Method of generating a multi-level signal using selective equalization, method of transmitting data using the same, and transmitter and memory system performing the same

Abstract

In a method of generating a multi-level signal having one of three or more voltage levels that are different from one another, input data including two or more bits is received. A drive strength of at least one of two or more driving paths is changed based on the two or more bits such that a first transition time, during which an output data signal is transitioned from a first voltage level to a second voltage level, is changed. The output data signal that is the multi-level signal is generated such that the first transition time of the output data signal is changed and a second transition time, during which the output data signal is transitioned from the first voltage level to a third voltage level different from the second voltage level, is maintained.

1 . A method of generating a multi-level signal having one of three or more voltage levels that are different from one another, the method comprising:
 receiving input data including two or more bits;   changing a drive strength of at least one of two or more driving paths based on the two or more bits such that a first transition time, during which an output data signal is transitioned from a first voltage level to a second voltage level, is changed; and   generating the output data signal that is the multi-level signal such that the first transition time of the output data signal is changed and a second transition time, during which the output data signal is transitioned from the first voltage level to a third voltage level different from the second voltage level, is maintained.   
     
     
         2 . The method of  claim 1 , wherein changing the drive strength of the at least one of the two or more driving paths includes:
 dividing the input data into the two or more bits;   determining, based on the two or more bits, whether a first edge in which the output data signal is transitioned from the first voltage level to the second voltage level is detected; and   increasing the drive strength of the at least one of the two or more driving paths such that the first transition time decreases, when the first edge is detected.   
     
     
         3 . The method of  claim 2 , wherein each of the two or more driving paths includes a pre-emphasis driver circuit that operates based on a respective one of two or more pre-emphasis control signals, and
 wherein changing the drive strength of the at least one of the two or more driving paths further includes:   activating at least one of the two or more pre-emphasis control signals.   
     
     
         4 . The method of  claim 2 , wherein, as the first transition time decreases, the first transition time and the second transition time become different from each other. 
     
     
         5 . The method of  claim 1 , wherein:
 the two or more bits include a first bit and a second bit that are different from each other,   the two or more driving paths include a first driving path that operates based on the first bit and a second driving path that operates based on the second bit, and   the output data signal has one of the first voltage level, the second voltage level, the third voltage level, and a fourth voltage level that are different from one another.   
     
     
         6 . The method of  claim 5 , wherein:
 the first voltage level corresponds to a lowest voltage level, and the second voltage level corresponds to a highest voltage level, and   the drive strength of the at least one of the two or more driving paths is changed by activating a first pre-emphasis control signal applied to the first driving path to increase a first drive strength of the first driving path, or by activating a second pre-emphasis control signal applied to the second driving path to increase a second drive strength of the second driving path.   
     
     
         7 . The method of  claim 5 , wherein:
 the first voltage level does not correspond to a lowest voltage level, or the second voltage level does not correspond to a highest voltage level, and   the drive strength of the at least one of the two or more driving paths is changed by activating a first pre-emphasis control signal applied to the first driving path to increase a first drive strength of the first driving path, or by activating a second pre-emphasis control signal applied to the second driving path to increase a second drive strength of the second driving path.   
     
     
         8 . The method of  claim 5 , wherein the first bit is a least significant bit (LSB) of the input data, and the second bit is a most significant bit (MSB) of the input data. 
     
     
         9 . The method of  claim 1 , wherein:
 the two or more bits include a first bit, a second bit, and a third bit that are different from one another,   the two or more driving paths include a first driving path that operates based on the first bit, a second driving path that operates based on the second bit, and a third driving path that operates based on the third bit, and   the output data signal has one of the first voltage level, the second voltage level, the third voltage level, a fourth voltage level, a fifth voltage level, a sixth voltage level, a seventh voltage level, and an eighth voltage level that are different from one another.   
     
     
         10 . The method of  claim 1 , wherein a third transition time, during which the output data signal is transitioned from the first voltage level to a fourth voltage level different from the second and third voltage levels, is changed. 
     
     
         11 . The method of  claim 1 , wherein the first and second voltage levels are predetermined based on a characteristic of a channel transmitting the output data signal. 
     
     
         12 . The method of  claim 1 , wherein:
 the first and second voltage levels are determined in real time based on characteristic data, and   the characteristic data represents a characteristic of a channel transmitting the output data signal.   
     
     
         13 . A method of transmitting data based on a multi-level signal having one of three or more voltage levels that are different from one another, the method comprising:
 generating a first output data signal that is the multi-level signal based on first input data;   generating a second output data signal that is the multi-level signal based on second input data; and   transmitting the first output data signal and the second output data signal through a first channel and a second channel, respectively, that are different from each other,   wherein generating the first output data signal includes:
 receiving the first input data including two or more bits; 
 changing a drive strength of at least one of two or more driving paths based on the two or more bits included in the first input data such that a first transition time, during which the first output data signal is transitioned from a first voltage level to a second voltage level, is changed; and 
 generating the first output data signal such that the first transition time of the first output data signal is changed and a second transition time, during which the first output data signal is transitioned from the first voltage level to a third voltage level different from the second voltage level, is maintained. 
   
     
     
         14 . The method of  claim 13 , wherein generating the second output data signal includes:
 receiving the second input data including two or more bits;   changing a drive strength of at least one of two or more driving paths based on the two or more bits included in the second input data such that a third transition time, during which the second output data signal is transitioned from the first voltage level to the second voltage level, is changed; and   generating the second output data signal such that the third transition time of the second output data signal is changed and a fourth transition time, during which the second output data signal is transitioned from the first voltage level to the third voltage level, is maintained.   
     
     
         15 . The method of  claim 14 , wherein a characteristic of the first channel and a characteristic of the second channel are substantially the same as each other. 
     
     
         16 . The method of  claim 13 , wherein generating the second output data signal includes:
 receiving the second input data including two or more bits;   changing a drive strength of at least one of two or more driving paths based on the two or more bits included in the second input data such that a third transition time, during which the second output data signal is transitioned from a fourth voltage level different from the first voltage level to the second voltage level, is changed; and   generating the second output data signal such that the third transition time of the second output data signal is changed and a fourth transition time, during which the second output data signal is transitioned from the fourth voltage level to the third voltage level, is maintained.   
     
     
         17 . The method of  claim 16 , wherein a characteristic of the first channel and a characteristic of the second channel are different from each other. 
     
     
         18 . The method of  claim 13 , wherein:
 the method is performed by a memory system that includes a memory controller and a memory device, and   the first and second output data signals are generated by the memory controller.   
     
     
         19 . The method of  claim 13 , wherein:
 the method is performed by a memory system that includes a memory controller and a memory device, and   the first and second output data signals are generated by the memory device.   
     
     
         20 . A method of generating a multi-level signal having one of a first voltage level, a second voltage level, a third voltage level, and a fourth voltage level that are different from one another, the method comprising:
 receiving input data including a first bit and a second bit that are different from each other;   dividing the input data into the first and second bits;   determining, based on the first and second bits, whether a first edge in which an output data signal is transitioned from the first voltage level to the second voltage level is detected;   activating at least one of a first pre-emphasis control signal and a second pre-emphasis control signal, when the first edge is detected, wherein the first pre-emphasis control signal is applied to a first driving path that operates based on the first bit, and the second pre-emphasis control signal is applied to a second driving path that operates based on the second bit;   increasing a drive strength of at least one of the first and second driving paths based on at least one of the first and second pre-emphasis control signals such that a first transition time, during which the output data signal is transitioned from the first voltage level to the second voltage level, decreases; and   generating the output data signal that is the multi-level signal based on the first and second driving paths such that the first transition time of the output data signal is changed and a second transition time, during which the output data signal is transitioned from the first voltage level to the third voltage level, is maintained.   
     
     
         21 - 35 . (canceled)