Abstract:
PURPOSE: An operational amplifier circuit, an image sensor including the same, and a method for compensating a frequency response of an operational amplifier are provided to output a high frequency signal by widening a bandwidth and implementing stability by adjusting capacitance according to a feedback gain. CONSTITUTION: An operational amplifier circuit includes a first operational amplifier(10), a second operational amplifier(20), a feedback block(30) and a variable compensation capacitor(Cc). The first operational amplifier differentially amplifies an input signal. A load capacitor and the variable compensation capacitor are connected to an output port of the first operational amplifier. The feedback block adds a feedback gain to the output of the first operational amplifier and then feeds back the result to the input of the first operational amplifier. The capacitance of the variable compensation capacitor varies on the basis of the feedback gain.
Abstract:
PURPOSE: A sense amplifier including a negative capacitance circuit and apparatuses including the same are provided to improve a data readout speed by accurately sensing and amplifying input data at high operation speed. CONSTITUTION: A negative capacitance circuit(13) is connected between data line pairs. A current bias circuit supplies a bias current to the negative capacitance circuit. A voltage bias circuit(15) supplies a bias voltage to data line pairs. A differential-single-ended amplifier(19) is connected between the data line pairs.
Abstract:
PURPOSE: A two-path sigma-delta analog-to-digital converter and an image sensor including the same are provided to process two different inputs through one calculating amplifier by shaping the calculating amplifier. CONSTITUTION: An integrator(510) divides a clock signal into a front cycle and a back cycle by sharing one calculating amplifier. The integrator integrates a first input signal during the back cycle. The integrator integrates a second input signal during the first cycle. A quantizer(540) quantizes a signal which is integrated through the integrator and outputs first and second digital signals. A feedback path(550) feeds-back the first and the second digital signals.