Mixer with calibration circuit and calibration method thereof

摘要

A mixer with calibration circuit includes a first gm stage unit, a second gm stage unit, a first detecting unit, a second detecting unit, a comparison block, a control unit and a compensator. The first detecting unit and the second detecting unit are respectively connected to different gm stage unit, and the comparison block compares voltage signals of the first detecting unit and the second detecting unit. The control unit adjusts a current signal of the comparison block according to the comparative result of voltage signals of the first detecting unit and the second detecting unit. Further, the compensator adjusts the first gm stage unit and the second gm stage unit according to the current signal. Thereafter, the improvement of the LO leakage of the mixer can be achieved.

主权项

1. A mixer with calibration circuit, comprising:
an LO switch block having an input coupled to an output of a local oscillator; a gm stage block comprising a first gm stage unit and a second gm stage unit, wherein calibrated output currents from said first and second gm stage units are input to said LO switch block; a detector comprising a first detecting unit configured to switchably connect between said second gm stage unit and said first gm stage unit, and a second detecting unit configured to switchably connect between said first gm stage unit and said second gm stage unit, wherein a first switch unit is connected with said first detecting unit, said first gm stage unit, and said second gm stage unit to enable either of said first gm stage unit or said second gm stage unit to connect with said first detecting unit, and a second switch unit is connected with said second detecting unit, said first gm stage unit and said second gm stage unit to enable either of said first gm stage unit or said second gm stage unit to connect with said second detecting unit; a comparison block connected to said detector and said gm stage block adapted to compare voltage signals of said first detecting unit and said second detecting unit; a control unit connected to said comparison block adapted to adjust a current signal of said comparison block according to the comparative result of voltage signals of said first detecting unit and said second detecting unit, and generate a compensation signal according to said current signal; and a compensator connected with said control unit, said first gm stage unit and said second gm stage unit adapted to adjust said first gm stage unit and said second gm stage unit according to said compensation signal to provide said calibrated output current from said gm stage block.