Analog-to-digital converter

An analog-to-digital converter (ADC), comprising:

• a coarse ADC that samples an analog input voltage for a first period, generates a first digital signal based on the analog input voltage using a successive approximation register (SAR) method for a second period, and outputs a residual voltage remaining after the first digital signal is generated;
• an amplifier that receives the residual voltage for a third period, and generates a residual current by amplifying the residual voltage by a predetermined gain;
• a fine ADC that receives the residual current for a fourth period, and generates a second digital signal based on the residual current using the SAR method;
• and
• an auxiliary path that receives a test current and generates a gain correction signal based on the test current,
• wherein the gain of the amplifier is adjusted for the fourth period in which the fine ADC generates the second digital signal based on the residual current.

An analog-to-digital converter (ADC), comprising:

• a coarse ADC that receives an analog input voltage, generates a first digital signal based on the analog input voltage using a successive approximation register (SAR) method, and outputs a residual voltage remaining after the first digital signal is generated;
• a test voltage generator that outputs a test voltage;
• a selector that outputs one of the residual voltage and the test voltage in response to a selection signal;
• an amplifier that receives the residual voltage and the test voltage from the selector, generates a first residual current by amplifying the residual voltage by a predetermined gain, and generates a test current by amplifying the test voltage by the gain;
• a fine ADC that receives the first residual current, generates a second digital signal based on the first residual current using the SAR method, and outputs a second residual current remaining after the second digital signal is generated;
• an auxiliary path that receives the test current, and generates a gain correction signal based on the test current,
• wherein the gain of the amplifier is adjusted based on the gain correction signal;
• and
• a gain correction circuit that outputs a control signal that controls the amplifier such that the amplifier corrects the gain based on the gain correction signal,
• wherein regardless of a time at which the fine ADC converts the first residual current into the second digital signal, the auxiliary path generates the gain correction signal based on the test current.