US9271088B2 - Hearing aid with an H-bridge output stage and a method of driving an output stage - Google Patents

Hearing aid with an H-bridge output stage and a method of driving an output stage Download PDF

Info

Publication number
US9271088B2
US9271088B2 US13/845,721 US201313845721A US9271088B2 US 9271088 B2 US9271088 B2 US 9271088B2 US 201313845721 A US201313845721 A US 201313845721A US 9271088 B2 US9271088 B2 US 9271088B2
Authority
US
United States
Prior art keywords
level
voltage
output
terminal
voltage source
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.)
Active, expires
Application number
US13/845,721
Other languages
English (en)
Other versions
US20130188814A1 (en
Inventor
Henning Haugaard Andersen
Niels Ole KNUDSEN
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.)
Widex AS
Original Assignee
Widex AS
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 Widex AS filed Critical Widex AS
Assigned to WIDEX A/S reassignment WIDEX A/S ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KNUDSEN, NIELS OLE, ANDERSEN, HENNING HAUGAARD
Publication of US20130188814A1 publication Critical patent/US20130188814A1/en
Application granted granted Critical
Publication of US9271088B2 publication Critical patent/US9271088B2/en
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R25/00—Electric hearing aids
    • 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
    • H03F1/26—Modifications of amplifiers to reduce influence of noise generated by amplifying elements
    • 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
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R25/00—Electric hearing aids
    • 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
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/68—Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R2225/00—Details of deaf aids covered by H04R25/00, not provided for in any of its subgroups
    • H04R2225/49—Reducing the effects of electromagnetic noise on the functioning of hearing aids, by, e.g. shielding, signal processing adaptation, selective (de)activation of electronic parts in hearing aid
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; 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

  • This application relates to hearing aids. More specifically, it relates to hearing aids comprising digital output stages for driving acoustic output transducers. The invention further relates to a method for driving a digital output stage of a hearing aid.
  • a hearing aid is defined as a small, battery-powered device, comprising a microphone, an audio processor and an acoustic output transducer, configured to be worn in or behind the ear by a hearing-impaired person.
  • the hearing aid may amplify certain frequency bands in order to compensate the hearing loss in those frequency bands.
  • most modern hearing aids are of the digital variety.
  • Contemporary digital hearing aids incorporate a digital signal processor for processing audio signals from the microphone into electrical signals suitable for driving the acoustic output transducer according to the prescription.
  • some digital hearing aid processors use a digital output signal to drive the acoustic output transducer directly without performing a digital-to-analog conversion of the output signal. If the digital signal is delivered to the acoustic output transducer directly as a digital bit stream with a sufficiently high frequency, the coil of the acoustic output transducer performs the duty as a low-pass filter, allowing only frequencies below e.g. 15-20 kHz to be reproduced by the acoustic output transducer.
  • the digital output signal is preferably a pulse width modulated signal, a sigma-delta modulated signal, or a combination thereof.
  • An H-bridge is an electronic circuit for controlling inductive loads such as electric motors or loudspeakers. It operates by controlling the direction of a flow of current through a load connected between the output terminals of the H-bridge by opening and closing a set of electronic switches present in the H-bridge.
  • the switches may preferably be embodied as semiconductor switching elements such as BJT transistors or MOSFET transistors. This operating principle permits a direct digital drive output stage to be employed in order to enable a suitably conditioned digital signal to drive a loudspeaker directly, thus eliminating the need for a dedicated digital-to-analog converter and at the same time reducing the power requirements for the output stage.
  • a sigma-delta modulator is an electronic circuit for converting a signal into a bit stream.
  • the signal to be converted may be digital or analog, and the sigma-delta modulator is typically used in applications where a signal of a high resolution is to be converted into a signal of a lower resolution.
  • a sigma-delta modulator is used for driving the H-bridge output stage in the hearing aid.
  • the diaphragm of a loudspeaker has a resting or neutral position assumed whenever no current flows through the loudspeaker coil and two extreme positions assumed whenever the maximal allowable current flows in either direction through the loudspeaker.
  • a digital bit stream may control a loudspeaker directly.
  • a digital output stage for a hearing aid comprising a sigma-delta converter and an H-bridge for driving an acoustic output transducer for a hearing aid.
  • the output stage is denoted a three-state output stage because it is capable of delivering a bit stream consisting of three individual signal levels to the acoustic output transducer. In the following, these levels are denoted “+1”, “ ⁇ 1” and “0”, where “+1” equals the maximum positive voltage across the acoustic output transducer, “ ⁇ 1” equals the maximum negative voltage across the acoustic output transducer, and “0” equals no voltage.
  • the “+1”-levels and “ ⁇ 1”-levels both generate differential voltages over the wires and terminals of the acoustic output transducer. This is not the case with the “0”-level. With the “0”-level, both wires carry the same voltage simultaneously, and since this is a rapidly switching voltage it radiates more common mode signal to its immediate surroundings. This radiation results in increased crosstalk to nearby surroundings, such as telecoils or wireless transmission receiver coils typically present in the hearing aid. Since this crosstalk has frequencies above 1 MHz, it does not possess a problem to the telecoil, since a telecoil is configured to convey frequencies below 8-10 kHz. The wireless receiver coil, however, suffers a very considerable reduction in signal-to-noise ratio from the capacitive interference resulting from this crosstalk phenomenon, often to a degree where reliable signal reception becomes impossible.
  • This capacitive interference emanates mainly from electrically exposed parts of the output circuit, primarily the wires connecting the output pads of the electronic circuit chip of the hearing aid to the input terminals of the acoustic output transducer. It is not possible to shorten these wires further for mechanical reasons, but some reduction in the capacitive coupling between these wires and sensitive electronic circuits in the vicinity may be achieved by twisting the wires and keeping them physically close together.
  • the voltage pulses are presented to the output transducer at a frequency of 1-2 MHz, and the resulting noise components may thus disturb the operation of electronic circuits sensitive to capacitive interference at high frequencies.
  • the problems caused by electromagnetic interference are exceptionally severe, as the effective operating range of the wireless remote control is limited considerably by the capacitive interference emanating from the output stage and masking the remote control signals from proper reception.
  • WO-A1-03/047309 discloses a digital output driver circuit for driving a loudspeaker for a mobile device such as a hearing aid or a mobile phone.
  • the digital driver circuit comprises an input, a modulator and a three-level H-bridge and is integrated into the loudspeaker enclosure in order to shield the driver circuit from electromagnetic interference and to keep the wires connecting the driver output to the loudspeaker short.
  • the driver circuit further comprises a feedback circuit connected to the loudspeaker for regulating the supply voltage for the driver circuit.
  • An output driver integrated into a loudspeaker in the way described in WO-A1-03/047309 is not interchangeable with dynamic standard loudspeakers of the kind used in hearing aids. If, for example, a hearing aid housing and circuitry may be adapted for use with a range of different loudspeakers having different impedance values, e.g. for treating different degrees of hearing loss, a loudspeaker having an integrated output driver would not be well suited for this configuration. In cases where this type of flexibility is desired, long wires between the output stage terminals of the hearing aid circuit and the terminals of the loudspeaker of the hearing aid are unavoidable. An extra set of long wires for the signal from the loudspeaker to the feedback circuit would also be required by the prior art output driver, which would further increase capacitive interference noise.
  • the invention in a first aspect, provides a hearing aid comprising an input transducer, an analog-to-digital converter, a digital signal processor, a three-level output modulator connected to a three-level output driver, a first voltage source, a second voltage source, a common voltage node and an acoustic output transducer, wherein the output driver comprises an H-bridge output stage configured to control the connection of a first and a second terminal of the acoustic output transducer, the H-bridge being configured to connect the first voltage source to the first terminal of the acoustic output transducer and the common voltage node to the second terminal of the acoustic output transducer when the output modulator generates a first level, to connect the second voltage source to both the first and the second terminal of the acoustic output transducer when the output modulator generates a second level, and to connect the first voltage source to the second terminal of the acoustic output transducer and the common voltage node to the first terminal of the output
  • the invention in a second aspect, provides a method of driving an output stage of a hearing aid, said method comprising providing a single-bit digital signal representing an audio signal to be reproduced by the hearing aid, providing a first voltage source for generating a first voltage, providing a second voltage source for generating a second voltage, providing an acoustic output transducer, converting the single-bit digital signal into a three-level control signal comprising a positive level, a negative level, and a zero level, connecting the first voltage source to a first terminal of the acoustic output transducer, and connecting a second terminal of the acoustic output transducer to ground, whenever the control signal produces a negative level, connecting the first voltage source to the second terminal of the acoustic output transducer, and connecting the first terminal of the acoustic output transducer to ground, whenever the control signal produces a positive level, and connecting the second voltage source to both the first terminal and the second terminal of the acoustic output transducer whenever the control signal
  • FIG. 1 is a schematic of an output stage for a hearing aid according to the prior art
  • FIG. 2 is a schematic of an output stage for a hearing aid according to an embodiment of the invention
  • FIG. 3 is a schematic illustrating a first condition in the output stage of FIG. 2 .
  • FIG. 4 is a schematic illustrating a second condition in the output stage of FIG. 2 .
  • FIG. 5 is a schematic illustrating a third condition in the output stage of FIG. 2 .
  • FIG. 6 is a graph illustrating a typical input signal to the output stage of FIG. 2 .
  • FIG. 7 is a schematic of a hearing aid with an output stage according to an embodiment of the invention.
  • FIG. 1 shows a schematic of a three-state digital H-bridge output stage 1 of a hearing aid according to the prior art.
  • the output stage 1 comprises a control input 2 , a supply voltage node 3 carrying a positive voltage V bb , an acoustic output transducer shown as a loudspeaker 4 , a ground node 5 , a delay element 6 , and four controllable switches S 1 , S 2 , S 3 and S 4 , shown as MOSFET transistor elements.
  • the supply voltage node 3 provides electrical power to the H-bridge output stage 1
  • the control input 2 is capable of delivering a bit stream for controlling the four controllable switches S 1 , S 2 , S 3 and S 4 .
  • the purpose of the delay element 6 is to perform a delay of the bit stream for the switches S 2 and S 4 by one clock pulse. This function may also be performed by an inverter. In the following, the three different conditions produced by the output stage from the bit stream are denoted “ ⁇ 1”, “0” and “+1”.
  • the purpose of the switches S 1 , S 2 , S 3 and S 4 is to provide a current flow from the supply voltage node 3 and through the loudspeaker 4 , controlled by the bit stream from the control input 2 , to the ground terminal 5 .
  • the switches are controlled in the following manner. Whenever the bit stream produces a bit sequence comprising a “0” followed by a “0”, the switches S 2 and S 3 close, and the switches S 1 and S 4 open, corresponding to the condition “ ⁇ 1” in the output stage. This condition causes a current to flow from the supply voltage node 3 through S 2 , the loudspeaker 4 and S 3 , respectively, to ground. The current flow causes the membrane or diaphragm of the loudspeaker 4 to move in one direction, e.g. inwards.
  • the switches S 1 and S 2 close, and the switches S 3 and S 4 open, or vice versa, corresponding to the condition “0” in the output stage.
  • This condition causes the voltage potential of the supply voltage node 3 to be present on both sides of the loudspeaker 4 due to S 1 and S 2 being closed. If S 3 and S 4 are closed instead, the ground potential will be present on both sides of the loudspeaker 4 . Since the same voltage potential is present on both sides of the loudspeaker 4 , the diaphragm of the loudspeaker 4 will now move towards its neutral position.
  • This design does provide a very power-efficient output stage when compared to earlier two-level output stage designs. However, it also has the inherent drawback of producing a considerable amount of capacitive interference due to its mode of operation.
  • the switches When the output stage is in the condition “+1” or “ ⁇ 1”, the switches are controlled in a synchronous manner by the bit stream, but when the output converter is in the condition “0”, this synchronicity is lost due to the switches not being controlled from the same logic circuit.
  • the spikes resulting from this asynchronous switching are too high in frequency to affect the general operation of the acoustic output transducer but they do generate a considerable amount of capacitive interference, which may compromise wireless near field communication signals, e.g. from a wireless remote control adapted for communicating with receiver circuitry in the hearing aid, and thus reduce the effective operating range of the wireless remote control.
  • FIG. 2 is a schematic showing a sigma-delta modulator 10 , a decoder network 17 and an H-bridge output stage 7 for a hearing aid according to the invention.
  • the sigma-delta modulator 10 comprises a difference node 11 , a first summation node 12 , a second summation node 13 , a first unit delay block 14 , a second unit delay block 15 , and a quantizer 16 .
  • the output stage 7 comprises a first supply voltage node 3 , a ground node 5 , a second supply voltage node 8 , a NAND-gate 18 , a loudspeaker 4 , a first controllable switch S 1 , a second controllable switch S 2 , a third controllable switch S 3 , a fourth controllable switch S 4 , a fifth controllable switch S 5 , and a sixth controllable switch S 6 . Also shown in FIG. 2 is a table illustrating the operation of the decoder network 17 , denoted Table 1.
  • the input of the sigma-delta modulator 10 is connected to an output of a digital signal processor of a hearing aid (not shown), and the output of the sigma-delta modulator 10 is connected to an input of the decoder network 17 .
  • the decoder network 17 comprises a first output A and a second output B.
  • the first output A is connected to the inputs of the first controllable switch S 1 and the fourth controllable switch S 4
  • the second output B is connected to the third controllable switch S 3 and the second controllable switch S 2 .
  • the first supply voltage node 3 and the second supply voltage node 8 provides electrical power to the H-bridge output stage 7 , and four of the eight controllable switches, S 1 , S 2 , S 3 and S 4 , are controlled by the decoder network 17 for controlling three different conditions of the output stage 7 , denoted “ ⁇ 1”, “0” and “+1”, respectively.
  • the NAND-gate 18 has a first input connected to the first output A of the decoder network 17 , and a second input connected to the second output B of the decoder network 17 .
  • the operation of the decoder network 17 is illustrated in Table 1, where L denotes a LOW logical level, and H denotes a HIGH logical level.
  • the first supply voltage node 3 preferably carries the nominal supply voltage V bb of the hearing aid in order to maximize the output of the loudspeaker 4 , but other voltages may be used for driving the loudspeaker 4 , e.g. a voltage delivered by a voltage-doubler being powered by the battery of the hearing aid.
  • the second supply voltage node 8 preferably carries half the voltage of the first supply voltage node 3 . The reasoning behind this preference will be explained in greater detail in the following.
  • the four controllable switches S 1 , S 2 , S 3 and S 4 operate in a fashion generally similar to the prior art output stage 1 shown in FIG. 1 regarding generation of the output conditions “ ⁇ 1” and “+1”, but the output stage 7 has a novel way of generating the output condition “0”.
  • the NAND-gate 18 outputs a logical HIGH if, and only if, both the first output A and the second output B of the decoder network 17 are LOW.
  • the two controllable switches S 5 and S 6 are controlled by the NAND-gate 18 .
  • the fifth controllable switch S 5 When activated by a logical HIGH level, the fifth controllable switch S 5 connects the first loudspeaker terminal to the second supply node 8 , and the sixth controllable switch S 6 connects the second loudspeaker terminal to the second supply node 8 .
  • the fifth controllable switch S 5 and the sixth controllable switch S 6 respectively, disconnects both the loudspeaker terminals from the second supply node 8 . In other words, whenever the NAND-gate 18 outputs a logical HIGH, the first and the second loudspeaker terminal are both connected to the second supply node 8 .
  • the output stage 7 would operate in essentially the same way as the output stage of the prior art, including the problems with capacitive interference discussed earlier. However, if the voltage potential on the second supply voltage node 8 is set to be equal to V bb /2, or half the voltage of the first supply voltage node 3 , the capacitive interference from the output stage 7 is balanced out to the same degree as if the output stage 7 was a two-level output stage.
  • the acoustic output transducer has an effective voltage swing about the potential V bb /2 of the second voltage supply node 8 of the difference between the ground potential and the voltage potential V bb of the first supply voltage node 3 , but the voltage shifts on either wire connecting the output stage 7 of the hearing aid circuit to the loudspeaker 4 equals only half the potential V bb of the first supply voltage node 3 due to the three-level operation of the output converter.
  • the capacitive noise interference level is reduced by at least 6 dB.
  • a three-level output stage operation inherently has the benefits of a lower switching noise level over time, since shifts due to a typical signal are less frequent compared to a two-level switching output stage.
  • FIGS. 3 , 4 and 5 are simplified schematic diagrams of the output stage 7 shown in FIG. 2 , illustrating how the output stage 7 handles the conditions “ ⁇ 1”, “0” and “+1”.
  • the first voltage supply node 3 and the second voltage supply node 8 are shown in FIG. 3 , FIG. 4 and FIG. 5 .
  • the six switches S 1 , S 2 , S 3 , S 4 , S 5 and S 6 are only suggested in FIG. 3 , FIG. 4 and FIG. 5 , and the loudspeaker is suggested in FIG. 3 , FIG. 4 and FIG. 5 as a coil 4 .
  • FIG. 3 it is illustrated how the output stage 7 generates the condition “+1”.
  • the switches S 1 and S 4 are closed, while the switches S 2 , S 3 , S 5 and S 6 are open. Due to the voltage difference between the first supply voltage node 3 and ground, an electrical current I 1 flows from the first supply voltage node 3 through S 1 , through the loudspeaker 4 and through S 4 to ground, exerting an electromotive force on the loudspeaker coil, thus forcing the membrane of the loudspeaker 4 to move in one direction, e.g. inwards.
  • FIG. 4 is illustrated how the output stage 7 generates the condition “ ⁇ 1”.
  • the switches S 2 and S 3 are now closed, while the switches S 1 , S 4 , S 5 and S 6 are open.
  • An electrical current I 2 flows from the first supply voltage node 3 through S 2 , through the loudspeaker 4 in the opposite direction, and through S 3 to ground, exerting an electromotive force on the loudspeaker coil, thus forcing the membrane of the loudspeaker 4 move in the opposite direction, e.g. outwards.
  • FIG. 5 is illustrated how the output stage 7 generates the condition “0”.
  • the switches S 5 and S 6 are now closed, while the switches S 1 , S 2 , S 3 and S 4 are open.
  • the voltage potential of the second supply voltage node 8 is now applied on both terminals of the loudspeaker 4 simultaneously. Unless the membrane of the loudspeaker 4 is at its resting position, it is now forced to move towards this resting position. This movement causes an electrical current I 3 to flow in the closed circuit formed by the switch S 5 , the loudspeaker 4 and the switch S 6 .
  • the current I 3 originates solely from the electromotive force induced in the loudspeaker coil by the resilient force provided by the loudspeaker suspension.
  • the current I 3 is zero.
  • the voltage potential provided by the second supply voltage node 8 may, in a preferred embodiment, be generated by dividing the voltage potential of the first supply voltage node 3 by two, e.g. by providing a simple voltage divider having a sufficiently high output impedance and eventually being decoupled by a small capacitor.
  • a switched-capacitor voltage divider is provided for generating the voltage potential for the second supply voltage node 8 from the voltage potential of the first supply voltage node 3 .
  • a switched-capacitor voltage divider is a preferred choice in clocked, integrated circuit designs, and has the added advantage of having inherently high input impedance.
  • a three-level digital output stage has the advantage of performing fewer shifts for reproduction of the same signal when compared with a two-level digital output stage. This implies lower power consumption.
  • the circuit providing the control signals for the digital output stage utilizes a combination of pulse-width modulation and sigma-delta modulation. A sufficient driver frequency bandwidth may thus be obtained, even if the typical clock frequency of 1 MHz for the output stage is reduced to 256 kHz.
  • FIG. 6 shows a time-domain graph of a typical output signal from the H-bridge output converter according to the invention.
  • the H-bridge output signal is a series of equidistant, clocked signal pulses representing the audio signal to be reproduced. This signal may take one of three distinct values, “ ⁇ 1”, “0” or “+1”. Also shown in the graph in FIG. 6 is the resulting loudspeaker movement. “+1” corresponds to the innermost extreme position attainable by the loudspeaker membrane, “ ⁇ 1” corresponds to the outermost extreme position, and “0” corresponds to the loudspeaker resting position.
  • the curve representing the speaker movement is approximating a smoothed integral of the values presented by the H-bridge output signal.
  • FIG. 6 Below the graph in FIG. 6 is also shown a series of symbols representing the bit stream generating the output signal from the H-bridge.
  • FIG. 7 is a schematic of a hearing aid 20 having a digital output stage 7 according to the invention.
  • the hearing aid 20 comprises a microphone 21 , an A/D converter 22 , a digital signal processor 23 , a sigma-delta converter 24 , the output stage 7 and the loudspeaker 4 .
  • Acoustic signals are picked up by the microphone 21 and converted into an analog electrical signal.
  • the analog electrical signal from the microphone 21 is converted into a digital signal by the A/D converter 22 .
  • the A/D converter 22 provides the digital signal to the input of the digital signal processor 23 , where the majority of the processing of the digitized microphone signal takes place in the hearing aid 20 . From the output of the digital signal processor 23 , the processed digital output signal is used as an input signal for the sigma-delta converter 24 .
  • the sigma-delta converter 24 uses the processed, digital output signal from the digital signal processor 23 as an input signal for generating a three-level bit stream suitable as a digital input signal for the H-bridge output stage 7 .
  • the H-bridge output stage 7 is configured to drive the loudspeaker 4 directly, controlled by the three-level bit stream.
  • the hearing aid output stage according to the invention has significantly reduced capacitive interference without tradeoffs in the form of increased power consumption or added complexity.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Neurosurgery (AREA)
  • Otolaryngology (AREA)
  • Amplifiers (AREA)
  • Circuit For Audible Band Transducer (AREA)
US13/845,721 2011-02-28 2013-03-18 Hearing aid with an H-bridge output stage and a method of driving an output stage Active 2032-05-11 US9271088B2 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2011/052887 WO2012116720A1 (fr) 2011-02-28 2011-02-28 Aide auditive avec un étage de sortie en pont h et procédé de commande d'un étage de sortie

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2011/052887 Continuation-In-Part WO2012116720A1 (fr) 2011-02-28 2011-02-28 Aide auditive avec un étage de sortie en pont h et procédé de commande d'un étage de sortie

Publications (2)

Publication Number Publication Date
US20130188814A1 US20130188814A1 (en) 2013-07-25
US9271088B2 true US9271088B2 (en) 2016-02-23

Family

ID=44625186

Family Applications (1)

Application Number Title Priority Date Filing Date
US13/845,721 Active 2032-05-11 US9271088B2 (en) 2011-02-28 2013-03-18 Hearing aid with an H-bridge output stage and a method of driving an output stage

Country Status (9)

Country Link
US (1) US9271088B2 (fr)
EP (1) EP2681842A1 (fr)
JP (1) JP2014507890A (fr)
KR (1) KR101401817B1 (fr)
CN (1) CN103222189A (fr)
AU (1) AU2011360732B2 (fr)
CA (1) CA2828263C (fr)
SG (1) SG186817A1 (fr)
WO (1) WO2012116720A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10409545B1 (en) * 2018-04-17 2019-09-10 Starkey Laboratories, Inc. Digital identification of devices attached to serial communication cables
NL2023245B1 (en) * 2019-06-01 2020-12-11 Semiconductor Ideas To The Market Itom Bv Three level PWM Class D amplifier

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2736187B1 (fr) * 2012-11-22 2017-03-08 Nxp B.V. Procédé et circuit de récepteur sans fil
DK3235267T3 (en) 2014-12-17 2018-10-08 Widex As A HEARING DEVICE
JP6293951B1 (ja) * 2017-03-28 2018-03-14 中田　宏 音声再生装置
US10396779B2 (en) * 2017-05-31 2019-08-27 Texas Instruments Incorporated Ground switching for speaker current sense
CN109407579B (zh) * 2018-10-16 2021-06-01 浩云科技股份有限公司 一种独立声波算法控制电路
CN110677779B (zh) * 2019-09-29 2021-02-05 广东盈峰科技有限公司 一种消声电路以及声波式水位监测设备
CN114630167B (zh) * 2022-03-07 2023-04-25 歌尔智能科技有限公司 遥控器和电子系统

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997040644A1 (fr) 1996-04-23 1997-10-30 Phonak Ag Appareil auditif
US6344811B1 (en) * 1999-03-16 2002-02-05 Audio Logic, Inc. Power supply compensation for noise shaped, digital amplifiers
WO2003047309A1 (fr) 2001-11-30 2003-06-05 Sonion A/S Moteur a haute efficacite destine a des hauts-parleurs miniatures
EP1530286A1 (fr) 2003-11-06 2005-05-11 Marvell World Trade Ltd. Amplificateur classe-D
WO2005076664A1 (fr) 2004-02-08 2005-08-18 Widex A/S Etage de sortie pour aide auditive et procede d'excitation d'un etage de sortie
US20050231276A1 (en) * 2002-07-18 2005-10-20 Masao Goto Power amplifier
JP2006211523A (ja) 2005-01-31 2006-08-10 Asahi Kasei Microsystems Kk デジタルスイッチング回路
US20060192692A1 (en) 2005-02-15 2006-08-31 Torsten Niederdrank Hearing aid device with an output amplifier having a sigma-delta modulator
WO2007100334A1 (fr) 2006-03-03 2007-09-07 Semiconductor Components Industries, L.L.C. Amplificateur classe D et méthode associée
US7298209B1 (en) * 2003-11-06 2007-11-20 Marvell World Trade Ltd. Class D amplifier
US20080018393A1 (en) * 2006-07-07 2008-01-24 Yamaha Corporation Offset voltage correction circuit and class D amplifier
US20090243722A1 (en) 2008-03-25 2009-10-01 Jing-Meng Liu Reduction of power consumption and EMI of a switching amplifier
US20130223651A1 (en) * 2010-10-27 2013-08-29 Merus Audio Aps Audio amplifier using multi-level pulse width modulation
US8837758B2 (en) * 2011-02-28 2014-09-16 Widex A/S Hearing aid and method of driving an output stage

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1751854B1 (fr) * 2004-05-05 2016-03-23 Audera Acoustics Inc. Amplificateur audio et haut-parleur integrant un tel amplificateur audio
GB0715254D0 (en) * 2007-08-03 2007-09-12 Wolfson Ltd Amplifier circuit
US7969242B2 (en) * 2008-07-24 2011-06-28 Qualcomm Incorporated Switching power amplifier for quantized signals

Patent Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000509218A (ja) 1996-04-23 2000-07-18 フォーナック アーゲー 補聴器装置
WO1997040644A1 (fr) 1996-04-23 1997-10-30 Phonak Ag Appareil auditif
US6344811B1 (en) * 1999-03-16 2002-02-05 Audio Logic, Inc. Power supply compensation for noise shaped, digital amplifiers
WO2003047309A1 (fr) 2001-11-30 2003-06-05 Sonion A/S Moteur a haute efficacite destine a des hauts-parleurs miniatures
US20050231276A1 (en) * 2002-07-18 2005-10-20 Masao Goto Power amplifier
US7298209B1 (en) * 2003-11-06 2007-11-20 Marvell World Trade Ltd. Class D amplifier
JP2005143077A (ja) 2003-11-06 2005-06-02 Marvell World Trade Ltd Ｄ級増幅器
EP1530286A1 (fr) 2003-11-06 2005-05-11 Marvell World Trade Ltd. Amplificateur classe-D
WO2005076664A1 (fr) 2004-02-08 2005-08-18 Widex A/S Etage de sortie pour aide auditive et procede d'excitation d'un etage de sortie
JP2007522729A (ja) 2004-02-08 2007-08-09 ヴェーデクス・アクティーセルスカプ 補聴器用出力段および出力段駆動方法
JP2006211523A (ja) 2005-01-31 2006-08-10 Asahi Kasei Microsystems Kk デジタルスイッチング回路
US20060192692A1 (en) 2005-02-15 2006-08-31 Torsten Niederdrank Hearing aid device with an output amplifier having a sigma-delta modulator
WO2007100334A1 (fr) 2006-03-03 2007-09-07 Semiconductor Components Industries, L.L.C. Amplificateur classe D et méthode associée
US20080018393A1 (en) * 2006-07-07 2008-01-24 Yamaha Corporation Offset voltage correction circuit and class D amplifier
US20090243722A1 (en) 2008-03-25 2009-10-01 Jing-Meng Liu Reduction of power consumption and EMI of a switching amplifier
US20130223651A1 (en) * 2010-10-27 2013-08-29 Merus Audio Aps Audio amplifier using multi-level pulse width modulation
US8837758B2 (en) * 2011-02-28 2014-09-16 Widex A/S Hearing aid and method of driving an output stage

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
Communicated dated Mar. 24, 2015, issued by the Japanese Intellectual Property Office in counterpart Japanese Patent Application No. 2013-550778.
Communication dated Jul. 29, 2014, issued by the Japanese Intellectual Property Office in counterpart Japanese Patent Application No. 2013-550778.
International Search Report with Written Opinion for PCT/EP2011/052887 dated Oct. 20, 2011.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10409545B1 (en) * 2018-04-17 2019-09-10 Starkey Laboratories, Inc. Digital identification of devices attached to serial communication cables
NL2023245B1 (en) * 2019-06-01 2020-12-11 Semiconductor Ideas To The Market Itom Bv Three level PWM Class D amplifier

Also Published As

Publication number Publication date
KR101401817B1 (ko) 2014-05-29
JP2014507890A (ja) 2014-03-27
CN103222189A (zh) 2013-07-24
KR20130036118A (ko) 2013-04-10
AU2011360732B2 (en) 2015-06-11
AU2011360732A1 (en) 2013-07-25
SG186817A1 (en) 2013-02-28
WO2012116720A1 (fr) 2012-09-07
US20130188814A1 (en) 2013-07-25
EP2681842A1 (fr) 2014-01-08
CA2828263A1 (fr) 2012-09-07
CA2828263C (fr) 2015-05-19

Similar Documents

Publication Publication Date Title
US9271088B2 (en) Hearing aid with an H-bridge output stage and a method of driving an output stage
US8837758B2 (en) Hearing aid and method of driving an output stage
CN109479174B (zh) 具有包括电流输出转换器的数字反馈路径的麦克风组装件
EP1449404B1 (fr) Moteur a haute efficacite destine a des hauts-parleurs miniatures
US10264371B2 (en) Hearing instrument comprising switched capacitor DC-DC converter
CN109565636B (zh) 麦克风组件、半导体管芯、通信装置及操作麦克风的方法
JP2018207765A (ja) 低電磁放射のスイッチドキャパシタｄｃ−ｄｃコンバータを備える聴覚装置
CN104581591A (zh) 具有可中断麦克风电源的听力仪器
CN101312602B (zh) 具有低干扰耳机控制的助听设备以及相应的方法
JP2008271549A5 (fr)
US20240171071A1 (en) An ear level audio device and a method of operating an ear level audio device
KR101608725B1 (ko) 링잉을 방지하기 위한 통신 회로 및 그 통신 방법
WO2012177686A1 (fr) Système permettant une stimulation acoustique vibratoire de haute efficacité

Legal Events

Date Code Title Description
AS Assignment

Owner name: WIDEX A/S, DENMARK

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ANDERSEN, HENNING HAUGAARD;KNUDSEN, NIELS OLE;SIGNING DATES FROM 20130320 TO 20130402;REEL/FRAME:030444/0689

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

STCF Information on status: patent grant

Free format text: PATENTED CASE

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 4

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 8TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1552); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 8