Abstract:
A radio frequency (RF) matching control apparatus and method for a portable communication terminal is provided. An RF matching control apparatus for a portable communication terminal according to the present invention includes matching circuitry for performing RF matching on an RF signal input through an input line connected to an antenna and outputting a matched RF signal through an output line; and a decoding unit for generating matching control signals according to a utilization environment of the portable communication terminal and providing the matching control signals to the matching circuitry.

Description:
PRIORITY 
       [0001]    This application claims priority to an application entitled “RADIO FREQUENCY MATCHING CONTROL APPARATUS AND METHOD FOR PORTABLE COMMUNICATION TERMINAL” filed in the Korean Intellectual Property Office on Aug. 7, 2006 and assigned Serial No. 2006-0074205, the contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a portable communication terminal and, in particular, to an Radio Frequency (RF) matching control apparatus and method for a portable communication terminal. 
         [0004]    2. Description of the Related Art 
         [0005]    Typically, a portable communication terminal is implemented so as to optimize a radiation characteristic. In the case of using a single RF matching circuit, the portable communication terminal inevitably suffers from degradations in reception sensitivity and transmission power due to the radiation characteristic variation in accordance with the change of channel environment. 
         [0006]    In order to solve such problems, a multiple RF matching circuits-based portable communication terminal has been proposed. In the multiple RF matching circuits-based portable communication terminal, each RF matching circuit should be implemented with resistors, inductors, and capacitors, having preset resistances, inductances, and capacitances, respectively. That is, the values of the elements constituting each RF matching circuit are fixed in the manufacturing stage and each RF matching circuit operates independently. 
         [0007]    However, the conventional multiple RF matching circuits-based portable communication terminal is disadvantageous in that the increase in the number of the RF matching circuits requires additional space, resulting in difficulty of compact design. 
         [0008]    Further, the limited number of the RF matching circuits causes limitation of RF tuning performance of the portable communication terminal. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention has been made in an effort to solve the above problems, and it is an object of the present invention to provide an RF matching control apparatus and method for a portable communication terminal that are capable of optimizing a reception sensitivity and a transmission power. 
         [0010]    It is another object of the present invention to provide an RF matching control apparatus and method for a portable communication terminal that are capable of setting a RF matching circuitry adaptive to the environment of the portable communication terminal by configuring a plurality of matching circuits constituting the RF matching circuitry in a software-supported manner. 
         [0011]    In accordance with an aspect of the present invention, the above and other objects can be accomplished by a Radio Frequency (RF) matching control apparatus for a portable communication terminal. The RF matching control apparatus for a portable communication terminal includes matching circuitry for performing RF matching on an RF signal input through an antenna and outputting a matched RF signal through an output line; and a decoding unit for generating matching control signals according to an environment of the portable communication terminal and providing the matching control signals to the matching circuitry. 
         [0012]    Preferably, each matching circuit includes a matching device, and a switch arranged at an input line and a switch arranged at an output line of the matching device. Preferably, the decoding unit includes a decoder for generating a 16-bit matching control signal from a 4-bit condition signal preset according to the environment of the portable communication terminal; a buffer for temporarily storing the 16-bit matching control signal; and a strobe terminal that inputs a strobe signal for updating the 16-bit matching control signal stored in the buffer. 
         [0013]    In accordance with another aspect of the present invention, the above and other objects can be accomplished by a Radio Frequency (RF) matching control method of a portable communication terminal including RF matching circuitry for performing RF matching on RF signal received through an antenna and outputting a matched RF signal through an output line. The RF matching control method includes generating a matching control signal according to an environment of the portable communication terminal; selecting at least one among a plurality of matching circuits constituting the RF matching circuitry; and performing matching on the received RF signal using the selected matching circuit. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description in conjunction with the accompanying drawings, in which: 
           [0015]      FIG. 1  is a circuit diagram illustrating RF matching circuitry of a portable communication terminal according to the present invention; 
           [0016]      FIG. 2  is a schematic view illustrating a configuration of a matching circuit of  FIG. 1 ; and 
           [0017]      FIG. 3  is a block diagram illustrating a decoding unit for providing control signals to first and second unit cells of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0018]    Preferred embodiments of the present invention are described in detail with reference to the accompanying drawings. The same reference numbers are used throughout the drawings to refer to the same or like parts. Detailed descriptions of well-known functions and structures incorporated herein may be omitted to avoid obscuring the subject matter of the present invention. 
         [0019]    While the present invention may be embodied in many different forms, specific embodiments of the present invention are shown in drawings and described herein in detail, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
         [0020]    The RF matching circuitry according to the present invention includes at least one unit cell. The unit cell includes at least two matching circuits including resistors, inductors, and capacitors of different values. In this embodiment, the RF matching circuitry includes 2 stepwise unit cells and each unit cell includes  8  matching circuits. However, the quantity of the unit cells and of the matching circuits per unit cell can be changed. 
         [0021]    Referring to  FIG. 1 , an RF matching circuitry  3  includes first and second unit cells  10  and  20  connected in series between a radio frequency input terminal (RF in) connected to an antenna (not shown) and a radio frequency output terminal (RF out), for matching a radio frequency signal received through the radio frequency input terminal (RF in) and transferring the matched radio frequency signal to the radio frequency output terminal (RF out). 
         [0022]    First and second unit cells  10  and  20  each include devices such as resistors, inductors, and capacitors connected in series or parallel with each other. First unit cell  10  includes matching circuits  108 ,  109 ,  110 ,  111 ,  112 ,  113 ,  114 , and  115  interposed in parallel between the radio frequency input terminal (RF in) and the second unit cell  20 , and the second unit cell  20  includes matching circuits  100 ,  101 ,  102 ,  103 ,  104 ,  105 ,  106 , and  107  interposed in parallel between the first unit cell  10  and the radio frequency output terminal (RF out). 
         [0023]    Matching circuit  108  includes a grounded 64 nH inductor, Matching circuit  109  includes a grounded 47 nH inductor, and tenth matching circuit  110  includes a grounded 30 nh inductor. 
         [0024]    Matching circuit  111  includes a grounded 4 pF capacitor, matching circuit  112  includes a 4.7 nH inductor connected in series, matching circuit  113  includes a 2.7 nH inductor connected in series, matching circuit  114  includes a 4 pF capacitor connected in series, and matching circuit  115  includes a resistors connected in series. 
         [0025]    Matching circuit  100  includes a grounded 64 nH inductor, matching circuit  101  includes a grounded 47 nH inductor, and matching circuit  102  includes a grounded 30 nH inductor. 
         [0026]    Matching circuit  103  includes a grounded 4 pF capacitor, matching circuit  104  includes a 4.7 nH inductor connected in series, matching circuit  105  includes a 2.7 nH inductor connected in series, matching circuit  106  includes a 4 pF capacitor connected in series, and matching circuit  107  includes a resistor connected in series. 
         [0027]    In  FIG. 2 , each matching circuit includes at least one matching device  202  connected between a pair of switches  201  and  203  that are connected to an input terminal and an output terminal of matching device  202 , respectively. 
         [0028]    Matching device  202  can be a resistor, an inductor, or a capacitor. Switches  201  and  203  of each matching circuit are connected to a decoding unit (see  FIG. 3 ). 
         [0029]    Referring to  FIG. 3 , decoding unit  5  includes a decoder  30  and a buffer  40 . Decoder  30  generates the control signals for controlling switches  201  and  203  connected to the input and output terminals, respectively, of matching device  202 . Accordingly, the decoder is preferably implemented as a 4*16 decoder in consideration of the RF matching circuitry of  FIG. 1 . 
         [0030]    As described above, RF matching circuitry  3  includes two unit cells  10  and  20 , each unit cell including  8  matching circuits, such that decoder  30  generates control signals for selecting one matching circuit from each of first and second unit cells  10  and  20 . 
         [0031]    Referring to  FIG. 3 , decoding unit  5  includes a decoder  30  that generates condition values for selecting matching circuits according to an environment of the portable communication terminal, and a buffer  40  for temporarily storing the condition values generated by decoder  30 . The condition values stored in buffer  40  are updated by a signal input through a strobe terminal. 
         [0032]    Referring to  FIGS. 1 to 3 , matching circuits  100  to  115  are connected to buffer  40  of decoding unit  5  through respective signal lines, and each of switches  201  and  203  installed at the input and output terminals of each matching device  202  is either on or off simultaneously according to the state of buffer  40 . 
         [0033]    Since the RF matching circuitry of the present invention operates according to the condition values determined by the environment of the portable communication terminal, it is possible to optimize the RF matching adaptively to the environment. 
         [0034]    For example, during power-on, the portable communication terminal initializes buffer  40 . The initial value is ‘0000’ and the strobe is in a deactivated state by a pull-up resistance. The number of cases of 4 condition values is 16 and can be represented as in Table 1. If a 4 bit-value is input to decoding unit  5 , 16 unique status values are output such that the switches are turned on and off according to the corresponding status values. 
         [0000]    
       
         
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Select 
                 Buffer Output 
                   
               
             
          
           
               
                 (I3, I2, I1, I0) 
                 (S15~S8) 
                 (S7~S0) 
                 Matching Circuit 
               
               
                   
               
               
                 0000 
                 1000 0000 
                 1000 0000 
                 Serial 0 ohm + Serial 0 ohm 
               
               
                 0001 
                 0100 0000 
                 1000 0000 
                 Serial 4 pF + Serial 0 ohm 
               
               
                 0010 
                 0100 0000 
                 0100 0000 
                 Serial 4 pF + Serial 4 pF 
               
               
                 0011 
                 0100 0000 
                 0010 0000 
                 Serial 4 pF + Serial 2.7 nH 
               
               
                 0100 
                 0100 0000 
                 0001 0000 
                 Serial 4 pF + Serial 4.7 nH 
               
               
                 0101 
                 0100 0000 
                 0000 1000 
                 Serial 4 pF + Parallel 4 pF 
               
               
                 0110 
                 0100 0000 
                 0000 0100 
                 Serial 4 pF + Parallel 30 nH 
               
               
                 0111 
                 0100 0000 
                 0000 0010 
                 Serial 4 pF + Parallel 47 nH 
               
               
                 1000 
                 0100 0000 
                 0000 0001 
                 Serial 4 pF + Parallel 64 nH 
               
               
                 1001 
                 0010 0000 
                 0000 1000 
                 Serial 2.7 nH + Parallel 4 pF 
               
               
                 1010 
                 0010 0000 
                 0000 0100 
                 Serial 2.7 nH + Parallel 30 nH 
               
               
                 1011 
                 0010 0000 
                 0000 0010 
                 Serial 2.7 nH + Parallel 47 nH 
               
               
                 1100 
                 0001 0000 
                 0000 1000 
                 Serial 4.7 nH + Parallel 4 pF 
               
               
                 1101 
                 0001 0000 
                 0000 0100 
                 Serial 4.7 nH + Parallel 30 nH 
               
               
                 1110 
                 0001 0000 
                 0000 0010 
                 Serial 4.7 nH + Parallel 47 nH 
               
               
                 1111 
                 0000 1000 
                 0000 0100 
                 Parallel 4 pF + Parallel 30 nH 
               
               
                   
               
             
          
         
       
     
         [0035]    In the present invention, the condition values are determined according to variations in the environment of the portable communication terminal. For example, when a folder of the portable communication terminal is opened or closed (or a slide body is moved up or down) the portable communication terminal retrieves values corresponding to the status of the folder or the slide body from a condition value table. The condition values are predetermined as shown in Table 2. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Environment and Status of the Portable 
                   
               
               
                   
                 Communication Terminal 
                 Condition value 
               
               
                   
                   
               
             
             
               
                   
                 Folder open 
                 0001 
               
               
                   
                 Folder close 
                 0011 
               
               
                   
                 Folder open &amp; High channel 
                 0100 
               
               
                   
                 Folder open &amp; Low channel 
                 0111 
               
               
                   
                 Folder close &amp; High channel 
                 0101 
               
               
                   
                 Folder close &amp; Low channel 
                 0110 
               
               
                   
                 Folder open &amp; Tx low power 
                 0111 
               
               
                   
                 Folder close &amp; Tx low power 
                 0110 
               
               
                   
                 Folder open &amp; Rx low power 
                 0100 
               
               
                   
                 Folder close &amp; Rx low power 
                 0101 
               
               
                   
                 Folder open &amp; ear jack insertion 
                 1001 
               
               
                   
                 Folder close &amp; ear jack insertion 
                 1011 
               
               
                   
                   
               
             
          
         
       
     
         [0036]    Buffer  40  of the decoding unit  5  is updated by an MSM of the portable communication terminal transmitting a strobe value from ‘high’ to ‘low’. 
         [0037]    According to the environment of the portable communication terminal, the condition value is automatically selected in a software supported manner and the strobe is activated such that the RF matching is controlled according to the condition value, resulting in optimization of the reception sensitivity and transmission power. 
         [0038]    As described above, the RF matching circuitry and method of the present invention can be implemented in the form of a universal integrated chip (IC) and can operate adaptively with respect to the environment of a portable communication terminal, whereby it is possible to improve transmission and reception characteristics and prevent the reception sensitivity from degradation by influence of a human body in a weak electric field. 
         [0039]    Also, the RF matching circuitry of the present invention can be tuned to operate such that the reception sensitivity is developed relative to the transmission power in a weak receive electric field and the transmission power increases relative to the reception sensitivity in a weak transmit electric field. 
         [0040]    Also, the RF matching circuitry of the present invention can effectively manage the transmission power adaptively to the utilization environment of the portable communication terminal, resulting in an increase of battery life. 
         [0041]    Also, the RF matching circuitry of the present invention can tune the RF matching characteristics in a software-supported manner, whereby it is possible to reduce the time and labor for developing a matching circuit for obtaining a specific radiation characteristic. 
         [0042]    Although exemplary embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that many variations and modifications of the basic inventive concepts herein taught which may appear to those skilled in the present art will still fall within the spirit and scope of the present invention, as further defined in the appended claims.