Abstract:
Portable ultrasound systems and associated devices and methods for managing power in such systems are disclosed herein. In one embodiment, a method for conserving power in a portable ultrasound system includes disabling one or more first amplifiers and/or at least one or more first analog to digital converters (ADCs) upon initiation of a first pulse repletion interval (PRI). The method further includes, upon initiation of a second PRI, enabling the one or more first amplifiers and/or the one or more of the first ADCs and disabling one or more second amplifiers of and/or one or more second ADCs.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of U.S. Patent Provisional Application Ser. No. 61/858,052, filed on Jul. 24, 2013 and entitled “PORTABLE ULTRASOUND SYSTEMS WITH FINE-GRAINED POWER MANAGEMENT ASSOCIATED DEVICES, SYSTEMS, AND METHODS”, which is hereby incorporated herein in its entirety by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The disclosed technology is related to medical imaging systems, and, in particular, some embodiments are related to portable ultrasound devices and power management in such devices. 
       BACKGROUND 
       [0003]    Portable ultrasound imaging devices are used by anesthesiologists, emergency and critical care personnel, and other medical professionals. A portable ultrasound device can include a clamshell-type base unit having a handle for carrying the base unit. The base unit can fold open to a display and a keypad, and a user can connect an ultrasound transducer wand to the base unit to acquire and view ultrasound images on the display. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a partially schematic, isometric diagram of an ultrasound system configured in accordance with an embodiment of the present technology. 
           [0005]      FIG. 2A  is a block diagram of transducer electronics of the ultrasound system of  FIG. 1  configured in accordance with an embodiment of the present technology. 
           [0006]      FIG. 2B  is a block diagram of a switch controller configured in accordance with an embodiment of the present technology. 
           [0007]      FIG. 3  is a flow diagram illustrating a routine for operating the transducer electronics of  FIG. 2A  in accordance with an embodiment of the present technology. 
           [0008]      FIGS. 4A and 4B  are signal line diagrams representing the power consumed by amplifiers and/or analog to digital converters during execution of the routine of  FIG. 3  in accordance with an embodiment of the present technology. 
           [0009]      FIGS. 5A-7B  are signal line diagrams representing the power consumed by amplifiers and/or analog to digital converters during execution of the routine of  FIG. 3  over various duty cycles in accordance with selected embodiments of the present technology. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    Various embodiments of portable ultrasound devices and power management techniques and associated devices, systems, and methods are described below. A person skilled in the relevant art, however, will understand that the technology may have additional embodiments, and that the technology may be practiced without several of the details of the embodiments described below with reference to  FIGS. 1-7B . 
         [0011]    Ultrasound devices include a variety of electronic components configured, for example, to generate and receive acoustic signals, process and store data, and display images. In a portable ultrasound device, each of the electronic components draws power from the battery based on its individual power requirements. Transducer-related circuitry, in particular, draws a significant amount of power. This circuitry can include, for example, waveform generators, transducer arrays, amplifiers, and analog to digital converters (ADCs). Of these components, the amplifiers and the ADCs draw a large portion of the power. In some instances, an ultrasound device can temporarily disable (e.g., remove power, shut down, etc.) certain components to conserve power when not in an imaging mode. However, many of the components are difficult to disable. In particular, amplifiers and ADCs require a significant amount of time to power-on and power-off. As such, it is not possible to power down these components to conserve power without sacrificing device performance, such as system speed. Embodiments of the present technology, however, address these and other limitations of conventional portable ultrasound devices. 
         [0012]      FIG. 1  is a block diagram of a portable ultrasound system  100  configured in accordance with an embodiment of the present technology. The ultrasound system  100  includes a transducer wand  102 , a display unit  103 , and a signal line  105  (e.g., a permanent or removable signal wire) operably coupling the transducer wand  102  with the display unit  103 . The transducer wand  102  includes an enclosure  106 , transducer electronics  108  at least partially contained by the enclosure  106 , and at least one input device  109  (e.g., a button, trigger, etc.) at the enclosure  106  and operably coupled to the transducer electronics  108 . As described in greater detail below, the transducer electronics  108  are configured to generate and receive acoustic signals, transmit and receive data, and/or otherwise process acoustic, digital, and analog signals. In one embodiment, the input device  109  is configured to toggle the ultrasound system  100  between an imaging mode and a scan mode. For example, the input device  109  can provide a user with a convenient way to toggle between modes without having to directly operate the display unit  103 . In another embodiment, however, the input device  109  can be omitted. Although not shown for purposes of clarity, the transducer wand  102  can include other features. For example, the enclosure  106  can have a variety of shapes, sizes, and configurations (e.g., ergonomic configurations) depending on the application or other considerations. 
         [0013]    The display unit  103  can include a touch-screen display  110 , a housing  112 , display unit (processor) electronics  113  (shown schematically) at least partially contained by the housing  112 , and at least one I/O port  115  (e.g., for communication with the transducer electronics  108  via the signal line  105 ). The touch-screen display  110  is configured to receive user-input and to present or display information, such as an image, a web-browser, an application interface, etc. In certain embodiments, the housing  112  can include controls (not shown), such as buttons, switches, or knobs in addition to or in lieu of the touch-screen display. The display unit electronics  113  can include a programmable processor (not shown) and system components (also not shown) configured to control and/or communicate with the transducer wand  102 , the touch-screen display  110 , and the I/O port  115 . In certain embodiments, the display unit electronics  113  can also carry out other functions, such as storing and accessing data, processing user-input, and communicating over a wireless interface via an internal radio antenna (not shown) or an external radio antenna  116 . Because many of the basic structures and functions of processor electronics are known, they have not been shown or described in further detail to avoid unnecessarily obscuring the described embodiments. 
         [0014]      FIG. 2A  is a block diagram of the transducer electronics  108  configured in accordance with an embodiment of the present technology. As shown, the transducer electronics  108  include a transducer array  220  having transducer elements  222  (e.g., 64, 128, or 256 transducer elements; shown schematically), waveform generators  223 , amplifiers  224   a,  and ADCs  224   b.  In one embodiment, the amplifiers  224   a  and the ADCs  224   b  are colocated on the same chip (e.g., application specific integrated circuit (ASIC)) with each other and/or with other circuit components of the transducer electronics  108 . In another embodiment, the amplifiers  224   a  and the ADCs  224   b  can be formed on separate chips or across multiple chips. As used herein, the term “amplifiers/ADCs” refers to at least one amplifier, at least one ADC, or a combination of at least one amplifier and at least one ADC. 
         [0015]    In the illustrated embodiment, the transducer electronics  108  further include a controller  225 , communication components  226  (for, e.g., communicating over the signal line  105 ), a communication bus  228 , and channels  229  (shown as a first through third sets of channels  229   a - 229   c ). As described in greater detail below, a switch controller (e.g., addressable switches, multiplexers, etc.) can couple individual transducer elements  222  with individual amplifiers  224   a  and/or individual ADCs  224   b.  In general, only certain aspects of the transducer electronics  108  are described in detail for purposes of illustration. For example, in various embodiments, the transducer electronics  108  can include a memory for storing processing instructions and data, a clock circuit, a power supply circuit, etc. Other components of the transducer electronics  108  are not described to avoid unnecessarily obscuring the various embodiments of the present technology. 
         [0016]    In operation, the transducer electronics  108  communicate with the display unit electronics  113  ( FIG. 1 ) over the signal line  105  and provides “frames” of digital ultrasound information to the display unit electronics  113  to produce and display ultrasound images. The controller  225  gathers these frames by collecting digital data over multiple pulse repetition intervals (PRIs). Over each PRI, the controller uses a transmit signal T 1  to control the transducer array  220  (via the waveform generators  223 ) and a return signal R 1  to produce ultrasound information. The transmit signal T 1  is based, for example, on forward beam forming and steering signals. The return signal R 1  can include acoustic information captured by the transducer array  223  (i.e., captured in response to ultrasonic echos). The controller  225  uses the amplifiers  224   a  and the ADCs  224   b  to amplify the return signal R 1  and then convert this signal into digital data (e.g., serial data). As digital data is collected for the frame, the controller  225  can carry out additional PRIs (i.e., involving different transmit and receive signals T 1  and R 1 ). The controller  225  produces the frames at a certain frame rate (FR) that can be based, for example, on Equation 1: 
         [0000]        FR =( n× PRI DUR ) −1 (Hz)  (1)
 
         [0000]    where RPI DUR  is the duration of a PRI. In one embodiment, the FR can be in the range of about 20 to 30 Hz. 
         [0017]    As discussed above, amplifiers and ADCs can consume a substantial amount of power. Typically, conventional ultrasound systems collectively enable or disable every amplifier and ADC at the same time, even when not every amplifier and ADC is producing relevant information. For example, only a portion of the amplifiers and ADCs may be needed for suitable beam forming at a given time. As such, conventional systems can waste a substantial amount of power by operating these amplifiers and ADCs when they are not needed. In accordance with various embodiments of the present technology, however, the controller  225  can selectively enable and disable individual amplifiers and ADCs to conserve power. In particular, the controller  225  can disable those amplifiers and ADCs that are not gathering relevant information. At one PRI, the controller  225  can disable individual amplifiers  224   a  and individual ADCs  224   b.  At the next PRI, the controller  225  can enable some of the previously disabled amplifiers and ADCs, while disabling other amplifiers and ADCs. In some embodiments, rather than disabling and enabling amplifiers/ADCs over the entire PRI, the controller  225  can enable and disable amplifiers/ADCs over a portion of the PRI. For example, the controller enable  225  can disable amplifiers/ADCs for half of the PRI and then enable those amplifiers/ADCs for the remaining half of the PRI. 
         [0018]      FIG. 2B  is a block diagram of a switch controller  240  configured in accordance with an embodiment of the present technology. The transducer electronics  108  can incorporate the switch controller  240  at a variety of locations, such as at an amplifier circuit, ADC circuit, and/or another suitable component. The switch controller  240  is operably coupled to individual amplifiers  224   a  and/or individual ADCs  224   b  (not shown in  FIG. 2B ). As shown, the switch controller  240  include switches  242  (e.g., logic gates) and power delivery circuitry  243 . In operation, the switch controller  240  is arranged to receive switch instructions that direct the switches  242  to connect a level of power P 1  (based, e.g., on a supply voltage) to particular amplifiers  224   a  and/or particular ADCs  224   b.  In the illustrated embodiment, the switch instructions are stored at one or more registers  245  that can be loaded, for example, by the controller  225  ( FIG. 2A ). In one embodiment, the registers  245  are located on the same chip as the amplifiers  224   a  and/or the ADCs  224   b.    
         [0019]    In various embodiments, the power delivery circuitry  243  can include capacitors, driver circuits, and other components for delivering an appropriate level of power to the amplifiers  224   a  and/or ADCs  224   b.  In one embodiment described in greater detail below, the power delivery circuitry  243  can deliver a minimum level of power to individual amplifiers  224   a  and/or individual ADCs  224   b  to maintain a minimum power level to those amplifiers  224   a  and/or ADCs  224   b  that are not enabled during a given frame. In an additional or alternate embodiment, the power delivery circuitry  243  can ramp up or ramp down power delivered to individual amplifiers  224   a  and/or individual ADCs  224   b  as they are respectively enabled and/or disabled. 
         [0020]      FIG. 3  is a flow diagram illustrating a routine  330  for operating the transducer electronics  208  ( FIG. 2A ) in accordance with an embodiment of the present technology. In one aspect of this embodiment, the routine  330  can be carried out by the controller  225  ( FIG. 2A ). In other embodiments, however, various aspects of the routine  330  can be carried out without the controller  225 . For example, in some embodiments, amplifiers/ADCs can self-regulate power. In these embodiments, the amplifiers/ADCs can include on-chip memory and related logic for carrying out processing instructions, algorithms, etc. 
         [0021]    The routine  330  starts when the controller  225  is instructed to begin ultrasound imaging. For example, the routine  330  can begin when a user actuates the input device  109  ( FIG. 1 ) on the transducer wand  102  ( FIG. 1 ). After the start block, the routine proceeds to block  331  to determine which amplifiers/ADCs are to be enabled or disabled over a given PRI. In one embodiment, the routine  330  can make this determination based on instructions from the display unit electronics  113  ( FIG. 1 ). In another embodiment, the routine  330  makes this determination independent of the display unit electronics  113  (based, e.g., on the acquisition geometry). For example, the controller  225  and/or the amplifiers/ADCs themselves can make this determination. In addition, in some embodiments, the routine  330  can dynamically determine which amplifiers/ADCs to enable or disable. For example, the routine  330  can make this determination after completing a PRI, but before completing a frame. 
         [0022]    As discussed above, the routine  330  can enable or disable amplifiers/ADCs based on whether particular amplifiers/ADCs are necessary for signal processing, such as whether the particular amplifiers and/or ADCs are necessary for beam forming. In some embodiments, the routine  330  can enable and disable amplifiers/ADCs based on the particular scanning mode or application. The routine  330 , for example, can conserve power by operating fewer amplifiers/ADCs in low-resolution, low-depth, or large-aperture (i.e., small F number) scan modes. In another mode, such as in a high-resolution, high-depth, or small-aperture scans, the routine  330  can enable additional amplifiers/ADCs. 
         [0023]    In the illustrated embodiment, the routine  330  can determine which amplifiers/ADCs to enable and disable before carrying out a particular frame and/or PRI. For example, the routine can make this determination based on the switching instructions stored at the registers  245 . As described in greater detail below, the switching instructions can include logic and/or algorithms for enabling individual amplifiers  224   a  and/or individual ADCs  224   b  of the various channels  229  of the transducer electronics  108 . Once this determination is made, the routine  330  can proceed to block  332  to begin or initiate a frame. As discussed above, a frame can include digital data acquired over multiple PRIs. The routine  330  can transmit these frames to the display unit electronics  113  ( FIG. 1 ) at various times during the execution of the routine  330  for further processing and eventual display. 
         [0024]    After initiating the frame, the routine  330  continues to block  333  to initiate a PRI and then continues to block  334  to enable and disable amplifiers/ADCs. At block  333 , the routine  330  can, e.g., connect array elements and amplifiers/ADCs over certain channels, generate a transmit signal, and process a return signal. At block  334 , the routine  330  enables and disables amplifiers/ADCs based on its determination at block  331 . In one aspect of this embodiment, the routine  330  enables amplifiers/ADCs by connecting power or increasing power and it disables certain amplifiers/ADCs by disconnecting power or reducing power (e.g., via the power delivery circuitry  243 ;  FIG. 2B ). In some embodiments, the routine  330  disables amplifiers/ADCs for an entire PRI (described further with reference to  FIGS. 4A-4B ). In additional or alternate embodiments, the routine  330  disables amplifiers/ADCs over a portion of the PRI (described further with reference to  FIGS. 5A-7B ). 
         [0025]    Once the PRI is complete, the routine  330  proceeds to decision block  335  to determine whether the frame is complete. If the frame is not complete, the routine  330  returns to block  333  to carry out another PRI. If, however, the frame is complete, the routine  330  proceeds to decision block  336  to determine whether to produce additional frames. If more frames are to be produced, the routine  330  proceeds to block  332  to begin another frame; otherwise, the routine  330  can terminate. 
         [0026]      FIGS. 4A and 4B  are signal line diagrams representing the power consumed by amplifiers/ADCs over a PRI for certain channels (e.g., the channel  219   c  in  FIG. 2A ) in accordance with an embodiment of the present technology. In one embodiment,  FIGS. 4A and 4B  represent the power consumed while the routine  330  ( FIG. 3 ) is executing blocks  333  and  334  ( FIG. 3 ). The power level “high” generally represents power consumed when amplifiers/ADCs are enabled for a given channel, and the power level “low” generally represents power consumed when amplifiers/ADCs are disabled for a given channel. In the illustrated embodiments, and for purposes of clarity, the signal lines diagrams only show five channels (“channel 1”-“channel 5”). 
         [0027]    Referring first to  FIG. 4A , over a first PRI, the routine  330  enables the amplifiers/ADCs of channels 1, 3, and 5 and disables the amplifiers/ADCs of channels 2 and 4. The routine  330 , thus, conserves power that would otherwise be consumed by those amplifier/ADCs not required during the first PRI. In  FIG. 4B , over a second PRI occurring after the first PRI, the routine  330  disables the amplifiers/ADCs of channels 1 and 5, enables the amplifiers/ADCs of channels2 and 4, and continues to enable the amplifiers/ADCs of channel 3. Again, the routine  330  conserves power by only powering those amplifiers/ADCs that are needed during the second PRI. After completing the second PRI, the routine  330  can continue to enable and disable amplifiers/ADCs for power conservation over a given PRI. 
         [0028]      FIGS. 5A-7B  are signal line diagrams representing the power consumed by amplifiers/ADCs over the first and second PRIs ( FIGS. 4A and 4B ) over various duty cycles of certain channels in accordance with selected embodiments of the present technology. 
         [0029]    In the illustrated embodiments, the routine  330  can enable or disable the amplifiers/ADCs for quantized time units Δt q . In some embodiments, the time units Δt q  can facilitate signal processing. For example, a binary number can represent the duty cycle in increments of the time units Δt q . In one aspect of this embodiment, the duration of the PRI can be represented in a number of time units based, for example, on Equation 2: 
         [0000]    
       
         
           
             
               
                 
                   
                     P 
                      
                     
                         
                     
                      
                     R 
                      
                     
                         
                     
                      
                     
                       I 
                       DUR 
                     
                   
                   = 
                   
                     
                       ∑ 
                       
                         q 
                         = 
                         0 
                       
                       k 
                     
                      
                     
                       Δ 
                        
                       
                           
                       
                        
                       
                         t 
                         q 
                       
                     
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
     
         [0000]    In some embodiments, the duty cycle can account for signal processing delays, such as line overhead delays, transmit delays, etc. For example, as shown in the illustrated embodiments, the various duty cycles account for a line overhead having a duration of 5 Δt q . In addition, in certain embodiments, the amplifiers/ADCs can process signals relating to the duty cycle. For example, the amplifiers  224   a  and/or the ADCs  224   b  ( FIG. 2A ) can use the logic to process a binary input or other suitable signal that represents the duty cycle. 
         [0030]    Referring to  FIGS. 5A-5B , the routine  330  enables and disables the amplifiers/ADCs of channels 1-5 according to different duty cycles. Over the first PRI ( FIG. 5A ), the routine  330  disables channels 2 and 4 for the duration of the first PRI. Over channels 1, 3, and 5, however, the routine  330  enables and disables the amplifiers/ADCs according to a different duty cycles. In particular, at channel 1, the routine  330  enables amplifiers/ADCs after 8 Δt q  have elapsed and then disables the amplifiers/ADC after 16 Δt q  have elapsed. At channel 3, the routine  330  enables the amplifiers/ADCs after 7 Δt q  have elapsed and then disables the amplifiers/ADCs after 17 Δt q  have elapsed. At channel 5, the routine  330  enables the amplifiers/ADCs after 11 Δt q  have elapsed and does not disable the amplifiers/ADCs for the remainder of the first PRI. 
         [0031]    Over the second PRI ( FIG. 5B ), the routine  330  disables channels 1 and 5 for the duration of the second PRI. Over channels 2, 3, and 5, however, the routine  330  enables the amplifiers/ADCs at different increments of the time units Δt q  (at 8 Δt q  for channel 2, at 12 Δt q  for channel 3, and at 5 Δt q  for channel 4). After they have been enabled for a certain number of increments, the routine  330  disables the amplifiers/ADCs of the channels 2, 3, 5 (at 16 Δt q  for channel 2, at 8 Δt q  for channel 3, and at 14 Δt q  for channel 4). 
         [0032]    Referring to  FIGS. 6A-6B , and similar to  FIGS. 5A-5B , the routine  330  enables and disables the amplifiers/ADCs of channels 1-5 according to different duty cycles. However, the routine  330  only changes the state of the amplifiers/ADCs a single time over a PRI (i.e., from enabled to disabled or from disabled to enabled). Over the first PRI ( FIG. 6A ), the routine  330  enables and disables the same amplifiers/ADCs as shown in  FIG. 5A . However, the routine  330  does not disable the channels 1, 3, 5 after they have been enabled. Similarly, over the second PRI ( FIG. 6B ), the routine  330  enables and disables the same amplifiers/ADCs as shown in  FIG. 5B , but does not disable channels 2, 3, and 4 after they have been enabled.  FIG. 6B  also shows the routine  330  accounting for the line overhead in the duty cycle. In particular, the routine  330  does not disable the channels 1 and 5 until 5 Δt q  have elapsed. 
         [0033]    Referring to  FIGS. 7A-7B , and similar to  FIGS. 6A-6B , the routine  330  enables and disables the amplifiers/ADCs of channels 1-5 according to different duty cycles. However, the amplifiers/ADCs operate at different power levels. Over the first PRI ( FIG. 7A ), the routine  330  enables and disables the same amplifiers/ADCs as shown in  FIG. 6A , but maintains the amplifier/ADCs of channels 1, 3, and 5 at a second power level (e.g., a standby power level) before enabling them. For those channels not being enabled (i.e., channels 2 and 4), the routine  330 , maintains the amplifiers/ADCs at a first power level (e.g., zero power level). In some embodiments, the routine  330  can use multiple power levels to facilitate switching speed. For example, the routine  330  can hold the amplifiers/ADCs at the second power level to charge capacitors and/or initialize other components to reduce signal delay. On the other hand, the routine  330  can hold the other (disabled) amplifiers/ADCs at the first power level to conserve additional power. In certain embodiments, the routine  330  can also account for ramp-up times (shown as a ramp  750  in the signal lines) in the duty cycle. Similarly, over the second PRI ( FIG. 7B ), the routine  330  can enable and disables the amplifiers/ADCs over the second PRI, but with more than two power levels. In certain embodiments, the power delivery circuitry  243  ( FIG. 2B ) can be configured to deliver multiple power levels. 
         [0034]    The processes and logic flows described in this specification can be performed by one or more programmable processors executing one or more computer programs to perform actions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). 
         [0035]    Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for performing actions in accordance with instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. However, a computer need not have such devices. Moreover, a computer can be embedded in another device, e.g., a mobile telephone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a Global Positioning System (GPS) receiver, or a portable storage device (e.g., a universal serial bus (USB) flash drive), to name just a few. Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry. 
         [0036]    From the foregoing, it will be appreciated that specific embodiments of the disclosure have been described herein for purposes of illustration, but that various modifications may be made without deviating from the disclosure. For example, the various waveforms shown in the Figures can have different slopes, magnitudes, shapes, etc. In addition, certain aspects of the disclosure described in the context of particular embodiments may be combined or eliminated in other embodiments. Further, while advantages associated with certain embodiments have been described in the context of those embodiments, other embodiments may also exhibit such advantages. Not all embodiments need necessarily exhibit such advantages to fall within the scope of the present disclosure. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.