Patent ID: 8749264

Claim:
A circuit, comprising: a first node; a second node; a third node; a plurality of resistors with different resistance, wherein a first terminal of each resistor is connected to the first node a plurality of capacitors with different capacitance; a plurality of first switches corresponding to the same number of resistors, wherein a second terminal of each resistor is connected to a first terminal of a corresponding one of the first switches, a second terminal of each first switch is connected to the second node; a plurality of second switches corresponding to the same number of capacitors; and a third switch, wherein a first terminal of the third switch is connected to the second terminal of each first switch, a second terminal of the third switch is connected to a first terminal of each capacitor, a second terminal of each capacitor is connected to a first terminal of a corresponding one of the second switches, a second terminal of each second switch is connected to the third node.