Abstract:
A USB device for decreasing the current at load is provided. The USB device comprises a Client USB device, having a client functional module electronically connected to a client USB controller, connected to a Digital-USB bus and a client USB Physical Layer individually, wherein the client USB Physical Layer is further connected to a Standard-USB bus. Through this Standard-USB bus, the Client USB device is connected to a host USB Physical Layer of an external host. On the other hand, via the Digital-USB bus, the Client USB device is connected to an external host without host USB Physical Layer. Because both of the Client USB device and the external host have the option of using the Digital-USB bus, hence their Physical Layers being removed or idled.

Description:
REFERENCE TO RELATED APPLICATION  
       [0001]     This Application is a Continuation-in-Part of patent application Ser. No. 10/885,117, filed on 7 Jul. 2004, currently pending. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention is related to a USB device, and more particularly to a USB device for decreasing the operation current consumption.  
       BACKGROUND OF THE INVENTION  
       [0003]     As already known, that the USB (Universal Serial Bus) is a serial transmittal interface used on the information products. After been promoted for many years, it has become the representative of the interfaces among the information products. It could fast and easily connect up plural information products without the inconvenience of having to open the external cases of these products for adding connections. The USB provides consumers with an interface that has advantages of convenience, highly expandability and fast transmission speed. Therefore, it is widely used in the fields of computer peripherals, Information appliances (IA) and consumable electronic products.  
         [0004]     Referring to  FIG. 1  and  FIG. 1A , show a structural block diagram and a three-dimensional diagram of the prior art USB device. The prior art USA transmitting devices can be categorized into two types, the Host USB device ( 15 ) and the Client USB device ( 11 ). The two can be connected together by a Standard-USB bus, which acts as the data transmission line between the two devices. Wherein, the Client USB device ( 11 ) comprises a client functional module ( 111 ), such as memory media, which is electronically connected to a client USB controller ( 113 ) and that is further electronically connected to a Client USB Physical Layer ( 115 ). Furthermore, the Host USB device ( 15 ) comprises a CPU ( 151 ), which can be directly connected to a host USB controller ( 153 ) or electronically connected thereto by a local CPU bus ( 152 ), and the host USB controller ( 153 ) is further electronically joined to a host USB Physical Layer ( 155 ).  
         [0005]     Moreover, the Standard-USB bus ( 19 ) is a substantial transmission line, which is mainly comprised by a bus with 4-circuit lines namely VBUS ( 191 ), D+ ( 192 ), D− ( 193 ), and ground line ( 194 ). The D+ ( 192 ) and D− ( 193 ) are utilized for data transmission and the power source of VBUS ( 191 ) could be provided either from the Host USB device ( 15 ) or a power supply (not shown).  
         [0006]     Referring to  FIG. 1B  shows a diagram according to the signal classification when the signal is transmitted through the prior art USB structure. The transmission line of the host USB device ( 15 ) is usually through an application program ( 1511 ), a USB driver ( 1513 ), a host controller driver ( 1515 ), a host USB controller ( 153 ), and a host USB physical layer ( 155 ) in order, wherein the application program ( 1511 ), the USB driver ( 1513 ), the host controller driver ( 1515 ) are within the CPU ( 151 ) or the memory, and transacted according to digital signal. And, the digital signal form host USB controller ( 153 ) can be transformed to an analog signal by the USB physical layer ( 155 ) according to the digital/analog (D/A) transforming function of which.  
         [0007]     The analog signal transformed by the host USB physical layer ( 155 ) is transmitted to the client USB physical layer ( 115 ) within the client USB device ( 11 ) through the standard USB bus ( 19 ), wherein the client physical layer ( 115 ) is also with the D/A transforming function, such that the analog signal can be transformed to return to the digital signal. Furthermore, the digital signal is transmitted to the client functional module ( 111 ) by the client USB controller ( 113 ) through a transmission line.  
         [0008]     As well as, the data signal can be transmitted to the host USB device ( 15 ) from the client functional module ( 111 ) through the same path.  
         [0009]     According to the Differential Pair circuit design of the D+ ( 191 ) and D− ( 192 ), the digital transformation device must be practiced by both the client USB Physical Layer ( 115 ) and the host USB Physical Layer ( 155 ) for USB digital and analog signal transforming. Hence, either the client USB Physical Layer ( 115 ) or the host USB Physical Layer ( 155 ) have to have some essentially designed components such as PLL (Phase Lock Loop), Data/Clock Recovery and Transmission Terminations etc. However, these components consume at least 55 mA of operation current, which a relatively large amount. Due to the existence of the client USB Physical Layer ( 115 ) and the host USB Physical Layer ( 155 ), the design and the usage of the USB device are facing a fundamental problem, which is that each component has a operation current draining threshold limitation. Without it, the functions of the other operating components will be seriously influenced or even hindered. The above-mentioned design and usage limitation of the components is especially serious to those movable and low operating current USB transmission devices. The examples of those are the consumable electronic products and mobile devices. This limitation prohibits these devices from acting probably as the Host USB device and further increases the design difficulties of the USB devices, yet also brings serious inconvenience when using these USB devices.  
       SUMMARY OF THE INVENTION  
       [0010]     Therefore, the main emphasis of the present invention is to provide a new design of USB device, especially a USB device that could effectively reduce the operation current consumption, whereby facilitating on the design process and enhancing the usage convenience of products.  
         [0011]     It is the primary object of the present invention to provide a USB device for reducing the operation current. The problem of excessive power consumption on the USB device is caused by the existence of the USB Physical Layers and Standard-USB bus. This would be solved by means of replacing the USB Physical Layers and Standard-USB bus with a Digital-USB bus.  
         [0012]     It is another object of the present invention to provide a USB device for decreasing the current at load. The current consumption of the USB device can be effectively reduced by means of removing or idling the USB Physical Layers within, whereby the design and usage convenience could be greatly enhanced.  
         [0013]     It is still another object of the present invention to provide a USB device for decreasing the current at load for the purpose of expending its application field and product types.  
         [0014]     Thus, for achieving the above-mentioned goal, in a preferred embodiment of the present invention should consist of: a Host USB device comprising at least a CPU, which is electronically connected to a host USB controller; and a Client USB device comprising at least a client functional module, which is electronically connected to a client USB controller. The client USB controller can be further connected to either the CPU or the host USB controller by means of the Digital-USB bus.  
         [0015]     In another preferred embodiment of the present invention consists of: a Host USB device comprising a CPU, which is electronically connected to a host USB controller that is further electronically joined to a host USB Physical Layer; a Client USB device comprising a client functional module, which is electronically connected to a client USB controller that is further electronically joined to a Client USB Physical Layer; a Digital-USB bus with two-connecting-ends where one of the end is connected to the client USB controller and the other is either connected to the host USB controller or directly to the CPU; a Standard-USB bus that is used to join the host USB Physical Layer and the Client USB Physical Layer.  
         [0016]     Other and further features, advantages and benefits of the invention will become apparent in the following description taken in conjunction with the following drawings. It is to be understood that the foregoing general description and following detailed description are exemplary and explanatory but are not to be restrictive of the invention. The accompanying drawings are incorporated in and constitute a part of this application and, together with the description, serve to explain the principles of the invention in general terms. Like numerals refer to like parts throughout the disclosure.  
         [0017]     The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings, in which: 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0018]      FIG. 1  shows a structural diagram of a prior art USB device;  
         [0019]      FIG. 1A  shows a three-dimensional diagram of the prior art USB device;  
         [0020]      FIG. 1B  shows a diagram according to the signal classification when the signal is transmitted through the prior art USB structure;  
         [0021]      FIG. 2  shows a structural diagram of a preferred embodiment of the present invention;  
         [0022]      FIG. 2A  shows a three-dimensional diagram of the preferred embodiment of the present invention;  
         [0023]      FIG. 2B  shows a three-dimensional diagram of another preferred embodiment of the present invention;  
         [0024]      FIG. 2C  shows a three-dimensional diagram of another preferred embodiment of the present invention;  
         [0025]      FIG. 2D  shows a diagram according to the signal classification when the signal is transmitted through the present invention DigitalUSB structure;  
         [0026]      FIG. 3  shows another structural diagram of a preferred embodiment of the present invention;  
         [0027]      FIG. 3A  shows a three-dimensional diagram of another preferred embodiment of the present invention;  
         [0028]      FIG. 4  shows another structural diagram of a preferred embodiment of the present invention; and  
         [0029]      FIG. 5  shows a flow chart during the processing of the mode setting. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]     Referring to  FIG. 2  and  FIG. 2A , show a structural diagram and a three dimensional diagram of a preferred embodiment of the present invention. As shown in the diagram, the present invention can be applied to a Client USB device ( 21 ) or a Host USB device ( 25 ). The examples of such devices are: data storing device comprising at least one USB (e.g. external hard disk, DVD-ROM, CD-R, CD-RW, or MO etc.), computer peripherals (e.g. scanner, printer, mouse, keyboard or card-reader etc.), computer devices (e.g. Notebook PC, Desktop PC, or Table PC etc.), electronic keys, multi-media devices, photographing device (e.g. digital camera, digital video camera, or computer camera etc.), communication devices (e.g. mobile phones etc.), 3C consumable electronic devices (e.g. PDA etc.), IA information appliances, or I/O functional devices.  
         [0031]     Wherein, the Client USB device ( 21 ) comprises at least a client functional module ( 211 ), which possesses a special function and purpose, such as data storage module, according to the different designs of the USB device. The client functional module ( 211 ) can be electronically connected to a client USB controller ( 213 ) that is connected to a Host USB device ( 25 ) by means of a Digital-USB bus ( 29 ). The Digital-USB bus ( 29 ) can also be defined as a low-power digital transmission USB bus. Moreover, the Host USB device ( 25 ) (also called an external Host) comprises at least one CPU ( 251 ), which is electronically connected to a host USB controller ( 253 ) either directly or by means of a local CPU bus ( 252 ). The host USB controller ( 253 ) can similarly connected with the Client USB device ( 21 ) by means of the Digital-USB bus ( 29 ).  
         [0032]     Due to the usage of Standard-USB bus as the data transmitting circuit in the prior art USB device, there must exist a USB Physical Layer in both Host USB device and Client USB device. This situation up brings the disadvantage that the operation current is not able to get effectively reduced. However, when the USB device is put to use, the Standard USB is not always a necessity; for example, one can directly connect up the Host USB device and Client USB device as one way of making the Digital-USB bus ( 29 ).  
         [0033]     The Digital-USB bus ( 29 ) can be implemented by the USB bus (or called as the USB connecting head) joined with device directly, wherein the four terminals of the Digital USB bus ( 29 ) can be defined as a VBUS ( 291 ), a data transmission line ( 292 ), a synchronizing clock line ( 293 ), and a ground line ( 294 ), surely, the structure of which are the same with the prior art structure, furthermore, the definition of that can be alternated depending on different connecting devices and transmission signals. The joined line with the USB bus is similar with the internal line of the host USB device  25  or the client USB device  21 , which can be used to transmit digital data signal.  
         [0034]     Therefore, there will be no requirement of USB Physical Layers in either Host USB device or Client USB device, whereby the current consumption can be reduced. According to the experiments done on the present invention, the saved current could be well above 55 mA and therefore, it is quite suitable to use on general 3C consumable products or mobile devices.  
         [0035]     Furthermore, referring to  FIG. 2B , shows a three-dimensional diagram of another preferred embodiment of the present invention. The above-mentioned Digital-USB bus ( 29 ) can be also as a prior art USB transmission line, comprising at least one data transmission line ( 292 ), which could be set to transmit data or control signals synchronously or asynchronously, and thus it is compatible to general USB transmission protocol. Further, a synchronizing clock line ( 293 ) is also needed if the transmission desires to be practiced synchronously. The above-mentioned data transmission line ( 292 ) could be designed in a serial or parallel configuration. If the data transmission line ( 292 ) adopts the parallel configuration, wherein the data transmission line ( 292 ) comprises a plurality of terminals and transmission lines, as shown on  FIG. 2C , which respectively comprises 8, 12, and 20 terminals and transmission lines. Surely, the data transmission line ( 292 ) can be also possibly designed with a 4-bit, 8-bit or 16-bit mode. Therefore, the Digital-USB bus ( 29 ) in a preferred embodiment of the present invention is a Data/Clock transmission line ( 292 / 293 ).  
         [0036]     Of course, the means of Digital USB bus ( 29 ) also comprises four transmission lines, which are respectively as a data transmission line ( 292 ), a synchronizing clock line ( 293 ), a VBUS ( 291 ), and a ground line ( 294 ), wherein the power source of the VBUS ( 291 ) can be selected from the host USB device ( 25 ) or a power supply (not shown).  
         [0037]     Referring to  FIG. 2D , shows a diagram according to the signal classification when the signal is transmitted through the present invention USB structure. The USB transmission signal of the host USB device ( 25 ) can be transmitted through an application program ( 2511 ), a USB driver ( 2513 ), a host controller driver ( 2515 ), and a host USB controller ( 253 ) in order, wherein the application program ( 2511 ), the USB driver ( 2513 ), the host controller driver ( 2515 ) are within the CPU ( 251 ) or the memory, and transacted according to digital signal. The digital signal is transmitted to the host USB controller ( 253 ) through a transmission line, further transmitted to the client USB controller ( 213 ) within the client USB device ( 21 ) through the means of Digital USB bus ( 29 ), and finally transmitted to the client functional module ( 211 ).  
         [0038]     As well as, the data signal can be transmitted to the host USB device ( 25 ) from the client functional module ( 211 ) through the same path; surely, the whole transmission is processed by digital signal.  
         [0039]     In accordance with another embodiment of the present invention, the clock mode comprises three types: 
        Mode 0: 1-way, 400K˜30 MHz;     Mode 1: 2-way, 50 MHz+/−5%; and     Mode 2: 2-way, 60 MHz+/−5%;        
 
         [0043]     The data rate also comprises three types: 
        Mode 0: 1-bit Bus: 0.05˜3.75 MB/sec; 
            4-bit Bus: 0.2˜15 MB/sec; and     8-bit Bus: 0.4˜30 MB/sec;    
            Mode 1: 1-bit Bus: 6.25 MB/sec; 
            4-bit Bus: 25 MB/sec;     8-bit Bus: 50 MB/sec; and     16-bit Bus: 100 MB/sec;    
            Mode 2: 1-bit Bus: 7.5 MB/sec; 
            4-bit Bus: 30 MB/sec;     8-bit Bus: 60 MB/sec; and     16-bit Bus: 120 MB/sec.    
               
 
         [0055]      FIG. 3  and  FIG. 3A , show a structural diagram and three dimensional diagram of another preferred embodiment of the present invention. As shown in this diagram, the present invention separately sets a Client USB device ( 31 ) and a Host USB device ( 35 ) as a dual-mode structure.  
         [0056]     Wherein, besides the said client functional module ( 211 ) and the client USB controller ( 312 ) in the previously described preferred embodiment, the Client USB device ( 31 ) in this preferred embodiment further comprises a client USB Physical Layer ( 315 ), which is the same as in the prior art USB device. The client USB Physical Layer ( 315 ) could also be electronically connected to the client USB controller ( 312 ). In the Host USB device of this preferred embodiment consists of a CPU ( 251 ), a local CPU bus ( 252 ) and a host USB controller ( 253 ) that could be connected to the client USB controller ( 312 ) of the Client USB device ( 31 ) by the transmission line  353 , the means of Digital-USB bus ( 29 ), and the transmission line  3125 .  
         [0057]     Moreover, the Host USB device ( 35 ) further comprises a host USB Physical Layer ( 355 ) that could also be electronically connected to the host USB controller ( 253 ) and the client USB Physical Layer ( 315 ) of the Client USB device ( 31 ) by the means of Standard-USB bus ( 39 ). Therefore, in either Client USB device ( 31 ) or Host USB device ( 35 ), one could choose to proceed with a Digital-USB bus Mode through Digital-USB bus ( 29 ) or a Standard-USB bus Mode through Standard-USB bus ( 39 ) according to the practical needs. Thus, the dual-mode structure could be formed in either Client USB device ( 31 ) or Host USB device ( 35 ); this setting differs from the single mode design in the previously said preferred embodiment.  
         [0058]     Between the client USB controller ( 312 ) and the Digital-USB bus ( 29 ) is placed with a communicating tool, adjuster ( 314 ), or wrapper, which is used to facilitate data transmission. The client USB controller ( 312 ) could act the same function as prior art client USB controller ( 312 ) by adding the design of the adjuster ( 314 ). Nevertheless, the function of the adjuster ( 314 ) could also get executed right within the client USB controller ( 312 ). Therefore, the client USB controller ( 312 ) and the adjuster ( 314 ) could also get further integrated to form a client controller ( 313 ).  
         [0059]     Furthermore, by taking the practical circuits design into consideration, the Digital-USB bus ( 29 ) could have options in ways of connecting to the CPU ( 251 ). Firstly, it could be directly connected to the CPU ( 251 ) by means of a first connecting circuit ( 351 ). Secondly, it could be connected to CPU ( 251 ) through a second connecting circuit ( 352 ) and the local CPU bus ( 252 ). Thirdly, it could be connected to CPU ( 251 ) through a third connecting circuit ( 353 ) and the host USB controller ( 253 ).  
         [0060]      FIG. 4  shows another structural diagram of a preferred embodiment of the present invention. As shown is this diagram, a Client USB device ( 41 ) and a Host USB device ( 45 ) are both a dual-mode structure that has options of proceeding with Digital-USB bus Mode through the USB Physical Layer, or Standard-USB bus Mode through the USB Physical Layer. Hence, a client mode switch ( 43 ) could be placed to join the client controller ( 313 ) (adjuster ( 314 ) and client USB controller ( 312 )) of the Client USB device ( 41 ), the client USB Physical Layer ( 315 ), and a USB ( 49 ) for switching the modes of the Client USB device ( 41 ) between the Digital-USB bus Mode and the Standard-USB bus Mode. The function of the client mode switch ( 43 ) could also be designed within the client USB controller ( 312 ), such as shown as client auto-mode switch ( 435 ) in  FIG. 4 .  
         [0061]     The same principles could be applied to the Host USB device ( 45 ) to comprise a Host mode switch ( 47 ) or place a host auto-mode switch ( 475 ) within the host USB controller ( 253 ). Thus, the Host USB device ( 45 ) could be set either in a Digital-USB bus Mode or a Standard-USB bus Mode.  
         [0062]     When the Client USB device ( 41 ) and the Host USB device ( 45 ) are individually set to the Digital-USB bus Mode, or both was designed to be the Digital-USB bus Mode of a single mode design, the USB ( 49 ) would function as the Digital-USB bus. On the contrary, if the Client USB device ( 41 ) and the Host USB device ( 45 ) are individually set to the Standard-USB bus Mode, or both was designed to be the Standard-USB bus Mode of a single mode design, the USB ( 49 ) would then function as the Standard-USB bus.  
         [0063]     Furthermore, the client mode switch ( 43 ), client auto-mode switch ( 435 ), host mode switch ( 47 ) and the host auto-mode switch ( 475 ) all could be designed as a manual switch for mode setting. Users could manually switch the Client USB device ( 41 ) and the Host USB device ( 45 ) between the Digital-USB bus Mode and the Standard-USB bus Mode. In the same manner, the client mode switch ( 43 ), client auto-mode switch ( 435 ), host mode switch ( 47 ) and the host auto-mode switch ( 475 ) all could be designed as a electronic switch for mode setting. By using electronic detection to decide and switch Client USB device ( 41 ) and the Host USB device ( 45 ) between the Digital-USB bus Mode and the Standard-USB bus Mode.  
         [0064]     The above-mentioned Client USB device ( 31 ) could be comprises at least an interface (not shown), which selected from one of xD, memory stick, MSPro, CF card, SD, MMC, and Smart Media.  
         [0065]     Lastly,  FIG. 5  shows the follow diagram during the processing of the mode setting. As shown in  FIG. 5 , if the client mode switch ( 43 ), client auto-mode switch ( 435 ), host mode switch ( 47 ) and the host auto-mode switch ( 475 ) are mode switches of electronic nature, whereof the electronic detection mode could have the following steps:  
         [0066]     Step  601  
        Detect whether the Client USB device ( 41 ), the Host USB device ( 45 ) and the USB ( 49 ) are in a Digital-USB bus Mode? If they are positive, detection proceed to Step  612 . If negative, then proceed to Step  602 .        
 
         [0068]     Step  602  
        Because the detection did not receive a definite signal to indicate that the Client USB device ( 41 ) and the Host USB device ( 45 ) are indeed in their Digital-USB bus Mode. Therefore, it further detects whether the setting time has been reached. If it is positive, then Step  603  is executed. If it is negative, then return to Step  601  and keep waiting for an assured positive signal of Digital-USB bus Mode.        
 
         [0070]     Step  603  
        At this stage, it shows that the Client USB device ( 41 ), the Host USB device ( 45 ) and the USB ( 49 ) are not in a Digital-USB bus Mode. Therefore, the setting will be switched to the Standard-USB bus Mode for transmitting USB data.        
 
         [0072]     Step  612  
        The Client USB device ( 41 ), the Host USB device ( 45 ) and the USB ( 49 ) are in a Digital-USB bus Mode. Therefore the data transmitting procedure would be done in Digital-USB bus Mode.        
 
         [0074]     To sum up, it should be clear that the present invention is related to a USB device for decreasing the current at load consumption, whereby it brings benefits and convenience on the design and usage of products.  
         [0075]     Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have suggested in the foregoing description, and other will occur to those of ordinary skill in art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.