Patent Publication Number: US-2007103115-A1

Title: Function-switching type linking apparatus

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a function-switching type linking apparatus. In particular, this invention relates to a linking apparatus that can switch its functions between transmitting data and charging a battery.  
      2. Description of the Related Art  
      Portable information products, such as PDAs, MP3s, and digital recorders etc, make daily life more convenient and enjoyable for their users. A portable information product links with a computer system and exchanges data with the computer system via a data transmission line. The power required for the portable information product is supplied from batteries. Because the usage frequency of the portable information product is high and the usage time of the portable information product is long, rechargeable batteries are usually used as the power source.  
      Traditionally, a power source line is used for charging the rechargeable battery of the portable information product. One end of the power source line is connected with the portable information product, and the other end of the power source line has a transformer and is connected with the power source. If the user wishes to execute a data transmission operation and the charging electricity operation at the same time, the portable information product has to simultaneously connect with the data transmission line and the power source line. It is very inconvenient. Therefore, devices integrating the data transmission line and the power source line into one line have been developed. An example of this is a universal serial bus (USB) transmission line.  
      Because the USB transmission interface has a lot of merits, such as plug and play, hot plug, bi-direction transmission and a high transmission rate etc, and can support 127 devices at the same time, peripherals commonly adopt USB interfaces to link with computers. The USB interface is used for transmitting data and can provide DC up to 5 voltages. Therefore, it can transmit data and charge the portable information product at the same time. Please refer to  FIG. 1 . TW patent 479, 393 that discloses a “USB automatic charging device and an operating method thereof”. The charging device is used for charging the battery. The host system  1  is used for detecting whether or not the charging device  2  exists and providing the power source to the charging device  2  to charge the battery. The USB transmission line  3  is used for linking the host system  1  with the charging device  2  and utilizes an operation system  12  to support the USB operation. The charging controller  25  utilizes the maximum power provided from the host system  1  to be the power source to automatically charge the battery in the charger  22  via the USB interfaces  24  and  11 . The charging controller  25  charges the battery with the maximum power that meets the USB&#39;s specifications. The USB automatic charging device can transmit the data and charge the battery at the same time. Furthermore, the charging information can be displayed on the indicator  23  and the status window  131  of the display  13 .  
      The portable information product usually uses a rechargeable battery as the power source for the system. According to the characteristics of the rechargeable battery, the rechargeable battery is divided into a rechargeable battery with memory effect, such as a nickel-hydrogen battery or a nickel-cadmium battery, and a rechargeable battery without memory effect, such as a lithium battery. The drawback of the rechargeable battery with memory effect is that it needs to be discharged before the battery is charged. If the battery is charged without being discharged, the battery life is reduced. When the USB transmission line is used for transmitting data, it will execute the charging operation if the power in the rechargeable battery does not reach 100%. Therefore, the charging numbers of the rechargeable battery are too many. The life of the rechargeable battery will be shortened.  
     SUMMARY OF THE INVENTION  
      One particular aspect of the present invention is to provide a function-switching type linking apparatus. This invention can switch its function between transmitting data and charging the battery and extend the life of the rechargeable battery.  
      The function-switching type linking apparatus includes a USB linking interface, a control unit, a data transmission unit and a charging unit. The control unit is electrically connected with the USB linking interface. The data transmission unit and the charging unit are individually electrically connected with the control unit for providing a path for the data transmission and a path for charging. The USB linking interface receives an external signal. Based on the external signal the control unit and executes the data transmission operation via the data transmission unit and/or executes the charging operation via the charging unit.  
      For further understanding of the invention, reference is made to the following detailed description illustrating the embodiments and examples of the invention. The description is only for illustrating the invention and is not intended to be considered limiting of the scope of the claim. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The drawings included herein provide a further understanding of the invention. A brief introduction of the drawings is as follows:  
       FIG. 1  is a perspective view of a USB automatic charging device of the prior art;  
       FIG. 2  is a circuit diagram of the first embodiment of the present invention;  
       FIG. 3  is a block diagram of the first embodiment of the present invention; and  
       FIG. 4  is a circuit diagram of the second embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Please refer to  FIGS. 2 and 3 , show a circuit diagram and a block diagram of the function-switching type linking apparatus of the present invention. The function-switching type linking apparatus  10  is electrically connected with a first system  20 , and a second system  30 . The first system  20  is a device having an operation/operating system. The second system  30  is a portable information product that can execute a data transmission operation and a charging operation with the first system  20 , such as a PDA, an MP3 portable player, or a digital recorder, etc. The function-switching type linking apparatus  10  includes a USB linking interface  11 , a data transmission unit  12 , a charging unit  13 , and a control unit  14 . The USB linking interface  11  is electrically connected with the first system  20 . The data transmission unit  12  is a serial peripheral interface (SPI), and includes a connection port J 1 . The charging unit  13  has a connection port J 2 . The data transmission unit  12  and the charging unit  13  are individually electrically connected with the second system  30  via the connection port J 1  and the connection port J 2 . The control unit  14  is a control circuit, and makes the second system  30  accept the request of the data transmission operation or the charging operation from the first system  20  via the two transistors Q 1  and Q 2 . The control unit  14  is electrically connected with the USB linking interface  11 , the data transmission unit  12 , and the charging unit  13 . The control unit  14  has a connection port J 3  and is electrically connected with the second system  30  via the connection port J 3 .  
      The linking method between the data transmission unit  12  and the USB linking interface  11  is implemented by electrically connecting the SPI interface with the USB interface. The two data transmission pins MISO and MOSI of the SPI interface are individually electrically connected with the two data transmission pins D− and D+ of the USB interface. The clock pin CLK of the SPI interface is electrically connected with the VUSB pin of the USB interface. The chip selection pin CSB of the SPI interface is electrically connected with the N pin of the USB interface.  
      When the data transmission operation is executed, the first system  20  sends an external (control) signal to the USB linking interface  11 . The external signal is a high-level signal. The high-level signal is outputted to the control unit  14  via the N pin of the USB linking interface  11 . The control unit  14  uses the transistor Q 2  to judge the high-level signal to make the Download-EN pin of the second system  30  turn on. Therefore, the second system  30  accepts the request of the data transmission. Furthermore, the high-level signal enables the SPI function via the chip selection pin CSB to make the first system  20  transmit the external data signals to the second system  30  via the data transmission unit  12  or receive the external data signals from the second system  30  via the data transmission unit  12 . Thereby, the data is exchanged.  
      When the charging operation is executed, the first system  20  sends another external (control) signal to the USB linking interface  11 . The other external signal is a low-level signal. The low-level signal is outputted to the control unit  14  via the N pin of the USB linking interface  11 . The control unit  14  uses the transistor Q 1  to judge the low-level signal to make the Charge-EN pin of the second system  30  turn on. Therefore, the second system  30  accepts the request for the charging operation. The first system  20  transmits the power to the rechargeable battery of the second system  30  to charge the battery via the charging unit  13 .  
      The first system  20  determines whether to execute the data transmission operation or the charging operation to the second system  30 . If the data transmission operation is executed, the first system  20  checks whether the data in the second system  30  has been updated or not. If the data in the second system  30  is not the latest data, the data updating process is automatically executed. If the charging operation is executed, the first system  20  checks whether the power in the rechargeable battery of the second system  30  is lower than a predetermined value or not. If the power in the rechargeable battery is lower than the predetermined value, the charging operation is executed. If the power in the rechargeable battery is not lower than the predetermined value and still wishes to execute the charging operation, the first system  20  can forcibly charge the second system  30 . Furthermore, each of the connection ports J 1 , J 2  and J 3  of the data transmission unit  12 , the charging unit  13 , and the control unit  14  may be independent ports, or may be integrated into a single port, which is then electrically connected with the second system  30 .  
      Please refer to  FIG. 4 , which shows a circuit diagram of the second embodiment of the present invention. The function-switching type linking apparatus  10  includes a USB linking interface  11 , a data transmission unit  12 , a charging unit  13 , and a control unit  14 . The pins N, D+, D−, and VUSB of the USB linking interface  11  are individually connected with the pins CSB, MOSI, MISO, and CLK of the data transmission unit  12  via two integrated circuits (IC) U 1  and U 2  in the control unit  14 . The pin VUSB is connected with the data transmission unit  12  via the control unit  14 , and also is connected with the charging unit  13 .  
      The function-switching type linking apparatus  10  is connected with a device having an operation/operating system (such as a computer host, not shown in the figure) via the USB linking interface  11  for receiving the signal from the device having an operation system. The function-switching type linking apparatus  10  is connected with a portable information product (such as a PDA, an MP3 portable player, or a digital recorder, etc.) via a connection port J 2  of the charging unit  13  and a connection port J 1  of the control unit  14  for executing the data transmission operation or the charging operation. When the control unit  14  receives the signal transmitted from the USB linking interface  11 , the ICs U 1  and U 2  in the control unit  14  analyzes and judges the signal to execute the data transmission operation and/or the charging operation to the portable information product linked by the function-switching type linking apparatus  10  via the data transmission unit  12  and the charging unit  13 .  
      The description above only illustrates specific embodiments and examples of the invention. The invention should therefore cover various modifications and variations made to the herein-described structure and operations of the invention, provided they fall within the scope of the invention as defined in the following appended claims.