The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 12, 2002
Filed:
Apr. 25, 2000
STMicroeletronics S.r.l., Agrate Brianza, IT;
Abstract
A class D amplifier includes an input integrating stage and a modulating stage for modulating the integrated input signal output by the integrating stage. The modulating stage uses as a carrier an alternate waveform of a frequency sufficiently higher than the frequency band of the analog input signal. The modulating stage further outputs a digital signal switching between a positive voltage and a negative voltage, and whose average value represents an amplified replica of the input analog signal. The class D amplifier further includes an output power stage producing an output digital signal. A feedback line including a resistor is connected between the output of the output power stage and an input node of an operational amplifier. The class D amplifier also includes a low-pass filter reconstructing an output analog signal, and a delay stage. The delay stage is functionally coupled in the direct path of propagation of the digital signal from the output of the modulating stage to an input of the output power stage. The delay stage delays the digital signal from the output of the modulating stage by a delay. The value of the delay is defined as a function of a desired broadening of the bandwidth and in consideration of the corresponding restriction of the range of variation of the duty cycle of the output digital signal.