Hearing device with low-energy warning

Abstract

The present invention regards a hearing device comprising a power source, a control unit, a power source charge state monitoring unit, a timing unit, and an output unit. The hearing device is configured to be worn on or at an ear of a user. The power source is configured to power the hearing device. The power source charge state monitoring unit is configured to monitor the charge state of the power source by determining a current output voltage value of the power source. The timing unit is configured to measure a duration between two points in time. The output unit is configured to generate output sounds corresponding to electrical sound signals. The control unit is configured to activate a low-energy warning mode, if the current output voltage value determined by the power source charge state monitoring unit is below a predetermined threshold output voltage value of the power source. The control unit is further configured to adjust the predetermined threshold output voltage value in dependence of a duration of the low-energy warning mode. The control unit operating in the low-energy warning mode is configured to generate electrical low-energy warning signals. The output unit is configured to generate output stimuli perceived by the user as sounds corresponding to the electrical low-energy warning signals and/or to transmit such output sounds and/or signals indicating low energy warning signals to another device.

Claims

1. A hearing device configured to be worn on or at an ear of a user comprising a power source configured to power the hearing device, a control unit, a power source charge state monitoring unit configured to monitor the charge state of the power source by determining a current output voltage value of the power source, a timing unit configured to measure a duration between two points in time, and an output unit configured to generate output stimuli perceived by the user as sound corresponding to electrical sound signals, wherein the control unit is configured to activate a low-energy warning mode, if the current output voltage value determined by the power source charge state monitoring unit is below a predetermined threshold output voltage value of the power source and to adjust the predetermined threshold output voltage value in dependence of a duration of the low-energy warning mode, wherein the control unit operating in the low-energy warning mode is configured to generate electrical low-energy warning signals, wherein the control unit is configured to generate an electrical final warning signal, if the current output voltage value determined by the power source charge state monitoring unit is below a predetermined final warning threshold output voltage value, and wherein the control unit is configured to increase the predetermined threshold output voltage value if a duration between the current output voltage value crossing the predetermined threshold output voltage value and the current output voltage value crossing the predetermined final warning threshold output voltage value is below a predetermined short warning duration, and to decrease the predetermined threshold output voltage value if a duration between the current output voltage value crossing the predetermined threshold output voltage value and the current output voltage value crossing the predetermined final warning threshold output voltage value is above a predetermined long warning duration.

2. A hearing device according to claim 1, wherein the output unit is configured to generate output stimuli corresponding to the electrical low-energy warning signals.

3. A hearing device according to claim 1, wherein the predetermined short warning duration has a smaller duration than the predetermined long warning duration, and the predetermined short warning duration is equal to or below 120 minutes, and the predetermined long warning duration is equal to or above 2 h.

4. A hearing device according to claim 1, wherein the hearing device is a hearing aid, further comprising at least a microphone and electric circuitry, wherein the microphone is configured to receive sound and to generate electrical sound signals representing the sound and wherein the electric circuitry is configured to process the electrical sound signals.

5. A hearing device according to claim 1, wherein the control unit is configured to adjust the predetermined threshold output voltage value to a value such that the duration of the low-energy warning mode is equal to or below 4 h.

6. A hearing device according to claim 1, wherein the electrical low-energy warning signals are electrical sound signals.

7. A hearing device according to claim 1, wherein the hearing device comprises a user interface, wherein the user interface is configured to receive an input by a user and wherein the control unit is configured to process the input by the user by deactivating the low-energy warning mode.

8. A hearing device according to claim 1, wherein the output unit comprises a transmitter for transmitting signals representative of output sounds and/or signals indicating low energy warning signals to an auxiliary device.

9. A hearing system comprising a hearing device according to claim 1 and an auxiliary device, the system being adapted to establish a communication link between the hearing device and the auxiliary device to provide that information can be exchanged or forwarded from one to the other.

10. A hearing system according to claim 9 wherein the auxiliary device comprises an audio gateway, a remote control for controlling functionality and operation of the hearing device or another such hearing device.

11. A hearing system according to claim 9 wherein the auxiliary device comprises a user interface allowing a user to exchange data with the hearing aid device.

12. A hearing system according to claim 9 wherein the auxiliary device comprises a SmartPhone, the SmartPhone being adapted to run an APP allowing to control functionality of the hearing device via the SmartPhone.

13. A method for determining a predetermined threshold output voltage value indicative for an activation of a low-energy warning mode, wherein the method comprises the steps: initializing the method with a predetermined threshold output voltage value corresponding to a value of a predetermined warning level counter, determining a current output voltage value, if the current output voltage value is below the predetermined threshold output voltage value, activating a low-energy warning mode in which low-energy warning signals are emitted and starting a timer, increasing the value of the predetermined warning level counter if a duration of the low-energy warning mode is below a predetermined short warning duration, and decreasing the value of the predetermined warning level counter if the duration of the low-energy warning mode is above a predetermined long warning duration, wherein the predetermined short warning duration has a smaller duration than the predetermined long warning duration.

14. Use of a hearing device according to claim 1.

15. A data processing system comprising a processor and program code means for causing the processor to perform the steps of the method of claim 13.

Description

(1) The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings in which:

(2) FIG. 1 shows a schematic illustration of an embodiment of a hearing aid;

(3) FIG. 2 shows a schematic illustration of an embodiment of a binaural hearing aid device worn at a left ear and at a right ear of a user;

(4) FIG. 3 shows two exemplary discharge curves corresponding to two different hearing aid use scenarios for an identical battery type with prior art low-energy warning;

(5) FIG. 4 shows two exemplary discharge curves corresponding to two different hearing aid use scenarios for an identical battery type with use scenario specific low-energy warnings;

(6) FIG. 5 shows a schematic block diagram with an embodiment of a method to generate use scenario specific low-energy warnings;

(7) FIG. 1 shows an embodiment of a hearing aid 10 with a microphone 12, a telecoil (or other wireless receiver) 14, electric circuitry 16, and output unit (here a speaker) 18, a user interface 20 and a battery 22. In another embodiment the telecoil 14 can also be a second microphone, or a Bluetooth-Receiver, Infrared-Receiver, or any other wireless sound signal input configured to receive electrical sound signals wirelessly (not shown). In another embodiment the speaker 18 can also be a bone vibrator of a bone anchored hearing aid or an array of electrodes of a cochlear implant (not shown). In another embodiment, the output unit comprises (e.g. instead of or in addition to the speaker) a transmitter for transmitting signals representative of output sounds (e.g. coded signals) and/or signals indicating low energy warning signals (e.g. to be presented at another device, e.g. to alert a parent or other caretaker).

(8) The electric circuitry 16 comprises a control unit 24, a processing unit 26, a power source charge state monitoring unit 28, a memory 30, a timing unit 31, a receiver unit 32, and a transmitter unit 34. In the present embodiment the processing unit 26, the power source charge state monitoring unit 28, the memory 30, and the timing unit 31 are part of the control unit 24. The hearing aid 10 is configured to be worn at an ear of a user. One hearing aid 10 can for example be arranged at a left ear 36 and one hearing aid 10′ can be arranged at a right ear 38 of the user (see FIG. 2) with an insertion part 40 of the hearing aid 10 being arranged in an ear canal 42 of the user.

(9) The hearing aid 10 can be operated in various modes of operation, which are executed by the control unit 24 and use various components of the hearing aid 10. The control unit 24 is therefore configured to execute algorithms, to apply outputs on electrical signals processed by the control unit 24, and to perform calculations, e.g., for filtering, for amplification, for signal processing, or for other functions performed by the control unit 24 or its components. The calculations performed by the control unit 24 are performed in the processing unit 26. Executing the modes of operation includes the interaction of various components of the hearing aid 10, which are controlled by algorithms executed on the control unit 24.

(10) In a hearing aid mode the hearing aid 10 is used as a hearing aid for hearing improvement by sound amplification and filtering. In a low-energy warning mode the hearing aid 10 is used to determine the charge state of the battery 22 and approximate time when the energy of the battery 22 will be depleted (see FIGS. 3 and 4). In a low-energy consumption mode the hearing aid 10 is used in a mode similar to the hearing aid mode, which, in contrast to only improving hearing further reduces the signal quality and sound pressure level of a low frequency range to reduce the energy consumption.

(11) The mode of operation of the hearing aid 10 can be manually selected by the user via the user interface 20 or automatically selected by the control unit 24, e.g., by receiving transmissions from an external device via the receiver unit 32, obtaining a low-energy indication, receiving environment sound, receiving wireless sound signals or other indications that allow to determine that the user is in need of a specific mode of operation. The hearing aid 10 can also execute two or more modes of operation in parallel, e.g., the hearing aid mode and the low-energy warning mode, the low-energy warning mode and the low-energy consumption mode, or any other combination of two or more modes of operation.

(12) The hearing aid 10 operating in the hearing aid mode receives environment sound 46 with the microphone 12 and wireless sound signals with the telecoil 14. The microphone 12 generates electrical environment sound signals 48 representing the environment sound 46 and the telecoil 14 generates electrical wireless sound signals 50 representing the wireless sound signals, which are provided to the control unit 24. If both electrical sound signals 48 and 50 are present in the control unit 24 at the same time, the control unit 24 can decide to process one or both of the electrical sound signals 48 and 50, e.g., as a linear combination or in dependence of the signal-to-noise ratio of the electrical sound signals 48 and 50. The processing unit 26 of the control unit 24 processes the electrical sound signals 48 and 50, e.g., by spectral filtering, frequency dependent amplifying, filtering, or other typical processing of electrical sound signals in a hearing aid generating an output sound signal 52. The processing of the electrical sound signals 48 and 50 by the processing unit 26 depends on various parameters, e.g., sound environment, sound source location, signal-to-noise ratio of incoming sound, user specific hearing ability, mode of operation, type of output transducer, battery charge state, and/or other user specific parameters and/or environment specific parameters. The output sound signal 52 is provided to the speaker 18, which generates an output sound 54 corresponding to the output sound signal 52 which stimulates the hearing of the user.

(13) The hearing aid 10 is powered by the battery 22 (see FIG. 1). The battery 22 has an initial output voltage between 1.35 V and 1.65 V. The initial output voltage can also be below 7 V, e.g. in the range of 1 V to 5 V, such as between 1.2 V and 3 V.

(14) The embodiment of the hearing aid 10 presented in FIG. 1 automatically activates the low-energy warning mode, when a current output voltage value 64, 64′ determined by the power source charge state monitoring unit 28 is below a predetermined threshold output voltage value 66, 66′ indicative of low-energy of the battery 22 (see FIG. 4). The low-energy warning mode can also be activated manually by the user. The predetermined threshold output voltage value can be equal to or above 1.05 V (68, 68′ in FIG. 4), such as equal to or above 1.10 V (66, 66′ in FIG. 4), such as equal to or above 1.125 V (70, 70′ in FIG. 4), such as equal to or above 1.15 V (72, 72′ in FIG. 4). The predetermined threshold output voltage value in FIG. 4 has an initial predetermined threshold output voltage value 66, 66′ of 1.10 V. In the embodiment of the hearing aid 10 presented in FIG. 1 the predetermined threshold output voltage value used by the low-energy warning mode is determined by the low-energy warning mode starting with the initial predetermined threshold output voltage value 66, 66′ in the first use of the hearing aid 10. The predetermined threshold output voltage value can be increased or decreased continuously, by adaptive steps, or by fixed steps, e.g., with step sizes of 0.001 V, 0.002 V, 0.005 V, 0.01 V, 0.02 V, or 0.05 V by the low-energy warning mode or manually by the user. In every subsequent use after the first use the predetermined threshold output voltage value of the previous use of the hearing aid 10 is used. The hearing aid 10 can also use a predetermined threshold output voltage value stored in the memory 30, e.g., manually selected by the user or automatically selected by the control unit 24 based on parameters, e.g. initial battery capacity, battery type, battery brand, user specific parameters loaded by the user, or the like, determined when the hearing aid 10 is switched in an on state.

(15) The hearing aid 10 operating in the low-energy warning mode causes the timing unit 31 to start a timer and the control unit 24 to generate electrical low-energy warning signals, when the low-energy warning mode is activated due to the current output voltage value 64, 64′ crossing the predetermined threshold output voltage value.

(16) The control unit 24 operating in the low-energy warning mode generates electrical low-energy warning signals in periodic time intervals. The control unit 24 can also generate electrical low-energy warning signals only at predetermined durations of the low-energy warning mode or when predetermined warning threshold output voltage values are crossed by the current output voltage value 64, 64′. In the present embodiment the periodic time interval is 15 minutes. The periodic time intervals can for example also be 30 minutes, 1 h, or 2 h. The low-energy warning signals in the present embodiment are electrical sound signals representing bursts of sound with a predefined sound pressure level. The electrical sound signals are provided to the speaker 18 which generates an output sound 54 corresponding to the low-energy warning signal. The low-energy warning signals can also change with the interval or change over time. The low-energy warning signals can for example increase in intensity, e.g., sound pressure level, over time. The low energy-warning signals can also be other predetermined sounds, e.g., a tune, a beep, a voice informing the user about the approximate time when the power source is expected to run out of energy, or other sounds that can be understood as a low-energy warning by the user. The low-energy warning signals are e.g. stored in the memory 30 and can also or alternatively be received by the receiver unit 32 from an external device. The low-energy warning signals can also be data signals comprising information which can be displayed on a display of the hearing aid 10 (not shown) or on a display of an external device, e.g., a mobile phone, a personal computer, tablet computer, or the like, connected to the hearing aid 10 via the receiver unit 32 and the transmitter unit 34. The data signals transmitted to the external device can for example comprise an order for new batteries or a reminder to recharge batteries, which can be used by a third person or an appliance. This allows a third person caring for an impaired person using a hearing aid to receive the low-energy warning signals on the third persons external device and prepare for a replacement or recharging of the battery 22.

(17) The timing unit 31 operating in the low-energy warning mode provides a duration determined from the timer between the activation of the low-energy warning mode and the current point of time to the control unit 24. The timing unit 31 can also provide the duration to the control unit 24 in periodic intervals or provide an activation signal to the control unit 24 after predetermined durations. The control unit 24 in response to the activation signal performs an action, e.g., generates a low-energy warning signal, activates/deactivates a mode of operation or performs another type of action. In the present embodiment of the hearing aid 10 the timer of the timing unit 31 determining the duration of the low-energy warning mode stops when the hearing aid 10 is turned off. In an embodiment, the timer of the timing unit 31 can also measure the time when the hearing aid 10 is offline. The timing unit 31 can provide an offline and online time to the control unit 24. The control unit 24 can discount the offline time, when determining a duration of the low-energy warning mode, e.g., multiplying the offline time with a factor before adding online time and offline time of the hearing aid 10 in low-energy warning mode to determine the duration of the low-energy warning mode. When the hearing aid 10 is reactivated and the power source charge state monitoring unit 28 determines a current output voltage value below the predetermined threshold output voltage value, the timer of the timing unit 31 continues running. If the power source charge state monitoring unit 28 determines a current output voltage value above the predetermined threshold output voltage value, indicating a replaced or recharged battery 22, when the hearing aid 10 is reactivated, the duration of the low-energy warning mode is provided to the control unit 24 and the timer of the timing unit 31 is reset. The control unit 24 uses the duration of the low-energy warning mode to determine a new predetermined threshold output voltage value.

(18) In an alternative embodiment the low-energy warning mode executed on the control unit 24 of the hearing aid 10 stops, when the power source charge state monitoring unit 28 determines a current output voltage value below a predetermined final warning threshold output voltage value 68, 68′ (see FIG. 4). The timing unit 31 operating in the low-energy warning mode stops, when the low-energy warning mode is stopped and provides the duration of the low-energy warning mode determined by the timer to the control unit 24. The control unit 24 uses the duration of the low-energy warning mode to determine a new predetermined threshold output voltage value.

(19) The control unit 24 executing the low-energy warning mode determines a new predetermined threshold output voltage value using the duration of the low-energy warning mode, when the low-energy warning mode is stopped. In the present embodiment the predetermined threshold output voltage value can have one of three different values proportional with output voltage, a high predetermined threshold output voltage value 72, 72′ with 1.15 V, a middle predetermined threshold output voltage value 70, 70′ with 1.125 V, or a low predetermined threshold output voltage value 66, 66′ with 1.10 V (see FIG. 4). The predetermined threshold output voltage value can also be any other value between the initial output voltage value of the battery 22 and a final output voltage value of the battery 22 which leads to break down of the battery (i.e. to exhibit a substantial drop in output voltage over a short time, prohibiting electronic circuitry of the hearing aid to function properly). The initial predetermined threshold output voltage value 66, 66′ is 1.10 V in the present embodiment of FIG. 4, because a too low initial predetermined threshold output voltage value is more easily corrected. A too high predetermined threshold output voltage value, which results in a long duration of the low-energy warning mode, would need many hours of low-energy warning mode to be corrected. The predetermined final warning threshold output voltage value 68, 68′ that stops the low-energy warning mode in the alternative embodiment is 1.05 V (see FIG. 4). The predetermined threshold output voltage value is selected in dependence of the duration of the low-energy warning mode. If the duration of the low-energy warning mode is below 30 minutes, a higher predetermined output voltage value is selected and if the duration of the low-energy warning mode is above 4 h, a lower predetermined output voltage value is selected by the control unit 24. The selection of the predetermined output voltage value can be stepwise, e.g., from middle to high, or from 1.10 V to 1.101 V, etc. in steps of 0.001 V, or can depend on a function, e.g., an increase or decrease of output voltage value defined by a function in dependence of the duration of the low-energy warning mode, such as each minute below 30 minutes leading to an increase of 0.001 V and each minute above 4 h leading to a decrease of 0.001 V, or the like. The predetermined output voltage value selected by the control unit 24 is provided to the memory 30, which stores the value for a subsequent use of the low-energy warning mode of the hearing aid 10 (e.g. after a power-down, and a subsequent power-up of the hearing aid).

(20) The memory 30 is used to store data, e.g., user specific hearing aid usage parameters, predetermined threshold output voltage values, predetermined final warning threshold output voltage values, predetermined output sounds, predetermined electrical sound signals, predetermined time delays, user specific audiograms, algorithms, operation mode instructions, or other data, e.g., used for the processing of electrical sound signals or operating the hearing aid 10.

(21) The receiver unit 32 and transmitter unit 34 (one or both e.g. wireless or one or both e.g. wired) allow the hearing aid 10 to connect to one or more external devices, e.g., a second hearing aid 10′ (see FIG. 2), a mobile phone, an alarm, a personal computer, a tablet computer, or other devices. The receiver unit 32 and transmitter unit 34 receive and/or transmit, i.e., exchange, data with the external devices. The hearing aid 10 can for example exchange user specific hearing aid usage parameters, predetermined threshold output voltage values, predetermined final warning threshold output voltage values, low-energy warning signals, predetermined output sounds, predetermined electrical sound signals, predetermined time delays, user specific audiograms, algorithms, operation mode instructions, or other data used, e.g., for operating the hearing aid 10. The receiver unit 32 and transmitter unit 34 can also be combined in a transceiver unit, e.g., a Blue-tooth-transceiver, a wireless transceiver, or the like. The receiver unit 32 and transmitter unit 34 can also be connected with a connector for a wire, a connector for a cable or a connector for a similar line to connect an external device to the hearing aid 10. The battery 22 can be wirelessly recharged, or recharged using a wire or cable connected to the connector for a wire or cable of the hearing aid 10 (not shown).

(22) FIG. 2 shows an embodiment of a binaural hearing aid system comprising first and second hearing aids 10 and 10′ each with a Behind-The-Ear (BTE) unit 56 and 56′ connected via a wireless connection 44. One BTE-unit 56 is mounted behind the right ear 38 and one BTE-unit 56′ is mounted behind the left ear 36 of a user. Each of the BTE units comprises the microphone 12, the telecoil 14, the electric circuitry 16, the user interface 20, and the battery 22 (cf. FIG. 1). The speaker 18 is arranged in the insertion part 40, which is connected to the BTE-unit 56 via the lead 58. The insertion part 40 is e.g. arranged fully or partially in a bony portion 60 of the ear canal 42 of the user close to an ear drum 62. The insertion part 40 adheres to a skin portion of the bony portion 60 of the ear canal 42 to close and seal the ear canal 42, which prevents the escape and intrusion of sound. Output sound 54 generated by the speaker 18 stimulates the ear drum 62 which allows auditory perception for the user. Alternatively, the speaker 18 can be arranged further away from the ear drum in a more soft part of the ear canal 42.

(23) Hearing aid 10 and hearing aid 10′ each comprise a receiver unit 32 and a transmitter unit 34. The combination of receiver unit 32 and transmitter unit 34 can be used to connect the hearing aid 10 with other devices, e.g., with the hearing device 10′ for binaural operation of the hearing aids 10 and 10′. If the hearing aids 10 and 10′ are operated binaurally the two hearing aids 10 and 10′ are connected with each other wirelessly. The transmitter unit 34 of the hearing aid 10 transmits data to the hearing aid 10′ and the receiver unit 32 of the hearing aid 10 receives data from the hearing aid 10′, and vice versa. The hearing aids 10 and 10′ can exchange data, e.g., user specific hearing aid usage parameters, electrical sound signals 48 and 50, output sound signals 52, predetermined threshold output voltage values, predetermined final warning threshold output voltage values, current output voltage values, data signals, user specific audiograms, or other data, via the wireless connection 44. Additionally or alternatively, the transceiver units 32, 34 (or separate dedicated transceiver units) may be configured to exchange some or all the mentioned data with one or more auxiliary devices, e.g. a remote control unit, e.g. a SmartPhone. In an embodiment, the binaural hearing aid system is configured to exchange data between the two hearing aid devices 10, 10′ via an inductive link. In an embodiment, the binaural hearing aid system is configured to exchange data between the two hearing aid devices 10, 10′ and an auxiliary device via link based on radiated fields (e.g. according to Bluetooth or similar specification).

(24) FIG. 3 shows a discharge curve graph 74 of the battery 22 of the hearing aid 10 with two exemplary discharge curves 76, 76′ for the same battery types but with two different use scenarios, meaning different current draws. The discharge curve graph 74 shows the current output voltage 64, 64′ of the respective discharge curve 76 (low current draw), 76′ (high current draw) plotted against the time of use of the hearing aid 10. The current output voltage 64, 64′ decreases due to the increase of internal resistance in the battery 22. The low-energy warning mode presented in FIG. 3 corresponds to a low-energy warning mode of the prior art. The low-energy warning mode is activated when a predetermined pre-warning threshold output voltage value 78, 78′ is reached. In the low-energy warning mode of the embodiment of FIG. 3 a low-energy warning signal is generated every 15 minutes and presented to the user. The low-energy warning mode runs until a predetermined final-warning threshold output voltage 80, 80′ is reached.

(25) The duration of the low-energy warning mode mainly depends on the use scenario and battery type as the battery discharge curve 76, 76′ is easily influenced by the current draw. The hearing aid 10 corresponding to the solid discharge curve 76 (low current draw) has a duration of 5 hours of the low-energy warning mode, while the hearing aid corresponding to the dashed discharge curve 76′ (higher current draw) has a duration of 20 hours of low-energy warning mode. The duration is determined as the duration between the current output voltage value 64, 64′ crossing the predetermined pre-warning threshold output voltage value 78, 78′ and the current output voltage value 64, 64′ crossing the predetermined final-warning threshold output voltage value 80, 80′. The target duration is around 2 hours. Some users have reported the duration of the low-energy warning mode to last up to 4 days, while other users experienced a very short duration of low-energy warning mode of only a few minutes.

(26) FIG. 4 shows the discharge curve graph 74 of the battery 22 of the hearing aid 10 with the two exemplary discharge curves 76, 76′ for the same battery types but with two different use scenarios, meaning different current draws.

(27) In contrast to the embodiment of the low-energy warning mode of the prior art presented in FIG. 3, the embodiment of the low-energy warning mode presented in FIG. 4 has a dynamic pre-warning correction (DPC), meaning, that the predetermined threshold output voltage value is adjusted by the low-energy warning mode in order to find a predetermined threshold output voltage value that is suitable for the current user. Adjusting the predetermined threshold output voltage value allows to adjust the duration of the low-energy warning mode, e.g., which allows to adjust the duration to the target duration of for example 2 h.

(28) The energy consumption, i.e., current consumption, of a hearing device depends on the choice of device, user specific hearing loss and user activity. The battery discharge curve 76, 76′ depends on the parameters of the battery 22, e.g., battery capacity, battery type, battery brand, or other battery parameters and energy consumption, i.e., current consumption determined by the use scenario. A typical user tends to use batteries 22 in subsequent uses of a hearing device, e.g., hearing aid 10, with identical parameters and typically has a user specific use scenario that does not differ significantly over the use cycle of the hearing device, i.e., the user continuously uses the same battery brand and has a steady energy consumption. This leads to a battery discharge curve 76 or 76′ specific to a specific user using a specific hearing aid 10 that has the somewhat same properties day after day.

(29) The control unit 24 operating in the low-energy warning mode, i.e., the dynamic pre-warning correction (DPC) feature running on the control unit 24, monitors and analyses the duration of the low-energy warning mode to determine if a current low-energy warning level corresponding to a predetermined threshold output voltage value, e.g., 72, 70, or 66, is suitable for the current user with the discharge curve 76. Another user with the discharge curve 76′ might have another suitable predetermined threshold output voltage value, e.g., 72′, 70′, or 66′. If the predetermined threshold output voltage value is not suitable for the current user, the predetermined threshold output voltage value is increased or decreased by the low-energy warning mode to better fit the user needs. If the predetermined threshold output voltage value is suitable for the current user, meaning that the duration of the low-energy warning mode is in between a favourable duration range, the predetermined threshold output voltage value, i.e., the current low-energy warning level is unchanged. The favourable duration for the low-energy warning mode in the present embodiment is between 30 minutes and 4 h.

(30) The end of the low-energy warning mode can be determined by a user replacing the battery 22, therefore the current output voltage value determined by the power source charge state monitoring unit will be above the predetermined threshold output voltage value and the low-energy warning mode stops. Alternatively, the end of the low-energy warning mode can be determined by the current output voltage value crossing a predetermined final warning threshold output voltage value 68, 68′, which then leads to a stop of the low-energy warning mode. Also, both aforementioned constraints can be implemented in the low-energy warning mode, meaning that the low-energy warning mode either stops when the current output voltage value crosses the predetermined final warning threshold output voltage value 68, 68′ or when the battery 22 is recharged or replaced earlier. Therefore the user behaviour is taken into account. If the user tends to replace or recharge the battery 22 shortly after the activation of the low-energy warning mode the duration can be reduced to a shorter duration for the low-energy warning mode, e.g., 30 minutes or below. If the user tends to replace or recharge the battery 22 only after a significant duration after the activation of the low-energy warning mode the duration can be increased to a longer duration for the low-energy warning mode, e.g., 4 h or above.

(31) The low-energy warning mode can be easily implemented in prior art systems.

(32) FIG. 5 shows a schematic block diagram with an embodiment of a method to generate use scenario specific low-energy warnings by determining a predetermined threshold output voltage value, which is indicative for the activation of the low-energy warning mode. The method comprises the steps: 100 initializing the method with a predetermined threshold output voltage corresponding to a value of a predetermined warning level counter; 110 determining a current output voltage value; 120 if the current output voltage value is below the predetermined threshold output voltage value, activating a low-energy warning mode in which low-energy warning signals are emitted and starting a timer; 130 increasing the value of the predetermined warning level counter if a duration of the low-energy warning mode is below a predetermined short warning duration;
and 140 decreasing the value of the predetermined warning level counter if the duration of the low-energy warning mode is above a predetermined long warning duration.

(33) The predetermined short warning duration has a smaller duration than the predetermined long warning duration. The predetermined short warning duration in the present embodiment of the method is 30 minutes and the predetermined long warning duration is 4 h. The predetermined short warning duration can be equal to or below 120 minutes, such as equal to or below 60 minutes, such as equal to or below 30 minutes. The predetermined long warning duration can be equal to or above 2 h, such as equal to or above 4 h, such as equal to or above 8.5 h. The predetermined short warning duration and predetermined long warning duration can also be adjustable, e.g., by the user of the hearing device. The predetermined short warning duration and predetermined long warning duration can be increased or decreased continuously, by adaptive steps, or by fixed steps, e.g., with step sizes of 1 minute, 10 minutes, 30 minutes, 1 h, 2 h, or 4 h.

REFERENCE SIGNS

(34) 10 hearing aid 12 microphone 14 telecoil 16 electric circuitry 18 speaker 20 user interface 22 battery 24 control unit 26 processing unit 28 power source charge state monitoring unit 30 memory 31 timing unit 32 receiver unit 34 transmitter unit 36 left ear 38 right ear 40 insertion part 42 ear canal 44 wireless connection 46 environment sound 48 electrical environment sound signals 50 electrical wireless sound signals 52 output sound signal 54 output sound 56 Behind-The-Ear (BTE) unit 58 lead 60 bony portion 62 ear drum 64 current output voltage 66 low predetermined threshold output voltage value 68 predetermined final-warning threshold output voltage value 70 middle predetermined threshold output voltage value 72 high predetermined threshold output voltage value 74 discharge curve graph 76 discharge curve 78 pre-warning threshold output voltage value 80 predetermined final-warning threshold output voltage value of prior art