GB201119956D0 - Amplifier circuit with offset control - Google Patents

Amplifier circuit with offset control

Info

Publication number
GB201119956D0
GB201119956D0 GB201119956A GB201119956A GB201119956D0 GB 201119956 D0 GB201119956 D0 GB 201119956D0 GB 201119956 A GB201119956 A GB 201119956A GB 201119956 A GB201119956 A GB 201119956A GB 201119956 D0 GB201119956 D0 GB 201119956D0
Authority
GB
United Kingdom
Prior art keywords
amplifier
offset
turned
reduce
current
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.)
Granted
Application number
GB201119956A
Other versions
GB2496664A (en
GB2496664B (en
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 GB1119956.9A priority Critical patent/GB2496664B/en
Publication of GB201119956D0 publication Critical patent/GB201119956D0/en
Publication of GB2496664A publication Critical patent/GB2496664A/en
Application granted granted Critical
Publication of GB2496664B publication Critical patent/GB2496664B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
    • H03F1/305—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters in case of switching on or off of a power supply
    • 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
    • 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
    • H03F3/45—Differential amplifiers
    • H03F3/45071—Differential amplifiers with semiconductor devices only
    • H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
    • H03F3/45475—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using IC blocks as the active amplifying circuit
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/45—Differential amplifiers
    • H03F3/45071—Differential amplifiers with semiconductor devices only
    • H03F3/45479—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection
    • H03F3/45484—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection in differential amplifiers with bipolar transistors as the active amplifying circuit
    • H03F3/45596—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection in differential amplifiers with bipolar transistors as the active amplifying circuit by offset reduction
    • H03F3/456—Differential amplifiers with semiconductor devices only characterised by the way of common mode signal rejection in differential amplifiers with bipolar transistors as the active amplifying circuit by offset reduction by using a feedback circuit

Abstract

The offset voltage at the output of an amplifier may give rise to an unwanted and wasteful DC current in the load, and when an output capacitor is used to block this current the offset may cause an undesirable audio transient when the amplifier is turned on or off. To reduce the offset in a class-D amplifier a low-gain digital integrator 407 accumulates the difference in the number of occurrences of the amplifier s positive and negative output states and feeds back the integral signal for subtraction from the input signal Din. When the amplifier is turned on the gain of the offset correction loop may be increased temporarily to provide rapid offset compensation and so reduce the audio transient. The offset correction value may be held while the amplifier is disabled.
GB1119956.9A 2011-11-18 2011-11-18 Amplifier circuit with offset control Active GB2496664B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1119956.9A GB2496664B (en) 2011-11-18 2011-11-18 Amplifier circuit with offset control

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1119956.9A GB2496664B (en) 2011-11-18 2011-11-18 Amplifier circuit with offset control

Publications (3)

Publication Number Publication Date
GB201119956D0 true GB201119956D0 (en) 2012-01-04
GB2496664A GB2496664A (en) 2013-05-22
GB2496664B GB2496664B (en) 2016-03-23

Family

ID=45475391

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1119956.9A Active GB2496664B (en) 2011-11-18 2011-11-18 Amplifier circuit with offset control

Country Status (1)

Country Link
GB (1) GB2496664B (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2534440B (en) * 2014-10-24 2019-01-09 Cirrus Logic Inc Amplifier with adjustable ramp up/down gain for minimizing or eliminating pop noise
US9673762B2 (en) 2014-10-24 2017-06-06 Cirrus Logic, Inc. Amplifier with adjustable ramp up/down gain for minimizing or eliminating pop noise
US9503023B2 (en) 2015-04-01 2016-11-22 Nxp B.V. Class-D amplifier
GB2562125B (en) * 2017-01-20 2019-09-18 Cirrus Logic Int Semiconductor Ltd Closed-loop digital compensation scheme
US10236827B2 (en) * 2017-01-20 2019-03-19 Cirrus Logic, Inc. Offset calibration for amplifier and preceding circuit
US10224877B2 (en) 2017-01-20 2019-03-05 Cirrus Logic, Inc. Closed-loop digital compensation scheme
US11799426B2 (en) * 2021-11-30 2023-10-24 Cirrus Logic Inc. Class D amplifier circuitry

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4016833B2 (en) * 2002-12-26 2007-12-05 ヤマハ株式会社 Pulse width modulation amplifier
GB2459865B (en) * 2008-05-07 2011-03-16 Wolfson Microelectronics Plc Amplifier Circuit
KR20110036371A (en) * 2009-10-01 2011-04-07 삼성전자주식회사 Audio amplifier
EP2323254B1 (en) * 2009-11-16 2012-06-06 Nxp B.V. A plop-free amplifier
WO2011064787A1 (en) * 2009-11-30 2011-06-03 ST-Ericsson India Pvt. Ltd. Pop-up noise reduction in a device
EP2375566B1 (en) * 2010-04-12 2014-11-26 Dialog Semiconductor GmbH Duplicate feedback network in class D amplifiers

Also Published As

Publication number Publication date
GB2496664A (en) 2013-05-22
GB2496664B (en) 2016-03-23

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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