GB2435559B - Class D amplifier - Google Patents

Class D amplifier

Info

Publication number
GB2435559B
GB2435559B GB0709301A GB0709301A GB2435559B GB 2435559 B GB2435559 B GB 2435559B GB 0709301 A GB0709301 A GB 0709301A GB 0709301 A GB0709301 A GB 0709301A GB 2435559 B GB2435559 B GB 2435559B
Authority
GB
United Kingdom
Prior art keywords
bit
class
bridge
amplifier
flipping
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
GB0709301A
Other versions
GB0709301D0 (en
GB2435559A (en
Inventor
Anthony James Magrath
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cirrus Logic International UK Ltd
Original Assignee
Wolfson Microelectronics PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Wolfson Microelectronics PLC filed Critical Wolfson Microelectronics PLC
Priority to GB0709301A priority Critical patent/GB2435559B/en
Priority claimed from GB0321589A external-priority patent/GB2406008B/en
Publication of GB0709301D0 publication Critical patent/GB0709301D0/en
Publication of GB2435559A publication Critical patent/GB2435559A/en
Application granted granted Critical
Publication of GB2435559B publication Critical patent/GB2435559B/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
    • H03F3/217—Class D power amplifiers; Switching amplifiers
    • H03F3/2173—Class D power amplifiers; Switching amplifiers of the bridge type
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
    • H03F3/217—Class D power amplifiers; Switching amplifiers
    • H03F3/2175—Class D power amplifiers; Switching amplifiers using analogue-digital or digital-analogue conversion
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M3/00—Conversion of analogue values to or from differential modulation
    • H03M3/02—Delta modulation, i.e. one-bit differential modulation
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M3/00—Conversion of analogue values to or from differential modulation
    • H03M3/04—Differential modulation with several bits, e.g. differential pulse code modulation [DPCM]
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M7/00—Conversion of a code where information is represented by a given sequence or number of digits to a code where the same, similar or subset of information is represented by a different sequence or number of digits
    • H03M7/30—Compression; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
    • H03M7/3002—Conversion to or from differential modulation
    • H03M7/3004—Digital delta-sigma modulation
    • H03M7/3006—Compensating for, or preventing of, undesired influence of physical parameters
    • H03M7/3011—Compensating for, or preventing of, undesired influence of physical parameters of non-linear distortion, e.g. by temporarily adapting the operation upon detection of instability conditions
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/03—Indexing scheme relating to amplifiers the amplifier being designed for audio applications
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/33—Bridge form coupled amplifiers; H-form coupled amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/331—Sigma delta modulation being used in an amplifying circuit
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M7/00—Conversion of a code where information is represented by a given sequence or number of digits to a code where the same, similar or subset of information is represented by a different sequence or number of digits
    • H03M7/30—Compression; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
    • H03M7/3002—Conversion to or from differential modulation
    • H03M7/3004—Digital delta-sigma modulation
    • H03M7/3015—Structural details of digital delta-sigma modulators
    • H03M7/302—Structural details of digital delta-sigma modulators characterised by the number of quantisers and their type and resolution
    • H03M7/3024—Structural details of digital delta-sigma modulators characterised by the number of quantisers and their type and resolution having one quantiser only
    • H03M7/3026—Structural details of digital delta-sigma modulators characterised by the number of quantisers and their type and resolution having one quantiser only the quantiser being a multiple bit one
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M7/00—Conversion of a code where information is represented by a given sequence or number of digits to a code where the same, similar or subset of information is represented by a different sequence or number of digits
    • H03M7/30—Compression; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
    • H03M7/3002—Conversion to or from differential modulation
    • H03M7/3004—Digital delta-sigma modulation
    • H03M7/3015—Structural details of digital delta-sigma modulators
    • H03M7/3031—Structural details of digital delta-sigma modulators characterised by the order of the loop filter, e.g. having a first order loop filter in the feedforward path
    • H03M7/3033—Structural details of digital delta-sigma modulators characterised by the order of the loop filter, e.g. having a first order loop filter in the feedforward path the modulator having a higher order loop filter in the feedforward path, e.g. with distributed feedforward inputs
    • H03M7/3035—Structural details of digital delta-sigma modulators characterised by the order of the loop filter, e.g. having a first order loop filter in the feedforward path the modulator having a higher order loop filter in the feedforward path, e.g. with distributed feedforward inputs with provisions for rendering the modulator inherently stable, e.g. by restricting the swing within the loop, by removing part of the zeroes using local feedback loops, by positioning zeroes outside the unit circle causing the modulator to operate in a chaotic regime
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M7/00—Conversion of a code where information is represented by a given sequence or number of digits to a code where the same, similar or subset of information is represented by a different sequence or number of digits
    • H03M7/30—Compression; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
    • H03M7/3002—Conversion to or from differential modulation
    • H03M7/3004—Digital delta-sigma modulation
    • H03M7/3015—Structural details of digital delta-sigma modulators
    • H03M7/3031—Structural details of digital delta-sigma modulators characterised by the order of the loop filter, e.g. having a first order loop filter in the feedforward path
    • H03M7/3033—Structural details of digital delta-sigma modulators characterised by the order of the loop filter, e.g. having a first order loop filter in the feedforward path the modulator having a higher order loop filter in the feedforward path, e.g. with distributed feedforward inputs
    • H03M7/304—Structural details of digital delta-sigma modulators characterised by the order of the loop filter, e.g. having a first order loop filter in the feedforward path the modulator having a higher order loop filter in the feedforward path, e.g. with distributed feedforward inputs with distributed feedback, i.e. with feedback paths from the quantiser output to more than one filter stage

Abstract

A sigma-delta modulator for a class D audio amplifier has a three-level quantiser output suitable for driving a transistor bridge (figure 12). A bit-flipping mechanism reduces the frequency of output transistor switching in the bridge and hence improves efficiency, which is important in portable audio apparatus. The integrators Ila1 and Ila0 in the loop filter are adjusted when bit-flipping occurs. The controller C may decide not to enforce a bit flip if this would cause too much noise.
GB0709301A 2003-09-15 2003-09-15 Class D amplifier Expired - Lifetime GB2435559B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0709301A GB2435559B (en) 2003-09-15 2003-09-15 Class D amplifier

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0709301A GB2435559B (en) 2003-09-15 2003-09-15 Class D amplifier
GB0321589A GB2406008B (en) 2003-09-15 2003-09-15 Class D amplifier

Publications (3)

Publication Number Publication Date
GB0709301D0 GB0709301D0 (en) 2007-06-20
GB2435559A GB2435559A (en) 2007-08-29
GB2435559B true GB2435559B (en) 2008-04-02

Family

ID=38219420

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0709301A Expired - Lifetime GB2435559B (en) 2003-09-15 2003-09-15 Class D amplifier

Country Status (1)

Country Link
GB (1) GB2435559B (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009153449A2 (en) * 2008-06-16 2009-12-23 Universite Aix-Marseille I D-class digital amplifier configured for shaping non-idealities of an output signal
FR2932623B1 (en) * 2008-06-16 2010-07-30 Univ D Aix Marseille I DIGITAL CLASS D AMPLIFIER CONFIGURE FOR SHAPING NON-IDEALITIES OF AN OUTPUT SIGNAL
WO2010076672A1 (en) 2009-01-05 2010-07-08 Freescale Semiconductor, Inc. Amplifier circuitry, integrated circuit and communication unit
DE102011121139B4 (en) 2011-12-15 2016-11-24 IAD Gesellschaft für Informatik, Automatisierung und Datenverarbeitung mbH Device having a delta-sigma modulator and a MOSFET output stage connected thereto
CN111865125B (en) * 2020-07-29 2021-07-20 中车青岛四方车辆研究所有限公司 Traction inverter control system and PWM modulation method

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4772871A (en) * 1986-05-16 1988-09-20 Oki Electric Industry Co., Ltd. Delta sigma modulator circuit for an analog-to-digital converter
US5949361A (en) * 1997-05-12 1999-09-07 The United States Of America Represented By The Secretary Of The Navy Multi-stage delta sigma modulator with one or more high order sections
US6472933B2 (en) * 1999-09-27 2002-10-29 Waytech Investment Co., Ltd. Switching amplifier incorporating return-to-zero quaternary power switch

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4772871A (en) * 1986-05-16 1988-09-20 Oki Electric Industry Co., Ltd. Delta sigma modulator circuit for an analog-to-digital converter
US5949361A (en) * 1997-05-12 1999-09-07 The United States Of America Represented By The Secretary Of The Navy Multi-stage delta sigma modulator with one or more high order sections
US6472933B2 (en) * 1999-09-27 2002-10-29 Waytech Investment Co., Ltd. Switching amplifier incorporating return-to-zero quaternary power switch

Also Published As

Publication number Publication date
GB0709301D0 (en) 2007-06-20
GB2435559A (en) 2007-08-29

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Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)

Free format text: REGISTERED BETWEEN 20150820 AND 20150826

PE20 Patent expired after termination of 20 years

Expiry date: 20230914