Method of operating a hearing aid and hearing aid

Abstract

For compensation of an interference signal coupled from an interferer line (8) into a receiver line (14) as a result of parasitic capacitances, an electronic circuit (4) of a hearing aid (2) has a compensation part 18 which has at least one coupling line (20) with a capacitor (22) arranged therein, a compensation interference signal being coupled into the receiver line (14) via the coupling line (20) during operation. The compensation interference signal is in particular in antiphase with the interference signal.

Description

[0001] Description

[0002] Method of operating a hearing aid and hearing aid

[0003] The invention relates to a method of operating a hearing aid and to a hearing aid.

[0004] The hearing aid is in particular a hearing aid intended to compensate for a hearing impairment of a hearing-impaired person.

[0005] Hearing aids of this kind, but also hearing aids in general, have an electronic circuit via which a receiver in particular is controlled. The receiver is typically designed as a loudspeaker. The receiver is regularly connected to an amplifier part of the circuit via a two-wire connection line.

[0006] Hearing aids regularly also have input transducers, in particular microphones, which convert for example an acoustic sound signal into an electrical signal which is then further processed by the electronic circuit and transmitted to the receiver as a processed output signal. For example an analogue microphone is connected with the electronic circuit and there in particular with an analogue-digital converter.

[0007] Furthermore, antennas, especially inductive antennas, are often provided for wireless communication. Especially in binaural systems, so-called NFMI (near-field magnetic inductive) antennas are used, with the help of which the two hearing aids of a binaural system communicate with each other. The signal of the antenna is amplified by an amplifier, especially an LNA (low noise amplifier).

[0008] Due to the compact design of the hearing aids, there is generally the problem that interference signals can be transmitted between the connection lines due to coupling effects. In particular, the connection line leading to the receiver acts as a source of interference and therefore can be designated as an interferer line. Data signals transmitted via the connection lines from the antenna and / or from the microphone are very sensitive to interference. Various measures are known to avoid interference, such as shielding or laying the various connection lines as spatially separated as possible.

[0009] An object of the invention is to avoid or at least reduce such unwanted interference effects.

[0010] A method for operating a hearing aid and a hearing aid are provided to solve this problem. The hearing aid has the following features:

[0011] - an electronic circuit with several circuit parts,

[0012] - a first electronic component, in particular a receiver, which is connected to a first circuit part of the electronic circuit, in particular an amplifier part of the electronic circuit, via a first connection line referred to as an interferer line,

[0013] - a second electronic component which is connected to a second circuit part of the electronic circuit via a second electrical connection line referred to as a receiver line, wherein

[0014] - parasitic capacitances exist between the two connection lines, so that a parasitic interference signal is coupled into the receiver line during operation.

[0015] For compensation of the parasitic interference signal, the electronic circuit has a compensation part which has at least one coupling line that connects the two connection lines to each other. A capacitor is arranged in the coupling line, so that during operation a compensation interference signal is coupled into the receiver line via the at least one coupling line.

[0016] The advantages and preferred further embodiments listed below in connection with the method are also applicable to the hearing aid and vice versa. The hearing aid is generally designed to carry out the method.

[0017] The invention is based on the consideration that parasitic capacitances are responsible for the undesired coupling of interference signals into the second connection line (receiver line). A basic concept of the invention generally envisages mapping these parasitic capacitances in the circuit by means of suitable circuit components, so that in addition to the parasitic interference signal caused by the parasitic effects, an additional interference signal is generated, namely the compensation interference signal, which is also coupled into the second connection line (receiver line).

[0018] The coupling via the parasitic capacitances is therefore reproduced by the at least one coupling line, which connects the interferer line with the receiver line electrically and by wire. At the same time, a capacitor with a predetermined, defined capacity is arranged in this coupling line. The circuit components of the compensation part, i.e. in particular the at least one capacitor, is selected in such a way that the coupled compensation interference signal compensates for the parasitic interference signal.

[0019] Compensation of the parasitic interference signal is generally understood to mean that an effect caused by the parasitic interference signal or the interference signal itself are at least reduced and preferably cancelled.

[0020] Depending on the configuration, there are different design options.

[0021] According to a first variant, a compensation interference signal is coupled in as an antiphase signal compared to the parasitic interference signal, so that the parasitic interference signal is reduced or eliminated by the antiphase compensation interference signal. An antiphase signal is generally understood as a signal with an amplitude opposite to that of the reference signal (i.e. the parasitic interference signal), i.e. one signal has a positive amplitude and the other signal has a negative amplitude. The compensation signal preferably has the same amplitude in terms of amount as the parasitic interference signal.

[0022] In the following phrases like "compensation interference signal in antiphase to the parasitic interference signal" and "the antiphase compensation signal" may be used interchangeably. In a second variant, and especially in the case of a two-wire receiver line into which an unbalanced, asymmetrical parasitic interference signal is coupled during operation, an in-phase compensation interference signal is preferably coupled in. This reduces the asymmetry of the parasitic interference signal and preferably eliminates it. In this embodiment, the compensation interference signal therefore ensures that symmetrical, in-phase interference signals with preferably identical amplitude are present on both line wires of the receiver line. This means that, in the case of an amplification with a differential amplifier, the interference signal is no longer contained in the amplified signal or is at least reduced compared to a variant without the compensation interference signal.

[0023] In a preferred embodiment, the electronic circuit is part of an IC and in particular part of an ASIC.

[0024] Generally, the interferer line and the receiver line are designed as single-wire or two-wire lines. The interferer line is usually designed as a two-wire line. Due to the parasitic effects, there is in principle the danger that a parasitic interference signal is coupled from each wire of the interferer line into each wire of the receiver line, so that there can be a large number of individual interference paths.

[0025] Preferably, a separate coupling line is formed for each of these interference paths, each with a capacitor arranged therein. Therefore, if both the interferer line and the receiver line are a two-wire line, a total of four coupling lines are provided. This embodiment reproduces the possible parasitic coupling paths, so that an efficient compensation is achieved.

[0026] With regard to the first variant mentioned above according to which a compensation interference signal is coupled in as an antiphase signal compared to the parasitic interference signal, an inverter is preferably arranged in the at least one coupling line. Due to the inverter the signal from the interferer line coupled into the receiver line via the coupling line is inverted. The inverter therefore achieves the inversion for the desired antiphase compensation interference signal. The inverter is preferably arranged on the side of the interferer line and the at least one capacitor is subsequently arranged in the coupling line in the direction of the receiver line.

[0027] Such an antiphase compensation interference signal is coupled in each line wire of the receiver line. Each of the compensation interference signal preferably has the same amplitude as the parasitic interference signal on this line wire. The expression “same amplitude” is understood to mean a substantially equal amplitude, with the amplitudes differing from one another by a maximum of 20%, preferably by a maximum of 10% and in particular by less than 5%. Preferably, the capacitance in the at least one coupling line is selected in such a way that the amplitudes are identical.

[0028] This compensates for the parasitic interference signal on each wire of the receiver line by mutually eliminating the antiphase signals. The signal arriving at the second part of the circuit is therefore already free of interference, i.e. it no longer contains any interference signal components.

[0029] The receiver line is preferably a single-wire or a two-wire line with one line wire or with two line wires. During operation, a compensation interference signal is preferably coupled into each line wire, which is in antiphase to a parasitic interference signal applied to this line wire.

[0030] With regard to the design of the capacitance of the at least one capacitor, this capacitance corresponds to a maximum parasitic capacitance. The maximum parasitic capacitance depends on the configuration of the hearing aid with the components used and is - based on the current configuration of the hearing aid - the maximum possible capacitance of a capacitive parasitic coupling between the interferer line and the receiver line. This maximum possible capacitance can be calculated or at least estimated based on the design of the hearing aid.

[0031] Depending on the configuration, the maximum parasitic capacitance varies, for example, between 50fF and 50pF. Especially in an embodiment with a two-wire receiver line, which in particular connects an antenna, especially an NFMI antenna with an amplifier, especially with a differential amplifier (e.g. LNA), the maximum parasitic capacitance is in the range of 50fF to 500fF and in particular in the range of 1 OOfF. Accordingly, the at least one capacitor has a capacitance in this range.

[0032] Especially In the embodiment with a single-wire receiver line with only one line wire, i.e. in a so-called single-end design, and especially in a variant in which an analogue microphone is connected to an analogue-digital converter via the receiver line, the maximum parasitic capacitance and thus the capacitance of the at least one capacitor is in the range of 1 pF to 50 pF and especially in the range of 10 pF.

[0033] In the case of a multi-wire interferer line and / or multi-wire receiver line, preferably exactly one coupling line is provided for each possible parasitic interference path. A capacitor is arranged in each coupling line. Each of these capacitors has the maximum capacitance specified above.

[0034] As already mentioned, the first circuit part is in particular an amplifier part, for example an H-bridge and in particular a so-called class D amplifier. Alternatively or additionally, the first circuit part is a signal generator, which feeds an especially digital, preferably clocked signal into the interferer line . The first circuit part can, for example, also be a so-called charge pump or have other circuit components, especially components with short transition or switching times of, for example, less than 1 ns and / or components which generate a high-frequency data signal (greater than or equal to one megahertz). For example, a differential data signal is transmitted via the interferer line .

[0035] Furthermore, the first component is preferably a receiver, especially a loudspeaker. The second electronic component is an antenna, in particular an inductive antenna and especially an NFMI antenna. The receiver line is designed in particular as a two-wire line.

[0036] Furthermore, in this variant with the antenna, the second circuit part is designed in particular as a differential amplifier (LNA).

[0037] Alternatively or additionally, the second electronic component is a microphone, in particular an analogue microphone, especially a so-called PINNA microphone, which is used to generate the PINNA effect.

[0038] Especially in this embodiment, the receiver line is preferably formed by a singlewire line.

[0039] Preferably - especially in this embodiment - the second circuit part is designed as an analogue-digital converter.

[0040] The parasitic effects typically vary from hearing aid to hearing aid and can also change over time, for example due to external influences or also due to ageing effects. According to a preferred embodiment, the capacitance of the at least one capacitor is adjustable. The capacitor therefore is an electronic component with a variable capacitance. Preferably, when using several coupling lines in each coupling line an adjustable capacitor is arranged.

[0041] The above mentioned values for the capacitances of the at least one capacitor are therefore the maximum capacitance of each of the capacitors of the individual coupling lines. The capacitance of the adjustable capacitor can therefore preferably be set between 0 and the maximum capacitance

[0042] In order to enable a sufficiently fine adjustment, the respective capacitor is preferably adjustable in steps between 1 fF and 5fF, in particular for the above-described case of a two-wire receiver line. Alternatively, the respective capacitor is preferably adjustable in steps between 20fF and 50fF, in particular for the above-described case of a single-wire receiver line.

[0043] According to one variant, the respective capacitors are preferably adjusted at the manufacturer's factory as part of an initial configuration, so that hearing aid-specific parasitic effects are compensated.

[0044] With regard to a simple adjustment, an adjustment process is provided in a preferred embodiment, wherein the electronic circuit has an adjustment part for this purpose, which is designed to detect at least an effect of the interference signal and to adjust the at least one capacitor. In particular, a setting element is arranged for the adjustment, which can adjust the capacitance of the respective capacitor.

[0045] An effect of the interference signal is to be understood in general as any disturbance or amendment of the normal data signal transmitted via the receiver line due to the parasitic interference signal. An effect is for example noise or a signal-to- noise ratio on the receiver line or downstream of the second circuit part.

[0046] To detect the effect of the parasitic interference signal, a measuring element is formed as part of the circuit which. Alternatively the measuring element for example directly measures the parasitic interference signal. Preferably, however, a noise and in particular a signal-to-noise ratio is determined as a parameter for the parasitic interference signal. The measuring element can consist of various electronic components.

[0047] The adjustment process is in particular an iterative process in which one or more of the capacitors are repeatedly adjusted and the effect of this adjustment is checked on the basis of the measurement results, i.e. specifically on the basis of the noise. In the course of the adjustment process, the noise is preferably reduced to a minimum.

[0048] Due to the unknown parasitic effects, which can lead to complex mutual reactions that complicate the adjustment process, a defined test signal is preferably first fed into only one of the conductors of the interferer line. No signal is fed to the other line wire. Then one or more capacitors are adjusted, especially to reduce noise. Subsequently, another test signal is fed into the other wire of the interferer line and the capacitors are again adjusted and optimised. Preferably the test signals are fed alternately into each of the line wires.

[0049] Preferably, the electronic circuit is designed to carry out the adjustment process automatically. The adjustment process is therefore carried out automatically and, in particular, also initiated automatically. The adjustment process is preferably initiated at predefined states, for example when the hearing aid is switched on and / or after defined time intervals or defined operating times of the hearing aid.

[0050] An example of an embodiment is explained in more detail below with reference to the figures.

[0051] Figure 1 shows a partial representation of a hearing aid by means of a circuit diagram according to a first embodiment, and

[0052] Figure 2 shows a partial representation of a hearing aid by means of a circuit diagram according to a second embodiment.

[0053] The hearing aid 2 is in particular a hearing aid in which an electronic input signal is generated via an input transducer, in particular a microphone. This electronic input signal is processed in a signal processing unit (electronic circuit, e.g. part of an IC, ASIC....). The processed and especially amplified signal is fed to an output transducer, in particular a receiver / loudspeaker. The hearing aid is especially designed and adjusted to compensate for a hearing impairment of a hearing-impaired person.

[0054] The hearing aid 2 generally has an electronic circuit 4, which is formed in particular by a microchip, an IC or in particular a so-called ASIC. This electronic circuit 4 has as a first circuit part an amplifier part 6, which in particular has an output bridge circuit, for example a so-called H-bridge. The amplifier part 6 is designed in particular as a so-called class D amplifier part. This is connected to a first electronic component via a first connection line, which is referred to as an inter- ferer line 8. In the shown embodiment, this is a receiver 10 (loudspeaker). The amplifier part 6 controls the receiver 10 via a digital control signal which is transmitted via the interferer line 8.

[0055] In addition, the circuit 4 has a second circuit part, which in the shown embodiment is designed as a differential amplifier 12 (LNA).

[0056] The amplifier 12 is connected with a second electronic component via a second connection line, which is referred to as the receiver line 14. In the shown embodiment of Figure 1 this is designed as an antenna 16, in particular as a so-called NFMI antenna. The differential amplifier 12 receives a signal from the antenna 16, amplifies it and outputs it for further processing.

[0057] The hearing aid 2 is in particular a hearing aid 2 of a binaural system and a communication signal of a second hearing aid of the binaural system is received via the antenna 16.

[0058] Both the interferer line 8 and the receiver line 14 are each designed as two-core lines with two line wires each.

[0059] The electronic circuit 4 further comprises a compensation part 18. The compensation part 18 has several coupling lines 20, whereby an individually adjustable capacitor 22 is arranged in each of the coupling lines 20. Furthermore, an inverter 24 is additionally arranged in each coupling line 20. Preferably, the inverter is arranged on the side of the interferer line 8 and thus in the direction of the receiver line 16 upstream of the respective capacitor 22. Each line wire of the interferer line 8 is connected to each line wire of the receiver line 14. In this embodiment, a total of four coupling lines 20 are therefore arranged, each with a capacitor 22. In principle, the capacitor 22 can also be formed by several individual capacitors.

[0060] Finally, the electronic circuit 4 further comprises an adjustment part 26 . This comprises as essential components a measuring element 28, i.e. a special arrangement of circuit components, and an setting element 30. In the shown embodiment, the measuring element 28 is used to determine a signal-to-noise ratio, namely for the amplified output signal of the amplifier 12. The setting element 30 is connected to each of the adjustable capacitors 22 and is used to adjust and to set the capacitance of these capacitors 22 in a controlled manner.

[0061] The circuit 4 is formed by at least one electronic component like a microchip, an IC or an ASIC.

[0062] The figure also shows interfaces 32 of this electronic component with the various connection lines 8, 14. Inside of this electronic component, the connection lines are designed in particular as conductor tracks and outside the component, for example, as sheathed conductors.

[0063] During operation of the hearing aid, the typically high-frequency control signal transmitted via the interferer line 8 causes interference signals to be coupled into the receiver line 14 due to existing parasitic capacitances. These coupling effects thus lead to a coupling between the individual line wires of the interferer line 8 and the line wires of the receiver line 14. This capacitive coupling is represented by dashed parasitic coupling lines 34 and by parasitic capacitors 36. These are not real components. They only serve to describe the parasitic effects.

[0064] Via the parasitic capacitances, an interference signal is in principle coupled from each line wire of the interferer line 8 into each line wire of the receiver line. Overall, there is a resulting interference signal on each line wire, which is composed of the interference signal components coupled into the line wire via the various coupling paths leading to this specific line wire.

[0065] The capacitances of the capacitors 22 of the coupling part 18 are now set in such a way that a (preferably) identical compensation interference signal is coupled into each line wire of the receiver line 14, which is, however, in antiphase to the parasitic interference signal. The compensation interference signal for each line wire consists of the compensation interference signal components which are coupled into this specific line wire via the different coupling lines 20 which are connected to this specific line wire.

[0066] The (resulting) parasitic interference signal and the (resulting) compensation interference signal therefore mutually cancel each other out so that a respective line wire is free of interference signals.

[0067] The maximum capacitance of the capacitors 22 in this embodiment is preferably 100fF.

[0068] Figure 2 shows an alternative embodiment in which an analogue microphone 38 is arranged as the second electronic component, which is connected to an analoguedigital converter 40 via a single-wire receiver line 14. In this embodiment, there are two parasitic coupling paths, each between one of the wires of the interferer line 8 and the one wire of the receiver line 14. The coupling mechanism and also the compensation mechanism are similar as described above for the embodiment of Figure 1 . A parasitic interference signal component is coupled in via each coupling path. These interference signal components are combined to form the (resulting) parasitic interference signal.

[0069] These parasitic coupling paths are simulated by the two coupling lines 20, so that antiphase compensation interference signal components are coupled in, which form a resulting antiphase compensation interference signal and which are selected in such a way that the resulting parasitic interference signal is eliminated.

[0070] With the help of the adjustment part 26, a suitable adjustment of the capacitances of the capacitors 22 is carried out. For this purpose, the signal-to-noise ratio is measured and in several iteration loops the capacitances of the capacitors 22 are varied until an optimal adjustment, especially an optimal signal-to-noise ratio is achieved. Overall, the parasitic effects are reproduced by the compensation part.

[0071] At the end of the adjustment process, a compensation interference signal is present on each line wire of the receiver line 14 (Figure 1 ) or on the one line wire of the receiver line 14 (Figure 2), which is in antiphase to the parasitic (resulting) interference signal present at this line wire, but with the same amplitude.

[0072] For a simple adjustment of the capacitors 22, during the adjustment process a first test signal is preferably fed to one line wire of the interferer line 8, then an optimisation is carried out with the aid of the adjustment part 26. Subsequently, a second test signal, which can be identical to the first test signal, is fed to the second wire of the interferer line 8 and optimisation is carried out again. This process is preferably repeated several times until the best possible setting is achieved.

[0073] List of reference signs

[0074] 2 Hearing aid

[0075] 4 Electronic circuit

[0076] 6 Amplifier part

[0077] 8 Interferer line

[0078] 10 Receiver

[0079] 12 Differential amplifier

[0080] 14 Receiver line

[0081] 16 Antenna

[0082] 18 Compensation part

[0083] 20 Coupling line

[0084] 22 Adjustable capacitor

[0085] 26 Adjustment part

[0086] 28 Measuring element

[0087] 30 Setting element

[0088] 32 Interface

[0089] 34 parasitic coupling line

[0090] 36 parasitic capacitor

[0091] 38 Microphone

[0092] 40 Analogue to digital converter

Claims

Claims1 . Method of operating a hearing aid (2) comprising- an electronic circuit (4) with several circuit parts (6,12, 40),- a first electronic component (10) which is connected to a first circuit part (6) of the electronic circuit (4) via a first connection line designated as an inter- ferer line (8),- a second electronic component (16) which is connected to a second circuit part (12, 40) of the electronic circuit (4) via a second connection line designated as a receiver line (14), wherein- parasitic capacitances exist between the two connection lines, so that a parasitic interference signal is coupled into the receiver line (14), characterized in that- for compensation of the parasitic interference signal, the electronic circuit (4) has a compensation part (18) which has at least one coupling line (20) which connects the two connection lines to one another, a capacitor (22) being arranged in the coupling line (20), so that a compensation interference signal is coupled into the receiver line (14) via the at least one coupling line (20).

2. Method according to the preceding claim, in which an inverter (24) is arranged in the at least one coupling line (20), so that the compensation interference signal is in antiphase to the parasitic interference signal which is coupled into the receiver line (14).

3. Method according to the preceding claim, in which the antiphase compensation signal has the same amplitude as the parasitic interference signal.

4. Method according to any one of the preceding claims, in which the receiver line is a single-wire or a two-wire receiver line with one line wire or with twoline wires, wherein a compensation interference signal is coupled into each line wire, which is in antiphase to a parasitic interference signal applied to this line wire.

5. A method according to any one of the preceding claims, wherein the capacitance of the at least one capacitor (22) corresponds to a maximum parasitic capacitance.

6. The method according to any one of the preceding claims, wherein the capacitance of the at least one capacitor (22) is- especially for the case of a two-wire receiver line (14) in the range of 50Ff to 500fF, especially in the range of 100fF and- especially for the case of a single-wire receiver line (14) in the range of 1 pF to 50pF and especially in the range of 10 pF.

7. Method according to one of the preceding claims, wherein the first circuit part is an amplifier part (6) and / or a signal generator which feeds a data signal, in particular a digital data signal, into the interferer line (8).

8. Method according to any one of the preceding claims, wherein- the first electronic component is a receiver (10) and / or wherein- the second electronic component is an antenna (16), in particular an inductive antenna and especially an NFMI antenna, or a microphone (38) and / or wherein- the second circuit part is an analogue-to-digital converter (40).

9. Method according to one of the preceding claims, in which the capacitance of the at least one capacitor (22) is adjustable, the capacitance preferably being adjustable in steps of 1 fF to 5fF, in particular for the case of a two-wire receiver line (14), or in steps of 20fF to 50fF, in particular for the case of a single-wire receiver line (14).

10. Method according to the preceding claim, in which an adjustment process for adjusting the capacitance of the at least one capacitor (22) is provided and the circuit (4) has for this purpose an adjustment part (26) which is designed to detect at least an effect of the parasitic interference signal and to adjust the at least one capacitor (22).

11. A method according to the preceding claim, wherein noise on the receiver line (14) is measured and the at least one capacitor (22) is varied such that a reduction of the noise occurs.

12. Method according to one of the two preceding claims, in which a defined test signal is fed into only one of the line wires of the interferer line (8), with a test signal preferably being transmitted alternately on the two line wires.

13. Method according to one of claims 10 to 12, wherein the electronic circuit (4) is designed to automatically carry out the adjustment process, the adjustment process being activated repeatedly, for example when the hearing aid (2) is switched on or after defined time intervals or operating times of the hearing aid (2).

14. Hearing aid (2) with- an electronic circuit (4) comprising several circuit parts (6, 12, 40),- a first electronic component (10) which is connected to a first circuit part (6) of the electronic circuit (4) via a first connection line designated as an interferer line (8),- a second electronic component (16, 38) which is connected to a second circuit part (12, 40) of the electronic circuit (4) via a second connection line designated as a receiver line (14), wherein- parasitic capacitances exist between the two connection lines which, in operation, lead to a parasitic interference signal being coupled into the receiver line (14), characterized in that- for compensation of the parasitic interference signal, the electronic circuit (4) has a compensation part (18) which is designed to generate and couple a compensation interference signal into the receiver line (14),- the compensation part (18) having for this purpose at least one coupling line (20) connecting the two connection lines and a capacitor (22) arranged in the coupling line (20).

15. Hearing aid according to the preceding claim, in which the compensation part(18) is designed in such a way that, in operation, a compensation interference signal in antiphase to the parasitic interference signal is coupled into the receiver line.

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