Abstract:
A memory system includes a controller suitable for providing a data to be written on a memory cell array and a control data for indicating whether or not the data has a preset data pattern and a memory device suitable for selectively writing an patterned data or the data provided by the controller on the memory cell array in response to the control data, wherein the patterned data is stored in the memory device and has the preset data pattern.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority of Korean Patent Application No. 10-2013-0094754, filed on Aug. 9, 2013, which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field 
     Exemplary embodiments of the present invention relate to a memory design technology, and more particularly, to a memory device and a memory system including the same. 
     2. Description of the Related Art 
     A memory device such as a dynamic random access memory (DRAM) receives data, which is to be written, from a controller and transmits data, which is read therefrom, to the controller. In case of a synchronous memory device, the controller and the memory device are synchronized with a system clock. During the transmission of data, a data strobe signal is used to synchronize the controller and the memory device for data communication. 
     Especially, the memory device performs a toggling operation to synchronize the data with an edge of the data strobe signal. The toggling operation is performed on the data irrespective of a type of data. For example, although the data have a predetermined pattern of “all one” or “all zero”, e.g., ‘11111’ or ‘00000’, the memory device performs the toggle operation, which causes power consumption. 
     SUMMARY 
     Exemplary embodiments of the present invention are directed to a memory device and a memory system for improving an operation speed and reducing power consumption. 
     In accordance with an exemplary embodiment of the present invention, a memory system may include a controller suitable for providing a data to be written on a memory cell array and a control data for indicating whether or not the data has a preset data pattern and a memory device suitable for selectively writing an patterned data or the data provided by the controller on the memory cell array in response to the control data, wherein the patterned data is stored in the memory device and has the preset data pattern. 
     In accordance with an exemplary embodiment of the present invention, a memory device may include a memory cell array, a data pattern storage unit suitable for storing a plurality of patterned data and outputting one of the plurality of patterned data in response to a first control signal, a selection unit suitable for selectively transmitting of the patterned data outputted by the data pattern storage unit to the memory cell array in response to a second control signal and a control unit suitable for generating the first and second control signal based on a control data provided by an external device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating an exemplary memory system in accordance with an embodiment of the present invention. 
         FIG. 2  is a block diagram illustrating an exemplary memory device in accordance with an embodiment of the present invention. 
         FIG. 3  is a timing diagram illustrating a single rank operation mode of a memory device in accordance with an embodiment of the present invention. 
         FIG. 4  is a timing diagram illustrating a conventional multi-rank operation mode. 
         FIG. 5  is a timing diagram illustrating an exemplary multi-rank operation mode of a memory device in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Throughout the disclosure, reference numerals correspond directly to the like parts in the various figures and embodiments of the present invention. 
     The drawings are not necessarily to scale and in some instances proportions may have been exaggerated in order to dearly illustrate features of the embodiments. In this specification, specific terms have been used. The terms are used to describe the present invention, and are not used to qualify the sense or limit the scope of the present invention. 
     It is also noted that in this specification, ‘and/or’ represents that one or more of components arranged before and after ‘and/or’ is included. Furthermore, “connected/coupled” refers to one component not only directly coupling another component but also indirectly coupling another component through an intermediate component. In addition, a singular form may include a plural form as long as it is not specifically mentioned in a sentence. Furthermore ‘include/comprise’ or ‘including/comprising’ used in the specification represents that one or more components, steps, operations, and elements exists or are added. 
       FIG. 1  is a block diagram illustrating an exemplary memory system in accordance with an embodiment of the present invention. 
     Referring to  FIG. 1 , the memory system  1000  may include a controller  100  and a memory device  200 . 
     The controller  100  may output an external command signal CMD a clock signal CLK and an address signal ADDR for controlling the memory device  200 . The controller  100  may input and output a data strobe signal DQS and data DQ. The external command signal CMD may include a chip selection signal CS, a column address strobe signal CAS, a row address strobe signal RAS and a write enable signal WE. 
     The controller  100  may include a control signal generation unit  150  for outputting a control data CTL_PAT, which may indicate that the data DQ transmitted therewith has a preset data pattern. That is, when the memory device  200  receives a predetermined bit sequence of the preset data pattern from the controller  100 , the controller  100  may output the control data CTL_PAT for indicating the preset data pattern. The preset data pattern may be a preset protocol between the controller  100  and the memory device  200 . For example, data to be transferred to the memory device  200 , which is the predetermined bit sequence with the preset data pattern of “all ones” or “all zeros”, may be known to both of the controller  100  and the memory device  200 . 
     The memory device  200  may operate in response to various signals provided from the controller  100 . When the memory device  200  receives the preset data pattern from the controller  100 , the memory device  200  may not perform the toggling operation to the preset data pattern or the data strobe signal DQS in response to the control data CTL_PAT received from the control signal generation unit  150  included in the controller  100 . Thus, the memory device  200  may prevent the power consumption, which is caused by the toggling of the data DQ or the data strobe signal DQS. 
     When the memory device  200  receives data having the preset data pattern and the control data CTL_PAT from the controller  100 , the memory device  200  in response to the control data CTL_PAT may use data stored therein and having the same pattern as the received data without toggling the received data. 
       FIG. 2  is a block diagram illustrating an exemplary memory device in accordance with an embodiment of the present invention. 
     Referring to  FIG. 2 , a memory device  200  may include a data reception unit  210 , a data pattern storage unit  220 , a control unit  230 , a selection unit  240 , and a memory cell array  250 . 
     The data reception unit  210  may receive a data strobe signal DQS and the data DQ from the controller  100 . The data DQ and the data strobe signal DQS may be toggled by the data reception unit  210 . The data DQ may be synchronized with the data strobe signal DQS. 
     The data pattern storage unit  220  may store a patterned data or the predetermined bit sequence having the preset data pattern. For example, the data pattern storage unit  220  may store the patterned data of 8 bits with value of “all ones” or “all zeros”, e.g., ‘11111111’ or ‘00000000’. The data pattern storage unit  220  may further store various data patterns, which are also known to the controller  100 . That is, two data patterns such as ‘11111111’ and ‘00000000’ may be stored in the data pattern storage unit  220 . The patterned data having the preset data pattern such as “11110000” and ‘10101010’ may be further stored in the data pattern storage unit  220 . 
     The control unit  230  may receive the control data CTL_PAT indicating whether or not the data DQ transferred therewith from the controller  100  has the preset data pattern. When the data DQ received from the controller  100  has the preset data pattern of the predetermined bit sequence, which is indicated by the control data CTL_PAT, the control unit  230  may control the data reception unit  210  not to toggle the received data DQ and the received data strobe signal DQS. 
     And, when the data DQ received from the controller  100  has the preset data pattern of the predetermined bit sequence, the control unit  230  may control the data storage unit  220  and the selection unit  240  in order to write the patterned data, which is stored in the data pattern storage unit  220 , on the memory cell array  250 . 
     The control data CTL_PAT may include a first signal ADDR[m:n] and a second signal ADDR[ 1 ]. The first signal ADDR[m:n] may include a plurality of bits and have information about the pattern of the data received with the control data CTL_PAT. The second signal ADDR[ 1 ] may indicate that the data received with the control data CTL_PAT have the preset data pattern of the predetermined bit sequence. In accordance with the embodiment of the present invention, the first signal ADDR[m:n] and the second signal ADDR[ 1 ] may be a redundant part of an address signal, which does not engage in selecting the memory cell array. 
     The control unit  230  may generate and output a first control signal CTL 1  and a second control signal CTL 2  in response to the first signal ADDR[m:n] and the second signal ADDR[ 1 ]. The data pattern storage unit  220  may operate in response to the first control signal CTL 1 . The data reception unit  210  and the selection unit  240  may operate in response to the second control signal CTL 2 . 
     The selection unit  240  may select and output one of the patterned data stored in the data pattern storage unit  220  and the data DATA outputted from the data reception unit  210  to the memory cell array  250  in response to the second control signal CTL 2 . 
     When the data DQ received from the controller  100  have the preset data pattern of the predetermined bit sequence, one of the plurality of patterned data stored in the data pattern storage unit  220  may be outputted to the selection unit  240  in response to the first control signal CTL 1 , in which the first signal ADDR[m:n] having information about the pattern of the received data DQ is reflected. And, the data reception unit  210  may disable the toggling operation to the received data DQ or the received data strobe signal DQS in response to the second control signal CLT 2 , in which the second signal ADDR[ 1 ] indicating that the received data have the preset data pattern of the predetermined bit sequence is reflected. That is, the selection unit  240  may select and output the patterned data outputted from the data pattern storage unit  220  to memory cell array  250 . 
     On the contrary, when the data DQ received from the controller  100  does not have the preset data pattern of the predetermined bit sequence, the data pattern storage unit  220  may be disabled in response to the first control signal CTL 1 . And, the data reception unit  210  may enable the toggling operation to the received data DQ or the received data strobe signal DQS and output the result of the toggling operation as the data DATA in response to the second control signal CLT 2 . The selection unit  240  may select and output the data DATA outputted from the data reception unit  210  to the memory cell array  250 . 
     As described above, when the preset data pattern of the predetermined bit sequence is received from the controller  100 , the memory device  200  in accordance with the embodiment of the present invention may write the preset data pattern, which is stored in the data pattern storage unit  220 , into each memory cell of the memory cell array  250  instead of processing, for example, toggling the preset data pattern transmitted from the controller  100 . Thus, a power consumption caused by the toggling of the preset data pattern may be reduced and an operation speed of the memory device  200  may increase. 
     An operation of the memory system including the controller and the memory device will be described in details with a multi rank operation of the memory device  200 . 
     A rank in the memory device  200  indicates a memory region, which operates independently in response to a chip selection signal. One of a plurality of memory chips in a memory module may be a single rank. When each of two or more memory cell arrays in a single memory chip is separated and operates independently, the single memory chip may have a plurality of ranks. Controlling the memory region as the single rank is referred to as a single rank operation. 
     When a plurality of data are written in the single rank operation, the plurality of data may be sequentially written on the memory cell array without synchronizing with the data strobe signal DQS. 
     When the plurality of data are written in a different rank during a multi rank operation, the plurality of data may be written after one or two cycles that are required for the data strobe signal DQS to be synchronized. 
       FIG. 3  is a timing diagram illustrating a single rank operation mode of a memory device in accordance with an embodiment of the present invention. 
     Referring to  FIG. 3  in a single rank operation mode, after a first write command WR_A is inputted, a second write command WR_B is sequentially inputted. In case of a back-to-back type where data may be written sequentially, when data are to be written in a same rank, the data are outputted to the memory cell array without synchronizing with the data strobe signal DQS. 
       FIG. 4  is a timing diagram illustrating a conventional multi rank operation mode. 
     Referring to  FIG. 4 , when the data is written on a memory cell included in a different or changed rank, it takes a time of 2*T to synchronize with the data strobe signal DQS according to the change of rank, where ‘T’ is referred to as a cycle of the data. That is, after a controller  100  provides a write command WR_A, when a write command WR_B is inputted in the different or changed rank, it takes the time of 2*T to synchronize data DQ with the data strobe signal DQS. 
       FIG. 5  is a timing diagram illustrating an exemplary multi rank operation mode of a memory device in accordance with an embodiment of the present invention. 
     Referring to  FIG. 5 , when a preset data pattern is confirmed by the controller  100  using the control data, an input timing of a command to be transferred to the memory device  200  may be shortened by the amount of 2*T. In the embodiment of the present invention, when data to be transferred to the memory device  200  have the preset data pattern, the preset data pattern, which is stored in the data pattern storage unit  220 , is written into each memory cell of the memory cell array  250  instead of process, for example, the toggling operation to the preset data pattern transmitted from the controller  100 , and thus it is not necessary to synchronize the data DQ with the data strobe signal DQS. 
     In conclusion, during a multi rank operation mode, it is not necessary to synchronize the data DQ to be written on the different or changed rank with the data strobe signal DQS after a write operation to one rank is completed. Thus, after a controller  100  provides the write command WR_A, when the write command WR_B is inputted in the different or changed rank, the amount of time of 2*T is not required because the synchronization is not required. 
     While the present invention has been described with respect to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.