US Patent 7142143 Time-continuous sigma/delta analog-to-digital converter

Time-continuous sigma/delta analog-to-digital converter for converting an analog input signal into a digital output signal (D), having at least one analog filter (3) which filters the analog input signal present at a signal input (2) of the analog filter (3), a quantizer (12) which is clocked by a clock signal (CLK) and quantizes the filtered analog signal, output by the analog filter (3), in order to generate the digital output signal (D), and having at least one reference capacitor (28) which can be continuously charged to a reference voltage (VREF) by a current source (31) for displacing a constant charge (Q) to/from the analog filter (3), such that no voltage jumps occur at the analog filter (3).