Patent Publication Number: US-9887472-B2

Title: Multimedia interface connector and electronic device having the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Korean Patent Application No. 10-2015-0149185, filed on Oct. 27, 2015 the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field 
     Apparatuses and methods consistent with the exemplary embodiments relate to a multimedia interface connector and electronic device having the same. 
     2. Discussion of Related Art 
     High Definition Multimedia Interface (HDMI) is one of uncompressed digital video and audio interface standards, providing an interface between multimedia sources, such as set-top boxes, digital versatile disc (DVD) players, etc., and multimedia target devices, such as audio video (AV) devices, monitors, digital televisions, etc. 
     The HDMI may send images, sounds, or control signals via a single cable. Such an HDMI link includes a plurality of transition minimized differential signaling (TMDS) data channels and a single TMDS clock channel. 
     The TMDS clock channel works continuously at a speed proportional to the pixel rate of transmitted videos. During every cycle of the TMDS clock channel, three TMDS data channels each send a 10-bit character. The 10-bit character is encoded using one of many encoding technologies. 
     An HDMI clock signal varies depending on the resolution up to 297 MHz at a resolution of 4K×2K. 
     Since the HDMI does not employ any Electro Magnetic Interference (EMI) reduction technology for the clock, it may suffer from noise that violates the Electro Magnetic Compatibility (EMC) radiation standard, thereby failing to satisfy the EMI criteria. 
     For example, resonance characteristics appear at a frequency of 891 MHz resulting from ×3 multiplication of a pixel frequency of 297 MHz, and thus radiated EMI data that exceeds a reference value of 37 dB (uV/m) may be generated. 
     The reason has been found that the radiation has occurred by the HDMI clock (CLK) among the lines connected to the HDMI connector. 
     SUMMARY 
     Exemplary embodiments provide a multimedia interface connector and electronic device having the same, which reduces overall electromagnetic interference (EMI) as well as components radiated from a clock line by additionally arranging an auxiliary ground. 
     In accordance with an aspect of an exemplary embodiment, there is provided a multimedia interface connector including: a connection terminal combined with a printed circuit board (PCB); a main ground formed to cover one side of the connection terminal while leaving it opened in a first direction; and an auxiliary ground arranged between the main ground and the PCB to form a return path for a signal received through the connection terminal, wherein the other end of the connection terminal and the main ground are combined with the PCB. 
     The connection terminal may include multiple clock terminals, and the auxiliary ground may be arranged to be adjacent to the clock terminal. 
     The main ground may be formed to cover the one side of the connection terminal at a distance. 
     The multimedia interface connector may further include: a terminal holder for fixing the connection terminal at a particular position a predetermined distance away from the main ground. 
     The terminal holder may be made of an insulating material. 
     In accordance with another aspect of the present disclosure, a multimedia interface connector includes: multiple groups of connection terminals combined with a printed circuit board (PCB); a plurality of main grounds formed to cover one sides of the respective groups of connection terminals while leaving them opened in a first direction; and a first auxiliary ground arranged to connect the plurality of main grounds, wherein the main grounds are combined with the PCB. 
     The plurality of main grounds may be located to be separated from one another, and the first auxiliary ground may be formed to connect one sides of the plurality of main grounds located to be separated from one another. 
     The multimedia interface connector may further include: a plurality of second auxiliary grounds arranged between the respective main grounds and the PCB to form a return path for a signal received through the connection terminals. 
     The plurality of main grounds may be each formed to cover one side of the connection terminal at a distance. 
     The multimedia interface connector may further include: a terminal holder for fixing the connection terminal at a particular position a predetermined distance away from the main ground. 
     A number of terminal holders may be arranged to correspond to the number of the plurality of main grounds. 
     The terminal holder may be made of an insulating material. 
     In accordance an aspect of an exemplary embodiment, there is provided an electronic device includes: a semiconductor device; a printed circuit board (PCB) having the semiconductor device mounted thereon; and a multimedia interface connector coupled with a source device for receiving a multimedia execution signal transmitted from the source device, wherein the multimedia interface connector comprises a connection terminal combined with the PCB; a main ground formed to cover one side of the connection terminal while leaving it opened in a first direction; and an auxiliary ground combined with the main ground. 
     The auxiliary ground may be arranged between the main ground and the PCB to form a return path for a signal received through the connection terminal. 
     The connection terminal may include multiple clock terminals, and the auxiliary ground may be arranged to be adjacent to the clock terminal. 
     If there are a plurality of main grounds, the auxiliary ground may be arranged to connect the plurality of main grounds. 
     The plurality of main grounds may be located to be separated from one another, and the auxiliary ground may be formed to connect one sides of the plurality of main grounds located to be separated from one another. 
     If there are a plurality of main grounds, the auxiliary ground may include a first auxiliary ground arranged to connect the plurality of main grounds; and a plurality of second auxiliary grounds arranged between the respective main grounds and the PCB to form a return path for a signal received through the connection terminals. 
     The multimedia interface connector may include a terminal holder for fixing the connection terminal at a particular position a predetermined distance away from the main ground. 
     The multimedia interface connector may include a High Definition Multimedia Interface (HDMI) connector. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and/or other aspects will become more apparent by describing in detail exemplary embodiments with reference to the accompanying drawings, in which: 
         FIG. 1  shows connections between source and electronic devices; 
         FIG. 2  shows a multimedia interface connector mounted on an electronic device; 
         FIG. 3  is a control block diagram illustrating operation between an electronic device and a source device; 
         FIGS. 4 and 5  show a multimedia interface connector, according to an exemplary embodiment; 
         FIG. 6  shows transmission and return paths between an electronic device and a source device; 
         FIG. 7  shows an electronic device having a multimedia interface connector applied thereto; 
         FIGS. 8 and 9  are diagrams for explaining signal transmission and return paths in a multimedia interface connector; 
         FIGS. 10 and 11  are illustrations for explaining examples of field distribution analysis in cases that respective multimedia interface connectors are applied to an electronic device, according to an exemplary embodiment; 
         FIG. 12  shows a multimedia interface connector, according to an exemplary embodiment; 
         FIG. 13  shows a multimedia interface connector, according to an exemplary embodiment; and 
         FIG. 14  shows results of measuring radiated electromagnetic interface (EMI) data of a multimedia interface connector. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The present disclosure will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the disclosure are shown. The disclosure may, however, be embodied in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein; rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the disclosure to those skilled in the art Like reference numerals in the drawings denote like elements, and thus their description will be omitted. In the description, if it is determined that a detailed description of commonly-used technologies or structures related to the embodiments may unnecessarily obscure the subject matter of the exemplary embodiments, the detailed description will be omitted. It will be understood that, although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. 
     Exemplary embodiments will now be described with reference to accompanying drawings. 
       FIG. 1  shows connections between source and electronic devices, and  FIG. 2  shows a multimedia interface connector mounted on an electronic device. 
     Referring to  FIG. 1 , an electronic device  100  is a sink device connected to a source device  200  via a multimedia interface cable for receiving audio and video signals transmitted from the source device  200 . The source device  200  may transmit audio and video signals in sync with a pixel clock. 
     The multimedia interface cable may be a High Definition Multimedia Interface (HDMI) cable. 
     For example, the source device  200  may be a set-top box  200   a , a game console  200   b , an Audio/Video (A/V) receiver  200   c , and a mobile phone  200   d , without being limited thereto, and may be any device connected to the electronic device  100  via an HDMI cable for transmitting signals. The A/V receiver  200   c  may include a video output end to be wiredly connected to a video input end (not shown) of the electronic device  100 , and an audio output end to be wiredly connected to an audio input end (not shown) of the electronic device  100 . 
     The electronic device  100  may be a digital television, without being limited thereto. 
     Referring to  FIG. 2 , the electronic device  100  and the source device  200  may include respective multimedia interface connectors  300 ,  210  to transmit or receive signals via an HDMI cable connected to the multimedia interface connectors  300 ,  210 . 
       FIG. 3  is a control block diagram illustrating operation between an electronic device and a source device. 
     Referring to  FIG. 3 , the electronic device  100  may include a multimedia interface connector  300 , a signal receiver  110 , a display  130 , an audio output  150 , a memory  170 , and a processor  190 . 
     The multimedia interface connector  300  may be configured for a multimedia interface cable, e.g., the HDMI cable, to be connected between the electronic device  100  and the source device  200  for signal transmission or reception, and may be equipped in the electronic device  100 . The multimedia interface connector  300  may be installed at any location in the electronic device  100  as long as the location allows easy connection with the source device  200 . 
     The signal receiver  110  may receive video and/or audio signals transmitted from a signal transmitter  230  of the source device  200 . 
     Although not shown, the signal receiver  110  may include a Transition Minimized Display Signaling (TMDS) decoder for performing TMDS decoding on HDMI signal converted into a format available for transmission from the multimedia interface. 
     The processor  190  may perform a video process function that processes a video signal received through the signal receiver  110  and outputs the result through the display  130 , and an audio process function that processes an audio signal received through the signal receiver  110  and outputs the result through the audio output  150 . 
     The memory  170  may be configured to store data related to the electronic device  100 . 
     The memory  170  may also serve as an electrically erasable programmable read-only memory (EEPROM) for storing Extended Display Identification Data (EDID) data. The EDID data refers to a data format defined by the Video Electronics Standards Association (VESA), including information about a maker or a standard, basic display attributes, such as resolution and color format that may be supported, property information, and the like. 
     Referring to  FIG. 3 , the source device  200  may include a multimedia interface connector  210 , a signal transmitter  230 , and a processor  250 . 
     The multimedia interface connector  210  may be configured for a multimedia interface cable, e.g., the HDMI cable, to be connected between the electronic device  100  and the source device  200  for signal transmission or reception, and may be equipped in the source device  200 . 
     The signal transmitter  230  may transmit video and/or audio signals to the signal receiver  110  of the electronic device  100 . 
     Specifically, the signal transmitter  230  may transmit the decoded video signal and/or audio signal in a format that fits the HDMI multimedia interface. Although not shown, the signal transmitter  230  may include a TMDS encoder (not shown) for performing TMDS encoding on the decoded data into a format available for transmission from the HDMI multimedia interface, and transmitting the encoding result to the electronic device  100  via the HDMI cable. 
     The processor  250  is configured to obtain EDID data in a data format to recognize the electronic device  100  through a display data channel (DDC) line (not shown) while being connected to the HDMI cable. For example, the processor  250  may check a communication state of the DDC line and a signal state of a hot plug to detect whether the HDMI cable is connected to the electronic device  100 , and if it is determined that the HDMI cable is connected to the electronic device  100 , control the output port to be automatically set to HDMI. 
     In the following, a multimedia interface connector equipped in the electronic device  100  will be described as an example. 
       FIGS. 4 and 5  show a multimedia interface connector, according to an exemplary embodiment. 
     A multimedia interface connector will now be described in connection with  FIG. 6  that shows transmission and return paths between an electronic device and a source device,  FIG. 7  that shows arrangement of an electronic device having the multimedia interface connector applied thereto,  FIGS. 8 and 9  that show diagrams for explaining signal transmission and return paths in the multimedia interface connector, and  FIGS. 10 and 11  that show diagrams for explaining examples of field distribution analysis in cases that respective multimedia interface connectors are applied to the electronic device, according to an exemplary embodiment. 
     Referring to  FIG. 4 , a multimedia interface connector  300  may include connection terminals  310 , a main ground, an auxiliary ground  330 , and a terminal holder  340 . 
     The connection terminals  310  may be combined with a Printed Circuit Board (PCB). 
     Referring to  FIG. 5 , one end of the connection terminals  310  is exposed to be connected to a connector of an HDMI cable, while the other end is combined with a PCB  410  to deliver signals transmitted from the source device  200 . The terminal holder  340  is omitted in  FIG. 5  for convenience of explanation. 
     The connection terminals  310  are made of a conducting material to receive audio and video signals transmitted from the source device  200  via the HDMI cable. 
     The connection terminals  310  include multiple clock terminals. 
     Specifically, the connection terminals  310  has 19 pins, including a differential pair of one clock (CLK) lane and three data lanes, DDC I2C, Hot Plug Detect (HPD) lines, etc. 
     The main ground  320  has a form to cover one side of the connection terminals  310  while leaving them opened in a first direction. In this regard, as shown in  FIG. 4 , the main ground  320  may be formed to cover the one side of the connection terminals  310  at a distance. 
     As shown in  FIG. 4 , the main ground  320  may be combined with the PCB  410 . 
     The auxiliary ground  330  is arranged between the main ground  320  and the PCB  410  to form a return path for a signal received through the connection terminals  310 . 
     The auxiliary ground  330  may be arranged to be adjacent to the clock terminal. 
     Among the lines connected to the electronic device  100 , in particular, the clock terminal (CLK) causes electromagnetic interference (EMI), and it is thus expected that the auxiliary ground  330  arranged to be adjacent to the clock terminal may reduce the EMI produced from the clock terminal. 
     Referring to  FIGS. 6 and 7 , the electronic device  100  may be connected to the source device  200  via the HDMI cable for receiving video and audio signals, and may form a return path R of  FIG. 7  with the main ground  320  and the auxiliary ground  330 . 
     Referring to  FIGS. 8 and 9 , since the auxiliary ground  330  arranged between the main ground  320  and the PCB  410  of  FIG. 7  forms a return path of the multimedia interface clock line, it may change resonance characteristics of the radiated noise produced by the connection terminals  310 , particularly, the clock terminal. The terminal holder  340  is omitted in  FIG. 9  for convenience of explanation. 
     Specifically, in a case that only the main ground  320  is equipped in the multimedia interface connector  300 , a longer return path may be formed than in the case that the auxiliary ground  330  is also arranged. 
     The present disclosure is about a structure in which the auxiliary ground  330  connects the main ground  320  and the PCB  410 . With this structure, an effect of reducing EMI may be expected by shortening the return path by arranging the auxiliary ground  330  in addition to the main ground  320  rather than arranging only the main ground  320 . 
     As shown in  FIG. 4 , the terminal holder  340  may be arranged to fix the connection terminals  310  at a certain position a predetermined distance away from the main ground  320 . The terminal holder  340  may be made of an insulating material. 
     As shown in  FIG. 4 , the terminal holder  340  may be formed to cover the connection terminals  310  while leaving one side of the connection terminals  310  connected to the HDMI cable connector and the other side of the connection terminals that comes in contact with the PCB  410  exposed. 
       FIGS. 10 and 11  show examples of field distribution analysis (about e.g., surface current and radiation pattern at a frequency of 2.6 GHz) in cases that a general multimedia interface connector ((a) of  FIG. 10 )) and the multimedia interface connector  300  of  FIG. 4  ((a) of  FIG. 11 )) are applied to the electronic device. Referring to area E 1  in (b) of  FIG. 10  and area E 2  in (b) of  FIG. 11 , it is seen that EMI characteristics do not appear when the multimedia interface connector of  FIG. 4  is applied as compared to when the general multimedia interface connector is applied. (b) of  FIG. 10  and (b) of  FIG. 11  show EMI characteristics in the area where the multimedia interface connectors are mounted. 
       FIG. 12  shows a multimedia interface connector, according to an exemplary embodiment. 
     In the following, the same description as described in connection with  FIGS. 1 to 9  will be omitted. 
     The multimedia interface connector  300  may include multiple groups of connection terminals  310  combined with the PCB  410 , a plurality of main grounds  320  formed to cover one side of the respective groups of connection terminals while leaving them opened in a first direction, an auxiliary ground  350  arranged to connect the plurality of main grounds  320 , and a terminal holder  340  for fixing the connection terminals  310  at a certain position a predetermined distance away from the main grounds  320 . The main grounds  320  may be combined with the PCB  410 . As shown in  FIG. 12 , the main grounds  320  include supporters  321  that extend downward to be combined with the PCB  410 . 
     The plurality of main grounds  320  are placed to be separated from one another, as shown in  FIG. 12 . The auxiliary ground  350  may be formed to connect one sides of the plurality of main grounds  320  located to be separated from one another. 
     Because of the auxiliary ground  350  additionally arranged to connect the plurality of main grounds to one another, an effect may be expected to cancel a resonance frequency radiated as the number of supporters  321  even increases. 
     While the auxiliary ground  350  connects  2  main grounds  320  in  FIG. 12 , it is not limited thereto but more main grounds  320  may be connected via the auxiliary ground  350  as needed by the user. 
     The respective main grounds  320  may be formed to cover the one side of the connection terminals  310  at a distance. 
     There may be a number of terminal holders  340  to correspond to the plurality of main grounds  320 . The terminal holder  340  may be made of an insulating material. 
       FIG. 13  shows a multimedia interface connector, according to an exemplary embodiment. 
     The multimedia interface connector  300  may include multiple groups of connection terminals  310  combined with the PCB  410 , a plurality of main grounds  320  formed to cover one sides of the multiple groups of connection terminals while leaving them opened in a first direction, a first auxiliary ground  351  arranged to connect the plurality of main grounds  320 , a plurality of second auxiliary grounds  331  arranged between the respective main grounds  320  and the PCB  410  to form a return path of a signal received through the connection terminals  310 , and a terminal holder  340  for fixing the connection terminals  310  at a certain position a predetermined distance away from the main grounds  320 . The main grounds  320  may be combined with the PCB  410 . 
     The plurality of main grounds  320  are placed to be separated from one another, as shown in  FIG. 13 . The first auxiliary ground  351  may be formed to connect one sides of the plurality of main grounds  320  located to be separated from one another. 
     Results of measuring radiated EMI data of the multimedia interface connector  300  may be the same as what is listed in the following table 1. 
     Referring to  FIG. 14  and table 1, as the first auxiliary ground  351  and the second auxiliary grounds  331  are applied to the multimedia interface connector  300 , resonance characteristics do not appear at the respective frequencies of table 1, not exceeding a reference value of 37 [dBuV/m] and securing the margin from 4.8 [dBuV/m] to 8.9 [dBuV/m] compared to the reference value, which meets the EMI criteria. 
     In  FIG. 14 , ‘A’ indicates ‘horizontal’, and ‘B’ indicates ‘vertical’. 
     
       
         
           
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Frequency 
                   
                 Reading 
                 Factor 
                 Level PK 
                 Limit QP 
                 Margin QP 
                 Height 
                 Angle 
               
               
                 [MHz] 
                 (P) 
                 [dBuV/m] 
                 [dBuV/m] 
                 [dBuV/m] 
                 [dBuV/m] 
                 [dBuV/m] 
                 [cm] 
                 [degree] 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 891.117 
                 H 
                 36 
                 −3.8 
                 32.2 
                 37 
                 4.8 
                 400 
                 257.9 
               
               
                 296.993 
                 H 
                 43.4 
                 −14.5 
                 28.9 
                 37 
                 8.1 
                 300 
                 340.3 
               
               
                 594.055 
                 H 
                 35.6 
                 −7.5 
                 28.1 
                 37 
                 8.9 
                 100 
                 130.1 
               
               
                 594.055 
                 V 
                 25.9 
                 −6.7 
                 29.2 
                 37 
                 7.8 
                 200 
                 149.3 
               
               
                   
               
            
           
         
       
     
     In the following, a case where the multimedia interface connector  300  is equipped in the electronic device  100  will be described by taking an example of what is described above in connection with  FIGS. 4, 7, 9, 12 and 13 . 
     The same description as described in connection with  FIGS. 1 to 13  will be omitted. 
     Referring to  FIG. 7 , the electronic device  100  may include a semiconductor device  430 , a PCB  410  having the semiconductor device  430  mounted thereon, and a multimedia interface connector  300  combined with a source device e.g.,  200  of  FIG. 6 , for receiving multimedia signals (e.g., video and audio signals) transmitted from the source device  200 . 
     The multimedia interface connector  300  may include connection terminals  310  combined with the PCB  410 , a main ground  320  formed to cover one side of the connection terminals while leaving them opened in a first direction, an auxiliary ground  330  combined with the main grounds  320 , and a terminal holder  340  for fixing the connection terminals  310  at a certain position a predetermined distance away from the main ground  320 . The multimedia interface connector  300  may be a High Definition Multimedia Interface (HDMI) connector. 
     First, turning back to  FIG. 4 , the auxiliary ground  330  is arranged between the main ground  320  and the PCB  410  to form a return path for a signal received through the connection terminals  310 . The connection terminals may include a plurality of clock terminals. The auxiliary ground  330  may be placed to be adjacent to the clock terminals. 
     Second, referring to  FIG. 12 , if there are multiple main grounds  320 , the auxiliary ground  350  may be formed to connect the multiple main grounds  320 . 
     The multiple main grounds  320  are placed to be separated from one another, as shown in  FIG. 12 , and the auxiliary ground  350  may be formed to connect one sides of the plurality of main grounds  320  located to be separated from one another. 
     Third, referring to  FIG. 13 , if there are multiple main grounds  320 , the auxiliary ground  350  may include a first auxiliary ground  351 , and a plurality of second auxiliary grounds  331  arranged between the respective main grounds  320  and the PCB  410  to form a return path of a signal received through the connection terminals  310 . 
     In the embodiments, the return path and ground for the multimedia interface clock is reinforced, thereby suppressing resonance characteristics at a multiplied frequency of 297 MHz. 
     According to exemplary embodiments, an auxiliary ground additionally arranged adjacent to a clock terminal may reduce a ground return path and thus reduce EMI radiated around the clock line. 
     Furthermore, an auxiliary ground additionally arranged to connect a plurality of main grounds with each other enables use of the plurality of main grounds, thereby reducing EMI. 
     Several embodiments have been described, but a person of ordinary skill in the art will understand and appreciate that various modifications can be made without departing the scope of the present disclosure. Thus, it will be apparent to those ordinary skilled in the art that the disclosure is not limited to the embodiments described, which have been provided only for illustrative purposes.