Abstract:
An interface unit of a mobile device coupled to an auxiliary device, the interface unit including: a first plurality of switches configured for power delivery to the auxiliary device; at least one isolation unit coupled to the first plurality of switches, the at least one isolation unit configured to isolate the multiple signals and to prevent disruption of data communication between the mobile device and the auxiliary device; and a second plurality of switches configured for the data communication between the mobile device and the auxiliary device, the second plurality of switches configured to bypass the at least one isolation unit.

Description:
BACKGROUND 
       [0001]    Field 
         [0002]    The present disclosure relates generally to a mobile device with multiple communication capabilities, and more specifically, to an interface unit of the mobile device. 
         [0003]    Background 
         [0004]    Mobile devices may provide multiple communication capabilities including digital data communication between the mobile device and an auxiliary device coupled to the mobile device. In one example, the auxiliary device may be a headset. The multiple communication capabilities may also include a frequency modulation (FM) radio operation with the connected headset used as an antenna (i.e., a long wire connecting the headset to the mobile device is used as an antenna). Thus, the ground terminal of the headset may be coupled to an FM receiver residing on the mobile device. 
         [0005]    A mobile device with an FM receiver may require ferrite beads (FBs) or radio frequency chokes (RFCs) to isolate the FM signal and ensure sensitivity of the FM receiver. However, the presence of the FBs may disrupt the digital data communication between the mobile device and the auxiliary device such as a headset. 
       SUMMARY 
       [0006]    The present disclosure describes various implementations of an interface unit of a mobile device. 
         [0007]    In one embodiment, an interface unit of a mobile device coupled to an auxiliary device is disclosed. The interface unit includes: a first plurality of switches configured for power delivery to the auxiliary device; at least one isolation unit coupled to the first plurality of switches, the at least one isolation unit configured to isolate the multiple signals and to prevent disruption of data communication between the mobile device and the auxiliary device; and a second plurality of switches configured for the data communication between the mobile device and the auxiliary device, the second plurality of switches configured to bypass the at least one isolation unit. 
         [0008]    In another embodiment, a mobile device coupled to an auxiliary device is disclosed. The mobile device includes: a radio frequency (RF) transceiver configured to communicate with other mobile devices; an audio codec coupled to the RF transceiver; and an interface unit coupled to the audio code, the interface unit comprising: a first plurality of switches configured for power delivery to the auxiliary device; at least one isolation unit coupled to the first plurality of switches; and a second plurality of switches configured for the data communication between the mobile device and the auxiliary device, the second plurality of switches configured to bypass the at least one isolation unit. 
         [0009]    In another embodiment, a method for enabling multiple communication capabilities for an interface unit of a mobile device coupled to an auxiliary device is disclosed. The method includes: detecting a type of the auxiliary device coupled to the mobile device; configuring a first plurality of switches coupled to at least one isolation unit based on the detected type, the first plurality of switches configured for power delivery to the auxiliary device; configuring a second plurality of switches configured for the data communication between the mobile device and the auxiliary device based on the detected type, the second plurality of switches configured to bypass the at least one isolation unit. 
         [0010]    In another embodiment, a mobile device coupled to an auxiliary device is disclosed. The mobile device includes: means for detecting a type of the auxiliary device coupled to the mobile device; means for configuring a first plurality of switches coupled to at least one isolation unit based on the detected type, the first plurality of switches configured for power delivery to the auxiliary device; mean for configuring a second plurality of switches configured for the data communication between the mobile device and the auxiliary device based on the detected type, the second plurality of switches configured to bypass the at least one isolation unit. 
         [0011]    Other features and advantages of the present disclosure should be apparent from the present description which illustrates, by way of example, aspects of the present disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The details of the present disclosure, both as to its structure and operation, may be gleaned in part by study of the appended further drawings, in which like reference numerals refer to like parts, and in which: 
           [0013]      FIG. 1  is an exemplary wireless device communicating with a wireless communication system; 
           [0014]      FIG. 2  is a functional block diagram of an exemplary design of a wireless device that is one embodiment of the wireless device shown in  FIG. 1 ; 
           [0015]      FIG. 3  is a schematic diagram of a mobile device (e.g., a wireless device shown in  FIG. 2 ) with multiple communication capabilities which is coupled to an auxiliary device (e.g., headset and/or microphone shown in  FIG. 2 ); and 
           [0016]      FIG. 4  is a schematic diagram of a mobile device including an interface unit in accordance with one embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    As explained above, the presence of the ferrite beads (FBs) disrupts the digital data communication between the mobile device and the auxiliary device coupled to the mobile device. Thus, a solution for providing uninterrupted digital data communication between the mobile device and the auxiliary device in the presence of disturbing units such as ferrite beads (FBs) is needed. One solution is to bypass the FBs using switches that provide relatively low ON resistance (e.g., less than 1Ω to keep the voltage drop low) and also provide relatively low OFF capacitance (e.g., less than 20 pF) to maintain the FM sensitivity. However, switches with such tight specifications are relatively expensive. Accordingly, a new design of the mobile device includes two sets of relatively low cost switches, with one set for data communication which bypasses the FBs and another set for power delivery. 
         [0018]    After reading this description it will become apparent how to implement the present disclosure in various implementations and applications. Although various implementations of the present disclosure will be described herein, it is understood that these implementations are presented by way of example only, and not limitation. As such, this detailed description of various implementations should not be construed to limit the scope or breadth of the present disclosure. 
         [0019]    The term “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other designs. The detailed description includes specific details for the purpose of providing a thorough understanding of the exemplary designs of the present disclosure. It will be apparent to those skilled in the art that the exemplary designs described herein may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the novelty of the exemplary designs presented herein. 
         [0020]      FIG. 1  is an exemplary wireless device  110  communicating with a wireless communication system  100 . Wireless communication system  100  may be a Long Term Evolution (LTE) system, a Code Division Multiple Access (CDMA) system, a Global System for Mobile Communications (GSM) system, a wireless local area network (WLAN) system, or some other wireless system. A CDMA system may implement Wideband CDMA (WCDMA), CDMA 1X, Evolution-Data Optimized (EVDO), Time Division Synchronous CDMA (TD-SCDMA), or some other version of CDMA. For simplicity,  FIG. 1  shows wireless communication system  100  including two base stations  120  and  122  and one system controller  130 . In general, a wireless system may include any number of base stations and any set of network entities. 
         [0021]    Wireless device  110  may also be referred to as a user equipment (UE), a mobile station, a terminal, an access terminal, a subscriber unit, a station, etc. Wireless device  110  may be a cellular phone, a smartphone, a tablet, a wireless modem, a personal digital assistant (PDA), a handheld device, a laptop computer, a smartbook, a netbook, a cordless phone, a wireless local loop (WLL) station, a Bluetooth device, etc. Wireless device  110  may communicate with wireless system  100 . Wireless device  110  may also receive signals from broadcast stations (e.g., broadcast station  124 ), signals from satellites (e.g., satellite  140 ) in one or more global navigation satellite systems (GNSS), etc. Wireless device  110  may support one or more radio technologies for wireless communication including LTE, WCDMA, CDMA 1X, EVDO, TD-SCDMA, GSM, 802.11, etc. 
         [0022]      FIG. 2  is a functional block diagram of an exemplary design of a wireless device  200  that is one embodiment of the wireless device  110  of  FIG. 1 . In this exemplary design, the wireless device  200  includes an antenna  202 , a switch  204 , a radio frequency (RF) transceiver unit  210 , a digital-to-analog converter (DAC)/analog-to-digital converter (ADC)  220 , a baseband processor  230 , a digital controller  240 , a display unit  250 , and a keyboard/touch screen  252 . The wireless device  200  may also include an audio codec  260  having an audio amplifier, an external amplifier  262 , and a speaker/headphone jack  270 . In one embodiment, the speaker/headphone jack  270  includes a 3.5 mm audio jack. In other embodiments, the speaker/headphone jack  270  includes a USB port, mini USB port, micro USB port, USB type-C port, Lightning port, or any other type of interface. 
         [0023]    The wireless device  200  may also include a microphone/headset interface  280  which interfaces with an auxiliary device such as a headset/microphone  282 . The wireless device  200  may further include other units (not shown) including a universal serial bus unit (USB), a camera, a wireless network interface unit, a subscriber identity module (SIM) card, a battery, memory unit, etc. It should be noted that not all blocks of the wireless device in  FIG. 2  are necessary. For example, the DAC/ADC  220  can be subsumed within the baseband processor  230 . In another example, the external amplifier  262  may be removed from some configurations. 
         [0024]    The RF transceiver unit  210  includes two circuits, a transmitter and a receiver. A wireless device  200  uses the transmitter and the receiver to communicate with other wireless devices. The transmitter transmits radio signals and the receiver receives the radio signals. The transmitter includes, among other units, an RF up converter that converts modulated baseband signal (I and Q) either at zero Intermediate frequency (IF) or some IF to RF frequency. The receiver includes, among other units, an RF down converter that converts RF signal to baseband signal (I and Q). The basic component used for frequency conversion is an RF mixer. 
         [0025]    The antenna  202  is a metallic object which converts electro-magnetic signal to electric signal and vice versa. Exemplary antennas in the wireless device are of various types such as helix type, planar inverted type, whip or patch type. Micro-strip based patch type of antennas are often used in mobile devices/phones due to its size, easy integration on the PCB, and multi-frequency band of operation. Since only one antenna may be used for both transmit (Tx) and receive (Rx) paths at different times, a Tx/Rx switch  204  may be used to connect both the Tx path and the Rx path with the antenna  202  at different times. For a frequency division duplex (FDD) system, a diplexer may be used in place of the switch which acts as filter to separate various frequency bands. 
         [0026]    The DAC/ADC  220  may be used to convert the analog speech signal to the digital signal and vice versa in the wireless device  200 . In the Tx path, the converted digital signal is sent to the speech coder such as an audio codec. The types of ADCs include sigma delta, flash, dual slope, and successive approximation. In the Rx path, the automatic gain control (AGC) and the automatic frequency control (AFC) may be used to control gain and frequency. The AGC controls proper maintenance of the DAC by keeping the signal within the dynamic range of the DAC. The AFC controls receiver performance by maintaining the frequency error within a limit. 
         [0027]    The baseband processor  230  may convert voice/data to I/Q baseband signal. The baseband processor  230  is sometimes referred to as a physical layer (or Layer  1 ). The baseband processor  230  may add redundant bits to enable error detection (e.g., using cyclic redundancy check (CRC)) and error correction using forward error correction techniques (e.g., a convolutional encoder (used in the Tx path) and a Viterbi decoder (used in the Rx path). The baseband processor  230  may also perform power management and distribution functions. 
         [0028]    The audio codec  260  may be used to compress and decompress the signals to match the data rate to the frame. The audio codec  260  may convert the speech signal at 8 KHz sampling rate to 13 kilobits per second (kbps) rate for a full rate speech traffic channel. The audio codec  260  may couple to the speaker and/or headphone  270  through the external amplifier  262 . The audio codec  260  may also couple to the headset/microphone  282  through the microphone/headset interface  280 . 
         [0029]    The digital controller  240  may control data input and output signals such as switching and driving applications, commands, memory accesses, and executions of programs. The digital controller  240  may also interpret and execute commands to and from the user interface including the display unit  250 , the keyboard/touchscreen  252 , etc. The digital controller  240  may further manage and execute various applications in an application layer (Layer  7 ). Applications may include audio, video and image/graphics applications. 
         [0030]      FIG. 3  is a schematic diagram of a mobile device  300  (e.g., a wireless device  200 ) with multiple communication capabilities which is coupled to an auxiliary device  302  (e.g., headset and/or microphone  282  shown in  FIG. 2 ) via a connector such as a jack  350 . In the illustrated embodiment of  FIG. 3 , the mobile device  300  provides digital data communication with the headset  302  through the microphone pin (MIC) at node  336  and the ground pin (GND) at node  330 . The mobile device  300  also may communicate with an FM radio operation. Further, the mobile device  300  may communicate with the headset  302  using the headphone left (HPH_L) pin at node  332  and/or the headphone right (HPH_R) pin at node  334 . The headphone detect (HS-DET) pin at node  338  may be used to detect the presence or type of the headphone connected to the mobile device  300 . In the illustrated embodiment of  FIG. 3 , the HPH_L pin at node  332 , HPH_R pin at node  334 , and the HS-DET pin at node  338  are not connected for simplicity. However, in one embodiment, those pins  332 ,  334 ,  338  can be connected to an audio codec (e.g., audio codec  260  in  FIG. 2 ) so that an audio signal from the mobile device  300  can be sent to a headset (e.g., headset/microphone  282 ). 
         [0031]    The mobile device  300  may include an interface unit  304  (e.g., a microphone/headset interface  280  shown in  FIG. 2 ). The interface unit  304  includes switches  310 ,  312  to reverse the polarity of the output of the headset  302  to conform to various different standards, such as the United States and European headset standards. One exemplary solution for the switches  310 ,  312  is to use switches that provide low ON resistance (e.g., less than 1Ω to keep the voltage drop below 0.1V), but relatively high OFF capacitance (e.g., around 100 pF). In one embodiment, the FM receiver (FM Rx) connects to the ground pin (GND) at node  330 . However, the FM Rx can be connected to headphone left (HPH_L) pin at node  332  or the headphone right (HPH_R) pin at node  334 . 
         [0032]    The exemplary mobile device  300  of  FIG. 3  is in digital data communication with an FM radio operation with an interface unit  304  that includes ferrite beads (FBs)  320 ,  322  or radio frequency chokes (RFCs) to isolate the FM signal and maintain sensitivity of the FM receiver in the mobile device  300 . However, as stated above, the presence of the FBs  320 ,  322  may disrupt the digital data communication between the mobile device  300  and the headset  302 . 
         [0033]      FIG. 4  is a schematic diagram of a mobile device  400  including an interface unit  404  in accordance with one embodiment of the present disclosure. In the illustrated embodiment of  FIG. 4 , the interface unit  404  includes two sets of switches  410 ,  412 ,  420 ,  422  which can provide multiple communication capabilities for the mobile device  400 . 
         [0034]    The first set  410 ,  412  is a switch set substantially similar to switches  310 ,  312  in  FIG. 3 . These switches  410 ,  412  are configured for power delivery from a low drop-out (LDO) regulator (at node  442 ), with relatively low ON resistance (e.g., less than 1Ω to keep the voltage drop low), but with relatively high OFF capacitance (e.g., greater than 100 pF). 
         [0035]    The second set  420 ,  422  is a switch set configured for data communication between the receiver/transmitter (RX/TX) of the mobile device  400  (at node  440 ) and the headset  402 . These switches  420 ,  422  are configured with relatively high ON resistance (e.g., less than 5Ω but greater than 1Ω and relatively low OFF capacitance (e.g., less than 10 pF) to maintain the sensitivity of the FM receiver. Accordingly, the two set solution may provide a relatively low cost solution to maintaining multiple communication capabilities for the mobile device  400  including digital data communication and FM radio operation. 
         [0036]    Data communication node  440  couples to switch  420  through resistor R and capacitor C. The value of resistor R is adjusted to be R TX −2*R SW , wherein R TX  represents a typical transmission resistance value, while 2*R SW  represents the ON resistance value of switches  420 ,  422 . Power delivery node  442  couples to switch  410  through inductor L. Typical values for capacitor C may be 1 μF and inductor L may be 22 μH. 
         [0037]    Accordingly, the configurations of two sets of switches with different sizes of ON resistances and OFF capacitances enable multiple communication capabilities for the mobile device  400 . Further, the operation of switches  410 ,  412 ,  420 ,  422  may be based on the detected type of the connected device (e.g., headset/microphone  282 ). For example, switches  410 ,  420  are connected to ‘a’ output pins and switches  412 ,  422  are connected to ‘b’ output pins for one type of device (e.g., a device meeting the United States headset standard), while switches  410 ,  420  are connected to ‘b’ output pins and switches  412 ,  422  are connected to ‘a’ output pins for another type of device (e.g., a device meeting the European headset standard). Therefore, the polarity of each set of switches is reversed based one the detected type of the connected device to conform to various different standards. 
         [0038]    In an exemplary embodiment, inputs of the microphone switches  410 ,  420  can be optionally shorted together via a shorting connection  450  to combine data going to/from the RX/TX with power from the LDO. In a further embodiment, the switches  410 ,  412 ,  420 ,  422  can be integrated into a single codec chip in the mobile device  400 . 
         [0039]    Although several embodiments of the present disclosure are described above, many variations of the present disclosure are possible. For example, although the illustrated embodiments of the present disclosure show only two set of switches, additional sets of switches can be added to provide uninterrupted digital data communication between the mobile device and the auxiliary device in the presence of disturbing units such as ferrite beads (FBs). Further, features of the various embodiments may be combined in combinations that differ from those described above. Moreover, for clear and brief description, many descriptions of the systems and methods have been simplified. Many descriptions use terminology and structures of specific standards. However, the disclosed systems and methods are more broadly applicable. 
         [0040]    Those of skill will appreciate that the various illustrative blocks and modules described in connection with the embodiments disclosed herein can be implemented in various forms. Some blocks and modules have been described above generally in terms of their functionality. How such functionality is implemented depends upon the design constraints imposed on an overall system. Skilled persons can implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure. In addition, the grouping of functions within a module, block, or step is for ease of description. Specific functions or steps can be moved from one module or block without departing from the present disclosure. 
         [0041]    The various illustrative logical blocks, units, steps, components, and modules described in connection with the embodiments disclosed herein can be implemented or performed with a processor, such as a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor can be a microprocessor, but in the alternative, the processor can be any processor, controller, microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Further, circuits implementing the embodiments and functional blocks and modules described herein can be realized using various transistor types, logic families, and design methodologies. 
         [0042]    The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles described herein can be applied to other embodiments without departing from the spirit or scope of the present disclosure. Thus, it is to be understood that the description and drawings presented herein represent presently preferred embodiments of the present disclosure and are therefore representative of the subject matter which is broadly contemplated by the present disclosure. It is further understood that the scope of the present disclosure fully encompasses other embodiments that may become obvious to those skilled in the art and that the scope of the present disclosure is accordingly limited by nothing other than the appended claims.