US 12,244,282 B2
Impedance calibration circuit and method
Ming-Yen Tsai, Hsinchu (TW); and Tze-Hsiang Chao, Hsinchu (TW)
Assigned to M31 TECHNOLOGY CORPORATION, Hsinchu County (TW)
Filed by M31 TECHNOLOGY CORPORATION, Hsinchu County (TW)
Filed on Mar. 10, 2023, as Appl. No. 18/182,172.
Prior Publication US 2024/0305275 A1, Sep. 12, 2024
Int. Cl. H03H 11/28 (2006.01); G11C 7/10 (2006.01); H03K 5/24 (2006.01)
CPC H03H 11/28 (2013.01) [G11C 7/1048 (2013.01); H03K 5/24 (2013.01); G11C 2207/2254 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An impedance calibration circuit, comprising:
a variable impedance circuit, comprising a plurality of conduction paths connected in parallel between a supply terminal and an output terminal, the supply terminal being coupled to a first supply voltage, the variable impedance circuit being configured to adjust an impedance at the output terminal by enabling one or more of the conduction paths according to a calibration code;
a detection circuit, configured to detect a change in impedance of the conduction paths by applying a second supply voltage to a reference terminal through a detection path of the detection circuit, and accordingly generate an input voltage at the reference terminal, wherein an electric potential of the second supply voltage is equal to an electric potential of the first supply voltage; and
a control circuit, coupled to the variable impedance circuit and the detection circuit, the control circuit having a plurality of input terminals arranged to receive a plurality of reference voltages respectively, the control circuit being configured to compare the input voltage with the reference voltages, received from the input terminals respectively, to generate the calibration code.