Hearing device with multiple-input multiple-output dc-dc converter

Abstract

The present invention relates to a hearing device configured to be worn at an ear of a user. The hearing device comprises an input transducer adapted to capture sound and to provide a microphone input transducer signal based on the captured sound. The hearing device comprises a signal processing unit adapted to process an input transducer signal and to provide an output signal based on the processed input transducer signal. The hearing device comprises an output transducer adapted to provide an excitation output signal based on an output signal. The hearing device includes a battery configured to provide a battery cell voltage. A hearing device includes a multiple-input multiple-output switched capacitor MIMO SC DC-DC converter coupled to a battery. The MIMO SC DC-DC converter includes two or more input terminals, each of which is adapted to receive a voltage input. The MIMO SC DC-DC converter includes more than two output terminals, each output terminal being adapted to provide a voltage output of a different voltage than the other output terminals. At least two of the more than two output ends can provide voltage output at the same time. The MIMO SC DC-DC converter is configured to convert each voltage input to a voltage output of a different voltage.

Description

Technical Field

[0001] The present invention relates to a hearing device comprising a multiple-input multiple-output (MIMO) switched capacitor (SC) DC-DC converter. Background Art

[0002] Modern hearing devices include chipsets incorporating various switched capacitor (SC) DC-DC power converters for efficient voltage conversion from the input voltage of a power supply unit (e.g., a lithium-ion battery) to a lower voltage, which typically provides a battery cell voltage in the range of 4.2V to 2.8V depending on the battery's state of charge. This down-conversion is critical to ensure a durable power supply while also allowing for increasingly power-demanding features in hearing devices. Many hearing devices utilize multiple voltage levels below the input voltage level in order to minimize power consumption. To provide these supply voltages, hearing devices are equipped with multiple SC DC-DC converters in addition to several linear regulators, each of which reduces power conversion efficiency.

[0003] From a power efficiency perspective, the use of such converters is often inefficient. Even though every SC DC-DC power converter has good power conversion efficiency, achieving good power conversion efficiency when stepping down the voltage multiple times is challenging.

[0004] The use of multiple SC converters also requires a large number of off-chip multilayer ceramic capacitors. This increases the printed circuit board area and thus the overall size of the electronic device, which is a problem, especially for miniature devices such as hearing aids and headphones. In addition, many SC converter topologies require high voltage (HV) power switches and therefore require HV transistor processes, which limits the integrability of SC converter topologies in modern low-voltage integrated circuit (IC) process nodes and requires dedicated HV processes or additional process options.

[0005] Furthermore, SC converters are a source of electromagnetic interference (EMI) interference with varying switching frequencies, pulse widths and / or pulse densities, which means that the switching frequency / load current needs to be carefully planned to avoid interference with adjacent microphone systems.

[0006] Furthermore, systems including multiple SC converters are interdependent, resulting in additional design challenges including startup sequencing.

[0007] EP3447894B1 relates to a head-mounted hearing device comprising a multi-output switched capacitor DC-DC converter. The multi-output switched capacitor DC-DC converter comprises a switch matrix comprising a plurality of individually controllable semiconductor switches and a plurality of flying capacitors connected between groups of circuit nodes of the switch matrix. A controller is connected to respective control terminals of the plurality of individually controllable semiconductor switches of the switch matrix to configure first and second converter sections for forming first and second converter topologies, respectively, according to a topology selection rule. However, this solution does not support multiple input voltages, and depending on the configuration of the SC DC-DC converter circuit, only a single output voltage can be provided at a time.

[0008] It is an object of the present invention to overcome one or more of the above-mentioned disadvantages. Summary of the invention

[0009] The present invention achieves this object by a hearing device configured to be worn at the ear of a user. The hearing device includes an input transducer adapted to capture sound and provide a microphone input transducer signal based on the captured sound. The hearing device includes a signal processing unit adapted to process the input transducer signal and provide an output signal based on the processed input transducer signal. The hearing device includes an output transducer adapted to provide an excitation output signal based on the output signal. The hearing device includes a battery configured to provide a battery cell voltage. The hearing device includes a multiple input multiple output (MIMO) switched capacitor (SC) DC-DC converter coupled to the battery. The MIMO SC DC-DC converter includes more than two input terminals, each of which is adapted to receive a voltage input. The MIMO SC DC-DC converter includes more than two output terminals, each of which is adapted to provide a voltage output having a different voltage from the other output terminals. At least two of the more than two output terminals can provide a voltage output simultaneously. The MIMO SC DC-DC converter is configured to convert each voltage input into a voltage output having a different voltage.

[0010] An advantage of the present invention is that the MIMO SC DC-DC converter includes multiple input terminals configured to receive different input voltages, which enables the hearing MIMO SC DC-DC converter to maintain efficient power conversion and power supply even when the battery is depleted and the battery cell voltage drops during use, because the battery can be connected to the input terminal configured to receive a voltage input that is closest to the current battery cell voltage.

[0011] The disclosed MIMO SC DC-DC converter can replace multiple current SC converters in existing hearing devices while providing higher conversion efficiency to more voltage levels. The converter can utilize an integrated voltage input demultiplexer, which enables efficient conversion during the battery (e.g., lithium-ion battery) discharge cycle. For zinc-air battery support, the battery circuit only needs to be connected to another voltage input terminal, with minimal product changes.

[0012] Although the MIMO SC DC-DC converter is slightly more complicated to start up than some existing series-parallel converters, the overall system complexity can be reduced by replacing multiple converters with one MIMO SC DC-DC converter. This also applies to the electromagnetic interference problems that are often encountered with current SC converters.

[0013] The power switch of the MIMO SC DC-DC converter disclosed in the present invention can occupy less than 0.5mm 2 This is because the power switches can be implemented as efficient oxide thin film devices in semiconductor process nodes suitable for chips of the signal processing unit of the hearing device. Typically, SC converters are implemented in more mature process nodes with EMI and noise sensitive analog circuits (such as analog-to-digital converters or microphones). By moving the SC converter to an inherently noise-resistant chip, the noisy switching regulator can be removed from the sensitive circuit type. Therefore, the disclosed MIMO SC DC-DC converter helps allow for a more integrated hearing device solution and a lower number of integrated circuits in the product.

[0014] One or more first electronic components of the hearing device are coupled to a first output terminal of the two or more output terminals, and one or more second electronic components of the hearing device are coupled to a second output terminal of the two or more output terminals. It should be noted that any of the above components (e.g., a microphone, a signal processing unit, and an output transducer) may be included in the one or more first electronic components, or in the one or more second electronic components.

[0015] It is worth noting that the numerical definition of low voltage and high voltage depends on the context. In this article, the terms high voltage and low voltage are used in the context of microelectronic devices and are used in relative situations. Therefore, in this article, the voltage difference between high voltage and low voltage can be less than 1V, which is a large voltage difference for the processing performed by certain types of transistors, which is very different from other fields of electrical engineering or layman's definitions that classify high voltage as starting at about 1000-1500V based on the use of AC voltage or DC voltage.

[0016] It should be noted that the voltage output terminal is considered to be an output terminal that can draw an output current. The current flowing out of the output voltage node can be positive or zero. For example, when the output node is used as an input node, the current flowing out of the output node can also be negative. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] For those skilled in the art, the above and other features and advantages of the present invention will be apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings:

[0018] Figure 1a is a diagram of a hearing device,

[0019] Figure 1b is a schematic diagram of a hearing device.

[0020] Figure 2 is a schematic diagram of the voltage level,

[0021] Figure 3 is a schematic diagram of a multiple-input multiple-output switched capacitor DC-DC converter,

[0022] Figure 4 is a schematic diagram of a multiple-input multiple-output switched capacitor DC-DC converter,

[0023] Figure 5 is a schematic diagram of a multiple-input multiple-output switched capacitor DC-DC converter,

[0024] Figure 6 is a schematic diagram of a multiple-input multiple-output switched capacitor DC-DC converter,

[0025] Figure 7 is a graph showing the relative displacement of the first clock signal and the second clock signal, and

[0026] Figure 8 is a graph showing a first clock signal and a second clock signal. DETAILED DESCRIPTION

[0027] Various exemplary embodiments and details will be described below with reference to the relevant drawings. It should be noted that the drawings may be drawn to scale or not to scale, and the same reference numerals are used in the various drawings to represent the same structure or function. It should also be noted that the drawings are only used to facilitate the description of the embodiments. The drawings are not intended to be exhaustive of the invention or to limit the scope of the invention. In addition, the embodiments shown need not have all the aspects or advantages shown. The aspects or advantages described in conjunction with a specific embodiment are not limited to that embodiment, and may be implemented in any other embodiment, even if not shown as such or not explicitly described as such.

[0028] The hearing device is configured to be worn by a user. The hearing device may be arranged at the user's ear, on the user's ear, above the user's ear, in the user's ear, in the user's ear canal, behind the user's ear and / or in the user's cochlea, i.e. the hearing device is configured to be worn in the user's ear, on the user's ear, above the user's ear and / or at the user's ear. The user may wear two hearing devices, one at each ear. The two hearing devices may be connected, such as wirelessly and / or by a wire, e.g. a binaural hearing aid system.

[0029] The hearing device may be a wearable device such as a headset, headphones, earphones, earplugs, hearing aids, personal sound amplification products (PSAPs), over-the-counter (OCT) hearing devices, hearing protection devices, universal hearing devices, custom hearing devices, or other head-worn hearing devices. The hearing device may include prescription devices and over-the-counter devices.

[0030] A hearing device may be embodied in a variety of housing styles or form factors. Some of these form factors include behind-the-ear (BTE) hearing devices, receiver-in-the-canal (RIC) hearing devices, receiver-in-the-ear (RIE, also known as RITE) hearing devices, or microphone-in-the-ear (MaRIE) hearing devices. These devices may include BTE devices configured to be worn behind a user's ear and in-the-ear devices (ITE) configured to be partially or fully inserted into a user's ear canal. In general, a BTE device may include at least one input transducer, a battery, and a processing unit. The term BTE hearing device refers to a hearing device in which a receiver (i.e., an output transducer) is mounted in a BTE unit and sound is directed to the ITE unit via an acoustic tube connecting the BTE and ITE units, while the terms RIE, RIC, and MaRIE hearing devices refer to hearing devices in which a receiver may be included in an ITE unit that is coupled to the BTE unit via a connector cable or wire configured to transmit electrical signals between the BTE and ITE units.

[0031] Some of these form factors include in-ear (ITE) hearing devices, completely in-the-canal (CIC) hearing devices, or concealed-in-the-canal (IIC) hearing devices. These hearing devices may include an ITE unit, wherein the ITE unit may include at least one input transducer, a battery, a processing unit, and an output transducer. These form factors may be custom devices, meaning that the ITE unit may include a housing having a shell made of a hard material (such as a hard polymer or metal) or a soft material (such as a rubbery polymer) molded to have an outer shape that conforms to the shape of a specific user's ear canal.

[0032] Some of these form factors include earphones, headphones on the ear, or headphones over the ear. A person skilled in the art is well aware of different kinds of hearing devices, and different options for arranging the hearing device in, on, over, and / or at the ear of a hearing device wearer. A hearing device (or a pair of hearing devices) may be custom fit, standard fit, open fit, and / or closed fit.

[0033] In an embodiment, the hearing device may include one or more input transducers, such as microphones. The one or more input transducers may include one or more microphones. The one or more input transducers may include one or more vibration sensors for detecting bone vibrations. The one or more input transducers may be configured to convert an acoustic signal into a first electrical input signal. The first electrical input signal may be an analog signal. The first electrical input signal may be a digital signal. The one or more input transducers may be connected to one or more analog-to-digital converters configured to convert the analog first input signal into a digital first input signal.

[0034] In an embodiment, the hearing device may include one or more antennas configured for wireless communication. The one or more antennas may include an electronic antenna. The electronic antenna may be configured for wireless communication at a first frequency. The first frequency may be above 800 MHz, preferably with a wavelength between 900 MHz and 6 GHz. The first frequency may be between 902 MHz and 928 MHz. The first frequency may be between 2.4 and 2.5 GHz. The first frequency may be between 5,725 GHz and 5,875 GHz. The one or more antennas may include a magnetic antenna. The magnetic antenna may include a magnetic core. The magnetic antenna may include a coil. The coil may be coiled around the magnetic core. The magnetic antenna may be configured for wireless communication at a second frequency. The second frequency may be below 100 MHz. The second frequency may be between 9 MHz and 15 MHz.

[0035] In an embodiment, the hearing device may include one or more wireless communication units. The one or more wireless communication units may include one or more wireless receivers, one or more wireless transmitters, one or more transmitter-receiver pairs and / or one or more transceivers. At least one of the one or more wireless communication units may be coupled to one or more antennas. The wireless communication unit may be configured to convert a wireless signal received by at least one of the one or more antennas into a second electrical input signal. The hearing device may be configured for wired / wireless audio communication, for example, enabling a user to listen to media such as music or radio and / or enabling a user to make a phone call.

[0036] In an embodiment, the wireless signal may come from one or more external sources and / or external devices, such as one or more paired microphone devices, one or more wireless audio transmitters, one or more intelligent computers, and / or one or more distributed microphone arrays associated with a wireless transmitter. The one or more wireless input signals may come from, for example, another hearing device as part of a binaural hearing system, and / or from one or more accessory devices (such as a smartphone and / or a smart watch).

[0037] In an embodiment, the hearing device may include a processing unit. The processing unit may be configured to process one or more first and / or second electrical input signals. The processing may include compensating for the user's hearing loss, i.e., applying a frequency-dependent gain to the input signal according to the user's frequency-dependent hearing impairment. The processing may include performing feedback cancellation, beamforming, tinnitus reduction / shielding, noise reduction, noise cancellation, speech recognition, bass adjustment, treble adjustment, and / or user input processing. The processing unit may be a processor, an integrated circuit, an application, a functional module, etc. The processing unit may be implemented in the form of a signal processing chip or a printed circuit board. The processing unit may be configured to provide a first electrical output signal based on the processing of one or more first and / or second electrical input signals. The processing unit may be configured to provide a second electrical output signal. The second electrical output signal may be based on the processing of one or more first and / or second electrical input signals.

[0038] In an embodiment, the hearing device may include an output transducer. The output transducer may be coupled to a processing unit. The output transducer may be a receiver. Note that in this case, the receiver may be a speaker and the wireless receiver may be a device configured to process wireless signals. The receiver may be configured to convert the first electrical output signal into an acoustic output signal. The output transducer may be coupled to the processing unit via a magnetic antenna. The output transducer may be included in an ITE unit of the hearing device or in an earpiece, for example, for a receiver in the ear (RIE) unit or a microphone and receiver in the ear (MaRIE) unit. One or more input transducers may be included in the ITE unit or the earpiece.

[0039] The battery may be a rechargeable battery, such as a lithium ion battery. The battery may be a replaceable battery. The hearing device may include a power management unit. The battery may be coupled to a charging coil configured to wirelessly charge the battery. The charging coil may be provided by a magnetic antenna. The battery may be a non-rechargeable battery, such as a zinc oxide battery.

[0040] In an embodiment, the hearing device may comprise memory including both volatile and non-volatile forms of memory.

[0041] The voltage input may be a battery cell voltage.

[0042] The hearing device may further comprise an input power demultiplexer comprising:

[0043] ·Connect to the demultiplexer input of the battery,

[0044] a first demultiplexer output coupled to a first of the two or more inputs, and

[0045] - A second demultiplexer output coupled to a second one of the two or more inputs.

[0046] The input power demultiplexer may include one or more additional demultiplexer outputs, each of which is coupled to a different one of the two or more inputs. By providing a demultiplexer, the battery may be coupled to the MIMO SC DC-DC converter in a manner that allows efficient switching between inputs. This is particularly advantageous when the battery is operating in its discharge cycle, as the demultiplexer may deliver the battery cell voltage to the input of the two or more inputs that is best suited to handle the current battery cell voltage.

[0047] The MIMO SC DC-DC converter may include multiple voltage stages, each voltage stage including:

[0048] a flying capacitor having an upper flying capacitor terminal and a lower flying capacitor terminal,

[0049] a second capacitor having an upper second capacitor terminal and a lower second capacitor terminal,

[0050] a first switch, and

[0051] · Second switch.

[0052] The first switch may be a controllable semiconductor switch, such as a transistor. The first switch may include:

[0053] an upper first switch terminal connected to an upper second capacitor terminal, and

[0054] • A lower first switch terminal connected to the lower flying capacitor terminal.

[0055] The second switch may be a controllable semiconductor switch, such as a transistor. The second switch may include:

[0056] an upper second switch terminal connected to an upper flying capacitor terminal, and

[0057] • A lower second switch terminal connected to the upper second capacitor terminal.

[0058] In this document, the terms "upper" and "lower" are used to describe the arrangement with respect to the upper and lower voltage domains of the MIMO SC DC-DC converter, rather than the spatial arrangement.

[0059] Alternatively, the term “primary” may be used instead of “upper”, for example, the upper flying capacitor terminal may also be represented as the primary flying capacitor terminal, and the term “secondary” may be used instead of “lower”, for example, the lower second capacitor terminal may also be represented as the secondary second capacitor terminal.

[0060] The voltage levels may be linked together such that each voltage level below the highest voltage level comprises:

[0061] a connection from the upper flying capacitor terminal to the lower flying capacitor terminal of a voltage level higher than that voltage level, and

[0062] • A connection from the upper second capacitor terminal to the lower second capacitor terminal at a voltage level higher than this voltage level.

[0063] The term "highest" voltage stage is used to denote the voltage stage that is configured to handle the highest voltage among the voltage stages.

[0064] The first switch may be controlled by a first clock signal, and the second switch may be controlled by a second clock signal, wherein the first and second clock signals do not overlap. The non-overlapping clock signals ensure that the first and second clock signals never cause the first and second switches associated with them to be closed (conductive, in a low impedance state) at the same time to prevent cross conduction. Therefore, the first switch and the second switch alternate between the first switch being closed and the second switch being open, and the first switch being open and the second switch being closed. In this document, the term "closed" is used for a switch that is "on", meaning that a low-resistance electrical path is provided between its primary and secondary terminals. Similarly, the term "open" is used for a switch that is "off", meaning that a low-impedance electrical path is not provided between its primary and secondary terminals.

[0065] The first and second clock signals may include a first phase and a second phase, in which the first switch is closed and the second switch is open, and in which the first switch is open and the second switch is closed, wherein the first phase and the second phase are separated in time by a pause period during which the first switch and the second switch are both open. This ensures that the first and second switches are never closed at the same time, which results in cross conduction and possible damage to the MIMO SC DC-DC converter and / or a connected system.

[0066] One or more of the voltage levels may include an input terminal of the two or more input terminals and / or a middle output terminal of the two or more output terminals. The MIMO SC DC-DC converter may include five to ten voltage levels. The MIMO SC DC-DC converter may have a ladder topology, such as an asymmetric ladder topology.

[0067] Each voltage level below the highest voltage level can be configured as:

[0068] when the first switch is closed, the lower flying capacitor terminal of each voltage level has a low resistance connection to the lower second capacitor terminal of the voltage level above that voltage level, and the lower flying capacitor terminal has a low resistance electrical connection to the upper second capacitor, and

[0069] When the second switch is closed, the upper flying capacitor terminal of each voltage level has a low resistance connection to the upper second capacitor terminal above the voltage level, and the upper flying capacitor terminal of each voltage level has a low resistance connection to the lower second capacitor terminal of the voltage level above the voltage level.

[0070] The MIMO SC DC-DC may include a bootstrap capacitor and / or a bootstrap diode arranged to connect the highest voltage level flying capacitor to the input terminal configured to receive the highest voltage input among the two or more input terminals. Including the bootstrap capacitor and / or the bootstrap diode is advantageous because it makes startup of the MIMO SC DC-DC easier and provides a voltage level higher than the input voltage level to effectively drive the N-type transistor.

[0071] The MIMO SC DC-DC may include a third capacitor coupled to an input terminal configured to receive a highest voltage input among the two or more input terminals, and an input terminal configured to receive a second highest voltage input among the two or more input terminals. The third capacitor is arranged between the input terminal configured to receive a highest voltage input among the two or more input terminals, and the input terminal configured to receive a second highest voltage input among the two or more input terminals. This enables the MIMO SC DC-DC to function as a boost converter when the battery cell voltage drops to a certain voltage level, at which the input terminal configured to receive the highest voltage input among the two or more input terminals is no longer a suitable input terminal, and thus the battery cell voltage is routed to one of the lower input terminals. In this case, it is advantageous that the MIMO SC DC-DC can function as a boost converter if the hearing device includes electronic components that require a voltage higher than the current battery cell voltage.

[0072] The signal processing unit may include a signal processing chip, and the MIMO SC DC-DC converter may be integrated or co-integrated in the signal processing chip. When the MIMO SC DC-DC converter is co-integrated in the signal processing chip, one or more of the flying capacitors and / or one or more of the second capacitors may be implemented as, for example, discrete multilayer ceramic capacitors or capacitors integrated in a silicon interposer outside the signal processing chip. When the MIMO SC DC-DC converter is co-integrated in the signal processing chip, one or more of the first switches and / or one or more of the second switches may be implemented in the signal processing chip. The first switch and / or the second switch may be an integrated metal oxide semiconductor field effect transistor (MOSFET). The flying capacitor, the second capacitor, the third capacitor and / or the bootstrap capacitor may be an integrated metal oxide semiconductor (MOS) capacitor, a metal oxide metal (MOM) capacitor, a metal insulator metal (MIM) capacitor or a (deep) trench capacitor.

[0073] The voltage output provided by each output terminal may depend on the voltage level of the voltage input and / or to which input terminal the voltage input is provided.

[0074] Figure 1a A hearing device 100 is shown, which in the illustrated embodiment is a RIE or MaRie type hearing aid. The hearing device 100 comprises a BTE component 102 adapted to be worn behind a user's ear and an ITE component 104 adapted to be worn in the user's ear. The hearing device comprises one or more input transducers 106, such as one or more microphones and / or one or more bone vibration sensors configured to capture sound in ambient air or through vibrations of the user's body, respectively. The one or more input transducers may be arranged in the BTE component 102 and / or the ITE component 104. The hearing device 100 comprises at least one output transducer, such as a speaker, which in the illustrated embodiment is arranged in the ITE component 104, but may alternatively be arranged in the BTE component 102. The BTE component 102 and the ITE component 104 are coupled by a connector 103, which comprises one or more conductive wires for transmitting electrical signals between the BTE component 102 and the ITE component 104. In embodiments where the output transducer is arranged in the BTE component 102, the connector 103 comprises a hollow core for providing a fluid connection with the ITE component 104 so as to direct the sound generated by the output transducer to the ear.

[0075] Figure 1b Show Figure 1aSchematic diagram of a BTE component 102 of a hearing device 100 is shown. The BTE component 102 comprises an input transducer 106 in the form of a microphone. The input transducer 106 is coupled to a signal processing unit 108, which is adapted to process a signal representing sound captured by the input transducer 106. The BTE component 102 comprises an electrical interface 114, which is configured to be connected to the connector 103 and to the ITE component 104 through the connector 103. Through the electrical interface 114, the signal processing unit 108 is connected to the output transducer, so that the processed signal can be sent to the output transducer and converted into a sound output.

[0076] The hearing device 100 further comprises a battery 110, preferably a rechargeable battery, such as a lithium-ion battery. The battery may supply a cell voltage of, for example, 4.2 V when fully loaded. As the battery 110 goes through its discharge cycle, the cell voltage will drop, and the battery 110 will supply a reduced cell voltage. The battery 110 is connected to an input power demultiplexer 112, which is configured to receive the cell voltage and, depending on the current cell voltage, route the cell voltage to the appropriate input of the MIMO SC DC-DC converter 300.

[0077] The MIMO SC DC-DC converter 300 includes a plurality of input terminals, each of which is configured to receive a voltage input. Thus, the MIMO SC DC-DC converter 300 may receive a battery cell voltage at one of the input terminals and convert the battery cell voltage, for example, step up or step down, so that the output terminal may provide a voltage output depending on the voltage level of the voltage input and to which input terminal the voltage input is supplied. The MIMO SC DC-DC converter 300 is configured to convert a battery cell voltage received from one of the input terminals into a plurality of voltage outputs having different voltages and provide the voltage outputs from the corresponding output terminals.

[0078] Thus, different electronic components of the hearing device 100 (e.g. the input transducer 106, the output transducer and the signal processing unit 108) may be supplied with power from the output of the MIMO SC DC-DC converter 300, which provides an output voltage that is closest to the voltage at which the corresponding electronic components are configured to operate. Examples of the MIMO SC DC-DC converter 300 and the voltage stage 200 will be disclosed in detail below.

[0079] Figure 2An example of a voltage stage 200 including a MIMO SC DC-DC converter 300 is shown. The voltage stage 200 includes a first upper connection node 202 and a second upper connection node 204, which are used to connect the voltage stage 200 to another voltage stage 200 in a higher voltage domain and / or an input terminal 218 of a plurality of input terminals. The voltage stage 200 includes a first lower connection node 206 and a second lower connection node 208, which are used to connect the voltage stage 200 to another voltage stage 200 in a low voltage domain and / or a ground connection terminal 312.

[0080] The voltage stage 200 includes a flying capacitor 210 having an upper flying capacitor terminal connected to the first upper connection node 202 and a lower flying capacitor terminal connected to the first lower connection node 206. The voltage stage 200 includes a second capacitor 212 having an upper second capacitor terminal electrically connected to the second upper connection node 204 and a lower second capacitor terminal connected to the second lower connection node 208.

[0081] The voltage stage 200 includes a first switch 214 having a lower first switch terminal electrically connected to the first lower connection node 206 and the lower flying capacitor terminal, and an upper first switch terminal electrically connected to the second upper connection node 204 and the upper second capacitor terminal. The voltage stage 200 includes a second switch 216 having an upper second switch terminal electrically connected to the first upper connection node 202 and the upper flying capacitor terminal, and a lower second switch terminal electrically connected to the first upper connection node 204, the upper first switch terminal, and the upper second capacitor terminal.

[0082] By this configuration, the second switch 216 is adapted to selectively provide a low-resistance electrical connection between the upper flying capacitor terminal and the upper second capacitor terminal, and the first switch 214 is adapted to selectively provide a low-resistance electrical connection between the lower flying capacitor terminal and the upper second capacitor terminal. Each of the first switch 214 and the second switch 216 is preferably provided by a controllable semiconductor switch such as a transistor. Each of the first switch 214 and the second switch 216 can be implemented using a fully depleted silicon on insulator (FDSOI) semiconductor process.

[0083] The first switch 214 is driven by the first clock signal The second switch 216 is controlled by the second clock signal Control. First clock signal and the second clock signal are complementary, which means that the first and second clock signals control the first switch 214 and the second switch 216 so that the first switch 214 and the second switch 216 are never closed at the same time. and the second clock signal Separated by a pause period 506 between opening the first switch 214 and closing the second switch 216, and between closing the first switch 214 and opening the second switch 216, during which the first switch 214 and the second switch 216 are open, i.e., in an off state. In this case, the clock signals are considered to be non-overlapping.

[0084] The voltage stage 200 may include an input node 218 that provides an input to one or more input terminals. The input node 218 may be coupled to the battery 110, for example via the input power demultiplexer 112, so that the input node 218 may receive a voltage input. The voltage stage 200 may include an output node 220 that provides an output to one or more output terminals. The output node 220 may be coupled to an electronic component of the hearing device 100 that is configured to operate at a voltage provided by the output node 220.

[0085] Figure 3 Shown including Figure 2 An example of a MIMO SC DC-DC converter 300 having multiple voltage levels 200 is shown. The MIMO SC DC-DC converter 300 includes a highest voltage level 302, i.e., a voltage level 200 configured to be in the highest voltage domain among the multiple voltage levels. The MIMO SC DC-DC converter 300 includes a lowest voltage level 304, i.e., a voltage level 200 configured to be in the lowest voltage domain among the multiple voltage levels. The MIMO SC DC-DC converter 300 includes n intermediate voltage levels 306, where n is a positive integer or 0.

[0086] The voltage levels 302, 304, 306 are connected so that the corresponding voltage level will be connected to its adjacent upper voltage level through the connection of the first upper connection node 202 of the corresponding voltage level to the first lower connection node 206 of the adjacent upper voltage level, and the connection of the second upper connection node 204 of the corresponding voltage level to the second lower connection node 208 of the adjacent upper voltage level. For the highest voltage level 302 without an adjacent upper voltage level, the first upper connection node 202 is connected to the highest input node 314, that is, the input terminal configured to receive the highest voltage among the two or more inputs. The first upper connection node 202 is connected to the highest input node 314 via the first switch 308. In the illustrated embodiment, the second upper connection node 204 is not connected.

[0087] Likewise, the corresponding voltage level is connected to the adjacent lower voltage level through the connection of the first lower connection node 206 of the corresponding voltage level to the first upper connection node 202 of the adjacent lower voltage level, and the connection of the second lower connection node 206 of the corresponding voltage level to the second upper connection node 204 of the adjacent lower voltage level. For the lowest voltage level 304 without an adjacent lower voltage level, the first lower connection node 206 and the second lower connection node 208 are connected to the ground 312. The first lower connection node 206 is connected to the ground via the second switch 310, and the second lower connection node 208 is directly connected to the ground 312.

[0088] With this arrangement of the voltage levels 200, the MIMO SC DC-DC converter 300 has a ladder topology that allows for a voltage output for each voltage level 200. In addition, these multiple voltage outputs can be used simultaneously, meaning that all voltage outputs are available at the same time. For the ladder topology shown, the voltage output provided at each voltage level is given by:

[0089]

[0090] Where x is the number of the voltage level starting from the lowest voltage level; V ox is the output voltage of voltage level x; V bat is the input voltage provided by the battery; and y is the number of the voltage level to which the voltage input is applied, counting from the lowest voltage level 304. Here, it should be noted that the voltage level of the corresponding voltage level 200 is not constant, but varies depending on the voltage input and the voltage level to which the voltage input is applied. This also means that the MIMO SC DC-DC converter 300 shown has more possible output voltages than the number of voltage levels, because the voltage output of the voltage level can be changed by controlling the voltage level of the voltage input and / or the voltage level to which the voltage input is applied.

[0091] Figure 4 Show Figure 3 Other evolutions of the MIMO SC DC-DC converter 300 are shown. This MIMO SC DC-DC converter 300 also includes a third capacitor 320, which is arranged between and connects the highest input terminal 314 of the highest voltage stage 302 and the second upper connection node 204. Including the third capacitor 320 is advantageous because it enables the MIMO SC DC-DC converter 300 to perform a step-up conversion on the voltage input applied to the lower voltage stage to reach the voltage level of the highest input terminal 314, so that the highest input terminal 314 can also serve as an output.

[0092] The MIMO SC DC-DC converter 300 further includes a bootstrap diode 316 and a bootstrap capacitor 318, which are arranged between the first upper connection node 202 of the highest voltage stage 302 and the highest voltage node 314. The bootstrap diode 316 and the bootstrap capacitor 318 are arranged in series with each other, and both are arranged in parallel with the first switch 308 connecting the first upper connection node 202 of the highest voltage stage 302 and the highest voltage node 314. The bootstrap diode 316 and the bootstrap capacitor 318 are advantageous because they make startup of the MIMO SC DC-DC converter 300 easier.

[0093] Figure 5 Show Figure 4 , wherein n is 3, so that the MIMO SC DC-DC converter 300 includes five voltage levels 200, namely a highest voltage level 302, a lowest voltage level 304, and three intermediate voltage levels 306. The MIMO SC DC-DC converter 300 shown also includes a third capacitor 320 for implementing boost conversion, and a bootstrap diode 316 and a bootstrap capacitor 318 that facilitate startup. The first switch (S even ) by the first clock signal control, while the second switch (S odd ) by the second clock signal control.

[0094] In this configuration, the MIMO SC DC-DC converter 300 includes six voltage nodes, one for each voltage level, and a highest input node 314 that can be used as an input and / or output. The voltage nodes are denoted as V o1 、V o2 、V o3 、V o4 、V o5 and V o6 , where o is short for output, but it can also be used for input, and the numbers 1-6 represent the numbers of the voltage nodes counting upward from the lowest voltage level 304.

[0095] The MIMO SC DC-DC converter 300 includes an input power demultiplexer 112, 400, also denoted as Batmux, which selectively connects the battery 110 to at least some of the input terminals, i.e., routes the input voltage to a selected one of the input terminals. The input power demultiplexer 112, 400 includes a demultiplexer input terminal 402, which is coupled to the battery 110 to receive the battery cell voltage. The input power demultiplexer 112, 400 also includes a demultiplexer input terminal 402 coupled to the highest input node 314 (V o6) is connected to the first demultiplexer output terminal 404, and the input node of the highest voltage level (V o5 ) and an input node (V o4 ) is connected to a third demultiplexer output terminal 408. The input power demultiplexer 112, 400 may include fewer or more demultiplexer output terminals and / or the demultiplexer output terminals may be connected to other voltage input terminals. It should be noted that the input power demultiplexer 112, 400 is controlled to select one of the demultiplexer output terminals at a time so that only one input terminal receives the input voltage at any given time.

[0096] The input power demultiplexer 112, 400 can route the battery cell voltage to a desired input of the MIMO SC DC-DC converter 300 via the demultiplexer outputs 404, 406, 408, thereby providing a voltage input for conversion. The input power demultiplexer 112, 400 includes one or more control ports 410, 412 that can be coupled to the signal processing unit 108 or a dedicated control circuit. Through the one or more control ports 410, 412, the input power demultiplexer 112, 400 can be controlled to set which of the demultiplexer outputs 404, 406, 408 should be used and to set which input of the MIMO SC DC-DC converter 300 should receive the voltage input.

[0097] According to Equation 1, the voltage node V o1 、V o2 、V o3 、V o4 、V o5 and V o6 The voltage at depends on the level of the voltage input and to which input terminal the input power demultiplexer 112, 400 provides the voltage input. Table 1 below shows the voltage level of the voltage output provided by each voltage node, depending on the voltage applied to the highest input node 314 (V o6 )'s voltage input voltage level.

[0098]

[0099] Table 1 shows the voltage output (in volts) provided by the voltage nodes, depending on the voltage applied to V o6 The voltage level of the voltage input.

[0100] For the example shown in Table 1, the battery is provided by a lithium-ion battery, which has a cell voltage of 4.2V when fully charged. Although each electronic component of the hearing device 100 is configured to operate at a corresponding optimal voltage, the electronic component may also operate at a voltage that deviates from the optimal voltage if the voltage provided is not so high as to damage the electronic component or so low as to fail to power the corresponding component. However, it is desirable for the component to operate at a voltage as close to its optimal voltage as possible, as this improves power efficiency and component performance. Therefore, it is very advantageous to have multiple voltage outputs available at the same time, as this allows multiple electronic components with different optimal voltages to be operated simultaneously and at maximum efficiency. In addition, if necessary, a linear low dropout regulator can also be used to alleviate the problem of excessive voltage.

[0101] If the hearing device requires a different voltage output, the voltage input can be applied to another input node. Tables 2 and 3 below show the voltage inputs applied to V o5 and V o4 The voltage output at .

[0102]

[0103] Table 2 shows the voltage applied to V o5 The voltage level of the voltage input and the voltage output provided by the voltage node.

[0104]

[0105] Table 3 shows the voltage applied to V o4 The voltage level of the voltage input and the voltage output provided by the voltage node.

[0106] In Table 3, the asterisks indicate the overvoltage in the case where all switches (i.e., first and second switches) are effectively thin oxide (nominal voltage 1.0V (max +10%)) NMOS transistors. This is possible due to the superimposed voltage domains created by using this topology. These superimposed voltage domains further simplify the gate drive even when using high side NMOS transistors. By adding a simple integrated bootstrap circuit (C boot and D boot ), the use of PMOS power switches can be avoided completely.

[0107] exist Figure 6 Shown in Figure 6 The MIMO SC DC-DC converter 300 does not require input power demultiplexers 112 and 400, and the battery 110 is provided by a zinc air battery (ZnO) which can provide a battery cell voltage of 1.3V when fully loaded. The battery 110 is connected to the second lowest input terminal Vo2 An alternative use case may require two zinc oxide batteries connected in series, in which case the series connected batteries (see Figure) may be connected to the fourth lowest input terminal V o4 , or connected to the third lowest input terminal V o3 The three tables on the right show the possible voltage outputs provided by the output terminals, depending on the voltage level of the voltage input and to which input terminal the voltage input is provided.

[0108] Due to the inherent bidirectionality of the topology of the MIMO SC DC-DC converter 300 shown, boost conversion can be performed. Therefore, when one or more zinc oxide batteries are connected to the input node V o2 、V o3 or V o4 When the converter is used, it will be able to supply the same voltage as the lithium-ion battery, thus achieving compatibility between zinc oxide and lithium-ion devices without any changes in the device.

[0109] Figure 7 is a graph showing that the first clock signal The voltage and the second clock signal As explained above, the first clock signal is applied to the gate of the first switch 214, and the second clock signal is applied to the gate of the second switch 216. Figure 7 In, with the first clock signal After a simple comparison, the second clock signal Shifting upward, it can be seen from the figure that the first clock signal and the second clock signal The first and second switches are alternately in an open and closed state by changing and complementing each other between the corresponding upward cycle (also called positive duty cycle) and downward cycle. If the first switch 214 and the second switch 216 are implemented with NMOS transistors, the first switch 214 and the second switch 216 are closed / conducted during the upward cycle of the control clock signal of the first switch 214 and the second switch 216 and are opened / isolated during the downward cycle of the control clock signal of the first switch 214 and the second switch 216.

[0110] Figure 8 and Figure 7 Similar, but showing the superimposed first clock signal and the second clock signal Here, it can be seen that at the first clock signal The positive duty cycle of the second clock signal There is a pause period 502 between the positive duty cycles of the first switch 214 and the second switch 216 so that the first switch 214 and the second switch 216 are never closed at the same time, i.e., they do not overlap. This makes it easier to control the MIMO SC DC-DC converter 300 because it avoids the first switch 214 and the second switch 216 being closed at the same time, which may cause damage to various components of the MIMO SC DC-DC converter 300.

[0111] The use of the terms "first", "second", "third" and "fourth", "primary", "secondary", "tertiary", etc. does not imply any particular order, but is used to identify individual elements. Furthermore, the use of the terms "first", "second", "third" and "fourth", "primary", "secondary", "tertiary", etc. does not indicate any order or importance, but rather the terms "first", "second", "third" and "fourth", "primary", "secondary", "tertiary", etc. are used to distinguish one element from another. It should be noted that the terms "first", "second", "third" and "fourth", "primary", "secondary", "tertiary", etc. are used here and elsewhere for labeling purposes only and are not intended to indicate any particular spatial or temporal order. Furthermore, labeling a first element does not imply the presence of a second element, and vice versa.

[0112] It should be noted that the wording "comprising" does not exclude the presence of other elements or steps than the listed elements or steps. It should be noted that "a / an" before an element does not exclude the presence of a plurality of such elements.

[0113] It should also be noted that any reference signs do not limit the scope of the claims, that exemplary embodiments may be implemented at least partially by hardware and software, and that multiple "devices," "units," or "means" may be represented by the same item of hardware.

[0114] Although features have been shown and described, it is understood that it is not intended to limit the claimed invention by these features. It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Therefore, the description and drawings should be regarded as illustrative rather than restrictive. The claimed invention is intended to cover all alternatives, modifications and equivalents.

[0115] Reference numerals list

[0116] 100 Hearing Devices

[0117] 102 BTE components

[0118] 103 Connectors

[0119] 104 ITE components

[0120] 106 Input transducer

[0121] 108 Signal Processing Unit

[0122] 110 Batteries

[0123] 112 Input Power Demultiplexer

[0124] 114 Electrical interface

[0125] 200 Voltage level

[0126] 202 First upper connection node

[0127] 204 Second upper connection node

[0128] 206 First connection node

[0129] 208 Second connection node

[0130] 210 Flying Capacitor

[0131] 212 Second capacitor

[0132] 214 First Switch

[0133] 216 Second switch

[0134] 218 Input Node

[0135] 220 Output Node

[0136] 300 MIMO Switched Capacitor DC-DC Converter 302 Highest voltage level

[0137] 304 Lowest voltage level

[0138] 306 Intermediate voltage level

[0139] 308 First Switch

[0140] 310 Second switch

[0141] 312 Ground

[0142] 314 Highest input

[0143] 316 Bootstrap Diode

[0144] 318 Bootstrap Capacitor

[0145] 320 The third capacitor

[0146] 400 Input Power Demultiplexer

[0147] 402 Demultiplexer input

[0148] 404 First demultiplexer output terminal

[0149] 406 Second demultiplexer output terminal

[0150] 408 Third demultiplexer output terminal

[0151] 410 Control port

[0152] 412 Control port First clock signal Second clock signal 502 Timeout

Claims

1. A hearing device configured to be worn at an ear of a user, wherein: The hearing device comprises: - an input transducer adapted to capture sound and to provide a microphone input transducer signal based on the captured sound, - a signal processing unit adapted to process the input transducer signal and to provide an output signal based on the processed input transducer signal, - an output transducer adapted to provide an excitation output signal based on the output signal, - a battery configured to provide a battery cell voltage, and - a multiple-input multiple-output switched capacitor MIMO SC DC-DC converter coupled to the battery and comprising: Two or more input terminals, each of which is configured to receive a voltage input, and Two or more output terminals, each output terminal being configured to provide a voltage output having a voltage different from that of the other output terminals, wherein at least two of the two or more output terminals are capable of providing voltage outputs simultaneously, The MIMO SC DC-DC converter is configured to convert each voltage input into a voltage output of a different voltage.

2. The hearing device according to claim 1, wherein The hearing device further comprises an input power demultiplexer, the input power demultiplexer comprising: · A demultiplexer input connected to the battery, a first demultiplexer output coupled to a first of the two or more inputs, and • A second demultiplexer output coupled to a second one of the two or more inputs.

3. The hearing device according to claim 1 or 2, wherein: The MIMO SC DC-DC converter includes a plurality of voltage stages, each voltage stage including: a flying capacitor having an upper flying capacitor terminal and a lower flying capacitor terminal, a second capacitor having an upper second capacitor terminal and a lower second capacitor terminal, a first switch, and · Second switch.

4. The hearing device according to claim 3, wherein: The plurality of voltage levels are coupled together such that each voltage level below the highest voltage level comprises: an electrical connection from the upper flying capacitor terminal to the lower flying capacitor terminal at a voltage level higher than the voltage level, and • An electrical connection from the upper second capacitor terminal to the lower second capacitor terminal at a voltage level higher than the voltage level.

5. The hearing device according to claim 3 or 4, wherein: The first switch is controlled by a first clock signal and the second switch is controlled by a second clock signal, wherein the first clock signal and the second clock signal are complementary.

6. The hearing device according to any one of claims 3 to 5, wherein: The MIMO SC DC-DC converter includes 5-10 voltage levels.

7. The hearing device according to any one of claims 3 to 6, wherein: Each voltage level below the highest voltage level is configured such that: when the first switch is closed, the upper flying capacitor terminal of the voltage level has a low resistance electrical connection with the upper second capacitor terminal of the voltage level higher than the voltage level, and the lower flying capacitor terminal of the voltage level has a low resistance electrical connection with the lower second capacitor terminal of the voltage level higher than the voltage level, and When the second switch is closed, the upper flying capacitor terminal of the voltage stage has a low resistance electrical connection with the upper second capacitor terminal of the voltage stage, and the lower flying capacitor terminal of the voltage stage has a low resistance electrical connection with the lower second capacitor terminal of the voltage stage.

8. A hearing device according to any one of the preceding claims, wherein: The MIMO SC DC-DC converter has a ladder topology structure.

9. A hearing device according to any one of the preceding claims, wherein: The signal processing unit includes a signal processing chip, and wherein the MIMO SC DC-DC converter is integrated or co-integrated in the signal processing chip.

10. A hearing device according to any one of the preceding claims, wherein: The voltage output provided by each output terminal depends on the voltage level of the voltage input and / or which input terminal the voltage input is provided to.

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