BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to an offset compensation device, and more particularly to a configurable offset compensation device.

2. Description of the Prior Art

Since the differential signal has a better immunity against ambient noises, it is widely adopted in various circuits. However, in the actual manufacturing of differential amplifiers or other types of differential circuits, due to process deviations, the direct current (DC) voltage level is often shifted unexpectedly, causing offset voltages and/or offset currents at the terminals of the differential pair. Since the offset voltage and/or offset current at the terminals of the differential pair will interfere with the differential signal and cause distortion, additional voltage or current must be applied to compensate the offset and reduce the impact brought by the shift of the DC voltage level.

Furthermore, as the manufacturing technology grows, the size of electronic components becomes smaller and smaller. However, when the size of the electronic component becomes smaller, the influence of the same offset voltage and/or offset current on the differential circuit will also become more significant, and thus, the requirements for accurate compensation to the offset voltage and/or the offset current would be higher.

SUMMARY OF THE INVENTION

One embodiment of the present invention discloses an offset compensation device. The offset compensation device includes a first bias module and a second bias module.

The first bias module is coupled to a first bias node and includes a plurality of first current control circuits and a plurality of second current control circuits. Each of the plurality of first current control circuits generates a first reference current, and each of the plurality of second current control circuits generates a second reference current. The second bias module is coupled to a second bias node and includes a plurality of third current control circuits and a plurality of fourth current control circuits. Each of the plurality of third current control circuits generates a third reference current, and each of the plurality of fourth current control circuits generates a fourth reference current.

The plurality of first current control circuits and the plurality of second current control circuits are coupled in parallel and coupled to the first bias node. The plurality of third current control circuits and the plurality of fourth current control circuits are coupled in parallel and coupled to the second bias node. The second reference current is greater than the first reference current, and the fourth reference current is greater than the third reference current.

Another embodiment of the present invention discloses a method for operating an offset compensation device. The offset compensation device includes a first bias module and a second bias module. The first bias module includes a plurality of first current control circuits and a plurality of second current control circuits. The second bias module includes a plurality of third current control circuits and a plurality of fourth current control circuits. The plurality of first current control circuits and the plurality of second current control circuits are coupled in parallel and coupled to a first bias node, and the plurality of third current control circuits and the plurality of fourth current control circuits are coupled in parallel and coupled to a second bias node.

The method includes enabling a first number of second or fourth current control circuits according to an offset value for making a preliminary compensation to the offset value, and enabling a second number of first or third current control circuits according to the offset value after the preliminary compensation is made for making a further compensation to the offset value.

A second reference current generated by each of the second current control circuits is greater than a first reference current generated by each of the first current control circuits, and a fourth reference current generated by each of the fourth current control circuits is greater than a third reference current generated by each of the third current control circuits.

These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.

