuit comprising: a first constant current generating circuit for generating a first constant current in proportion to a positive voltage applied thereto; a second constant current generating circuit for generating a second constant current in proportion to a negative voltage applied thereto; a current selecting circuit, which includes a plurality of high impedance elements, for alternately and periodically selecting the first constant current and the second constant current; a first integrator in which an amplifier is coupled with a capacitor, wherein the first integrator produces a triangular wave in response to charged electricity that is stored in the capacitor in response to the first constant current or the second constant current, which is selectively applied thereto; and a second integrator for integrating the triangular wave output from the first integrator so as to produce a phase correction instruction, which is negatively fed back to the first integrator.