ANALOG COMPARATIVE REFERENCE SIGNAL GENERATOR AND METHOD THEREOF, ANALOG TO DIGITAL CONVERTER HAVING THE SAME AND IMAGE SENSOR HAVING THE SAME

摘要

An analog comparative reference voltage generating circuit, a generating method thereof, an A/D digital converter and an image sensor including the same are provided to output the output voltage in a desired level more rapidly than the frequency of a clock. The first clock(Clk1) and the second clock(Clk2) are signals which are generated by using a part of a master clock. An OP amplifier receives an OFFSET voltage through the first input terminal and outputs an OUT voltage through an output terminal. A feedback capacitor(C52) forms a feedback loop between the second input terminal and an output terminal of the OP amplifier. A reset switch (S59) maintains the output voltage of the OP amplifier output terminal in the OFFSET voltage in response to a reset signal.