WO2005076664A1 - Output stage for a hearing aid and method of driving output stage - Google Patents
Output stage for a hearing aid and method of driving output stage Download PDFInfo
- Publication number
- WO2005076664A1 WO2005076664A1 PCT/DK2005/000077 DK2005000077W WO2005076664A1 WO 2005076664 A1 WO2005076664 A1 WO 2005076664A1 DK 2005000077 W DK2005000077 W DK 2005000077W WO 2005076664 A1 WO2005076664 A1 WO 2005076664A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- output
- output stage
- control signal
- driver
- time
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
- H04R25/50—Customised settings for obtaining desired overall acoustical characteristics
- H04R25/505—Customised settings for obtaining desired overall acoustical characteristics using digital signal processing
-
- 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
- H03F1/02—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
-
- 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
- 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
- H03F2200/331—Sigma delta modulation being used in an amplifying circuit
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2460/00—Details of hearing devices, i.e. of ear- or headphones covered by H04R1/10 or H04R5/033 but not provided for in any of their subgroups, or of hearing aids covered by H04R25/00 but not provided for in any of its subgroups
- H04R2460/03—Aspects of the reduction of energy consumption in hearing devices
Definitions
- the present invention relates to hearing aids.
- the invention more specifically relates to an output stage for a hearing aid and to a method of driving an output transducer for a hearing aid.
- the invention still more specifically, relates to an output stage for driving the output transducer in a hearing aid.
- US 5 578 963 discloses an improved class B driver-circuit (a so-called push-pull driver).
- This is an analog driver that may be used in hearing aids with a digital processor, provided the processor is followed by a DAC (Digital -Analog Converter) for transforming digital signals emanating from the signal processor into analog output signals that control the output driver.
- DAC Digital -Analog Converter
- US 5 878 146 relates to a digital hearing aid with a special type of output stage known as a Sigma-Delta converter.
- a Sigma-Delta converter a Sigma-Delta modulator is controlled by a digital input and produces a high-speed pulse-modulated binary signal, which is fed to a series-connected low-pass filter, wherein the signal is converted into a low-frequent analog signal.
- the low-pass filtering of the high-bitrate output signal from the Sigma-Delta (S-D) converter is provided by the driver coil in the output transducer, the transducer driver coil performing in this way a dual-function.
- the converter may be said to comprise both the modulator, the output driving circuitry and the output transducer.
- the output stage is a direct digital output stage, since no DA-conversion, in the ordinary sense, is performed in the hearing aid.
- the DAC is replaced by an S-D modulator, which transforms the digital output from the signal processor into a binary signal suitable for driving the digital (switching) output driver. It is a disadvantage with this system that power consumption it relatively high for low amplitude input signals.
- a low- amplitude signal is represented by a binary signal that continually switches between two states at a high rate, causing frequent re-charging of the transistors in the output driver.
- the high power consumption is a disadvantage due to the reduced battery lifetime.
- WO03/047309-A1 discloses an S-D DAC.
- an S-D modulator capable of operating with three output states, is utilized.
- This three-state signal controls a push-pull output driver — a so- called H-bridge, whose output is filtered in a lowpass filter.
- the prior art also has examples on output drivers that utilize more than two states in the driver circuitry.
- the advantage of this is a reduction in power consumption in the driver stage. It has never been suggested, though, that corresponding three-level control signals can be derived from a simple 1-bit S-D modulator.
- the high-speed single-bit (i.e. two-state) bitstream from the Sigma- Delta modulator is transformed in the output driver into a time-averaged three-state drive condition that represents the current to be driven through the output transducer.
- the invention in a second aspect provides a hearing aid as recited in claim 8.
- the invention in a third aspect, provides a method as recited in claim 9. Further embodiments appear from the dependent claims.
- Fig. 1 shows a hearing aid with a DAC and an analog output driver of the prior art
- Fig. 2 shows a hearing aid with a digital output stage of the prior art
- Fig. 3a shows the configuration of the prior art output driver of figure 2;
- Fig. 3b shows the configuration of an output driver according to the invention
- Fig. 4 shows a hearing aid according to the invention
- Fig. 5a shows the S-D modulator output
- Fig. 5b shows the S-D modulator output delayed by one clock-pulse
- Fig. 5c shows the three-state drive conditions of the output driver.
- Fig. 1 illustrates a digital hearing aid 11 with an analog output stage.
- This hearing aid 11 basically comprises a microphone 12, an Analog-Digital Converter 13, a Digital Signal Processor DSP 14, a Digital-Analog Converter DAC 15, an analog output driver 16 and a receiver 17.
- the components 12, 13 and 14 are standard components within this field of the art.
- the microphone 12 could be replaced by a microphone array, possibly including analog means for providing the hearing aid with a directional sound receptive characteristic.
- the DSP could be of any known construction, in particular, it could be a hardwired ASIC which is controlable/programmable through the use of a configuration/parameter RAM storage.
- the processor outputs either a serial or a parallel series of binary digits suitable for being processed in a DAC 15. Suitable implementations will be evident to the skilled person.
- the input bitstream 18 is converted to low-pass filtered analog output signals 19 that control the analog output driver 16 which in turn feeds power to the output transducer 17.
- the output driver could be a class B amplifier stage with a voltage gain of one, sometimes referred to as an impedance converter.
- US 5 578 963 discloses an improved class B driver-circuit (a so-called push-pull driver).
- FIG. 2 shows a hearing aid with an H-bridge digital output stage according to the prior art.
- This hearing aid 61 basically comprises components 12, 13, 14 and 17 similar to those described above in connection with the description of figure 1.
- the device in Fig. 2 employs an H-bridge digital output stage 20.
- This stage comprises an S-D modulator 21 and a switching output driver 22.
- the S-D modulator 21 is a first order single-bit S-D modulator that generates a pulse density modulated, single-bit output signal 23.
- the output driver is a class D driver, also known as a switched H-bridge, controlled by the output 23 of the S-D modulator 21. This driver is shown in detail on figure 3a.
- Figure 3a depicts the switching output driver 22, by way of example, as a switched class D stage of bipolar transistors in a bridge configuration with a left and a right branch.
- the left branch comprises NPN-transistor 30 and PNP-transistor 31 connected in a push-pull arrangement to control the voltage of the left output terminal TL.
- the right branch comprises PNP-transistor 32 and NPN-transistor 33 connected in a push- pull arrangement to control the voltage of the right output terminal TR.
- the receiver 17 is connected across the output terminals TL, TR and driven by the voltage differential across the output terminals.
- NPN-transistors 30, 33 would be implemented in the form of appropriate, e.g. n-channel FET, devices and the PNP- transistors 31, 32 would be implemented by appropriate, e.g. p-channel FET, devices.
- a high state of the input 23 will result in a current driven through the transducer 17 in one direction, while a low state of the input 23 will result in a current driven the opposite way. Hence, there is no possible state wherein no current is driven through the transducer 17.
- a low level input signal to the input transducer 12 will need to be represented by a rapidly shifting sequence of bits in the S-D modulator output 23, arranged to provide an average pulse density value close to zero.
- FIG. 4 shows a hearing aid 62 according to an embodiment of the invention.
- This hearing aid 62 has components 12, 13 and 14 similar to those described above in connection with the description of figure 2 and then, in the place of the digital output stage 20, a time-averaging digital output stage 63 comprising S-D-modulator 21 and averaging output driver 42.
- the Sigma-Delta modulator 21 is similar to the Sigma- Delta modulator 21 in figure 2.
- the averaging output driver 42 introduces a modified version of the driver shown on figure 3a. This time-averaging output driver transforms a two-state output from the S-D modulator 21 into a three-state set of transducer drive conditions.
- the curve 53 represents the result of the logical calculation (B "1 -B')(B*B' ) 1 , where * is the XOR-operator, B is the state of the control signal 43a and B' is the state of the control signal 43b, which actually is a delayed version of the output signal 23.
- control signal 23 and the output transducer current 51 can be summarized in a table as follows: State of 23 in previous clock cycle Table of output transducer current 1 0
- the driver is capable of outputting pulses and steady state signals in either direction as well as a zero output.
- the averaging output driver uses a standard S-D modulator and achieves the desired driving of the output transducer but reduces the effective rate of switching of the driver transistors and thereby does not rely solely on the transducer driver coil for averaging the drive current.
- the corresponding output transducer current is indicated by the curve 51 (assuming that the transducer provides the filtering, and the drive condition state is shown by the curve 53.
- the drive condition is in the state +1 for a substantial period of time
- the drive condition is in the state -1 for a substantial period of time
- drive currents close to zero labelled seq.2 are represented by a drive condition which is in the state 0 for a substantial period of time.
- the sequence of NPN- and PNP-transistors on the right side of the driver stage 33, 32 has been inverted.
- the inverted arrangement of the transistors inverts the relationship between the level of the respective control signal 43b and the voltage of the respective output terminal TR.
- the inverted relationship can be offset to avoid changing the performance by incorporating an inverter 34 in the line of the control signal 34b, provided the delay between the control signals 34a and 34b is substantially zero. This will all be evident to the skilled person.
- the time-averaging function of the output driver is obtained by use of a clocked inverter, whereby the required delay is obtained through the one clock-pulse delay inherent in the inverter.
- the time-averaging function of the output driver is obtained by use of a clocked, inverting flip-flop, whereby the required delay is obtained through the one clock-pulse delay inherent in the flip-flop.
- the time-averaging function can be obtained by either a delay or an inverter-delay combination, in dependency of whether the H-bridge is inverting or non-inverting.
- the skilled person will of cause be capable of suggesting other solutions, e.g. replacing the delay with a so-called Flip-Flop — or an inverting Flip-Flop.
- other kind of averaging devices may be suggested, e.g. an averaging filter.
- the skilled person will be aware that the S-D modulator may be replaced by higher order modulators.
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Neurosurgery (AREA)
- Otolaryngology (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Amplifiers (AREA)
- Compression, Expansion, Code Conversion, And Decoders (AREA)
- Control Of Amplification And Gain Control (AREA)
Abstract
Description
Claims
Priority Applications (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2005209787A AU2005209787B2 (en) | 2004-02-08 | 2005-02-04 | Output stage for a hearing aid and method of driving output stage |
EP05700627A EP1716723B1 (en) | 2004-02-08 | 2005-02-04 | Output stage for a hearing aid and method of driving output stage |
CA2554515A CA2554515C (en) | 2004-02-08 | 2005-02-04 | Output stage for a hearing aid and method of driving output stage |
JP2006551717A JP4124797B2 (en) | 2004-02-08 | 2005-02-04 | Hearing aid output stage and output stage driving method |
CN2005800040239A CN1914951B (en) | 2004-02-08 | 2005-02-04 | Output stage for a hearing aid, hearing aid and method of driving output tranducer of hearing aid |
DK05700627T DK1716723T3 (en) | 2004-02-08 | 2005-02-04 | Output stage for hearing aid and method for operating an output stage |
DE602005010827T DE602005010827D1 (en) | 2004-02-08 | 2005-02-04 | OUTPUT LEVEL FOR A HEARING DEVICE AND METHOD FOR CONTROLLING AN OUTPUT LEVEL |
US11/499,769 US7853029B2 (en) | 2004-02-08 | 2006-08-07 | Output stage for a hearing aid and method of driving output stage |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DKPA200400188 | 2004-02-08 | ||
DKPA200400188 | 2004-02-08 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/499,769 Continuation-In-Part US7853029B2 (en) | 2004-02-08 | 2006-08-07 | Output stage for a hearing aid and method of driving output stage |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2005076664A1 true WO2005076664A1 (en) | 2005-08-18 |
Family
ID=34833504
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/DK2005/000077 WO2005076664A1 (en) | 2004-02-08 | 2005-02-04 | Output stage for a hearing aid and method of driving output stage |
Country Status (10)
Country | Link |
---|---|
US (1) | US7853029B2 (en) |
EP (1) | EP1716723B1 (en) |
JP (1) | JP4124797B2 (en) |
CN (1) | CN1914951B (en) |
AT (1) | ATE413788T1 (en) |
AU (1) | AU2005209787B2 (en) |
CA (1) | CA2554515C (en) |
DE (1) | DE602005010827D1 (en) |
DK (1) | DK1716723T3 (en) |
WO (1) | WO2005076664A1 (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007104308A1 (en) * | 2006-03-16 | 2007-09-20 | Gn Resound A/S | A hearing aid with adaptive data reception timing |
WO2011110582A1 (en) | 2010-03-09 | 2011-09-15 | Widex A/S | Two part eeg monitor with databus and method of communicating between the parts |
US8150049B2 (en) * | 2006-10-24 | 2012-04-03 | Korea Advanced Institute Of Science And Technology | Digital hearing aid adaptive to structures of human external ear canals |
CN101444112B (en) * | 2006-03-16 | 2012-11-07 | Gn瑞声达A/S | A hearing aid with adaptive data reception timing |
US20130188814A1 (en) * | 2011-02-28 | 2013-07-25 | Widex A/S | Hearing aid with an h-bridge output stage and a method of driving an output stage |
US9473857B2 (en) | 2005-08-23 | 2016-10-18 | Widex A/S | Hearing aid with increased acoustic bandwidth |
EP2076065B2 (en) † | 2007-12-27 | 2016-11-16 | Oticon A/S | Hearing device and method for a wireless receiving and/or sending of data |
JP6293951B1 (en) * | 2017-03-28 | 2018-03-14 | 中田 宏 | Audio playback device |
EP4248870A2 (en) | 2010-03-09 | 2023-09-27 | T&W Engineering A/S | Two part eeg monitor with databus and method of communicating between the parts |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4124797B2 (en) * | 2004-02-08 | 2008-07-23 | ヴェーデクス・アクティーセルスカプ | Hearing aid output stage and output stage driving method |
WO2009047370A2 (en) * | 2009-01-21 | 2009-04-16 | Phonak Ag | Partially implantable hearing aid |
US8649540B2 (en) * | 2009-10-30 | 2014-02-11 | Etymotic Research, Inc. | Electronic earplug |
US8594346B2 (en) * | 2010-06-15 | 2013-11-26 | Silverplus, Inc. | Audio output drivers for piezo speakers |
JP5580946B2 (en) | 2011-02-28 | 2014-08-27 | ヴェーデクス・アクティーセルスカプ | Hearing aid and method for driving an output stage |
US9794703B2 (en) | 2014-06-27 | 2017-10-17 | Cochlear Limited | Low-power active bone conduction devices |
DK3343763T3 (en) * | 2016-12-29 | 2020-01-27 | Gn Hearing As | OUTPUT DRIVER INCLUDING MOS CONTACTS WITH ADJUSTABLE BACK GATE Bias |
WO2020028086A1 (en) | 2018-07-31 | 2020-02-06 | Earlens Corporation | Inductive coupling coil structure in a contact hearing system |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020186155A1 (en) * | 1999-07-01 | 2002-12-12 | Erlend Olson | Method and apparatus for efficient mixed signal processing in a digital amplifier |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
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US5276910A (en) * | 1991-09-13 | 1994-01-04 | Resound Corporation | Energy recovering hearing system |
JP3731179B2 (en) * | 1999-11-26 | 2006-01-05 | 昭栄株式会社 | hearing aid |
ATE338440T1 (en) * | 2001-11-30 | 2006-09-15 | Sonion As | HIGHLY EFFICIENT DRIVER FOR MINIATURE SPEAKERS |
US6867722B2 (en) * | 2003-02-13 | 2005-03-15 | Texas Instruments Incorporated | H-bridge common-mode noise reduction circuit |
JP4124797B2 (en) * | 2004-02-08 | 2008-07-23 | ヴェーデクス・アクティーセルスカプ | Hearing aid output stage and output stage driving method |
-
2005
- 2005-02-04 JP JP2006551717A patent/JP4124797B2/en active Active
- 2005-02-04 CA CA2554515A patent/CA2554515C/en not_active Expired - Fee Related
- 2005-02-04 AT AT05700627T patent/ATE413788T1/en not_active IP Right Cessation
- 2005-02-04 CN CN2005800040239A patent/CN1914951B/en active Active
- 2005-02-04 DE DE602005010827T patent/DE602005010827D1/en active Active
- 2005-02-04 WO PCT/DK2005/000077 patent/WO2005076664A1/en active Application Filing
- 2005-02-04 EP EP05700627A patent/EP1716723B1/en active Active
- 2005-02-04 AU AU2005209787A patent/AU2005209787B2/en active Active
- 2005-02-04 DK DK05700627T patent/DK1716723T3/en active
-
2006
- 2006-08-07 US US11/499,769 patent/US7853029B2/en active Active
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020186155A1 (en) * | 1999-07-01 | 2002-12-12 | Erlend Olson | Method and apparatus for efficient mixed signal processing in a digital amplifier |
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9473857B2 (en) | 2005-08-23 | 2016-10-18 | Widex A/S | Hearing aid with increased acoustic bandwidth |
US10111015B2 (en) | 2005-08-23 | 2018-10-23 | Widex A/S | Hearing aid with increased acoustic bandwidth |
US8229146B2 (en) | 2006-03-16 | 2012-07-24 | Gn Resound A/S | Hearing aid with adaptive data reception timing |
CN101444112B (en) * | 2006-03-16 | 2012-11-07 | Gn瑞声达A/S | A hearing aid with adaptive data reception timing |
WO2007104308A1 (en) * | 2006-03-16 | 2007-09-20 | Gn Resound A/S | A hearing aid with adaptive data reception timing |
US8150049B2 (en) * | 2006-10-24 | 2012-04-03 | Korea Advanced Institute Of Science And Technology | Digital hearing aid adaptive to structures of human external ear canals |
EP2076065B2 (en) † | 2007-12-27 | 2016-11-16 | Oticon A/S | Hearing device and method for a wireless receiving and/or sending of data |
US8923542B2 (en) | 2010-03-09 | 2014-12-30 | Widex A/S | Two part hearing aid with databus and method of communicating between the parts |
US9808199B2 (en) | 2010-03-09 | 2017-11-07 | Widex A/S | Two part EEG monitor with databus and method of communicating between the parts |
WO2011110582A1 (en) | 2010-03-09 | 2011-09-15 | Widex A/S | Two part eeg monitor with databus and method of communicating between the parts |
EP4248870A2 (en) | 2010-03-09 | 2023-09-27 | T&W Engineering A/S | Two part eeg monitor with databus and method of communicating between the parts |
US9271088B2 (en) | 2011-02-28 | 2016-02-23 | Widex A/S | Hearing aid with an H-bridge output stage and a method of driving an output stage |
US20130188814A1 (en) * | 2011-02-28 | 2013-07-25 | Widex A/S | Hearing aid with an h-bridge output stage and a method of driving an output stage |
JP6293951B1 (en) * | 2017-03-28 | 2018-03-14 | 中田 宏 | Audio playback device |
Also Published As
Publication number | Publication date |
---|---|
CN1914951A (en) | 2007-02-14 |
DE602005010827D1 (en) | 2008-12-18 |
CA2554515A1 (en) | 2005-08-18 |
EP1716723B1 (en) | 2008-11-05 |
CN1914951B (en) | 2011-06-29 |
JP2007522729A (en) | 2007-08-09 |
JP4124797B2 (en) | 2008-07-23 |
US20070036375A1 (en) | 2007-02-15 |
US7853029B2 (en) | 2010-12-14 |
DK1716723T3 (en) | 2009-02-16 |
EP1716723A1 (en) | 2006-11-02 |
ATE413788T1 (en) | 2008-11-15 |
AU2005209787B2 (en) | 2009-01-08 |
CA2554515C (en) | 2012-10-02 |
AU2005209787A1 (en) | 2005-08-18 |
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