Patent ID: 7915913

Claim:
A termination resistance adjusting circuit comprising: a first termination resistor circuit that has a variable resistance; a second termination resistor circuit that has a variable resistance, and is connected in parallel with the first termination resistor circuit; a resistor circuit for adjustment that adjusts the resistances of the first and second termination resistor circuits; a first amplifier circuit that receives a first voltage and a second voltage, equalizes the first and second voltages, and outputs a resistance adjusting signal to the first and second termination resistor circuits, the first voltage being determined by the resistor circuit for adjustment, and the second voltage being determined by a reference resistor connected externally; a first terminal connected to the first termination resistor circuit; a second terminal connected to the second termination resistor circuit; and a second amplifier circuit that receives a voltage based on a common voltage of a differential signal, and one of the first and second voltages, and equalizes the voltage based on the common voltage and the one of the first and second voltages, the differential signal being supplied to the first and second terminals.