Abstract:
PURPOSE: A comparator, an analog-to-digital (A/D) converter, a ramp signal slope compensating circuit, a complementary metal-oxide semiconductor (CMOS) image sensor containing the circuit, and a ramp signal slope compensating method in accordance with the above are provided to prevent the slope ratio of a fine ramp signal to a coarse ramp signal from being distorted due to the slope change of the fine ramp signal and to improve linearity of A/D conversion. CONSTITUTION: An A/D converter (10) includes an amplifier, a comparator (12), a first memory part (16), and a second memory part (18). The amplifier receives a pixel voltage, a reference voltage, a fine ramp voltage, and a coarse ramp voltage. The comparator is equipped with a switch, which is connected between a coarse ramp voltage input terminal receiving coarse ramp voltage input and the amplifier, and a capacitor. One end of the capacitor is connected between the switch and the amplifier, and the other end is connected to a ground voltage. The first memory part stores the most significant bit among 1 least significant bit (LSB) for the coarse ramp voltage. The second memory part stores the least significant bit among 1 LSB for the coarse ramp voltage. [Reference numerals] (12) Comparator; (14) Sink block part; (16) First memory part; (18) Second memory part; (21) Fine ramp generator; (22) Coarse ramp generator; (30) N bit counter
Abstract:
PURPOSE: An analog to digital converter (ADC) for outputting a digitized sample signal after comparing a sample signal and a ramp signal and an image sensing apparatus applying the same are provided to increase an analog to digital (A/D) conversion speed two times faster than when exclusively using an existing up-ramp, thereby providing a high-definition image without delay. CONSTITUTION: A pixel (110) outputs an analog pixel value. A sample and hold (S/H) amplifier (120) generates a sample signal by performing a sample-and-hold operation of the analog pixel value outputted from the pixel. An ADC (130) digitizes the sample signal generated in the S/H amplifier after comparing the sample signal and multiple ramp signals. [Reference numerals] (110) Pixel; (131) Comparator-1; (132) Comparator-2; (133) Memory; (135) Compensation converter; (141) Up-lamp signal generator; (142) Down-lamp signal generator; (150) Counter
Abstract:
An AD converter converting an inputted analog signal into a digital signal is provided with an integrator outputting integrated waveforms obtained by sequentially integrating a signal level of the analog signal, a digital converting part detecting transition timing when a size relation of the signal level of the integrated waveform and a prescribed reference value transits to a prescribed state with prescribed time resolution, a feedback part controlling the signal level of the integrated waveform in accordance with a detection result in the digital converting part at a control period larger than time resolution, and a signal processing part generating the digital signal based on the detection result in the digital converting part.
Abstract:
An analog-digital converter is provided to reduce a size and power consumption by using a small number of analog elements in comparison with a conventional analog-digital converter. An analog-digital converter includes a measurement signal generator(71), a variable delay unit(72), a fixed delay unit(73), and a delay calculating and data generating unit(80). The measurement signal generator(71) generates a measurement signal(in). When the generated measurement signal(in) is changed from a low level to a high level, a switch(SW) of the variable delay unit(72) connects a ground voltage and a first capacitor(C1). The variable delay unit(72) generates a sensing signal(sen) by delaying the measurement signal(in) for a first delay. The fixed delay unit(73) generates a reference signal(ref) by delaying the measurement signal(in) for a second delay. The delay calculating and data generating unit(80) calculates a delay difference between the reference signal(ref) and the sensing signal(sen), and generates digital data having a value corresponding to the calculated delay difference.
Abstract:
The present invention relates to a time-digital converter and a time-digital conversion method. The time-digital converter in accordance with an embodiment of the present invention includes a conversion unit converting a time difference of input signals into a voltage; a generation unit increasing a digital code and generating an analog signal corresponding to the digital code; a comparison unit comparing the voltage of the analog signal with the converted voltage; and an output unit outputting the digital code when the output signal of the comparison unit is converted.
Abstract:
The present invention relates to a technology which improves resolution by controlling the transient time to an analog level using a time-interpolation method in a digital-analog converter and suppresses the consequent increase in the area. The present invention includes a m-bit time-interpolation unit for receiving analog signals VREF(k) and VREF(k+1) supplied through (n-m)-bit reference voltage resistor column and (n-m)-bit first and second decoders, performing time-interpolation which controls the transient time from one analog level to other analog level, and outputting an analog signal (VC) having its resolution increased by m-bit. [Reference numerals] (120A) (n-m) bit decoder; (130) m-bit time-interpolation unit
Abstract:
PURPOSE: A double slope integrating ADC(Analog To Digital Converter) is provided to minimize a chip area by forming a switch control logic circuit part with a MCU(Micro Control Unit) and a single chip by using a standard CMOS(Complementary Metal Oxide Semiconductor) process. CONSTITUTION: An LOTA(Linear Operational Transconductance Amplifier) outputs a current by being applied with an analog input voltage and a reference voltage. First resistance applies the analog input voltage to an (+) input terminal in the LOTA. A first switch applies the analog input voltage to the first resistance according to a control signal. Second resistance applies the reference voltage to a (-) input terminal in the LOTA. The second switch applies the reference voltage to the second resistance according to the control signal. A capacitor outputs a voltage by charging an output current in the LOTA. A third switch initializes the output current in the LOTA and the voltage charged in the capacitor. A comparator outputs two constant voltages. A switch control logic circuit outputs the control signal controlling the operation of first, second, and third switches.
Abstract:
An analog to digital converter using a delay locked loop and an analog to digital converting method are provided to reduce difference between the delay due to the analog input signal and the delay of the reference signal converting a digital code to analog code by using a successive approximation method and a delay locked loop. A first delay unit(10) receives a first clock signal and delays the first clock signal as much as the first delay time according to the analog input signal. A second delay unit(20) delays the first clock signal as much as the second delay time according to the reference signal converting the N bit digital signal to the analog signal. The N is a positive integer. A compensation unit(300) generates the N bit digital bit to reduce the difference between the first delay time and the second delay time and supplies the reference signal by converting the N bit digital signal to the analog signal. The compensation unit includes a delay error compensation unit and a digital to analog converter.