Programmable gain amplifier and devices including the same

An image sensor, comprising:

• a pixel;
• and
• a programmable gain amplifier configured to amplify a pixel signal output from the pixel,
• the programmable gain amplifier including,
• a sampling circuit configured to perform correlated double sampling on an input signal using a reference voltage,
• a source follower,
• a first capacitor connected between the sampling circuit and the source follower, and
• an error amplifier connected between an input terminal of the source follower and an output terminal of the source follower, the error amplifier being configured to reset a voltage of the output terminal of the source follower to the reference voltage during a source follower reset operation that resets the source follower.

An image sensor, comprising:

• at least one pixel;
• a voltage generator configured to generate a reference voltage;
• a programmable gain amplifier connected to the at least one pixel and the voltage generator, the programmable gain amplifier including,
• a sampling circuit configured to perform correlated double sampling on an input signal using the reference voltage, the input signal being based on light incident to the at least one pixel, and
• a voltage transfer circuit configured to output a voltage from the sampling circuit;
• and
• a controller configured to control the programmable gain amplifier to operate in at least a reset phase and a signal phase, the reset phase being a phase in which an output terminal of the voltage transfer circuit is reset to the reference voltage, the signal phase being a phase in which the sampling circuit amplifies the input signal according to a capacitance ratio of capacitors within the sampling circuit and the voltage transfer circuit outputs the amplified signal.