INTEGRATED CALIBRATION CIRCUIT AND A METHOD FOR CALIBRATION OF A FILTER CIRCUIT

摘要

A calibration circuit and a method for calibrating a RC circuit, such as a high-pass filter, of an integrated circuit are provided. The calibration circuit comprises a filter arrangement having tuneable filter for filtering an input signal having a predetermined frequency. The filter comprises tuneable resistor elements, a saturation detector for detecting saturation and non-saturation of the tuneable filter by comparing a comparison voltage with the signal voltage of the filtered input signal, calibration control logic for providing incrementing and decrementing counter signals. The calibration circuit sets the comparison voltage to a first threshold voltage provides iteratively the incrementing counter signal to the filter until saturation is detected reduces the comparison voltage to a predetermined second threshold voltage after saturation is detected, the second threshold voltage being a lower value than the first threshold voltage, and provides the decrementing counter signal to the filter until non-saturation is detected.

主权项

1. A calibration circuit for calibrating a RC circuit of an integrated circuit, in particular for calibrating a high-pass filter arrangement, the calibration circuit comprising:
a filter arrangement comprising at least one tuneable filter configured to filter an input signal having a predetermined frequency wherein the tuneable filter comprises at least two tuneable resistor elements; a saturation detector configured to detect saturation and non-saturation of the tuneable filter by comparing a comparison voltage with the signal voltage of the filtered input signal; a calibration control logic configured to provide an incrementing counter signal and a decrementing counter signal; wherein the calibration circuit is further configured to: set the comparison voltage to a first threshold voltage; provide iteratively an incrementing counter signal to the tuneable filter until saturation is detected; after saturation is detected, reducing the comparison voltage to a predetermined second threshold voltage which is be a predetermined value lower than the first threshold voltage; and provide then iteratively a decrementing counter signal to the tuneable filter until non-saturation is detected.