Patent ID: 7218136
Filing Date: 2007-05-15
Classification: H04L

Abstract:
1. A transmission circuit transmitting a signal through first and second signal lines that form a differential pair, comprising: a current source coupled between a first power supply and a node; a first switching element inserted between the node and the first signal line; a second switching element inserted between the node and the second signal line; a circuit driving the first signal line or the second signal line through either the first switching element or the second switching element with a current provided from the current source; a first terminating resistor terminating the first signal line; a second terminating resistor terminating the second signal line; and a terminating resistance control circuit generating a control signal for controlling terminating resistance values of the first terminating resistor and the second terminating resistor, wherein the first terminating resistor and the second terminating resistor respectively have a variable resistor including first-nth resistors coupled each other, the first resistor takes a first resistance value if a first control signal is active, the nth resistor takes a nth resistance value if a nth control signal is active, one end of the coupled first-nth resistors is coupled to a reference potential, the other end of the coupled first-nth resistors is coupled to the first signal line or the second signal line and the terminating resistance control circuit generates the first to nth control signals based on a terminating resistance configuration information.