ABSTRACT
This paper presents the design of a low-power CMOS current-frequency (I–F) Analog–Digital Converter. The ADC is designed for implantable blood-glucose monitoring. This current frequency ADC uses nArange of input currents to set and compare voltage oscillations against a self-produced reference to resolve 0–32nA with an accuracy of 5-bits at a 225MHz sampling rate. The comparator used is a dynamic latch comparator and the output is fetched from a 5-bit counter. This is designed in 180nm CMOS technology with a supply of 1.8V, it operating voltage taken here is 0.0- 1.8V with power consumption of 12.3nW using Cadence tools.
Design of an ADC using High Precision Comparator with Time Domain Offset Canc...IJTET Journal
Abstract— The comparator is a combinational logic circuit that plays an important role in the design of analog to digital converter. One of its most important properties is its input referred offset. When mismatches are present in a dynamic comparator, due to internal positive feedback and transient response, it is always challenging to analytically predict the input-referred random offset voltages since the operating points of transistors are time varying. To overcome the offset effect a novel time-domain bulk-tuned offset cancellation method is applied to a low power dynamic comparator. Using this comparator in analog to digital converter it does not increase the power consumption, but at the same time the delay is reduced and the speed is increased. The comparator is designed using the 250-nm CMOS technology in mentor graphics tool. Operating at a supply voltage of 5v and clock frequency 100MHZ, the comparator together with the offset cancellation circuitry dissipates 335.49nW of power and dissipates 1.027uW of power for comparator without offset cancellation circuit. The simulation result indicates that the offset cancellation circuitry consumes negligible power and it does not draw any static current. Using this high precision offset cancelled comparator in the analog to digital converter circuit the static power consumption is less and it is able to work under very low supply voltage.
This chapter discusses digital control systems. It describes the components of a digital control loop including digital controllers, analog-to-digital converters (ADCs), and digital-to-analog converters (DACs). ADCs convert analog signals to digital words, while DACs convert digital words to analog signals. Proper sampling and holding is required for interfacing between analog and digital systems. The sampling frequency must be high enough to avoid aliasing, with a recommended rate of 6-25 times the bandwidth of the controlled process.
The document provides information on various types of input and output devices used in industrial control systems. It discusses binary, digital and analog I/O devices and provides examples. It also describes different types of mechanical switches, sensors, and solid state devices like diodes, transistors, SCRs and triacs. Additionally, it summarizes different photoelectric sensing techniques such as opposed, retroreflective, and proximity modes as well as concepts like effective beam, ambient light receivers and modulated light sources.
Development of Digital Controller for DC-DC Buck ConverterIJPEDS-IAES
This paper presents a design & implementation of 3P3Z (3-pole 3-zero)
digital controller based on DSC (Digital Signal Controller) for low voltage
synchronous Buck Converter. The proposed control involves one voltage
control loop. Analog Type-3 controller is designed for Buck Converter using
standard frequency response techniques.Type-3 analog controller transforms
to 3P3Z controller in discrete domain.Matlab/Simulink model of the Buck
Converter with digital controller is developed. Simualtion results for steady
Keyword: state response and load transient response is tested using the model.
The document describes the ADC0808 analog to digital converter chip. It has an 8-channel multiplexer that selects which analog input signal to convert to digital. The conversion process takes 64 clock cycles to complete. The chip outputs the digital conversion result on 8 pins and has control signal pins for start, clock, output enable and end of conversion notification. It converts analog voltages to 8-bit digital numbers for use by digital devices like microprocessors.
Design & implementation of 3 bit flash adc in 0.18µm cmosIAEME Publication
This document describes the design and implementation of a 3-bit flash analog-to-digital converter (ADC) using a 0.18um CMOS technology. It includes 7 comparators and a thermometer-to-binary encoder. The ADC architecture consists of a resistive ladder, comparators that compare the input voltage to reference voltages from the ladder, and an encoder that converts the thermometer code from the comparators to a binary code. Simulation results show the ADC operates up to 4GHz and correctly converts the input signal to a 3-bit digital output. A layout is designed with common centroid layout for the comparators to reduce fabrication errors.
Analog to digital converter is one of the most important feature of micro controller. here i am explaining about basic of ADC, working and how exactly controller do it. Here i also explaining registers of ADC and attached a sample code.
Design of an ADC using High Precision Comparator with Time Domain Offset Canc...IJTET Journal
Abstract— The comparator is a combinational logic circuit that plays an important role in the design of analog to digital converter. One of its most important properties is its input referred offset. When mismatches are present in a dynamic comparator, due to internal positive feedback and transient response, it is always challenging to analytically predict the input-referred random offset voltages since the operating points of transistors are time varying. To overcome the offset effect a novel time-domain bulk-tuned offset cancellation method is applied to a low power dynamic comparator. Using this comparator in analog to digital converter it does not increase the power consumption, but at the same time the delay is reduced and the speed is increased. The comparator is designed using the 250-nm CMOS technology in mentor graphics tool. Operating at a supply voltage of 5v and clock frequency 100MHZ, the comparator together with the offset cancellation circuitry dissipates 335.49nW of power and dissipates 1.027uW of power for comparator without offset cancellation circuit. The simulation result indicates that the offset cancellation circuitry consumes negligible power and it does not draw any static current. Using this high precision offset cancelled comparator in the analog to digital converter circuit the static power consumption is less and it is able to work under very low supply voltage.
This chapter discusses digital control systems. It describes the components of a digital control loop including digital controllers, analog-to-digital converters (ADCs), and digital-to-analog converters (DACs). ADCs convert analog signals to digital words, while DACs convert digital words to analog signals. Proper sampling and holding is required for interfacing between analog and digital systems. The sampling frequency must be high enough to avoid aliasing, with a recommended rate of 6-25 times the bandwidth of the controlled process.
The document provides information on various types of input and output devices used in industrial control systems. It discusses binary, digital and analog I/O devices and provides examples. It also describes different types of mechanical switches, sensors, and solid state devices like diodes, transistors, SCRs and triacs. Additionally, it summarizes different photoelectric sensing techniques such as opposed, retroreflective, and proximity modes as well as concepts like effective beam, ambient light receivers and modulated light sources.
Development of Digital Controller for DC-DC Buck ConverterIJPEDS-IAES
This paper presents a design & implementation of 3P3Z (3-pole 3-zero)
digital controller based on DSC (Digital Signal Controller) for low voltage
synchronous Buck Converter. The proposed control involves one voltage
control loop. Analog Type-3 controller is designed for Buck Converter using
standard frequency response techniques.Type-3 analog controller transforms
to 3P3Z controller in discrete domain.Matlab/Simulink model of the Buck
Converter with digital controller is developed. Simualtion results for steady
Keyword: state response and load transient response is tested using the model.
The document describes the ADC0808 analog to digital converter chip. It has an 8-channel multiplexer that selects which analog input signal to convert to digital. The conversion process takes 64 clock cycles to complete. The chip outputs the digital conversion result on 8 pins and has control signal pins for start, clock, output enable and end of conversion notification. It converts analog voltages to 8-bit digital numbers for use by digital devices like microprocessors.
Design & implementation of 3 bit flash adc in 0.18µm cmosIAEME Publication
This document describes the design and implementation of a 3-bit flash analog-to-digital converter (ADC) using a 0.18um CMOS technology. It includes 7 comparators and a thermometer-to-binary encoder. The ADC architecture consists of a resistive ladder, comparators that compare the input voltage to reference voltages from the ladder, and an encoder that converts the thermometer code from the comparators to a binary code. Simulation results show the ADC operates up to 4GHz and correctly converts the input signal to a 3-bit digital output. A layout is designed with common centroid layout for the comparators to reduce fabrication errors.
Analog to digital converter is one of the most important feature of micro controller. here i am explaining about basic of ADC, working and how exactly controller do it. Here i also explaining registers of ADC and attached a sample code.
This document discusses analog control systems used with programmable logic controllers (PLCs) and programmable automation controllers (PACs). It describes how analog signals have continuous values between on and off, unlike discrete signals. It then explains that PLCs and PACs use analog input/output modules to interface with field devices that have continuously varying signals, such as temperature sensors, pressure sensors, motors etc. The document provides details on analog signal processing, including analog to digital conversion using ADCs and digital to analog conversion using DACs. It discusses key specifications for analog I/O modules such as resolution, conversion time and settling time.
The document describes the design of a 12-bit digital to analog converter (DAC). It includes a binary weighted resistor ladder circuit to convert the digital input to an analog voltage, and an operational amplifier circuit to drive the output load. Simulation results show the DAC can operate at up to 25MHz with good linearity and accuracy. Layout design considerations are discussed to optimize circuit performance and minimize parasitics.
This document describes the design of a 4-bit R-2R ladder digital to analog converter (DAC) using a 90nm CMOS technology process. It first discusses the design of a two-stage CMOS operational amplifier that meets given specifications. The design parameters and SPICE simulation results of the op-amp are then presented. Next, the document explains the principles of an R-2R ladder DAC and provides the specifications for the 4-bit DAC. It shows the SPICE circuit diagram and simulated output waveforms of the DAC. Comparisons are made between the expected and simulated DAC output levels. The document concludes the DAC design is suitable for the 90nm process and future work could enhance the
The document discusses data acquisition, conversion, and distribution systems in digital control systems. It describes how physical variables are converted to electrical signals via transducers, then amplified and filtered before being multiplexed and converted to digital signals using analog-to-digital converters (ADCs). It provides examples of calculating quantization levels and ADC outputs. Counter-type and successive-approximation ADCs are discussed as common conversion methods.
Analog To Digital Conversion (ADC) Programming in LPC2148Omkar Rane
1) The document describes programming the on-chip 10-bit ADC of the LPC2148 microcontroller to implement a simple data acquisition system. It discusses the features of the ADC, the programming interface, control registers, and provides code to initialize the ADC and read conversion results.
2) The code configures the ADC ports and control registers, reads the conversion results when the ADC status indicates a conversion is complete, and prints the voltage levels to the UART.
3) The results show the ADC accurately converts analog voltages from 0-3.1V to their corresponding 10-bit digital values, which are printed to the UART terminal.
This document discusses digital-to-analog converters (DACs). It defines a DAC as a circuit that produces an analog output proportional to a digital input and reference voltage. The document describes two main DAC types - multiplying DACs which use an external reference, and non-multiplying DACs which use an internal reference. It also covers DAC circuit types, principles of operation, specifications, errors, and applications of DACs.
Simulation of 3 bit Flash ADC in 0.18μmTechnology using NG SPICE Tool for Hig...ijsrd.com
This paper provides the basic simulation result for the 3 bit flash type ADC in 0.18μm technology using the NG Spice device simulator tool. It includes two stages, first stage includes 7 comparators and second stage has a thermometer encoder. The simulation is done in NG spice tool developed by university of California at Berkeley (USA).The response time of the comparator and ADC are 3.7ns and 4.9ns respectively with 50.01μw power dissipation which makes the ADC more suitable for high speed application with lower power devices.
A microprocessor-compatible quadrature decoder/counter is used to interface an optical shaft encoder (OSE) to a microprocessor's system bus. Quadrature decoder/counter find application in digital data input subsystems and digital closed loop motion control systems.
Digital to analog converters (DACs) and analog to digital converters (ADCs) allow the conversion between analog and digital signals. DACs take a digital input and output a proportional analog voltage. Common DAC types include binary weighted resistor DACs and R-2R ladder DACs. ADCs take an analog input and output a digital code representing that voltage. Common ADC types are successive approximation ADCs, dual slope integrator ADCs, and counter/staircase ramp ADCs. Data converters are essential for digital signal processing and the interfacing of analog and digital systems.
This document discusses digital to analog converters (DACs). It explains that a DAC converts digital numbers into analog voltages or currents. The key components of a DAC are its digital input, analog output, and conversion process. Common DAC types include binary weighted resistor DACs and R-2R ladder DACs, which use resistors and switches to implement the conversion. Important DAC specifications are also outlined such as reference voltage, resolution, speed, settling time, and linearity. Common applications of DACs include function generators, digital oscilloscopes, and converting digital video signals to analog formats for display.
A successive approximation analog-to-digital converter (SAR ADC) operates by using a binary search process to convert an analog input voltage into a digital code. It consists of a sample and hold circuit, analog comparator, successive approximation register, and internal reference digital-to-analog converter. The SAR ADC uses a charge redistribution architecture with capacitors of weighted values, and performs conversion in three steps: sample mode, hold mode, and redistribution mode, where the actual conversion occurs by successively connecting capacitor plates to a reference voltage.
This document provides an overview of frequency response and different instruments used to measure it. It discusses how frequency response analyzers (FRAs) work and their advantages over other instruments. FRAs can measure gain and phase characteristics of a device over frequency with high precision. They generate a single frequency signal, measure the input and output separately, and calculate the frequency response at that point. This allows FRAs to achieve very high dynamic ranges and flexible frequency resolutions not possible with spectrum analyzers or FFT analyzers. Examples are given of common frequency response measurements and tips for reducing errors.
This document discusses different types of analog-to-digital converters (ADCs). It describes flash ADCs, sigma-delta ADCs, digital ramp ADCs, tracking ADCs, and successive approximation ADCs. For each type, it provides a brief explanation of how the circuit works and sometimes includes a diagram. It also lists some common applications of ADCs, such as in transducers, computers, cell phones, microcontrollers, digital signal processing, digital storage, and scientific instruments.
This document provides an overview of digital to analog converters (DACs). It begins with an introduction to analog, discrete, and digital signals. It then discusses the basic specifications of DACs including resolution, speed, linearity, settling time, reference voltages, and errors. The document outlines the main types of DACs - weighted resistor DACs, R-2R ladder DACs, switched current source DACs. It also discusses applications such as digital audio and discusses errors that can occur in DACs such as gain error and offset error. In closing, it thanks the reader.
The document discusses analog-to-digital and digital-to-analog converters. It covers key concepts like resolution, bandwidth, energy, sampling, quantization error, and signal-to-noise ratio. Common converter architectures are described, including parallel, R-2R ladder, weighted capacitor, and current-switched DACs as well as flash, pipelined, successive approximation, dual-slope, and sigma-delta ADCs. Tradeoffs between speed, accuracy, and chip area are also addressed.
Design of a High Speed, Rail-to-Rail input CMOS comparatorPushpak Dagade
The document describes the design of a high-speed, rail-to-rail input CMOS comparator. It discusses the comparator specifications, various circuit topologies including NMOS input, PMOS input, and combined rail-to-rail comparator. It also describes the circuit optimization process using simulation and optimization algorithms to meet the design goals of 2mV resolution and ≤500ps delay. Simulation results show the comparator operates as intended across the entire input common mode range from 0-1.2V with fast switching speeds under 500ps.
This document provides information about analog to digital conversion and digital to analog conversion. It discusses different types of converters including flash ADCs, successive approximation ADCs, dual slope ADCs, R-2R ladder DACs, and weighted resistor DACs. It also covers analog and digital signals, the conversion processes, and applications of ADCs and DACs in areas like data acquisition and fiber optic communication.
This document provides a summary of a progress report on the design of a 3-bit flash analog-to-digital converter (ADC). It describes the architecture and design of a comparator, which acts as a 1-bit ADC, and a 3-bit flash ADC. It also discusses characterization of the ADC's DC performance by measuring differential nonlinearity and integral nonlinearity from histograms. The document covers comparator design techniques, reference voltage generation using diode-connected transistors, and layout of the 3-bit flash ADC.
Mikro,
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Catalog Phụ Kiện Mikro, Catalog Phụ Kiện,
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This chapter discusses digital control systems, including their components and operation. Digital control systems consist of a digital controller, analog to digital converter (ADC), and digital to analog converter (DAC). The ADC converts analog signals from sensors into digital signals for the controller. The controller processes the digital signals and outputs digital signals to the DAC. The DAC then converts the digital outputs back into analog signals to act on the physical system. Key aspects covered include comparing analog and digital control loops, describing the operation of ADCs and DACs, and selecting appropriate sampling frequencies to avoid signal distortion.
This document describes a 10-bit 165MSPS video ADC. It uses a time-interleaved SAR architecture with multiple low-power SAR ADCs operating in parallel to achieve the high sampling rate. Each SAR ADC samples every nth cycle, resulting in an effective sampling rate that is n times higher than an individual ADC. The design achieves low power consumption and area through its digital nature and use of scaled CMOS technology. It provides offset correction through a calibration technique to improve accuracy for video applications.
This document discusses analog control systems used with programmable logic controllers (PLCs) and programmable automation controllers (PACs). It describes how analog signals have continuous values between on and off, unlike discrete signals. It then explains that PLCs and PACs use analog input/output modules to interface with field devices that have continuously varying signals, such as temperature sensors, pressure sensors, motors etc. The document provides details on analog signal processing, including analog to digital conversion using ADCs and digital to analog conversion using DACs. It discusses key specifications for analog I/O modules such as resolution, conversion time and settling time.
The document describes the design of a 12-bit digital to analog converter (DAC). It includes a binary weighted resistor ladder circuit to convert the digital input to an analog voltage, and an operational amplifier circuit to drive the output load. Simulation results show the DAC can operate at up to 25MHz with good linearity and accuracy. Layout design considerations are discussed to optimize circuit performance and minimize parasitics.
This document describes the design of a 4-bit R-2R ladder digital to analog converter (DAC) using a 90nm CMOS technology process. It first discusses the design of a two-stage CMOS operational amplifier that meets given specifications. The design parameters and SPICE simulation results of the op-amp are then presented. Next, the document explains the principles of an R-2R ladder DAC and provides the specifications for the 4-bit DAC. It shows the SPICE circuit diagram and simulated output waveforms of the DAC. Comparisons are made between the expected and simulated DAC output levels. The document concludes the DAC design is suitable for the 90nm process and future work could enhance the
The document discusses data acquisition, conversion, and distribution systems in digital control systems. It describes how physical variables are converted to electrical signals via transducers, then amplified and filtered before being multiplexed and converted to digital signals using analog-to-digital converters (ADCs). It provides examples of calculating quantization levels and ADC outputs. Counter-type and successive-approximation ADCs are discussed as common conversion methods.
Analog To Digital Conversion (ADC) Programming in LPC2148Omkar Rane
1) The document describes programming the on-chip 10-bit ADC of the LPC2148 microcontroller to implement a simple data acquisition system. It discusses the features of the ADC, the programming interface, control registers, and provides code to initialize the ADC and read conversion results.
2) The code configures the ADC ports and control registers, reads the conversion results when the ADC status indicates a conversion is complete, and prints the voltage levels to the UART.
3) The results show the ADC accurately converts analog voltages from 0-3.1V to their corresponding 10-bit digital values, which are printed to the UART terminal.
This document discusses digital-to-analog converters (DACs). It defines a DAC as a circuit that produces an analog output proportional to a digital input and reference voltage. The document describes two main DAC types - multiplying DACs which use an external reference, and non-multiplying DACs which use an internal reference. It also covers DAC circuit types, principles of operation, specifications, errors, and applications of DACs.
Simulation of 3 bit Flash ADC in 0.18μmTechnology using NG SPICE Tool for Hig...ijsrd.com
This paper provides the basic simulation result for the 3 bit flash type ADC in 0.18μm technology using the NG Spice device simulator tool. It includes two stages, first stage includes 7 comparators and second stage has a thermometer encoder. The simulation is done in NG spice tool developed by university of California at Berkeley (USA).The response time of the comparator and ADC are 3.7ns and 4.9ns respectively with 50.01μw power dissipation which makes the ADC more suitable for high speed application with lower power devices.
A microprocessor-compatible quadrature decoder/counter is used to interface an optical shaft encoder (OSE) to a microprocessor's system bus. Quadrature decoder/counter find application in digital data input subsystems and digital closed loop motion control systems.
Digital to analog converters (DACs) and analog to digital converters (ADCs) allow the conversion between analog and digital signals. DACs take a digital input and output a proportional analog voltage. Common DAC types include binary weighted resistor DACs and R-2R ladder DACs. ADCs take an analog input and output a digital code representing that voltage. Common ADC types are successive approximation ADCs, dual slope integrator ADCs, and counter/staircase ramp ADCs. Data converters are essential for digital signal processing and the interfacing of analog and digital systems.
This document discusses digital to analog converters (DACs). It explains that a DAC converts digital numbers into analog voltages or currents. The key components of a DAC are its digital input, analog output, and conversion process. Common DAC types include binary weighted resistor DACs and R-2R ladder DACs, which use resistors and switches to implement the conversion. Important DAC specifications are also outlined such as reference voltage, resolution, speed, settling time, and linearity. Common applications of DACs include function generators, digital oscilloscopes, and converting digital video signals to analog formats for display.
A successive approximation analog-to-digital converter (SAR ADC) operates by using a binary search process to convert an analog input voltage into a digital code. It consists of a sample and hold circuit, analog comparator, successive approximation register, and internal reference digital-to-analog converter. The SAR ADC uses a charge redistribution architecture with capacitors of weighted values, and performs conversion in three steps: sample mode, hold mode, and redistribution mode, where the actual conversion occurs by successively connecting capacitor plates to a reference voltage.
This document provides an overview of frequency response and different instruments used to measure it. It discusses how frequency response analyzers (FRAs) work and their advantages over other instruments. FRAs can measure gain and phase characteristics of a device over frequency with high precision. They generate a single frequency signal, measure the input and output separately, and calculate the frequency response at that point. This allows FRAs to achieve very high dynamic ranges and flexible frequency resolutions not possible with spectrum analyzers or FFT analyzers. Examples are given of common frequency response measurements and tips for reducing errors.
This document discusses different types of analog-to-digital converters (ADCs). It describes flash ADCs, sigma-delta ADCs, digital ramp ADCs, tracking ADCs, and successive approximation ADCs. For each type, it provides a brief explanation of how the circuit works and sometimes includes a diagram. It also lists some common applications of ADCs, such as in transducers, computers, cell phones, microcontrollers, digital signal processing, digital storage, and scientific instruments.
This document provides an overview of digital to analog converters (DACs). It begins with an introduction to analog, discrete, and digital signals. It then discusses the basic specifications of DACs including resolution, speed, linearity, settling time, reference voltages, and errors. The document outlines the main types of DACs - weighted resistor DACs, R-2R ladder DACs, switched current source DACs. It also discusses applications such as digital audio and discusses errors that can occur in DACs such as gain error and offset error. In closing, it thanks the reader.
The document discusses analog-to-digital and digital-to-analog converters. It covers key concepts like resolution, bandwidth, energy, sampling, quantization error, and signal-to-noise ratio. Common converter architectures are described, including parallel, R-2R ladder, weighted capacitor, and current-switched DACs as well as flash, pipelined, successive approximation, dual-slope, and sigma-delta ADCs. Tradeoffs between speed, accuracy, and chip area are also addressed.
Design of a High Speed, Rail-to-Rail input CMOS comparatorPushpak Dagade
The document describes the design of a high-speed, rail-to-rail input CMOS comparator. It discusses the comparator specifications, various circuit topologies including NMOS input, PMOS input, and combined rail-to-rail comparator. It also describes the circuit optimization process using simulation and optimization algorithms to meet the design goals of 2mV resolution and ≤500ps delay. Simulation results show the comparator operates as intended across the entire input common mode range from 0-1.2V with fast switching speeds under 500ps.
This document provides information about analog to digital conversion and digital to analog conversion. It discusses different types of converters including flash ADCs, successive approximation ADCs, dual slope ADCs, R-2R ladder DACs, and weighted resistor DACs. It also covers analog and digital signals, the conversion processes, and applications of ADCs and DACs in areas like data acquisition and fiber optic communication.
This document provides a summary of a progress report on the design of a 3-bit flash analog-to-digital converter (ADC). It describes the architecture and design of a comparator, which acts as a 1-bit ADC, and a 3-bit flash ADC. It also discusses characterization of the ADC's DC performance by measuring differential nonlinearity and integral nonlinearity from histograms. The document covers comparator design techniques, reference voltage generation using diode-connected transistors, and layout of the 3-bit flash ADC.
Mikro,
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Catalog Phụ Kiện Mikro, Catalog Phụ Kiện,
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Chi tiết các sản phẩm khác của Mikro tại https://dienhathe.com
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This chapter discusses digital control systems, including their components and operation. Digital control systems consist of a digital controller, analog to digital converter (ADC), and digital to analog converter (DAC). The ADC converts analog signals from sensors into digital signals for the controller. The controller processes the digital signals and outputs digital signals to the DAC. The DAC then converts the digital outputs back into analog signals to act on the physical system. Key aspects covered include comparing analog and digital control loops, describing the operation of ADCs and DACs, and selecting appropriate sampling frequencies to avoid signal distortion.
This document describes a 10-bit 165MSPS video ADC. It uses a time-interleaved SAR architecture with multiple low-power SAR ADCs operating in parallel to achieve the high sampling rate. Each SAR ADC samples every nth cycle, resulting in an effective sampling rate that is n times higher than an individual ADC. The design achieves low power consumption and area through its digital nature and use of scaled CMOS technology. It provides offset correction through a calibration technique to improve accuracy for video applications.
This summarizes a document describing a microcontroller-based digital trigger circuit for controlling output power of a converter. The circuit uses an ATmega 32 microcontroller to generate trigger pulses for thyristors based on a user-controlled input voltage and zero crossing detection of the AC mains. The microcontroller samples the input voltage, calculates a firing delay based on the voltage reading, and outputs trigger pulses through optical isolation to fire the thyristors at the appropriate phase angle to control output power. Experimental results showed the circuit can accurately control firing angle from 0 to 180 degrees and proportionally adjust converter output voltage based on the user input.
The document discusses different types of analog to digital converters (ADCs). It describes 6 main types - counter/ramp ADC, tracking ADC, successive approximation ADC, flash ADC, delta-sigma ADC, and dual slope integrating ADC. For each type it provides a brief overview of the operating principle and block diagram. It also discusses important ADC specifications and parameters such as resolution, quantization error, dynamic range, signal to noise ratio, aperture delay etc.
Design of 6 bit flash analog to digital converter using variable switching vo...VLSICS Design
This paper presents the design of 6-bit flash analog to digital Converter (ADC) using the new variable
switching voltage (VSV) comparator. In general, Flash ADCs attain the highest conversion speed at the
cost of high power consumption. By using the new VSV comparator, the designed 6-bit Flash ADC exhibits
significant improvement in terms of power and speed of previously reported Flash ADCs. The simulation
result shows that the converter consumes peak power 2.1 mW from a 1.2 V supply and achieves the speed of
1 GHz in a 65nm standard CMOS process. The measurement of maximum differential and integral
nonlinearities (DNL and INL) of the Flash ADC are 0.3 LSB and 0.6 LSB respectively.
A DAPTIVE S UPPLY V OLTAGE M ANAGEMENT F OR L OW P OWER L OGIC C IRCU...VLSICS Design
With the rise in demand of portable hand held devic
es and with the rise in application of wireless sen
sor
networks and RFID reduction of total power consumpt
ion has become a necessity. To save power we
operate the logic circuitry of our devices at sub-t
hreshold. In sub-threshold the drain current is
exponentially dependent on the threshold voltage he
nce the threshold variation causes profound variati
on
of I
ON
and I
OFF
the ratio of which affect the speed of a circuit d
rastically. So to mitigate this problem we
present a adaptive power management circuit which w
ill determine the minimum required supply voltage
to meet the timing requirement. Also to reduce the
power overhead and avoid bulky coil and EMI noise
we used the switch capacitor power regulator to reg
ulate and manage power instead of linear dropout
(LDO) and Inductor base switch mode power converter
The document describes an ASIC interface circuit for a gas sensor that includes various blocks: a signal path, clock divider, band gap reference, LDO regulator, sensor excitation circuit, front end amplification circuit, dechopping network, analog-to-digital conversion circuit using a sigma-delta modulator and decimation filter, linearization circuit, and serial interface circuit using I2C or SPI. The circuit can be implemented using Verilog, Verilog-AMS, and tested on an FPGA board before fabricating the ASIC chip using a 90nm or 45nm CMOS process.
IRJET- Implementation of 16-Bit Pipelined ADC using 180nm CMOS TechnologyIRJET Journal
This document describes the implementation of a 16-bit pipelined analog-to-digital converter (ADC) using 180nm CMOS technology. A 4-stage pipelined architecture is used, with each stage having a 4-bit resolution enabled by a successive approximation register (SAR) based sub-ADC. SAR ADCs consume low power but have speed and resolution limitations. To overcome these, a pipelined ADC is proposed that achieves high speed and low power consumption. Key blocks include SAR sub-ADCs, digital-to-analog converters, comparators, sample-and-hold circuits, and flip-flops. The design achieves medium sampling rate and 16-bit resolution for applications such as
A NEW APPROACH TO DESIGN LOW POWER CMOS FLASH A/D CONVERTERVLSICS Design
In the present paper, a 4-bit flash analog to digital converter for low power SoC application is presented. CMOS inverter has been used as a comparator and by adjusting the ratio of channel width and length, the switching threshold of the CMOS inverter is varied to detect the input analog signal. The simulation results show that this proposed 4-bit flash ADC consumes about 12.4 mW at 200M sample/s with 3.3V supply voltage in TSMC 0.35 µm process. Compared with the traditional flash ADC, this proposed method can reduce about 78% in power consumption.
An improved design of CMOS dynamic latch comparator with dual input dual output with a simple
design of three stages is represented. The basic disadvantages of latch type comparators are overcome by
producing an edge triggered comparison. The circuit is designed for a resolution of 300nV and the power
consumption is reduced to 450uW. It is designed for 1.8V DC supply voltage and 1 MHz clock frequency for
PVT variations. The simulation of the comparator is done in Cadence® Virtuoso Analog Design Environment
using 180nm technology. The error quotient is reduced less than 5% by adding a buffer stage. The delay is
brought down to 5nS. The active area appreciably is reduced. Layout of the proposed comparator has been
simulated in Cadence® Virtuoso Layout XL Design Environment. DRC and LVS have been verified.
On the Impact of Timer Resolution in the Efficiency Optimization of Synchrono...IJPEDS-IAES
Excessive dead time in complementary switches causes significant energy losses in DC-DC
power conversion. The optimization of dead time prevents the degradation of overall efficiency
by minimizing the body diode conduction of power switches and, as a consequence,
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Analog to Digitalconvertor for Blood-Glucose Monitoring
1. Circuits and Systems: An International Journal (CSIJ), Vol. 1, No.2, April 2014
13
ANALOG TO DIGITALCONVERTOR FOR
BLOOD-GLUCOSE MONITORING
Sunny Anand1
and Vemu Sulochana 2
1
Department of ECE, NIT, Jalandhar, India
2
CDAC, Mohali, India
ABSTRACT
This paper presents the design of a low-power CMOS current-frequency (I–F) Analog–Digital Converter.
The ADC is designed for implantable blood-glucose monitoring. This current frequency ADC uses nA-
range of input currents to set and compare voltage oscillations against a self-produced reference to resolve
0–32nA with an accuracy of 5-bits at a 225MHz sampling rate. The comparator used is a dynamic latch
comparator and the output is fetched from a 5-bit counter. This is designed in 180nm CMOS technology
with a supply of 1.8V, it operating voltage taken here is 0.0- 1.8V with power consumption of 12.3nW using
Cadence tools.
KEYWORDS
Current-frequency ADC; Low power; Dynamic Latch comparator
1.INTRODUCTION
Blood glucose meters measure the amount or the concentration of glucose in blood (glycaemia) of
diabetics patient allowing for the administration of the proper dose of insulin to maintain balance.
Particularly important in the care of diabetes mellitus. Blood glucose meters are small
computerized machines that "read" your blood glucose, then applying the blood to a chemically
active disposable 'test-strip'. Different manufacturers use different technologies, but most of them,
measure an electrical characteristic, and further use this to determine the glucose level in the
blood. There are many meters to choose from.
Monitoring and correcting the sugar level in the body accurately requires a sensitivity of 2 mg/dL
across a range of 20 to 600 mg/dL, or about eight bits of accuracy. However, 5-bits accommodate
an accuracy of 10 mg/dL across dangerously low and high extremes, from 20 to 340 mg/dL,
offering considerable value to the patient.
The ADC must resolve the current that a miniaturized ampere-metric glucose sensor generates,
which is typically in the range of 1 µA to 1 nA which in this case can reach up to 31nA with 5-
bits of resolution. Similarly, because miniaturized kinetic harvesters can generate less than 10µW,
the design aims to dissipate around 1µW. As alluded earlier, the time constant associated with
glucose variations in the body is on the order of minutes, so over-sampling the system at around
100 Hz is sufficient.
2. Circuits and Systems: An International Journal (CSIJ), Vol. 1, No.2, April 2014
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2. Organization of the paper
This paper presents a current–frequency (I–F) analog to digital convertor working at 180 nm
CMOS ADC that is able to resolve nA’s to within five bits of accuracy while drawing 1.1nA from
a 1.8-V supply. In this design a comparator [2] is used to compare the input value with the
reference voltage, a 5-bit counter [3] to get 5-bit output which further fetch to controller to find
the value of glucose in the blood by 5 bit latch [4]. The input range that the proposed ADC
receives corresponds to what ampere-metric sensors produce and the power level it requires to
operate is within the range that energy-harvested systems can supply [1].
Figure 1 Block Diagram of Current-Frequency ADC
The block diagram of I-F ADC is shown in Figure 1 in which, the input signal given to input
stage (contains low voltage current mirror and current steering switch)to drive the current to
comparator, then comparator will compare this value with the reference signal. Now we get a data
which we fetch to counter for getting the desired bits output.
3. Circuit Design
Frequency-based ADCs generally match the low-power and low-speed requirements that
harvester-powered ampere-metric glucose monitors impose. More particularly, because glucose
sensors ultimately generate a current, directing input current into the capacitor of a ramp-based
oscillator converts current into frequency directly, which means current–frequency ADCs of this
sort need not include additional power-consuming stages to condition the input. What is more, the
integrating capacitor inherent in these ADCs filters unwanted noise.
3.1 Schematic of I-F ADC
Current-frequency ADC is basically a voltage-to-frequency converter (VFC) and is an oscillator
whose frequency is linearly proportional to a control voltage. In this schematic we are feeding
input to the current mirrors, to drive the input to the comparator. As shown in Figure 2, cascode-
mirrors NM2–NM10 and PM0–PM4 receive and fold input current i1 or IR so switches PM5 and
PM6 can stear it into or away from integrating capacitor C1(1pF).
Comparator senses C1 voltage VC to determine the connectivity of NM0 and PM5. PM6 And
NM1 keep the mirrors conducting to the supply and ground when their corresponding switches
NM0 and PM5 are off, so the mirrors do not suffer from start-up delays, which would otherwise
extend the delay across the loop (i.e., increase td and distort VC’s ramp.
3. Circuits and Systems: An International Journal (CSIJ), Vol. 1, No.2, April 2014
15
Figure 2 Schematic of Current mirror and current steering circuit
Now as we give an analog signal at the input, it first goes through the current mirror and current
steering circuit, then this signal is compared with the reference signal at frequency of 225 MHz
and a voltage of 1.8V.
Figure 3 Schematic of Current-Frequency ADC
The output of comparator is given to counter which separate this digital signal into 5 different
samples, which is latched through which we get output of 5-bit resolution.
This resolution is calculated by the formula
(1)
Where VFS is full-scale output voltage range
δV is full-scale input voltage range
3.1.Dynamic Latch Comparator
The comparator comprised of three blocks, an input stage (current mirror and a current steering
circuit), a flip-flop block and SR latch block. This architecture uses two non-overlapping clocks
4. Circuits and Systems: An International Journal (CSIJ), Vol. 1, No.2, April 2014
16
(ϕ1 and ϕ2) shown in Figure 4, which operates in two modes, reset mode during ϕ2 and
regeneration mode during ϕ1.
Figure 4 Schematic of Dynamic Latch Comparator
During reset mode the input voltage difference is established at node A1 and A2. The regeneration
happens during a small time when ϕ1 is rising and ϕ2 is falling. At the end of regeneration
process the SR latch is driven to the digital output levels. The power consumption of the
comparator is 33µW at a frequency of 225MHz.
This design was implemented at 180 nm CMOS technology operating at a ±1.8 V power supply
with 8-bit of resolution and input range of 1.8 V. And transistor widths are calculated as per the
comparator requirement [2].
W12 = 4um, W1 = 6um,
W8 = 4um, W10 = 10um,
W6 = 30um
These widths are calculated by using following formula
(2)
Considering αW4 = Cp
3.1.Bit binary synchronous counter
Counters are among the most basic of designs in digital systems. Along with being simple to
make, counters, in general, are archetypical components of most digital systems as they are used
to store (and sometimes display) the number of times a particular event has occurred. The
different number of implementations of a 5-bit counter is vast. With options such as synchronous
vs asynchronous, why flip-flops to use, and the style of counting (binary, gray-code, etc).
The counter described here is designed to be a synchronous up-counter as shown in Figure 5. This
means that the whole design is controlled by one single clock and that the counter will only count
from 0 to F and start back over. This counter is realized using D flip-flops [6].
5. Circuits and Systems: An International Journal (CSIJ), Vol. 1, No.2, April 2014
17
Figure 5 Schematic of 5-bit counter
The D flip-flop was chosen because of its simplicity over the design of JK flip-flop; it only takes
one input instead of two, and requires less interconnect which should lead to less delay. Also, the
synchronous up-counter nature of the design was chosen because simple design. This counter is
counting from 0 to 1.8 volts, with a precision of 0.59375V.
3.1 5-Bit 2:1 Mux-Latch
With current topologies, dynamic latches are widely used in the high performance VLSI circuits,
mainly due to lower cost and higher operation speed than static latches. Figure 6 depicts the
preferred dynamic latch circuit. This latch circuit either transfers the input logic level to the
output (during clock signal is kept at logic “1”) or keeps the last output logic level (during clock
signal is kept at logic “0”) all depends on the controlling clock signal.
Figure 6 Schematic of Dynamic latch
In other words, clock “0” means conversion phase, and clock “1” means sampling phase. This
control between digital and analog parts of ADC is obtained. In fact, it is not possible to convert
an analog input level to its digital value immediately. A very small time period is essential for the
digital part to complete its job. Therefore, a dynamic latch circuit use to make inevitable for ADC
6. Circuits and Systems: An International Journal (CSIJ), Vol. 1, No.2, April 2014
18
design. This time is called as “conversion time” in general and it is shortest in I-F ADCs, but very
long for serial type of ADCs.
The output of the latch is given as input to 2:1 mux and is also used as select line for the mux of
next block as shown in Figure 7, for 5-bit resolution.
Figure 7. Circuit diagram of 2:1 mux type latch
3. POWER REDUCTION
While designing any CMOS circuit power is a very important issue and in ADC we always
required low power. This power can be reduced by using low power techniques such as
decoupling capacitor, variable frequency, Clock gating, scaling down voltage etc. Clock gating
technique is one of these power reduction techniques adopted in this design is shown in Figure 8
Figure 8 Circuit of Clock gating without latch
4. RESULTS
Designing, schematics, simulation and comparison of various performance parameters were done
for two different ADC’s. Simulations were carried out using Cadence Tools. The present work,
7. Circuits and Systems: An International Journal (CSIJ), Vol. 1, No.2, April 2014
19
technology taken is 12.3 nW with sampling frequency of 225MHz and a power supply of 1.8V. A
5-bit data is achieved with a power of 12.3nW, as shown in Table.1
Table.1 Design Specifications
Parameters Value
Technology 180nm
Sample frequency 225 MHz
Power Supply 1.8 V
Stop time 200 ns
Resolution 5 bits
Power 12.3nW
Reference Voltage 1.8 V
The transient response of the I-F ADC is shown in Fig.9 output waveform is collected from the 5-
bit latch, which is collected in parallel form. This 5 bit data has sampling rate of 225MHz.
Figure 9 Transient response of I-F ADC
8. Circuits and Systems: An International Journal (CSIJ), Vol. 1, No.2, April 2014
20
The waveform is taken with a stop time of 100ns.The first bit is MSB and last one in LSB of
ADC’s output. The designed ADC results are compared with the current I-F ADC and the flash
ADC [7]. Table2 shows the comparison between these two ADC’s. Reference ADC is done at 0.6
um, so firstly design with same parameters, then with 180 nm technology and got a improved
power of 1.1µW at a sampling frequency of 225 MHz with a improved resolution of 5 bit from
4.25 and by using clock gating technique get the power of 12.3nW.
Table1. Comparison between flash and current-frequency ADC’s
PREVIOUS WORK PRESENT WORK
Parameters Flash
ADC
I-F ADC I-F ADC I-F ADC
Technology 180nm 0.6 µm 0.6 µm 180nm
Resolution(bits) 3 4.25 5 5
Power supply 1.8 V 1.2 V 1.8V 1.8V
Power(W) 0.85m 1.3µ 1.1µ 12.3n
Sampling
Freq.(MHz)
150 225 225 225
5. CONCLUSION
This paper presented low power 5-bit current- frequency ADC design at 180 nm technology. This
ADC is designed for implantable blood glucose monitoring. With improvement in the power
consumption of 180nW at 225MHz sampling frequency and power supply of 1.8 V.
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Authors
Vemu Sulochana has obtained her Bachelor of Technology degree from JNTU Kakinada
and Master of Technology degree from NIT, Hamirpur in 2004 and 2009 respectively. In
2011, she joined C-DAC, Mohali to conduct innovative research in the area of VLSI
design, where she is now a Project Engineer - II. Her research is concerned with low
power VLSI design, Design of high speed VLSI interconnects. She is conducting
research in IC interconnect characterization, modelling, and simulation for the high speed
VLSl circuit design.
Sunny Anand has done her bachelor of technology degree in Electronics and
Communication Engineering from D.A.V.I.E.T, Jalandhar in year 2010 and Master of
Technology degree in VLSI Design from CDAC, Mohali. Currently pursuing his PhD.
From NIT Jalandhar. He work as Asst. professor in LPU for one year. His areas of
interests are Analog and Digital VLSI Design, mobile communication..