Abstract:
There is provided an earpiece or a headset comprising an audio input for receiving an audio signal to be reproduced, at least one electroacoustic reproduction transducer, an audio unit for effecting audio processing of the received audio signal, at least one converter unit for extracting power from the audio signal received at the audio input, a power storage means for at least partial intermediate storage of the power extracted from the audio signal, and a power control unit for controlling the extraction of the power from the audio signal and for controlling a power supply of the audio unit, in particular by way of the power stored in the power storage means and extracted from the audio signal.

Description:
The present application claims priority to German Patent Application No. DE 10 2014 211 181.1 filed on Jun. 11, 2014, the disclosures of which are incorporated herein by reference in their entirety. 
     FIELD OF THE INVENTION 
     The present invention concerns an earpiece and a headset. 
     It is noted that citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention. 
     Earpieces like for example headphones or earphones as well as headsets increasingly have electronics which have to be supplied with power. Those electronics can represent for example an active noise cancellation unit. As the earpieces or headsets are worn in a mobile context the power consumption of the electronics is an important factor. To avoid excessively frequent or excessively fast recharging of the power supply of the earphone or headset either the storage capacity of the power storage means has to be increased and/or the power consumption of the earpiece or the headset has to be reduced. 
     In the German application from which priority is claimed the German Patent and Trade Mark Office searched the following documents: US 2014/0018016 A1; DE 10 2007 009 176 A1; US 2013/0083927 A1; US 2012/0321097 A1; US 2013/0034237 A1; US 2012/0114125 A1; US 2012/0070014 A1; Jamal, G. R. A. et al; “Generation of usable electric power from available random sound energy”. In: International Conference on Informatics, Electronics and Vision (ICIEV), pp 1-4, May 2013 and Kuo, Y.-S. et al; “Hijacking Power and Bandwidth from the Mobile Phone&#39;s Audio Interface”. In: First Annual Symposium on Computing for Development, pp 1-10, December 2010. 
     It is noted that in this disclosure and particularly in the claims and/or paragraphs, terms such as “comprises”, “comprised”, “comprising” and the like can have the meaning attributed to it in U.S. patent law; e.g., they can mean “includes”, “included”, “including”, and the like; and that terms such as “consisting essentially of” and “consists essentially of” have the meaning ascribed to them in U.S. patent law, e.g., they allow for elements not explicitly recited, but exclude elements that are found in the prior art or that affect a basic or novel characteristic of the invention. 
     It is further noted that the invention does not intend to encompass within the scope of the invention any previously disclosed product, process of making the product or method of using the product, which meets the written description and enablement requirements of the USPTO (35 U.S.C. 112), such that applicant(s) reserve the right to disclaim, and hereby disclose a disclaimer of any previously described product, method of making the product, or process of using the product. 
     SUMMARY OF THE INVENTION 
     Therefore an object of the present invention is to provide an earpiece and a headset which manages with reduced power consumption of the mobile power supply of the earpiece or the headset. 
     Thus there is provided an earpiece or a headset comprising an audio input for receiving an audio signal to be reproduced, at least one electroacoustic reproduction transducer, an audio unit for effecting audio processing of the received audio signal, at least one converter unit for extracting power from the audio signal received at the audio input, a power storage means for at least partial intermediate storage of the power extracted from the audio signal, and a power control unit for controlling the extraction of the power from the audio signal and for controlling a power supply of the audio unit of the power stored in the power storage means and extracted from the audio signal. 
     According to an aspect of the present invention the power control unit is adapted to limit the mode of operation of the earphone or the headset, in particular the audio unit, if there is no longer sufficient power in the power storage means. In that way the power present can be firstly guaranteed for the functions considered to be important like for example reproduction of the audio signal by way of the electroacoustic reproduction transducer. 
     According to a further aspect of the present invention the power control unit monitors whether after extraction of power from the received audio signal there is correspondingly power in the audio signal to be able to drive the electroacoustic reproduction transducer and/or operate the audio unit. 
     The invention also concerns an earpiece or headset comprising an electroacoustic reproduction transducer, an audio unit for effecting audio processing of an audio signal, a boom microphone, at least one converter for extracting power from the microphone feed signal, an input for receiving a microphone feed supply for the boom microphone, a power storage means in which the power extracted from the microphone feed signal is at least partially put into intermediate storage, and a power control unit for controlling extraction of power from the microphone feed signal and for controlling the power supply of the audio unit. 
     The invention concerns the notion of using the power present in an input audio signal at least partially as the power supply for the electronics of the earpiece or the headset so that the storage capacity of a power storage means of the earpiece or headset can be reduced. If the power in the audio signal is not sufficient to supply all components of the electronics of the earpiece or headset with power then previously determined components or units of the electronics can be supplied with power preferentially. In other words, if there is not sufficient power in the input audio signal then parts of the electronics of the earpiece or the headset can be shut down or deactivated until there is once again sufficient power in the audio signal. The power stored in the audio signal can be extracted and put into intermediate storage for example in a capacitor, for example an ultra-cap. Upon extraction of the power from the input audio signal however it is necessary to provide (for on-going operation) that there is sufficient power in the audio signal to be able to sufficiently actuate the electroacoustic reproduction transducer. 
     According to the invention the power contained in the audio signal is used not only for the power supply to the electroacoustic reproduction transducer but also at least partially for supplying the electronics of the earpiece or headset. 
     The invention can be used in mobile audio devices and base stations which have an electronic system. According to the invention the DC/DC converter is so controlled that the input resistance is kept substantially constant. 
     An audio signal to be reproduced is an audio signal which has substantially no direct component DC. There is no bias but a normal or usual audio signal which is output from an audio output and can be converted into sound by an electroacoustic reproduction transducer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic block circuit diagram of a headphone or a headset according to a first embodiment; and 
         FIG. 2  shows a schematic block circuit diagram of a headphone or a headset according to a second embodiment. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for purposes of clarity, many other elements which are conventional in this art. Those of ordinary skill in the art will recognize that other elements are desirable for implementing the present invention. However, because such elements are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements is not provided herein. 
     The present invention will now be described in detail on the basis of exemplary embodiments. 
       FIG. 1  shows a schematic block circuit diagram of a headphone or a headset according to a first embodiment. The earpiece or the headset has an audio input  110  for receiving an audio signal to be reproduced, a rectifier unit  120  for rectifying the audio signal received by way of the audio input  110 , a DC/DC converter unit  130 , an audio unit  140 , at least one electroacoustic reproduction transducer  150 , an power control unit  160 , an power storage unit  170  and an electronic unit  180 . The audio signal can be output by an external audio source  200  (for example a media player, a smartphone etc). 
     The audio signal which is to be reproduced and which is produced or output by the external audio source  200  represents an audio signal substantially without direct component DC. That audio signal can optionally have no bias but can represent a normal audio signal to be reproduced. 
     The rectifier  120  converts the audio signal at the audio input  110  from the external audio source  200  into a DC signal. The output signal of the rectifier  120  can be converted to a higher or lower level by the DC/DC converter  130 . The audio unit  140  can effect audio signal processing, for example active noise cancellation, and the corresponding signal can be output by way of the electroacoustic reproduction transducer  150 . As the input signal the power control unit  160  has the voltage value of the audio signal and/or the current value of the audio signal and optionally the voltage value of the power storage means  170 . The power control unit  160  can output as its output signal a control signal to the unit  180  or to the audio unit  140  and can control the functioning of the electronic unit  180  or the audio unit  140 . 
     According to the first embodiment power is extracted from the input audio signal by means of the rectifier unit  150  and/or the DC/DC converter  130  and the extracted power can be put into intermediate storage in the power storage unit  170  or used for the power supply to the audio unit  140 , the power control unit  160  and/or the electronic unit  180 . If it should not be possible to extract sufficient power from the input audio signal then components of the electronic unit  180  and/or the audio unit  140  can be at least temporarily deactivated. For that purpose the power control unit  160  can be coupled to the audio unit  140  to be able to establish whether the audio unit  140  is receiving sufficient power from the audio signal to be able to suitably reproduce the audio signal on the electroacoustic reproduction transducer  150 , to be able to effect active noise cancellation or to be able to effect other audio signal processing. 
     According to the invention the DC/DC converter  130  can use the power from the power storage unit  170  to supply an electronic system of the earpiece with a suitable voltage. 
     According to the invention the DC/DC converter  130  is so controlled that the input resistance R L  is kept substantially constant. Power adaptation can be achieved by means of a variation in the input resistance for example by voltage maximization. It is possible in that way to provide for improved adaptation to the audio source. 
     The DC/DC converter  130  also serves to feed the power storage unit  170 . According to the invention the power which can be used for the system is proportional to the voltage U Q1 , wherein the voltage is controlled at the power storage unit by the power control unit. 
     Thus the efficiency of the earpiece or the headset can be improved in comparison with the state of the art which uses a linear regulator or a linear amplifier. 
     By virtue of the fact that a part of the power required for the earpiece or the headset is not extracted from a power storage means in the earpiece/headset, for example in the form of a battery or an accumulator, but is extracted from the input audio signal the power storage means (the battery/accumulator) can be dispensed with or at least the service life thereof is considerably increased. 
       FIG. 2  shows a schematic block circuit diagram of an earpiece or a headset according to a second embodiment. The earpiece or the headset  100  has a first DC/DC converter  121  connected to an external voltage supply  300  by way of a connection  111 , wherein the external voltage supply represents a microphone feed voltage or a feed voltage of a mobile device. The first DC/DC converter  121  converts the input voltage into an output voltage which can be higher or lower than the input voltage. A second DC/DC converter  130  is coupled to the first DC/DC converter  121 . The second DC/DC converter  130  serves to supply the audio unit  140  which for example can have an active noise cancellation unit or another audio processing unit with a suitable (for example constant) output voltage. The first DC/DC converter  121  can serve to feed the storage unit  170 . The storage unit  170  can be for example in the form of a capacitor, for example an ultra-cap. The earpiece or the headset according to the second embodiment further has a first microphone  191  and a second microphone  192 . The first microphone  191  serves as a microphone for active noise cancellation and the second microphone  192  can be in the form of a boom microphone supplied with a microphone feed voltage by way of the input  111 . The earpiece or the headset further has a power control unit  160  which provides for voltage monitoring of the storage unit  170 . The power control unit  160  can optionally also be adapted to limit the operation of the audio unit or the electronic unit  180  if there is not sufficient power in the storage unit  170 . For example the level of active noise cancellation can be reduced to reduce the power consumption. If however the storage unit  170  has for example a very great deal of power then that power can be used for example for the electronic unit  180 . 
     The first DC/DC converter  121  has for the target parameter a variable microphone voltage as a reference in order thus to achieve a voltage-dependent load resistance together with the first DC/DC converter. According to the second embodiment a maximum possible amount of power can be extracted from the microphone feed for the boom microphone  192  by the first converter unit  121 . The power which can be used for the earpiece or the headset is proportional to the voltage at the storage unit  170 . 
     The advantages of the earpiece or the headset according to the second embodiment correspond to the advantages of the earpiece or the headset of the first embodiment. 
     Depending on the audio source involved a differing amount of energy can be extracted from the audio signal. An aviation microphone connection provides for example a voltage of between 8 and 16 V with an output resistance of 470 ohms, that is to say the connection can provide at least 60 mW. An analog audio stereo signal with a 32 ohm load can provide 1 Vrms, that is to say a power of 62.5 mW. A microphone connection on a cellular phone or a mobile device can provide for example 3.3 V with an output resistance of 1 kohm, that is to say the mobile device can provide 5 mW. An analog audio stereo signal with a load of 8 ohms can provide a voltage of 150 mVrms and a power of 5.6 mW. 
     Optionally an ultra-cap can be used as the power storage means. 
     According to the invention between 0 and 100% of the power from the audio signal can be at least partly fed to the power storage means. 
     While this invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the inventions as defined in the following claims.