Analog-digital converter and image sensor including thereof

An analog-digital converter, comprising:

• a comparator to receive a first pixel signal during a first sensing cycle and to receive a second pixel signal during a second sensing cycle;
• and
• a counter to output a digital signal of the second pixel signal according to a count enable clock signal,
• wherein in the first and second sensing cycles, the counter does not output the digital signal when the count enable clock signal is a first level, and the counter outputs the digital signal when the count enable clock signal is a second level different from the first level, and
• wherein the first level is a logic level for when a count code is not stored and maintained in a latch, and
• wherein the second level is a logic level for when the count code is stored and maintained in the latch.

An image sensor comprising:

• a pixel array including a plurality of pixels;
• a reference signal generator to output a reference signal;
• and
• an analog-digital converter to receive a pixel signal output from each pixel connected to column lines and the reference signal,
• wherein the analog-digital converter includes:
• a comparator to compare the pixel signal with the reference signal and to output a comparison result signal,
• a count code generator to receive a code generation clock signal from a clock signal generator and to output a count code according to the code generation clock signal,
• a latch to latch the count code,
• an operating circuit connected to a terminal of the latch, to generate a count value of the count code, and to output a digital signal of the pixel signal based on the count value, and
• a transfer controller to transfer the count code to the operating circuit through the latch, the transfer controller to determine whether to transfer the count code according to a logic level of a count enable clock signal generated from the clock signal generator,
• wherein the logic level of the count enable clock signal is determined according to whether the count code is stored and maintained in the latch.