A CMOS imager with PFM/PWM based analog-to-digital converter

نویسنده

  • Amine Bermak
چکیده

An On-pixel Analog-to-Digital Converter based on both PFM and PWM schemes is reported. The proposed architecture uses a limited number of transistors that can be implemented in a small silicon area resulting in a 23% fill-factor. The digital sensor can be extemally configured in order to operate under either the PFM or PWM scheme. At high-light intensities, the PFM scheme is replaced by the PWM scheme which proves to be much more efficient in terms of power consumption and clock frequency requirements. An in-built light adaptation mechanism has also been implemented which allows the sensor to better adapt to low-light intensity or to adjust the sensor saturation level. As a consequence, the sensor features a programmable dynamic range. Image lag is reduced in both schemes since a reset of the photodetector is performed after the conversion period. The pixel based ADC has been designed and fabricated using CMOS 0.25pm technology.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

A High Efficiency Low-Voltage Soft Switching DC–DC Converter for Portable Applications

This paper presents a novel control method to improve the efficiency of low-voltage DC-DC converters at light loads. Pulse Width Modulation (PWM) converters have poor efficiencies at light loads, while pulse frequency modulation (PFM) control is more efficient for the same cases. Switching losses constitute a major portion of the total power loss at light loads. To decrease the switching losses...

متن کامل

An all-digital PWM-based ΔΣ ADC with an inherently matched multi-bit quantizer

An all-digital PWM-based delta-sigma (ΔΣ) ADC is proposed. This system takes advantages of the duration of a pulse, rather than voltage or current, as the analog operand used in its closed-loop operation. Unlike VCO-based ADCs, this ADC as a linear input sampling stage with adequate uncalibrated performance. Furthermore, the architecture allows inherently matched multi-bit quantizer/DAC blocks ...

متن کامل

A 4 s integration time imager based on CMOS single photon avalanche diode technology

An optical imager is reported based on single photon avalanche diodes. The imager, fabricated in 0.8 m CMOS technology, consists of an array of 1024 pixels each with an area of 58 m× 58 m for a total chip area of 2.5 mm× 2.8 mm. The architecture of the imager is reduced to a minimum since no A/D converter is required. Moreover, since the output of each pixel is digital, complex read-out circuit...

متن کامل

High-Frequency Digital PWM Controller IC for DC–DC Converters

This paper describes a complete digital PWM controller IC for high-frequency switching converters. Novel architecture and configurations of the key building blocks are A/D converter, compensator, and digital pulse-width modulator, are introduced to meet the requirements of tight output voltage regulation, high-speed dynamic response, and programmability without external passive components. The ...

متن کامل

The Design of PFM Mode DC-DC Converter with DT-CMOS Switch

The high efficiency power management IC (PMIC) with switching device is presented in this paper. PMIC is controlled with PFM control method in order to have high power efficiency at high current level. Dynamic Threshold voltage CMOS (DT-CMOS) with low on-resistance is designed to decrease conduction loss. The threshold voltage of DT-CMOS drops as the gate voltage increase, resulting in a much h...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2002