Patent ID: 8681034

Claim:
An analog-to-digital converter, comprising: a voltage generating unit including a plurality of variable resistors, wherein: the voltage generating unit is configured to divide a reference voltage by the variable resistors to generate a plurality of comparative voltages, each of the variable resistors includes no switch, each of the variable resistors includes a plurality of variable resistive elements connected in series, each of the variable resistive elements is configured to change between two resistance values according to an external signal; and a plurality of comparators each configured to compare one of the plurality of comparative voltages with an analog input voltage and output a digital signal based on a result of a comparison between the comparative voltage and the analog input voltage, wherein: the external signal includes a plurality of control signals, each of the control signals corresponding to one of the variable resistors, each of the control signals is represented by a plurality of bits, each of the bits corresponding to one of the variable resistive elements included in the corresponding variable resistor in a one-to-one manner, and each of the variable resistive elements is set to one of the resistance values according to the bit corresponding to the corresponding variable resistive element.