Audio accessory communication with active noise cancellation

This document discusses, among other things, an advanced slave circuit and method configured to transfer power from a master device to a battery through an advanced slave circuit in a first mode using a load switch in a first state, to isolate the battery from the master device using the load switch in a second state, and to selectively couple a microphone to the master device using the advanced slave circuit in a second mode using a microphone switch.

BACKGROUND

Mobile electronic devices include standard connectors configured to send or receive information or power to or from one or more accessories or other electronic devices. An example standard connector includes an audio jack, including left and right audio connections, a ground connection, and a microphone connection. In certain examples, an audio jack accessory, such as a mobile headset, can be configured to communication to or from the mobile electronic device using the microphone connection of the audio jack.

OVERVIEW

This document discusses, among other things, an advanced slave circuit and method configured to transfer power from a master device to a battery through an advanced slave circuit in a first mode using a load switch in a first state, to isolate the battery from the master device using the load switch in a second state, and to selectively couple a microphone to the master device using the advanced slave circuit in a second mode using a microphone switch.

DETAILED DESCRIPTION

The present inventors have recognized, among other things, audio jack authentication systems and methods to identify and verify audio jack accessories coupled to an audio jack of a mobile device, ensuring that mobile device users are provided vendor-known audio jack accessory quality and full system features. Audio jack microphone (MIC) connections currently provide voice and key press features. As such features depend on the type or model of audio jack accessory, in certain examples, the audio jack accessory must be identified prior to enabling full bi-directional communication.

Many audio jack accessories include features that require power, such as active noise cancellation (ANC), haptic feedback, etc. Accordingly, audio jack accessories can include a supplemental power source, such as a battery. The present inventors have recognized that, if the mobile device identifies the audio jack accessory as having or requiring power, in certain examples, the mobile device can provide additional power to either power the audio jack accessory or charge the a battery of the audio jack accessory using, for example, a microphone line or one or more other audio jack connections.

FIG. 1illustrates generally an example audio jack authentication and communication system100including a master device101(e.g., a mobile electronic device) and an accessory slave device102(e.g., a headset). In an example, the accessory slave device102can be coupled to an audio jack of the master device101using an audio jack plug. In an example, the accessory slave device102can include a microphone, left and right speakers, and one or more user-inputs (e.g., keys, such as a send/end key, one or more volume control keys, etc.) and ambient noise cancelling (ANC) circuitry. In certain examples, the ANC circuitry can require power. Accordingly, the accessory slave device102can include a battery.

The present inventors have recognized systems and methods to provide power to the accessory slave device102from a master device101, for example, when a microphone or speaker of the accessory slave device102is not in use (e.g., for communication, etc.) to, among other things, power or charge a battery of the accessory slave device102. In various examples, the systems and methods described herein can reduce the required accessory slave device battery size or capacity, reduce the cost of the accessory slave device102, prolong the use of the accessory slave device102between traditional charging periods.

FIG. 2illustrates generally an example audio jack authentication and communication system200including a master device circuit205, an audio jack215, an advanced slave circuit220, and a microphone230. In an example, the master device circuit205and the advanced slave circuit220are configured as a half-duplex interface for bi-directional communication between a master device including the master device circuit205and an advanced slave including the advanced slave circuit220through the audio jack215.

The master device circuit205can include an inter-integrated circuit (I2C) interface206, an oscillator and logic circuit207, one or more registers208, a transceiver (XCVR)210, and a comparator114. The transceiver210can include first and second drivers211,212and a low-dropout (LDO) regulator213.

In an example, the audio jack215can include left and right audio pins, a ground pin, and a microphone pin (J_MIC). In certain examples, the master device circuit205can include a jack and moisture detection circuit209, and the audio jack215can include a dedicated connection pin (J_DET) to, for example, detect when an audio jack plug is fully inserted into an audio jack receptacle, or to detect moisture or one or more other contaminant or false plug in the audio jack receptacle. In certain examples, the jack and moisture detection circuit209can have a reduced printed circuit board (PCB) area (e.g., WLCSP 9-ball, etc.) and can provide pop or click reduction or isolation when an audio jack plug is removed from or inserted into the audio jack receptacle.

The advanced slave circuit220includes an I2C interface221, an oscillator and logic circuit222, one or more registers223, a transceiver (XCVR)224including first and second drivers225,226, and a depletion mode switch227(e.g., a field effect transistor (FET)).

In an example, the master device or the advanced slave can include a microphone (MIC) switch configured to isolate signals to or from the MIC input of the master device or signals to or from the microphone230coupled to the advanced slave circuit220, for example, to reduce or isolate an audible pop or click during switching or communication. In an example, the depletion mode switch227can provide backwards compatibility with prior or existing systems.

In certain examples, the advanced slave can include an identifier, such as a fuse-programmable ID or one or more other identifiers. The fuse programmable ID can include, for example, a 6-bit code capable of providing 64 unique possible IDs. Accordingly, in this example, 64 unique advanced slave accessories can be identified, with different operations/functions assigned to or associated with each.

In an example, the master device circuit205and the advanced slave circuit220can communicate to identify one or both of the master device or the advanced slave, such as disclosed in the commonly assigned U.S. application Ser. No. 14/453,109, “AUDIO JACK SYSTEM,” to inventor Seth M. Prentice, filed on Aug. 6, 2014, included by reference in its entirety, including exchanging information between a master and slave device via a single conductive path of an audio jack connector using a digital communication protocol.

For a simple slave, the LDO213can supply power, and, in certain examples, no external supply is required. However, for certain advanced slaves, such as for advanced slaves having ambient noise cancellation circuitry, more power can be required.

FIG. 3illustrates generally an example mobile phone system300including a baseband processor301, an audio codec302, a master device circuit305, and an audio jack310configured to receive an audio jack plug and send or receive information to or from or otherwise provide power to or otherwise communicate with a slave device.

In an example, the master device circuit305can include an I2C interface306, an impedance and moisture detection circuit (Z/MOISTURE DET)307, a transceiver and detection circuit (XCVR & DET)308, and an LDO circuit309. In an example, the audio codec302can send or receive left and right audio information (LSPKR and RSPKR, respectively) to or from the left and right audio pins (L, R) of the audio jack310, and microphone information (MIC) to or from the audio jack310through the master device circuit305, for example, through a capacitor304or a resistor303.

FIG. 4illustrates generally an example headset system400including an advanced slave circuit405, an audio jack plug415, an ambient noise cancelling (ANC) integrated circuit (IC)416, a depletion mode switch417, a battery418, a send/end key (S/E KEY)419, one or more additional slave keys420, a microphone421, left and right ANC microphones (MIC_ANC_L, MIC_ANC_R)422,423, and left and right speakers (LSPKR, RSPKR)424,425.

In an example, the audio jack plug can include four pins: a left audio pin (L), a right audio pin (R), a ground pin (G), and a microphone (MIC) pin (M). In certain examples, the left and right audio pins can be reversed, one or more other pins can be in one or more other configurations, or the audio jack plug can include more or less than four pins.

The advanced slave circuit405includes a logic, oscillator, and charge pump circuit configured to control one or more components of the headset system400(e.g., the depletion mode switch417, etc.) and a transceiver410coupled to the microphone pin. The advanced slave can further include a key detection circuit412coupled to the one or more slave keys420, and a depletion mode switch413between the microphone pin of the audio jack plug415and the microphone421. A key press on the one or more slave keys420can be detected by the key detection circuit412and communicated to the master device through a one-wire interface, such as a MIC line. In an example, the depletion mode switch413can be configured to isolate the microphone421during this time.

The depletion mode switch417and send/end key419can allow the headset system400to be backwards compatible with existing master devices. For example, if the audio jack plug415is coupled to a master device that is not configured for bi-directional one-wire communication, instead only configured for traditional microphone and speaker headset functions, then the headset system400will appear as a traditional headset, with the left and right audio pins coupled through the depletion mode switch417to the left and right speakers424,425, respectively, and the microphone pin coupled to the microphone421(e.g., through a depletion mode switch413in the advanced slave circuit405), and to ground through the send/end key419.

However, if the headset system400is coupled to a master device configured for bi-directional one-wire communication, such as illustrated inFIGS. 2 and 3, or other master devices the advanced features of the headset system400(e.g., ANC, additional key press, charging via an audio jack pin, etc.) may be used. Example functions of the headset system400can be described with respect to two modes: an audio mode; and a voice mode. In certain examples, the baseband processor of a master device can control when the headset system400is in audio mode or voice mode. Example audio modes include providing music or other audio over the left and right speakers424,425. Example voice modes include during incoming or outgoing voice communication, when receiving voice commands, etc.

In an example audio mode, the microphone pin of the audio jack plug415can receive a MIC bias from the master device. The advanced slave circuit405, in audio mode, can be configured to provide power to the ANC IC416and, in certain examples, charge the battery418, such as using the MIC bias through a load switch411. In an example, the advanced slave circuit405can be configured to receive instructions from the master device (e.g., from a baseband processor of a mobile phone, etc.), and to control the load switch411(e.g., using the logic, oscillator, charge pump407, etc.) in accordance with the instructions from the master device. In other examples, the advanced slave circuit405can be configured to receive information from a user, such as using the send/end key419or the one or more slave keys. In an example, the advanced slave circuit405can transmit the received information to the master device and wait to receive return instructions, or can control one or more components of the headset system400directly in accordance with the received information.

In an example, the load switch411can include a true reverse-current blocking load switch having a max current limit to protect any coupled devices or to optimize the current through the switch provided to the battery418. In other examples, additional circuitry can be included in the load switch411, in the advanced slave circuit405, or between the load switch411and the battery418to optimize the received power to charge the battery418or to power the ANC IC416or one or more other circuits or components of the headset system400. In certain examples, to save power, when the battery418is fully charged and the ANC IC416is not in use, the advanced slave405can communicate to the master device to remove power from the MIC line, or one or more other lines providing power to the headset system400.

In an example voice mode, the advanced slave circuit405can receive a communication (e.g., from the baseband processor in the master device) to connect the microphone421to the MIC line, receive an audio signal from the microphone421, and provide the received audio signal, or one or more other key detection or other signals, to the master device. In the example voice mode, the ANC IC416can be powered by the battery418. The battery418can be sized to support a long call (e.g., 2 hours, etc.). If a voltage of the battery418is below a threshold (e.g., when the battery is drained below a level that can support operation of the ANC IC416, when the battery is missing, etc.), the depletion mode switch417can route the left and right audio signals from the audio jack plug415around the ANC IC416to the left and right speakers424,425, to maintain basic functionality of the headset system400without ANC. Further, if the advanced slave circuit405cannot be powered, the depletion mode switch413couples the microphone421to the microphone pin of the audio jack plug415. When the example voice mode is complete, the baseband processor can communicate to the advanced slave to isolate the microphone421, and audio mode, including charging the battery418, can resume.

FIG. 5illustrates generally example single-wire communication500(e.g., TinyWire™, etc.) between a master device and an advanced slave device. In an example, a short bit low is logic 1, and a long bit low is logic 0. A transmission frequency can be between 200 and 400 KHz. A complete master/slave transaction time (e.g., 400 Khz) can be less than 51 ms (e.g., 50 ms for master MIC switch slow tON for reduced pop and click). The signal amplitude can include the master internal LDO amplitude—500 mV (e.g., master internal LDO=2.8V). In certain examples, other amplitudes can be used for pair matching, depending on observed conditions or simulations. Example data words can include 12 bits in total: 2-bit address; 6-bit data; 1-bit parity (e.g., error detection); and 3-bit reserve. In other examples, data words of other bit sizes can be used.

FIG. 6illustrates generally an example device authentication signal transmission601. At602, a master device bypasses a bias resistor. In certain examples, the master device can also isolate a single conductive path from a baseband processor or an audio processor, for example, using a microphone switch. At603, a slave can isolate a microphone from a single conductive path (e.g., a MIC line), for example, using an isolation switch. In certain examples, the slave can detect a change in the voltage on the single conductive path using an optional bias voltage detection circuit. At604, the master device can detect if the voltage on the single conductive path has reached a threshold and can transit a verification code to the slave device over the single conductive path. At605, a first predetermined minimum delay is implemented. At606, the slave device can transmit an identification (ID) code to the master device over the single conductive path. At607, a second predetermined minimum delay is implemented. At608, the master device can transmit a power-down code to the slave device over the single conductive path. At609, a third predetermined minimum delay is implemented. At610, the slave device can couple the microphone to the single conductive path. At611, after detecting the connected microphone via the voltage on the single conductive path, the master device can couple the single conductive path to the baseband processor or an audio processor, and can disable a bypass transistor to couple the bias source to the single conductive path through the bias resistor.

FIG. 7illustrates generally an example slave write (e.g., key press) signal transmission701. In certain examples, the slave write signal transmission can occur when a parameter in a master device is updated by a slave device, when the slave device requests an update from the master device, when the slave device communicates an event to the master device (e.g., a key-press event, etc.), or combinations thereof.

At702, the slave device can isolate a microphone from a single conductive path. At703, the master device can detect a change in voltage level resulting from the isolation of the microphone and can isolate the single conductive path from the baseband processor or audio processor. At704, the master device can bypass a microphone bias resistor using a transistor. At705, the master device can detect if the voltage on the single conductive path has reached a threshold and can transit a verification code to the slave device over the single conductive path. At706, a first predetermined minimum delay is implemented. At707, the slave device can transmit the event information to the master. At708, a second predetermined minimum delay is implemented. At709, the master device can transmit a power down code to the slave device. At710, a third predetermined minimum delay is implemented. At711, the slave device can couple the microphone to the single conductive path. At712, after detecting the connected microphone via the voltage on the single conductive path, the master device can couple the single conductive path to the baseband processor or an audio processor, and can disable a bypass transistor to couple the bias source to the single conductive path through the bias resistor.

FIG. 8illustrates generally an example master write (e.g., volume up) signal transmission801. At802, a master device can bypass a bias resistor using a bypass transistor. At803, the master device can isolate a single conductive path from a baseband process or an audio processor, for example, using a microphone switch. At804, the slave device can isolate a microphone from the single conductive path, for example, using an isolation switch, if the microphone is not already isolated from the single conductive path. In certain examples, the slave device can detect a change in the voltage on the single conductive path that results from the master device bypassing the bias resistor using an optional bias voltage detection circuit. At805, the master device can detect if the voltage on the single conductive path has reached a threshold and can transmit a write code to the slave device over the single conductive path. At806, a first predetermined minimum delay is implemented. At807, the slave device can transmit an acknowledgment to the master device over the single conductive path. At808, a second predetermined minimum delay is implemented. At809, the master device can transmit write data to the slave device over the single conductive path. At810, a third predetermined minimum delay is implemented. At811, the slave device can couple the microphone to the single conductive path. At812, after detecting the connected microphone via the voltage on the single conductive path, the master device can couple the single conductive path to the baseband processor or an audio processor, and can disable a bypass transistor to couple the bias source to the single conductive path through the bias resistor.

Although, as described above, power is provided to an accessory slave device using a microphone line of an audio jack when the microphone is not in use, in other examples, power can be provided to the accessory slave device using one or more other lines of the audio jack, such as the left or right audio lines, when not in use, in accordance with the teachings above.

EXAMPLES

In Example 1, an accessory headset system, includes an advanced slave circuit configured to communicate with a master device using a first connection of an audio jack, an ambient noise cancelling (ANC) circuit configured to receive a left audio signal from a second connection of the audio jack and a right audio signal from a third connection of the audio jack, to receive ambient noise information, and to provide corrected left and right audio signals using the left and right audio signals and the ambient noise information, and a battery configured to provide power to the ambient noise cancelling circuit. The advanced slave circuit is configured to receive power from the master device using the first connection of the audio jack in a first mode, and to selectively couple a microphone to the master device using the first connection of the audio jack in a second mode, wherein the advanced slave circuit includes: a load switch configured to provide power to the battery through the first connection of the audio jack in a first state, and to isolate the battery from the first connection of the audio jack in a second state; and a microphone switch configured to couple the microphone to the first connection of the audio jack in a first state, and to isolate the microphone from the first connection of the audio jack in a second state.

In Example 2, the system of Example 1 optionally includes the audio jack, the microphone, and the master device, wherein the first connection of the audio jack optionally includes a microphone connection coupled to the advanced slave circuit, wherein the second connection of the audio jack optionally includes a left audio connection coupled to the ANC circuit, wherein the third connection of the audio jack optionally includes a right audio connection coupled to the ANC circuit, and wherein the master device optionally includes a mobile phone.

In Example 3, the system of any one or more of Examples 1-2 optionally includes a first ANC microphone and a second ANC microphone, wherein the ANC circuit is configured to receive ambient noise information from the first and second ANC microphones.

In Example 4, the first mode of the advanced slave circuit of any one or more of Examples 1-3 optionally includes an audio mode, wherein the microphone switch is in the second state when the advanced slave circuit is in the audio mode, and wherein the second mode of the advanced slave circuit of any one or more of Examples 1-3 optionally includes a voice mode, wherein the microphone switch is in the first state when the advanced slave circuit is in the voice mode.

In Example 5, the load switch of any one or more of Examples 1-4 is optionally in the second state when the advanced slave circuit is in the voice mode.

In Example 6, the system of any one or more of Examples 1-5 optionally includes a send/end key coupled between the first connection of the audio jack and a ground connection, wherein the send/end key is configured to receive a user request and to provide an indication of the user request to the master device, and a depletion mode switch coupled to the second and third connections of the audio jack, wherein, when the advanced slave circuit is in the second mode and the battery voltage falls below a low-power threshold, the depletion mode switch is in a closed state, bypassing the ANC circuit.

In Example 7, the load switch of any one or more of Examples 1-6 is optionally configured to provide power to the ANC circuit through the first connection of the audio jack in the first state, and to isolate the ANC circuit from the first connection of the audio jack in the second state.

In Example 8, an apparatus includes an advanced slave circuit configured to communicate with a master device using a first connection of an audio jack, wherein the advanced slave circuit is configured to receive power from the master device using the first connection of the audio jack in a first mode, and to selectively couple a microphone to the master device using the first connection of the audio jack in a second mode, wherein the advanced slave circuit includes: a load switch configured to provide power to a battery coupled to the advanced slave circuit through the first connection of the audio jack in a first state, and to isolate the battery from the first connection of the audio jack in a second state; and a microphone switch configured to couple the microphone to the first connection of the audio jack in a first state, and to isolate the microphone from the first connection of the audio jack in a second state.

In Example 9, the first connection of the audio jack of any one or more of Examples 1-8 optionally includes a microphone connection.

In Example 10, the first mode of the advanced slave circuit of any one or more of Examples 1-9 optionally includes an audio mode, wherein the microphone switch is in the second state when the advanced slave circuit is in the audio mode, and the second mode of the advanced slave circuit of any one or more of Examples 1-9 optionally includes a voice mode, wherein the microphone switch is in the first state when the advanced slave circuit is in the voice mode.

In Example 11, the load switch of any one or more of Examples 1-10 is optionally in the second state when the advanced slave circuit is in the voice mode.

In Example 12, the advanced slave circuit of any one or more of Examples 1-11 is optionally configured to control the load switch and the microphone switch.

In Example 13, the load switch of any one or more of Examples 1-12 is optionally configured to provide power to an ambient noise cancelling (ANC) circuit through the first connection of the audio jack in the first state, and to isolate the ANC circuit from the first connection of the audio jack in the second state.

In Example 14, a method includes transferring power from a master device to a battery through an advanced slave circuit in a first mode using a load switch in a first state, isolating the battery from the master device using the load switch in a second state, and selectively coupling a microphone to the master device using the advanced slave circuit in a second mode using a microphone switch.

In Example 15, the transferring power of any one or more of Examples 1-14 optionally includes receiving power from the master device at the advanced slave circuit using a first connection of an audio jack and providing power to the battery coupled to the advanced slave circuit using the first connection of the audio jack through the load switch in the first state, wherein selectively coupling the microphone to the master device optionally includes coupling a microphone to the first connection of the audio jack using the microphone switch in a first state and isolating the microphone from the first connection of the audio jack using the microphone switch in a second state.

In Example 16, the first connection of the audio jack of any one or more of Examples 1-15 optionally includes a microphone connection.

In Example 17, the first mode of the advanced slave circuit of any one or more of Examples 1-16 optionally includes an audio mode, and the second mode of the advanced slave circuit optionally includes a voice mode, wherein isolating the battery from the master device optionally includes when the advanced slave circuit is in the audio mode, and wherein selectively coupling the microphone to the master device optionally includes coupling the microphone to a first connection of an audio jack using the microphone switch when the advanced slave circuit is in the voice mode.

In Example 18, the isolating the battery from the master device of any one or more of Examples 1-17 optionally includes when the advanced slave circuit is in the voice mode.

In Example 19, any one or more of Examples 1-18 optionally includes controlling the load switch and the microphone switch using the advanced slave circuit.

In Example 20, any one or more of Examples 1-19 optionally includes transferring power to an ambient noise cancelling (ANC) circuit from the master device through the advanced slave circuit in the first mode using the load switch in the first state and isolating the ANC circuit from the master device using the load switch in the second state.

In Example 21, a system or apparatus can include, or can optionally be combined with any portion or combination of any portions of any one or more of Examples 1-20 to include, means for performing any one or more of the functions of Examples 1-20, or a machine-readable medium including instructions that, when performed by a machine, cause the machine to perform any one or more of the functions of Examples 1-20.

Additional Notes