Patent ID: 8502722

Claim:
An analog-to-digital converting (ADC) apparatus, comprising: a coarse comparing module, used to receive an input signal and compare the input signal and a plurality of first reference signals to generate a previous comparing result and a coarse comparing result in sequence; at least one pre-switching detection module, used to receive the previous comparing result and generate a previous selecting signal according to the previous comparing result; an encoder, coupled to the coarse comparing module, and used to generate a previous encoding result according to the coarse comparing result; and at least one fine comparing module, coupled to the pre-switching detection module and the encoder, and used to receive the input signal, the previous selecting signal, and the previous encoding result, the fine comparing module selects a plurality of primary reference signals from a plurality of second reference signals according to the previous selecting signal, and selects a selected reference signal from the primary reference signals according to the previous encoding result to be compared with the input signal for generating a fine comparing result.