CN114827345A

CN114827345A - Electronic device with wireless power control system

Info

Publication number: CN114827345A
Application number: CN202110108909.9A
Authority: CN
Inventors: 彭冬萌
Original assignee: Shenzhen X Live Electronics Co ltd
Current assignee: Shenzhen X Live Electronics Co ltd
Priority date: 2021-01-27
Filing date: 2021-01-27
Publication date: 2022-07-29

Abstract

An electronic device may include wireless circuitry configured to transmit wireless signals during operation. A maximum transmission power level may be established that serves as an upper limit on how much power is transmitted from the electronic device. The maximum transmission power level may be adjusted in real time based on sensor signals and other information about the operating state of the electronic device. The sensor signal may comprise a motion signal from an accelerometer. The sensor signal may also include ultrasonic waves detected by a microphone. Device orientation data may be used by the device to select whether to use a front-facing microphone or a rear-facing microphone to measure the ultrasound. The maximum transmission power level may also be adjusted based on whether sound is played through an ear speaker in the device.

Description

Electronic device with wireless power control system

Technical Field

The present invention relates to an electronic device, and more particularly, to an electronic device having a wireless communication circuit.

Background

Electronic devices such as portable computers and handheld electronic devices often have wireless communication capabilities. For example, the electronic device may have wireless communication circuitry to communicate using cellular telephone bands and to support communication with satellite navigation systems and wireless local area networks.

To meet consumer demand for wireless devices of small form factor, manufacturers are continually striving to reduce the size of components used in such devices while providing enhanced functionality. It is often impractical for a user transmitting a compact handheld device to completely shield the transmitted radio frequency signal. For example, cellular telephone handsets typically transmit a signal near the user's head during a telephone call. Government regulations limit radio frequency signal power. In particular, the so-called Specific Absorption Rate (SAR) standard, which imposes maximum energy absorption limits on the handpiece manufacturers, is appropriate. At the same time, wireless telecommunication vendors require that handsets used in their networks be capable of generating some minimum radio frequency power in order to ensure satisfactory operation of the handset.

As a result, manufacturers of electronic devices, such as portable wireless devices, face challenges in producing devices with sufficient radio frequency signal strength to comply with applicable government regulations.

It would be desirable to be able to address this challenge by providing improved wireless communication circuitry for wireless electronic devices.

Disclosure of Invention

In view of this, the present disclosure provides an electronic device that may include wireless circuitry configured to transmit wireless signals during operation. A maximum transmission power level may be established that serves as an upper bound (cap) on how much power is transmitted from the electronic device. The maximum transmission power level may be adjusted in real time based on sensor signals and other information about the operating state of the electronic device. The maximum transmission power level may be set to a maximum value when it is determined that the electronic device is operated while resting on an inanimate object on a table. The maximum transmission power may be set to a reduced level when it is determined that the electronic device is resting on a user's body. The maximum transmission power level may be set to a level between the reduced level and the maximum value when it is determined that the electronic device is being held near an ear of a user such that the device is offset from the user's body.

The sensor signals collected by the electronic device to ascertain how the electronic device is being used may include motion signals from an accelerometer. The sensor signal may also include ultrasonic waves detected by a microphone. Device orientation data may be used by the device to select whether a front or a back microphone is used to measure the ultrasound. The maximum transmission power level may also be adjusted based on whether sound is played through an ear speaker (ear speaker) in the device.

The technical scheme adopted by the invention is as follows:

an electronic device comprises a microphone, a radio frequency antenna and a circuit; the RF antenna is configured to transmit RF signals with an upper limit of transmit power set at a maximum transmit power level, and the circuitry is configured to adjust the maximum transmit power level based at least in part on data from the microphone.

Preferably, the electronic device further comprises a sound source that emits an audio signal, wherein the circuitry is configured to measure the emitted audio signal with the microphone.

Preferably, the circuit is configured to compare the determined transmitted audio signal with a predetermined audio signal threshold.

Preferably, the circuitry is configured to increase the maximum transmission power level at least partially in response to determining that the determined transmitted audio signal is greater than the predetermined audio signal threshold.

Preferably, the electronic device further comprises an accelerometer, wherein the circuitry is configured to collect motion information associated with motion of the electronic device with the accelerometer.

Preferably, the circuit is configured to compare the collected motion information to a predetermined motion threshold.

Preferably, the circuitry is configured to increase the maximum transmit power at least partially in response to determining that the collected motion information is less than the predetermined motion threshold.

Preferably, the electronic device further comprises an ear speaker, wherein the circuitry is configured to adjust the maximum transmission power level at least partially in response to determining that audio is not being played by the ear speaker.

Preferably, the electronic device has opposing front and back sides with a front microphone and a back microphone, respectively, and wherein the microphone for measuring the audio signal is a selected one of the front and back microphones.

Preferably, the circuitry is configured to collect orientation data from the accelerometer and to select the microphone from the front and rear microphones for measuring the audio signal based on the collected orientation data.

Drawings

FIG. 1A is a front perspective view of an illustrative electronic device having wireless communication circuitry in accordance with an embodiment of the present invention;

FIG. 1B is a rear perspective view of an illustrative electronic device having wireless communication circuitry in accordance with an embodiment of the present invention;

FIG. 2 is a schematic diagram of an illustrative electronic device having wireless communication circuitry in accordance with an embodiment of the present invention;

FIG. 3 is a diagram of an illustrative electronic device for use at a user's ear in accordance with an embodiment of the invention;

FIG. 4 is an illustration of an illustrative electronic device being used while resting on an inanimate object such as a table in accordance with an embodiment of the present invention;

FIG. 5 is a diagram of an illustrative electronic device being used while resting on a user's body portion, such as a user's leg, in accordance with an embodiment of the present invention;

fig. 6 is a schematic diagram of an illustrative electronic device configured to dynamically adjust a maximum wireless transmission power level in accordance with an embodiment of the invention;

FIG. 7 is a graph of how an accelerometer monitoring device movement may be used to detect use of an electronic device held or resting on a user's body by the user, according to an embodiment of the invention;

FIG. 8 is a cross-sectional side view of an illustrative electronic device being used while resting on an external structure such as a body part or resting on an inanimate object in accordance with an embodiment of the present invention;

fig. 9 is a graph showing how ultrasonic audio signals may be detected by microphones on opposite sides of an electronic device while the device is resting on a surface such as a leg or other body part, in accordance with an embodiment of the invention;

fig. 10 is a graph showing how ultrasonic audio signals may be detected by microphones on opposite sides of an electronic device while the device is resting on a surface of an inanimate object such as a table, according to an embodiment of the present invention.

Wherein:

10. electronics, 12, housing, 13, button, 14, display, 15, opening, 16, speaker port/ear speaker port, 18, speaker/ear speaker, 19, lower end/lower region, 20, microphone/front ambient noise reduction microphone, 21 upper end/upper region, 22, voice microphone/opening/microphone port, 23, button, 24, speakerphone speaker, 26, axis, 27, front camera, 28, storage and processing circuitry/control circuitry, 29, ambient light sensor, 30, input-output circuitry, 31 infrared-based proximity sensor, 32, input-output device, 33, camera/rear camera, 34, transceiver circuitry, 35, rear microphone/Global Positioning System (GPS) receiver circuitry, 36, transceiver circuitry, 37, flashlight, 38, cellular telephone transceiver circuitry, 40, antenna/antenna structure, 42, sensor and audio components.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the description of the present invention, it is to be understood that the terms "vertical", "lateral", "longitudinal", "front", "rear", "left", "right", "upper", "lower", "horizontal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description of the present invention, and do not mean that the device or component to which the present invention is directed must have a specific orientation or position, and thus, cannot be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1A and 1B, an embodiment of the invention provides an electronic device 10 having a wireless communication circuit. Information from the sensor circuit and other information may be used to control the operation of the wireless communication circuit. For example, the maximum power level of a transmitted wireless signal may be controlled in real time to ensure that regulatory limits are met or exceeded.

The electronic device 10 may be a portable electronic device or other suitable electronic device. For example, the electronic device 10 may be a laptop computer, a tablet computer, a somewhat smaller device such as a wristwatch device, a pendant device, a headset device, an earpiece device, or other wearable or small device, a cellular telephone, or a media player. The electronic device 10 may also be a television, set-top box, desktop computer, computer monitor (into which a computer has been integrated), wireless router, or other suitable electronic equipment.

The electronic device 10 may include a housing, such as housing 12. The housing 12, which may sometimes be referred to as a tank, may be formed of plastic, glass, ceramic, fiber composite, metal (e.g., non-milled steel, aluminum, etc.), other suitable materials, or a combination of such materials. In some cases, portions of housing 12 may be formed from dielectric materials or other low conductivity materials. In other cases, at least some of the housing 12 or the structures making up the housing 12 may be formed from metal elements.

Optionally, the electronic device 10 may have a display, such as display 14. For example, the display 14 may be a touch screen incorporating capacitive touch electrodes. Display 14 may include image pixels formed from Light Emitting Diodes (LEDs), Organic LEDs (OLEDs), plasma cells, electrowetting pixels, electrophoretic pixels, Liquid Crystal Display (LCD) components, or other suitable image pixel structures. A display overlay, such as a clear glass layer or a plastic layer, may cover the surface of display 14. A button, such as button 13, may pass through an opening in the cover layer. The cover of display 14 may also have other openings, such as openings for speaker ports 16. The speaker port 16 may include a speaker, such as a speaker 18, and a microphone 20. Microphone 20 may be used to detect sounds in the vicinity of speaker 18. The microphone 20 may, for example, be used to detect ambient noise so that ambient noise reduction features may be implemented for the speaker 18. Openings such as

openings

22, 15 and 24 may be located at the opposite lower end 19 of device 10. An opening, such as opening 15 in device housing 12, may be associated with a data port. Openings such as

openings

22 and 24 may be associated with microphone and speaker ports, respectively.

Such as front-facing camera 27, ambient light sensor 29, and infrared-based proximity sensor 31 may be formed in upper region 21 of device 10 or elsewhere on the front face of device 10, as examples.

As shown in fig. 1B, the electronic device 10 may include a button, such as button 23. Buttons 23 may include volume buttons, such as 5 volume up and volume down buttons, and buttons for placing electronic device 10 in a ring mode or a mute mode, as examples. The electronic device 10 may also include a rear camera such as camera 33, a camera flash such as flash 37, and a rear microphone such as microphone 35. Microphone 35 may be used to collect data from an object while a video clip of the object is being recorded using camera 33.

During operation of the electronic device 10, a user of the electronic device 10 may hold the electronic device 10 against the user's head. For example, the ear speaker 18 may be placed at the user's ear while the microphone port 22 is placed near the user's mouth. This position of the electronic device 10 allows the user to have a telephone conversation.

The electronic device 10 may also operate wirelessly when not held against the head of a user. For example, the electronic device 10 may be used to browse the Internet, to handle email and text messages, and to support other wireless communication operations. When not held against the user's head, the electronic device 10 may be used in a speakerphone mode, in which the microphone 22 is used to collect voice information from the user and the speaker 24 is used to play telephone call audio to the user. The speaker 24 may also be used to wirelessly play streaming audio, such as music, to a user when the electronic device 10 is not held against the user's head.

To ensure that regulatory limits on transmitted power are met, it may be desirable to limit the maximum wireless transmission power level for the electronic device 10 whenever it can be determined that the electronic device 10 is located near the user's body. For example, it may be desirable to limit the maximum wireless transmission power level for the electronic device 10 whenever it is determined that the electronic device 10 is being held against a user's head or that the electronic device 10 is being rested against another body part, such as a user's leg.

The electronic device 10 may adjust in real time the amount of wireless transmission power being used based on feedback from wireless devices communicating with the electronic device 10 and/or based on locally measured data. At the same time, the maximum wireless transmission power level may be used as an upper limit to ensure that the transmitted power does not exceed an acceptable level for the current environment of the electronic device, even if a higher transmission power is being requested by the external device. By dynamically adjusting the maximum allowed transmit power, the electronic device 10 may operate optimally in a variety of situations.

A user may sometimes rest the electronic device 10 on an external surface such as a table top or other inanimate object. In this type of situation, it may not be necessary to limit the maximum wireless transmission power (i.e., it may be necessary to set the maximum transmission power level to a maximum value). In this case, the electronic device 10 will not be adjacent to the user's body, and thus, excessive limitation of wireless transmission power can be avoided to avoid unnecessarily degrading wireless performance.

To ensure that regulatory limits for emitted radiation are met or exceeded, the electronic device 10 may monitor its operating status and may collect and analyze information from the sensors. Different transmission power limits may be imposed on the transmitted wireless signal depending on the operating mode of the electronic device 10.

As shown in fig. 2, the electronic device 10 may include control circuitry such as storage and processing circuitry 28. The storage and processing circuitry 28 may include memory, such as hard drive memory, non-volatile memory (e.g., flash memory or other electrically programmable read only memory configured to form a solid state machine), volatile memory (e.g., static or dynamic random access memory), and so forth. Processing circuitry in storage and processing circuitry 28 may be used to control the operation of electronic device 10. The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio codec chips, application specific integrated circuits, and the like.

The storage and processing circuitry 28 may be used to execute software on the electronic device 10, such as an internet browsing application, a Voice Over Internet Protocol (VOIP) phone call application, an email application, a media playing application, operating system functions, and so forth. To support interaction with external devices, the storage and processing circuitry 28 may be used to implement a communications protocol. Communication protocols that may be implemented using the storage and processing circuitry 28 include Internet protocol, wireless local area network, routing protocols (e.g., IEEE 802.11 protocols-sometimes referred to as IEEE 802.11 protocols)

) Agreements for other short-range wireless communication links (such as,

protocol), cellular telephone protocol, etc.

The circuit 28 may be configured to implement control algorithms that control the use of antennas and other wireless circuitry in the electronic device 10. For example, circuitry 28 may perform signal quality monitoring operations, sensor monitoring operations, and other data collection operations, and may control which antenna structures within electronic device 10 are being used to receive and process data in response to collected data and information regarding the communication bands to be used in electronic device 10, and/or may adjust one or more switches, tunable elements, or other adjustable circuitry in electronic device 10 to adjust antenna performance. As an example, circuitry 28 may control which of two or more antennas is being used to receive incoming radio frequency signals, may control which of two or more antennas is being used to transmit radio frequency signals, may control the process of routing incoming data streams in parallel over two or more antennas in electronic device 10, may tune antennas to encompass desired communication bands, and so forth.

Circuitry 28 may also control the wireless transmission power and maximum transmission power level settings based on sensor data and other information regarding the operating state of electronic device 10. For example, circuitry 28 may limit the maximum amount of power that may be transmitted by electronic device 10 depending on which mode the electronic device is operating in. The maximum transmission power may be reduced when the electronic device 10 is operating near the user's body. The maximum transmission power may be increased when the electronic device 10 is operating away from the user's body.

In performing this control operation, circuitry 28 may open and close switches, may turn on and off receivers and transmitters, may adjust impedance matching circuitry, may configure switches in front-end module (FEM) radio frequency circuitry (e.g., filtering and switching circuitry for impedance matching and signal routing) that may be interposed between the radio-frequency transceiver circuitry and the antenna structure, may adjust switches, may tune circuitry, and other adjustable circuit elements formed as part of the antenna or coupled to the antenna or signal path associated with the antenna, may adjust power amplifier gain settings, may control transceiver output power, and may otherwise control and adjust components of electronic device 10.

The input-output circuit 30 may be used to allow data to be supplied to the electronic device 10, and may be used to allow data to be provided from the electronic device 10 to an external electronic device. The input-output circuitry 30 may include input-output electronics 32. The input/output electronics 32 may include a touch screen, button' joy stick, click wheel (clickwheel), scroll wheel (scrollwheel), touch pad, keypad, keyboard, light emitting diodes and other status indicators, data ports, and the like. The input-output electronics 32 may also include sensors and audio components 42. For example, the input-output electronics 32 may include a light-ambient light sensor, such as the ambient light sensor 29 of fig. 1A, for monitoring the amount of light in the environment surrounding the electronic device 10. The input-output electronics 32 may include a light-based proximity sensor, such as a proximity sensor having an infrared light emitter and a corresponding infrared light detector for detecting infrared light reflected from external objects in the vicinity of the electronic device 10; or may include a capacitive proximity sensor or other proximity sensor structure (proximity sensor structure 31 of fig. 1A). Input and output electronics 32 may also include gyroscopes, accelerometers, cameras such as front camera 27 and rear camera 33, temperature sensors, and the like. The components 42 may include audio components such as speakers, and vibrators (e.g., a speaker such as the speakerphone speaker 24 of fig. 1A and the ear speaker 18) or other audio output electronics that generate sound. The audio components may also include microphones such as a speech microphone 22 on the front or lower side wall of the housing 12, a front ambient noise reduction microphone 20 in the ear speaker port 16, and a rear microphone 35.

During operation, a user may control the operation of device 10 by supplying instructions through input-output device 32, and may receive status information and other outputs from device 10 using the output resources of input-output device 32.

The wireless communication circuitry 34 may include Radio Frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low noise input amplifiers, passive RF components, one or more antennas, filters, duplexers, and other circuitry for handling RF wireless signals. The wireless signals may also be transmitted using light (e.g., using infrared communication).

WirelessThe communication circuitry 34 may include satellite navigation system receiver circuitry, such as Global Positioning System (GPS) receiver circuitry 35 (e.g., for receiving satellite positioning "signals at 1575 MHz) or satellite navigation system receiver circuitry associated with other satellite navigation systems. Wireless area network transceiver circuitry, such as transceiver circuitry 36, may be handled for

2.4GHz and 5GHz bands of (IEEE'802.11) communications, and can handle

A communication frequency band. Circuitry 34 may use cellular telephone transceiver circuitry 38 for handling wireless communications in cellular telephone bands, such as bands in a frequency range of about 700MHz to about 2700MHz or bands at higher or lower frequencies. Optionally, the wireless communication circuitry 34 may include circuitry for other short-range and long-range wireless links. For example, the wireless communication circuitry 34 may include wireless circuitry for receiving radio and television signals, paging circuitry, and the like. Near field communication (e.g., at 13.56 MHz) may also be supported. In that

And

in links and other short-range wireless links, wireless signals are typically used to deliver data across tens or hundreds of feet.

In cellular telephone links and other long-range links, wireless signals are typically used to deliver data in thousands of feet or miles.

Wireless communication circuitry 34 may have antenna structures such as one or more antennas 40. The antenna structure 40 may be formed using any suitable antenna type. For example, antenna structure 40 may include an antenna having a resonating element formed from: loop antenna structures, patch antenna structures, bowden-type antenna structures, dual-arm inverted-F antenna structures, closed-slot and open-slot antenna structures, planar inverted-F antenna structures, helical antenna structures, strip antennas, monopoles, dipoles, hybrids of these designs, and the like. Different types of antennas may be used for different frequency bands and combinations of frequency bands. For example, one type of antenna may be used to form an area wireless link antenna and another type of antenna may be used to form a remote wireless link. Antenna structures in electronic device 10, such as one or more of antennas 40, may be provided with one or more antenna feeds, fixed and/or adjustable components, and optionally parasitic antenna resonating elements, such that the antenna structures cover a desired communication frequency to operate electronic device 10 at a variety of positions relative to a user's body.

As shown in fig. 3, for example, the device 10 may be held adjacent to a user's head (e.g., head 44) when the user makes a telephone call. In this configuration, the upper end 21 of the device 10 is adjacent to the user's ear 46 so that the user can listen to audio being played via the speaker 18. The lower end 19 is aligned with the mouth 50 of the user. This allows the user's voice to be detected by the microphone 22.

Antennas 40 may include antennas in lower region 19 and/or upper region 21. As an example, device 10 may include an upper antenna in upper region 21 and a lower antenna in lower region 19. The lower antenna in area 19 may be used as the primary transmit antenna during a voice telephone call. The upper antenna in region 21 may be used as the secondary antenna. The antennas in the lower region 19 may be spaced apart from the head 44 by a non-zero distance D (e.g., 5 to 30 mm). This is typically greater than the separation between the antenna in the upper region 21 and the user's head, so it may be desirable to use the antenna 19 as the primary transmit antenna in the device 10 to reduce the wireless signal power at the user's head.

The mode of operation shown in fig. 3 may sometimes be referred to as a "head" mode of operation because device 10 is operated at a user's head 44 (i.e., adjacent ear 46). FIG. 4 shows another illustrative mode of operation of device 10. In the scenario of fig. 4, the apparatus 10 rests on an inanimate support structure such as a table or other piece of furniture. For example, the device 10 may rest on an upper surface 54 of the table 52. The table 52 and other inanimate support structures for the apparatus 10 may be formed from a material such as wood (e.g., a stiff material).

The device 10 may rest on the user's lap when the device 10 is operated in speaker mode or used for other functions that do not involve holding the device 10 against the user's ear. As shown in fig. 5, for example, the device 10 may rest on a surface 56 of a leg 58. Due to the soft and porous nature of the clothing worn by the user and due to the presence of soft flesh in the user's legs, surfaces such as the body surface 56 are generally softer and more likely to absorb high frequency sounds than the surface of a table (such as the table 52 of fig. 4). This behavior of the user's clothing and body may be employed when using sensors to detect the operating environment of the device 10.

The different operating modes of the electronic device 10 illustrated in fig. 3, 4, and 5 may be used to determine corresponding different maximum wireless transmission power levels for use by the electronic device 10.

For example, when a user uses the electronic device 10 in an environment such as the desktop environment of fig. 4, it may be desirable to operate the electronic device 10 at the maximum power rating of the electronic device 10 (i.e., the maximum transmission power of the electronic device 10 may be set to an "unrestricted" level-that is, a maximum value-that is selected based on free space operation and regulatory limits required by telecommunication vendors, but is not' further limited by issues related to transmission to nearby body parts).

In an operating environment of the type shown in fig. 3, the electronic device 10 (i.e., the lower antenna in region 19) is proximate to the user's body (i.e., head 44), but is typically separated by a distance D. In this scenario, it may be desirable to operate the electronic device 10 at a maximum transmission power level that is reduced by a first amount (e.g., 1 to 3dB or other suitable amount) from a maximum (unrestricted) value of the maximum transmission power level.

In an operating environment of the type shown in fig. 5, the electronic device 10 (e.g., the lower antenna in region 19) is generally closer to the user's body (e.g., leg 58) than in the operating environment of fig. 3. Thus, it may be desirable to operate electronic device 10 at a maximum transmission power level that is reduced by a second amount from the maximum (unrestricted) value of the maximum transmission power level (e.g., a maximum transmission power level that is reduced by 2 to 13dB from the unrestricted maximum transmission level or 1 to 10dB from the maximum transmission level used in the "head" mode of operation).

The electronic device 10 may use the sensor data and other information about the current operating state of the electronic device 10 to ascertain which maximum transmission power level to use. FIG. 6 is a schematic diagram of illustrative components in the electronic device 10 that may be used to monitor the operating environment of the electronic device 10 and enforce corresponding maximum transmission levels of transmitted wireless signals. As shown in fig. 6, the electronic device 10 may use the transceiver circuit 34, and the power amplifier 64 to generate a wireless rf signal 62 that is wirelessly transmitted to the wireless external device 60. The external device 60 may be a wireless local area network device (e.g., a device such as a wireless local area network base station), a cellular telephone base station, or other wireless base station. Optionally, external device 60 may include a peer electronic device, a network appliance, a computer, a handheld device, etc.

The control circuit 28 may control the amount of power Pt being wirelessly transmitted from the antenna 40 by controlling the power Pl of the transceiver circuit 34 and by controlling the gain G of the power amplifier 64. The control circuit 28 may determine in real time whether the output power Pt has reached the maximum transmission power limit. At output powers below the maximum transmission power, the control circuit 28 may increase and decrease the output power in real-time based on transmission power commands received from the external device 60, based on received signal strength indicator information, based on sensor data, or based on other information. Whenever the control circuit 28 reaches the maximum transmission power limit Pmax, an upper limit for further increase of the output power Pt will be set (i.e., Pt is limited to Pmax and will not exceed Pmax). Because the amount of transmitted signal power is limited to the value of Pmax and cannot exceed Pmax, Pmax is sometimes referred to as the upper or maximum transmit power limit (maximum transmit power limit) of the electronic device 10.

Control circuitry 28 may adjust maximum transmit power Pmax in real-time based on information about the operating state of electronic device 10 and based on data from one or more sensors in input-output electronics 32. In the illustrative configuration of fig. 6, the electronic device 10 has microphones, such as front microphone 20 and rear microphone 35. The electronic device 10 also has an accelerometer 66. The front microphone 20 may detect sound at the front of the electronic device 10. The rear microphone 35 may detect sound at the rear of the electronic device 10. The accelerometer 66 may also be used to measure motion of the electronic device 10 (e.g., movement of the type caused when a user holds the electronic device 10 on a user's lap or rests the electronic device 10 on other body parts) and may be used to determine the direction of the pull of earth gravity, and thus the orientation of the electronic device 10 relative to the earth.

Whenever it is determined that ear speaker 18 is to play sound to the user, control circuitry 28 may determine that electronic device 10 is likely to be used in the "ear" mode shown in FIG. 3 (i.e., the user is making a voice telephone call).

The signal from accelerometer 66 may be used to determine whether device 10 is resting on the user's body. The signal from accelerometer 66 may be used to determine whether electronic device 10 is resting on the user's body. FIG. 7 is a graph in which accelerometer data from accelerometer 66 has been plotted as a function of time. Accelerometer 66 may be, for example, a three-axis accelerometer that generates X, Y and Z-axis data. The accelerometer output signal in the graph of fig. 7 may correspond to the sum of X, Y and the Z channel of the accelerometer, may correspond to the sum of standard deviations of one-half polling of X, Y and Z channel data, may be time averaged or otherwise delayed (e.g., to implement a state persistence scheme in which abrupt state changes are filtered out; e.g., after detecting when the electronic device is placed on a table, allowing the electronic device to remain in a "table" state until large motion is detected), or may correspond to other data functions' from the x, Y, and/or Z channels. Line 68 corresponds to accelerometer signals from electronic device 10 in a configuration in which electronic device 10 rests on a table or other solid inanimate object, such as table 52 of fig. 4.

Lines

70 and 72 correspond to accelerometer signals from electronic device 10 in a configuration in which electronic device 10 rests on a user's body (see, e.g., leg 58 of fig. 5). The

lines

70 and 72 may be associated with different orientations of the electronic device 10 (e.g., portrait orientation versus landscape orientation, etc.).

To help the electronic device 10 distinguish between use scenarios in which the electronic device 10 rests on a portion of the user's body and in which the electronic device 10 rests on a structure such as a table, the control circuit 28 may compare the accelerometer output data from the accelerometer 66 to a threshold value such as the movement level threshold Ath of fig. 7. In response to determining that the accelerometer data is less than the movement threshold Ath, the control circuit 28 may conclude that the electronic device 10 is resting on the table 52. In response to determining that the accelerometer data is greater than the threshold Ath, the control circuit 28 may conclude that the electronic device 10 is not resting on the table 52 and therefore may be resting on the user's body. Larger accelerometer values (i.e., values greater than the values associated with lines 70 and 72) may be measured during active use of electronic device 10 (e.g., while the user is walking, etc.). In such cases, the control circuit 28 may also conclude that the electronic device 10 is not resting on a table.

The electronic device 10 may use the acoustic information to further analyze how the electronic device 10 is used by the user. For example, the electronic device 10 may emit an audio signal (sound) using a speaker such as the speaker 24 or other audio sensor (e.g., a vibrator, enunciator, speaker, or other audio signal source). The electronic device 10 may then use one or more microphones (such as the front microphone 20 or the rear microphone 35) in the electronic device 10 to detect the transmitted audio signal. The amount of detected audio in this type of scenario may reveal that the electronic device 10 is resting on a table or other inanimate object, or may rest on a leg or other body part.

As an example, consider the electronic device 10 of FIG. 8. In this scenario, the electronic device 10 rests on the upper surface 74 of the object 76. Initially, the electronic device 10 is unaware of the nature of the object 76. For example, the object 76 may be an inanimate object such as a table, or may be a leg or other body part of a user.

As shown in fig. 8, electronic device 10 may have opposing

surfaces

80A and 80B and opposing ends 19 and 21. One of

surfaces

80A and 80B may be a front face of electronic device 10, and the other of

surfaces

80A and 80B may be a rear face of electronic device 10. A user may place the electronic device 10 upside down or upside down on a surface, and thus, the orientation of the electronic device 10 is not generally known in advance.

The

microphones

78A and 78B may be located at the end 21 of the electronic device 10. The microphone 78A may be located on a surface 80A of the electronic device 10. The microphone 78B may be located on the opposite surface 80B. One of the

microphones

78A and 78B may be the front microphone 20 and the other of the

microphones

78A and 78B may be the rear microphone 35.

An audio source, such as the speaker 24 at the lower end 19 of the electronic device 10, may emit sound 82 when it is desired to use audio sensing techniques to help determine the nature of the item on which the electronic device 10 is resting. To avoid audible disruption to a user of the electronic device 10, the sound 82 is preferably outside the range of human hearing. For example, the sound 82 may be an ultrasonic tone, such as a tone at 30kHz, a tone at a frequency from 20 to 100kHz, a tone above 20kHz, a tone at 20kHz, or one or more ultrasonic tones at other ultrasonic frequencies. Lower frequency tones, such as tones at 10kHz, etc., may also be used.

The audio source that emits the ultrasonic audio signal may be a speaker, such as a speakerphone speaker 24, or the ultrasonic audio signal may be emitted by other types of ultrasonic audio sources (e.g., a speaker).

Due to the presence of structure 76, some of sound 82 (e.g., sound 82,) will pass through structure 76 and may be picked up by an underlying microphone in electronic device 10. A significantly reduced amount of sound 82 (i.e., sound that has been emitted out into the air surrounding the electronic device 10) will reach the upper microphone in the electronic device 10.

Accelerometer 66 may be used to determine the orientation of electronic device 10. In the example of FIG. 8, surface 80A of electronic device 10 faces upward in direction Z, and surface 80B of electronic device 10 faces downward in direction-Z. Accelerometer 66 may measure the direction of the earth's gravity and may use this information to determine whether microphone 78A or microphone 78B is currently the down microphone. The underlying microphone may then be used to monitor the surroundings of electronic device 10 for the possible presence of ultrasonic tones 82. If the ultrasonic signal 82 is received by the underlying microphone, the electronic device 10 may conclude that the electronic device 10 is resting on a table or other inanimate object. In the presence of a softer sound absorbing structure 76, such as the user's clothing and/or body, the sound 82 will be absorbed. If the ultrasonic signal 82 is not detected by the underlying microphone, the electronic device 10 may conclude that the electronic device 10 may not rest on an inanimate object and may rest on a portion of the user's body.

Fig. 9 and 10 are graphs showing how audio information collected using

microphones

78A and 78B while generating ultrasonic audio signals using speaker 24 can be used to determine whether electronic device 10 is resting on an inanimate object such as a table or may rest on a portion of a human body. To improve the signal-to-noise ratio of an audio system formed by a microphone and a speaker, the audio information collected by the microphone may be filtered with a low-pass filter, a band-pass filter, or other filters to remove ambient noise in addition to the ultrasonic signal generated using the speaker.

The graph of fig. 9 corresponds to a configuration in which the electronic device 10 rests on the user's leg. The dashed line 92 represents a baseline (average) sound level that may be used as a detection threshold. Line 90 corresponds to sound from the upper microphone that is not blocked by the presence of the user's body. Line 94 corresponds to sound from the underlying microphone that rests on surface 76 and is blocked (absorbed) by surface 76 of fig. 8.

The graph of fig. 10 corresponds to a configuration in which the electronic device 10 rests on a hard inanimate surface such as a table. The dashed line 92 represents a baseline sound level used as a detection threshold. Line 98 corresponds to sound from the upper microphone (i.e., the microphone is not blocked). Line 96 corresponds to sound from the underlying microphone that rests on surface 76 and is blocked by surface 76 of fig. 8.

As the graphs of fig. 9 and 10 show, the sound level (e.g., the amount of detected ultrasonic signal) measured by the unblocked (overhead) microphone does not change significantly between the table and the body environment. The magnitude of curve 90 in fig. 9 may be comparable to the magnitude of curve 96 of fig. 10, since this signal level corresponds to sound passing through free space between the speaker and the unobstructed microphone (rather than passing through or being transmitted near the surface on which the electronic device 10 rests). Thus, the nature of the surface 76 does not significantly affect the amount of sound detected by the unblocked microphone. Because the data from the unblocked microphone is not sensitive to the nature of the surface on which the electronic device 10 rests, the electronic device 10 preferably ignores the data from the unblocked microphone. Instead, the electronic device 10 uses the accelerometer 66 to identify the blocked (down-set) microphone and uses the blocked microphone to collect audio data.

Curve 94 of the graph of fig. 9 represents the audio signal measured by the blocked (down) microphone when the electronic device 10 is resting on the user's body, while curve 96 of fig. 10 represents the audio signal measured by the blocked (down) microphone when the electronic device 10 is resting on a table. The magnitude of curve 94 of fig. 9 is less than threshold 92 because the sound from speaker 24 (sound 82,) is attenuated due to the presence of soft clothing and body tissue associated with the user's body. The magnitude of curve 96 in fig. 10 is greater than threshold 92 because sound 82, tends to be efficiently transmitted between speaker 24 and the blocked (down-set) microphone through the desk on which electronic device 10 rests.

During the "desktop" mode, the maximum transmission power level may be adjusted to a level suitable for use when the user is operating the electronic device 10 on an inanimate object such as a desk. As an example, the maximum transmission power for the wireless signal may be adjusted to a level equal to the maximum of Pmax in the electronic device 10.

During operation of mode 102, electronic device 10 monitors accelerometer 66 to detect motion, compares the amount of detected motion to a predetermined motion threshold, monitors accelerometer 66 to determine an orientation of electronic device 10, generates an ultrasonic audio signal with speakerphone speaker 24, monitors the underlying microphone (as determined by the orientation of electronic device 10), compares audio data collected by the underlying microphone to the predetermined ultrasonic audio signal threshold, and monitors the state of electronic device 10 to determine whether audio is being played via earspeaker 18.

During the "on body" mode, the maximum transmission power level may be adjusted to a level suitable for use by a user when operating electronic device 10 while electronic device 10 is resting on the user's body. As an example, the maximum transmit power for a wireless signal may be adjusted to a level that is reduced by an amount APH relative to a maximum (unrestricted) value of Pmax, where APH is greater than APL °

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An electronic device, comprising a microphone, a radio frequency antenna and a circuit; the RF antenna is configured to transmit RF signals with an upper limit of transmit power set at a maximum transmit power level, and the circuitry is configured to adjust the maximum transmit power level based at least in part on data from the microphone.

2. The electronic device of claim 1, comprising a sound source that emits audio signals, wherein the circuitry is configured to measure the emitted audio signals with the microphone.

3. An electronic device according to claim 2, wherein the circuit is configured to compare the determined transmitted audio signal with a predetermined audio signal threshold.

4. The electronic device of claim 3, wherein the circuit is configured to increase the maximum transmission power level at least partially in response to determining that the determined transmitted audio signal is greater than the predetermined audio signal threshold.

5. The electronic device of claim 4, wherein the electronic device comprises an accelerometer, and wherein the circuitry is configured to collect motion information associated with motion of the electronic device using the accelerometer.

6. An electronic device as recited in claim 5, wherein said circuit is configured to compare said collected motion information to a predetermined motion threshold.

7. An electronic device as recited in claim 6, wherein said circuitry is configured to increase said maximum transmit power at least partially in response to determining that said collected motion information is less than said predetermined motion threshold.

8. The electronic device of claim 7, further comprising an ear speaker, wherein the circuitry is configured to adjust the maximum transmission power level at least partially in response to determining that audio is not being played by the ear speaker.

9. An electronic device as claimed in claim 8, wherein the electronic device has opposing front and back sides with a front microphone and a back microphone, respectively, and wherein the circuitry is configured to measure a selected one of the front and back microphones of the audio signal.

10. The electronic device of claim 9, wherein the circuitry is configured to collect orientation data from the accelerometer and to select the microphone from the front and rear microphones for measuring the audio signal based on the collected orientation data.