Pulse-width modulation circuit and power amplifier circuit
US6778011B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 2002 |
| Grant date | Aug 17, 2004 |
| Priority date | — |
| Expiry date | Jul 29, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/351
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A pulse-width modulation circuit comprises a comparator having hysteresis characteristics of positive feedback, and an integrator, whose integrated output is compared with an input signal to produce a pulse-width modulation (PWM) signal having an advanced phase characteristic due to differentiation of the input signal. A switching circuit amplifies the pulse-width modulation signal based on the positive and negative source voltages (VPX, VMX). The amplified pulse-width modulation signal is supplied to a speaker via an LC filter, and it is also negatively fed back to the pulse-width modulation circuit. Since the pulse-width modulation signal whose phase is advanced is transmitted through the LC filter, it is possible to reduce phase revolution in the output of the power amplifier circuit. Thus, it is possible to effect negative feedback on the pulse-width modulation signal in a stable manner.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.