Transmitting device for high speed communication, interface circuit and system including the same

Abstract

A transmission device may include a main driver configured to drive an output node based on an input signal, and may generate an output signal with multiple levels. The transmission device may include a variable emphasis driver configured to drive the output node with various driving forces based on transition information of the input signal.

What is claimed is: 
     
         1 . A transmission device comprising:
 a main driver configured to drive an output node based on an input signal, and generate an output signal with multiple levels; and   a variable emphasis driver configured to drive the output node with various driving forces based on transition information of the input signal.   
     
     
         2 . The transmission device according to  claim 1 , wherein the variable emphasis driver changes a strength for driving the output node, according to a voltage level change of the input signal. 
     
     
         3 . The transmission device according to  claim 1 , wherein the variable emphasis driver increases the strength for driving the output node, as a change in a voltage level of the input signal increases. 
     
     
         4 . The transmission device according to  claim 1 , wherein the multiple levels include a high level, a middle level and a low level, the high level has a potential higher than the middle level, and the middle level has a potential higher than the low level. 
     
     
         5 . The transmission device according to  claim 1 ,
 wherein the input signal transitions from one level to a plurality of different levels, and   wherein, when the input signal transitions from any one level to an adjacent level, the variable emphasis driver drives the output node with a predetermined strength, and, when the input signal transitions from the any one level to a level exceeding the adjacent level, the variable emphasis driver drives the output node with a strength larger than the predetermined strength in proportion to the level exceeding the adjacent level.   
     
     
         6 . The transmission device according to  claim 1 , further comprising:
 an output control unit configured to control a driving force of the main driver and a driving force of the variable emphasis driver based on the input signal.   
     
     
         7 . The transmission device according to  claim 1 , wherein the variable emphasis driver drives the output node until a voltage level of the output node transitions from any one level to another level. 
     
     
         8 . The transmission device according to  claim 1 , wherein the variable emphasis driver drives the output node to a power supply voltage or a ground voltage based on the transmission information of the input signal. 
     
     
         9 . The transmission device according to  claim 1 , wherein a driving strength and magnitude applied to the output node by the variable emphasis driver is less than a driving strength and magnitude applied to the output node by the main driver. 
     
     
         10 . The transmission device according to  claim 1 ,
 wherein the variable emphasis driver comprises a plurality of pre-emphasis drivers, and   wherein the variable emphasis driver increases the strength for driving by using a greater number of pre-emphasis drivers to drive the output node.   
     
     
         11 . A transmission device comprising:
 a main driver configured to output an output signal with one level among a high level, a middle level and a low level, to an output node, based on an input signal; and   a variable emphasis driver configured to drive the output node with one of first and second driving forces based on transition information of the input signal.   
     
     
         12 . The transmission device according to  claim 11 , wherein the high level has a potential higher by a unit level than the middle level, and the middle level has a potential higher by the unit level than the low level. 
     
     
         13 . The transmission device according to  claim 12 ,
 wherein the second driving force is larger than the first driving force, and   wherein the variable emphasis driver drives the output node with the first driving force when the input signal transitions from any one level by one unit level, and drives the output node with the second driving force when the input signal transitions by two unit levels.   
     
     
         14 . The transmission device according to  claim 11 , wherein the variable emphasis driver drives the output node to a voltage level corresponding to the middle level when the input signal does not transition from the middle level. 
     
     
         15 . The transmission device according to  claim 11 , wherein the variable emphasis driver drives the output node to a voltage level corresponding to the middle level when the input signal transitions from the low level or the high level to the middle level. 
     
     
         16 . The transmission device according to  claim 11 , wherein the variable emphasis driver comprises:
 a first pre-emphasis driver configured to drive the output node to one of a power supply voltage and a ground voltage according to the transition information of the input signal; and   a second pre-emphasis driver configured to drive the output node to one of the power supply voltage and the ground voltage according to the transition information of the input signal.   
     
     
         17 . The transmission device according to  claim 16 , wherein one of the first and second pre-emphasis drivers drives the output node to a level of the power supply voltage when the input signal transitions from the middle level to the high level, and both the first and second pre-emphasis drivers drive the output node to the level of the power supply voltage when the input signal transitions from the low level to the high level. 
     
     
         18 . The transmission device according to  claim 16 , wherein one of the first and second pre-emphasis drivers drives the output node to a level of the ground voltage when the input signal transitions from the middle level to the low level, and both the first and second pre-emphasis drivers drive the output node to the level of the ground voltage when the input signal transitions from the high level to the low level. 
     
     
         19 . The transmission device according to  claim 16 , wherein, when the input signal transitions to the middle level, one of the first and second pre-emphasis drivers drives the output node to the level of the power supply voltage, and the other drives the output node to the level of the ground voltage. 
     
     
         20 . The transmission device according to  claim 11 , wherein the variable emphasis driver drives the output node until a voltage level of the output node transitions from any one level to another level. 
     
     
         21 . The transmission device according to  claim 11 , further comprising:
 an output control unit configured to control a driving force of the main driver and a driving force of the variable emphasis driver based on the input signal.   
     
     
         22 . The transmission device according to  claim 21 , wherein the output control unit generates the transition information by comparing a previously inputted input signal and a currently inputted input signal. 
     
     
         23 . The transmission device according to  claim 11 , wherein the high level has 3/4 of a voltage level, the middle level has 2/4 of the voltage level, and the low level has 1/4 of the voltage level. 
     
     
         24 . A transmission device comprising:
 a variable emphasis driver configured to change a pre-emphasis strength according to a level by which an input signal transitions to control a transition time of an output signal.   
     
     
         25 . The transmission device according to  claim 23 ,
 wherein the variable emphasis driver comprises a plurality of pre-emphasis drivers, and   wherein the variable emphasis driver increases the strength for driving by using a greater number of pre-emphasis drivers.   
     
     
         26 . The transmission device according to  claim 24 ,
 wherein the variable emphasis driver increases the strength for driving the output node, as a change in a voltage level of the input signal increases.