Patent ID: 7619488

Claim:
A resistance adjusting circuit including a semiconductor integrated circuit comprising: a reference voltage generating circuit which generates a reference voltage having a value corresponding to a resistance of an external resistor element connected to the semiconductor integrated circuit; a comparison voltage generating circuit which comprises a replica resistor circuit whose resistance is adjusted according to a resistance control signal and generates a comparison voltage having a value corresponding to a resistance of the replica resistor circuit; a main body resistor circuit which has substantially the same configuration as that of the replica resistor circuit and whose resistance is adjusted according to the resistance control signal, and a control signal generating circuit which receives the reference voltage and the comparison voltage and converts the reference voltage and the comparison voltage to frequency signals having frequencies corresponding to values of the reference voltage and the comparison voltage, integrates the frequency signals of the reference voltage and the comparison voltage to produce integration data of the frequency signals, and generates the resistance control signal based upon a difference between the integration data.