Semiconductor apparatus and calibration method for analog to digital converter

摘要

In a conventional calibration method of an analog to digital converter, it has been difficult to easily derive a plurality of correction coefficients. A semiconductor apparatus according to an embodiment includes a plurality of unit elements that are provided to correspond to the total number of weights for each bit of the digital intermediate value b[1:0] output from a sub ADC, and the same capacitance, the same resistance value, or the same current value being set to the plurality of unit elements. Further included is a corresponding bit switching unit configured to switches the bits of the digital intermediate value based on which the plurality of unit elements generate analog values. At the time of calibration, combinations of the plurality of unit elements and the bits are rotated, and correction coefficients are derived by digital intermediate values obtained according to each combination.

主权项

1. A semiconductor apparatus comprising:
a sub ADC that outputs a digital intermediate value corresponding to a signal level of an input signal as a multi-bit digital value; a sub DAC that outputs an analog intermediate value corresponding to the digital intermediate value; a residue amplifier that amplifies a difference between the input signal and the analog intermediate value and outputs a residue signal; and an output stage circuit that outputs a digital output value, the digital output value being generated by correcting the digital intermediate value by a correction coefficient, wherein the sub DAC comprises:
a plurality of unit elements, the plurality of unit elements being provided to correspond to a total number of weights for each bit of the digital intermediate value, and the same capacitance, the same resistance value, or the same current value being set to the plurality of unit elements;a corresponding bit switching unit that switches the bits of the digital intermediate value based on which the plurality of unit elements generate analog values; anda calibration control unit that switches combinations of the unit elements and the bits used by the unit elements to generate the analog value at the time of an calibration operation, and the output stage circuit obtains the digital intermediate value for each of the combinations of the unit elements and the bits at the time of the calibration operation and calculates the correction coefficient according to the obtained digital intermediate value.