Patent ID: 8324928
Filing Date: 2012-12-04
Classification: H01C

Abstract:
1. A calibration circuit comprising: a pad connected between an external resistor connected to a first voltage source and a first node; a first resistor unit connected between the first node and a second voltage source and having an impedance that is determined in response to a first control signal; a second resistor unit connected between a second node and the second voltage source and having an impedance that is determined in response to a second control signal; a first control unit for generating and outputting a first output signal by using a voltage level of the first node and a voltage level of the second node; a first pull-down circuit connected between the second node and the first voltage source and having an impedance that is determined in response to the first output signal; a second pull-down circuit connected between a third node and the first voltage source and having an impedance that is determined in response to the first output signal; a second control unit for generating and outputting a second output signal by using a voltage level of the third node and a voltage level of a reference voltage; and a pull-up circuit connected between the third node and the second voltage source and having an impedance that is determined in response to the second output signal.