Terminal resistance device, semiconductor device, and control method for terminal resistance
View Patent ↗One aspect of the invention is a terminal resistance device including a variable terminal resistance unit including a plurality of first terminal resistance elements connectable to a transmission path and a terminal resistance control unit that transmits a first control signal of a thermometer code to the variable terminal resistance unit. The first terminal resistance elements have the same resistance value and the first control signal is a signal for selecting the first terminal resistance elements to be connected to the transmission path.
1. A terminal resistance device comprising:
a variable terminal resistance unit including a plurality of first terminal resistance elements connectable to a transmission path, and at least one second terminal resistance element connectable to the transmission path; and
a terminal resistance control unit that transmits a first control signal of a thermometer code to the variable terminal resistance unit and a second control signal of a binary code to the variable terminal resistance unit, the first control signal being for selecting the first terminal resistance elements to be connected to the transmission path, the second control signal being for selecting the at least one second terminal resistance element to be connected to the transmission path,
wherein the first terminal resistance elements have the same resistance value,
wherein the at least one second terminal resistance element has a resistance value which is 2 n times a resistance value of each of the first terminal resistance elements so as to define a series of terminal resistance elements having respectively resistance values R and R*2 n (R represents the resistance value of the plural first terminal resistance elements having the same resistance value, n represents a positive or negative integer, and R*2 n represents the resistance value of the second terminal resistance element), and
wherein the terminal resistance control unit comprises a binary code-thermometer code convert unit which converts a received binary code to the thermometer code.
2. The terminal resistance device according to claim 1 , wherein the terminal resistance control unit comprises:
a variable resistance unit which includes a plurality of compare resistance elements connectable to a detect point and respectively corresponding to the first terminal resistance elements, and a compare circuit that compares a voltage of the detect point and a reference voltage; and
a logic unit that selects the first terminal resistance elements to be connected to the transmission path based on a comparison result of the compare circuit,
wherein the compare resistance elements are switched to be connected to the detect point based on the first control signal which is transmitted to the corresponding first terminal resistance elements.
3. The terminal resistance device according to claim 1 , wherein each of the first terminal resistance elements has a resistance element having a resistance value set by adjusting a gate width and a switching element which switches a connection between the first terminal resistance element and the transmission path based on the first control signal.
4. The terminal resistance device according to claim 3 , wherein the switching element is configured with a metal-oxide semiconductor field-effect transistor.
5. The terminal resistance device according to claim 1 , wherein the first terminal resistance elements are configured with transistors.
6. A semiconductor device comprising a terminal resistance device according to claim 1 .
7. The semiconductor device according to claim 6 being a semiconductor memory.
8. A control method for a terminal resistance comprising:
transmitting a first control signal of a thermometer code to a variable terminal resistance unit including a plurality of first terminal resistance elements connectable to a transmission path and at least one second terminal resistance element connectable to the transmission path, the first control signal being for selecting the first terminal resistance elements to be connected to the transmission path, wherein the terminal resistance control unit has been derived from a binary code-thermometer code convert unit which converts a received binary code to the thermometer code; and
transmitting a second control signal of a binary code to variable terminal resistance unit, the second control signal being for selecting the at least one second terminal resistance element to be connected to the transmission path,
wherein the first terminal resistance elements have the same resistance value, and
wherein the at least one second terminal resistance element has a resistance value which is 2 n times a resistance value of each of the first terminal resistance elements so as to define a series of terminal resistance elements having respectively resistance values R and R*2 n (R represents the resistance value of the plural first terminal resistance elements having the same resistance value, n represents a positive or negative integer, and R*2 n represents the resistance value of the second terminal resistance element).
9. The terminal resistance device according to claim 1 , wherein,
the variable terminal resistance unit includes plural second terminal resistance elements connectable to the transmission path,
the second terminal resistance elements each have a resistance value which is 2 n times a resistance value of each of the first terminal resistance elements so as to define a series of resistance elements having respectively resistance values R, R, and R*2 n (R represents the resistance value of the plural first terminal resistance elements having the same resistance value, n represents a positive or negative integer, and R*2 n represents the resistance value of the second terminal resistance element), the terminal resistance control unit transmits the second control signal of a binary code to the variable terminal resistance unit,
the second control signal is for selecting the at least one second terminal resistance element to be connected to the transmission path, and
each of i) the terminal resistance elements controlled by the binary code and ii) the terminal resistance elements controlled by the thermometer code connected to the transmission path.
10. A terminal resistance device, comprising:
a variable terminal resistance unit including
i) a first terminal resistance unit having a plurality of first terminal resistance elements connectable to a transmission path, each of the first terminal resistance elements having the same resistance value, and
ii) a second terminal resistance unit having second terminal resistance elements connectable to a transmission path, the second resistance elements each having a resistance value which is 2 n times a resistance value of the first terminal resistance elements, so as to define a series of first and second terminal resistance elements having respectively resistance values R and R*2 n , where R is the resistance value of the plural first terminal resistance elements having the same resistance value, n is a non-zero integer, and R*2 n represents the resistance value of the second terminal resistance element; and
a terminal resistance control unit that transmits i) a first control signal of a thermometer code to the first variable terminal resistance unit, the first control signal being for selecting the first terminal resistance elements of to be connected to the transmission path, and ii) further transmits a second control signal of a binary code to the variable terminal resistance unit, the second control signal for selecting the second terminal resistance elements to be connected to the transmission path,
a gate width of the first terminal resistance elements is different from a gate width of the second terminal resistance elements.