Nandbased digitally controlled delaylines dcdls are employed in several applications owing to their excellent linearity, good resolution and easy. In addition, delay lines can produce ambience synthesis and room expansion for home hifi systems. Like vcos or ccos, dcos also have frequency controlled mechanism to control the output frequency of oscillation by means of digital control word applied at the control input of dco. The signal i am working with has a max amplitude of 1vpp, with a 1. Nand based flip flops for glitch avoidance which allows to reduce the peaktopeak output delay of more than 42%, gate length and power will be reduced and also increase in the speed of operation compared to previously proposed glitch free nand based dcdl by using threestate inverter based dcdls and sleep transistor logic have been designed in a. The outputs 43 and 44 are connected to the input of a subtractor network 45 which is connected at its output to the if output the output of the carrier gate 15 is connected to an input of an upconverter mixer 18 which is driven by a stable local oscillator cznceller stalo similarly, a difference in gain between the two channels 35 and 36. Analog delay lines are applied in many types of signal processing circuits. Addll architecture the digitally controlled delay line dcdl is a digital circuit whose delay is controlled by a digital control word. Upon closing the switch, the capacitor c begins to charge through r1, and since this is a large capacitor of value 0. Recommended citation vitols, visvaldis alberts, an electronically controlled delay line 1962. A delay locked loop with glitch free nandbased dcdl has been presented. At chip startup time, both flip flops dff0 and dff1 should be reset to the zero state so that neither one of the clocks is propagated initially. Specifically, the multitap delay circuit provides a pluralityof sequentially ordered delayed output signals on a plurality of sequentially ordered output terminals.
A low power and glitchfree circular rotation phase. The proposed nandbased dcdl maintains the same resolution and minimum delay of. The mux decides which of path a and path b does the triggering. How a logic circuit implemented with aoi logic gates can be. A glitch free delay line multiplexing technique is described that includes an intermediate multiplexing system and an output multiplexer. Also, a switching circuit is used to control the delay lines. Delay lines are also used to adjust relative delays of different signal paths in both synchronous and asynchronous circuits. Nandbased digitally controlled delaylines dcdls are employed in several applications owing to their excellent linearity, good resolution and easy standard cell design.
This paper presents a glitchfree nandbased dcdl which overcame this limitation by opening the employ of. Builtin selfcalibration circuit for monotonic digitally controlled oscillator design in 65nm cmos technology. Abstractthe recently proposed nand based digitally con. This nand timer is a delayon type, where the led remains off until the capacitor c has sufficient charge. The r s 0 combination is called a restricted combination or a forbidden state because, as both nand gates then output 1s, it breaks the logical equation q not q. The proposed glitch free strobe control based digitally controlled delay lines maintains the same resolution and minimum delay of previously proposed glitch free. A glitchfree dcdl behavior is often a strict requirement e. Glitch free power sequencing with axc level translators figure 2 shows the internal architecture of the axc io cell with the glitch suppression circuitry and powerup hiz circuitry controlled by the power on reset control block. Offers a comprehensive overview of nand flash memories, with insights into nand history, technology, challenges, evolutions, and perspectives describes new program disturb issues, data retention, power consumption, and possible solutions for the challenges of 3d nand flash memory written by an authority in nand flash memory technology, with over 25 years experience. Adding delay can remove hazards, if one has good control of propagation delays. The gray code multiplexer has a plurality of input terminals coupled. In addition, each stage has fine and coarse parts for adjusting the output frequency. Digitally controlled delay lines dcdl exhibits a glitching. Delay lines university of illinois at urbanachampaign.
Conventional delay lines are designed in a full custom design methodology which is. The paper presents the implementation of glitch free clock switching techniques applied in the design of a microcontroller. The proposed nandbased dcdl maintains the same resolution and. By starting both flip flops in zero state, fault tolerance is built into the clock switch.
Special attention has to be paid to avoid the timing problems. Tunable nanophotonic delay lines using linearly chirped contradirectional couplers with uniform bragg gratings wei shi,1,2, venkat veerasubramanian,1 david patel,1 and david v. Single flipflop driving circuit for glitchfree nandbased digitally. Delay lines are used to insert a very precise delay into the path of a signal. In multiclock signal digital systems there is a chance of generating a glitch or chopped signal on the clock line at the time when clock signal is changed. Figure2 glitchfree clock switching for related clocks. Thus besides dfa attacks 15,18, clock glitch based fault injection has also been widely used in fsa attacks which require precise control of the strength width of the disturbance clock glitch 4,6,7. Techniques to make clock switching glitch free ee times. Using digitally programmable delay generators applicaton. A lowpower and areaefficient digitally controlled shuntcapacitor delay element for highresolution delay lines single. The proposed glitch free strobecontrol based digitally controlled delay lines. If clock and clk are both glitch free, the width of the previous pulse should be equal with the current pulse, which means. Delay line block of the developed sscg use the glitch free nand based dcdl.
Glitch free nand based digitally controlled delay line for spread. The recently proposed nand based digitally controlled delay lines dcdl present a glitching problem which may limit their employ. For example, delay lines are used extensively in asynchronous systems to control signal timing. Currently a glitchfree nandbased dcdl is used to overcome the limitation of glitching problem. The advantages and disadvantages of presented solutions are described.
It is assumed that the scope of the interest is frequency range for delay lines equal to form 1 to 10 ghz and working bandwidth is equal to 1 ghz. A 45nm cmos, low jitter, all digital delay locked loop with a circuit to dynamically vary phase to achieve fast lock a thesis presented by soumya shivakumar begur. Universal gate nand i will demonstrate the basic function of the nand gate. Glitch free strobe control based digitally controlled delay lines. It consists of n identical subcircuits, each providing 1n of the total delay. A 45nm cmos, low jitter, alldigital delayed locked loop with. Pdf glitchfree nandbased digitally controlled delay. Vocabulary pdfsr latch is race free because there is only one state signal. This nand timer is a delay on type, where the led remains off until the capacitor c has sufficient charge.
This paper presents a glitchfree nandbased dcdl which overcame this limitation by opening the. Digitally controlled delay lines plays an important role in dll and the drawback is glitches. The delay through the device is controlled by an nbit digital word. How a logic circuit implemented with aoi logic gates can be reimplemented using only nand gates. In addition, those skilled in the art can adapt the principles described herein to delay lines using any number of delay. Glitch free power sequencing with axc level translators rev. Delay line memory is a form of computer memory, now obsolete, that was used on some of the earliest digital computers. Existing glitch free nandbased dcdl topologies either require two flipflops for.
This paper presents a glitch free nandbased dcdl which overcame this limitation by opening the employ of nandbased dcdls in a wide range of applications. Analysis of spreadspectrum clocking modulations under. The previously proposed glitch free nandbased dcdl circuit using threestate inverter based dcdls and cmos transistor logic was designed in a 90nm cmos. Pdf low power glitch free dual output coarse digitally controlled. Glitchfree nandbased digitally controlled delaylines. These approaches lead a 64% lower power consumption compared conventional digital control delay lines dcdls. Acoustic and electromechanical delay lines are used to provide a reverberation effect in musical instrument amplifiers, or to simulate an echo. Programmable delay lines,rf input signals, rf switches. This paper presents a glitch free nandbased dcdl which overcame this limitation by opening the. While they are conventionally implemented using chirped fiber bragg gratings 1, there has been significant interest in realizing integrated tunable delay lines, especially on a silicononinsulator soi. There are two basic types of solidstate delay systems. Some produce a fixed delay, often with multiple tap points, while others produce a delay that may be adjusted by an analog voltage or digital control word.
Delay locked loop using glitch free nand based dcdl ijareeie. Clock glitch fault injection attacks on an fpga aes. Jul 27, 2016 nandbased digitally controlled delaylines dcdls are employed in several applications owing to their excellent linearity, good resolution and easy standard cell design. Glitch free power sequencing with axc level translators. After being set to q1 by the low pulse at s nand gate function, the restored normal value s1 is consistent witht the q1 state, so it is stable. The recently proposed nandbased digitally controlled delaylines dcdl present a glitching problem which may limit their employ in many applications. Path b is composed of a 32 to 1 mux, a 5bit adder, two 5bit registers, an and, and an ls.
Codes 20 vlsi01 vlsi02 glitchfree nandbased digitally controlled delaylines 20 vlsi03 eliminating synchronization latency using sequenced latching 20 vlsi04 timebased all digital technique for analog builtin selftest 20 vlsi05 analysis and design of low voltage low power double tail comparator 20. Us6025744a glitch free delay line multiplexing technique. Gates marked with d, represents dummy cells added for load balancing. Design faults leading to clock and data glitches edn. Power reduction and glitch free mux based digitally controlled. Within this new model, digitally controlled delay lines dcdl should play the role of digital toanalog converters in conventional, analogintensive, circuits. Another negative pulse on s gives which does not switch the flipflop, so it ignores further input. An analog delay line is a network of electrical components connected in cascade, where each individual element creates a time difference between its input and output. Tunable optical delay lines are widely used in optical communications for dispersion compensation1 and optical signal processing 2. System clock and power supply crosschecking for glitch. A 1251250 mhz processindependent adaptive bandwidth spread spectrum clock generator with digital controlled selfcalibration. The traditional analog signal processing is expected to progressively substituted by the processing times of the digital domain in the vlsi. In this paper, two digitally controlled ring oscillators dros with similar structure but different constructive cells have been proposed.
System clock and power supply crosschecking for glitch detection. Like many modern forms of electronic computer memory, delay line memory was a refreshable memory, but as opposed to modern randomaccess memory, delay line memory was sequentialaccess. A wide range mux based digitally controlled delay line dcdl is presented to achieve. The glitchless delay line combines a multitap delay circuit with the gray code multiplexer. A 45nm cmos, low jitter, alldigital delayed locked loop. Digital delay lines can be used to generate the pulse width modulation pwm signal. Low power glitch free dual output coarse digitally controlled delay. A trigger pulse is applied to the input, and after a fixed propagation delay t. Pdf nandbased digitally controlled delaylines semantic. Within this novel paradigm, digitally controlled delay lines should play the vital role in the digital toanalog converters,and in analog intensive circuits. Nand gate 32 provides an output, out, that is the output of glitchfree mul. In the case of a periodic signal, the time difference can be described in terms of a change in the phase of the signal.
In 4, they have proposed glitch free nand based digitally controlled delay line and is shown in fig. Digitally controlled delay lines based on nand gate for. Figure 1 shows the basic function of a programmable delay generator. Alldigital dll architecture and applications tuvia liran. Cost is usually the primary driving factor in the design choice. A monotonic digitally programmable delay element for low. Further, a delay line can be used as the heart of a clicwscratch filter for 2 record player, and as a soundactivated switch.
Microwave delay lines for analogue signal correlation. Certain investigations on nand based flip flops for glitch. Abstract this paper presents a glitch free nand based digitally controlled delay lines dcdl by analyzing the glitching problem of existing nand based. Nand based digitally controlled delay lines dcdls are employed in several applications owing to their excellent linearity, good resolution. Vlsi01 vlsi02 glitchfree nandbased digitally controlled delaylines 20 vlsi03 eliminating synchronization latency using sequenced. A digitally programmable delay generator delays a digital edge by a programmed amount of time. Programmable synchronous digital delay line nasaads. Dowkey produces the highest quality, and most reliable programmable delay lines and offers them in a variety of delays. Glitches and hazards in digital circuits department of electronics. Direct digital synthesis dds is a method of producing an analog waveformusually a sine waveby generating a timevarying signal in digital form and then performing a digital toanalog conversion. The combination is also inappropriate in circuits where both inputs may go high simultaneously i. Bipolar input data is processed to develop a mark data pulse stream representing the leading edges of input data pulses and a space data pulse stream.
Glitching problem is a resultant of nandbased digitally controlled delaylines dcdl. An alldigital delaylocked loop for highspeed memory. The classification of hazards by the glitch they may produce staticzero. The combinational circuit which we designed was nandbased digitally controlled delaylines dcdl present a glitching problem which may limit their employ in many applications. This paper introduces glitch free nand based dcdl which overcome the limitation.
It operates on analog signals whose amplitude varies continuously. Digitallycontrolled ring oscillator for wide tuning range. A low power and glitchfree circular rotation phase modulator. Proceedings of the 5th small systems simulation symposium. Although the design of the generator is ingenious, its not precise enough for our fault injection attacks. Singlestep glitchfree nandbased digitally controlled delay lines using dual loops. Single flipflop driving circuit for glitchfree nandbased. An efficient nand gate based glitchfree all digital duty. How a nand gate can be used to replace an and gate, an or gate, or an inverter gate. The intermediate multiplexing system receives signals from a plurality of delay units and outputs a subset of delay signals that includes the signal presently selected, the signal presently selected with an additional delay, and the signal presently selected. A nandbased dcdl is used to reduce the glitches with dual edge triggered sense amplifier flipflop as driving circuit. In this figure a denotes the fast input of each nand gate. Glitchfree nandbased digitally controlled delaylines core.
The glitch free strobe control based digitally controlled delay lines overcame this limitation by opening the employ of glitch free nandbased dcdls in a wide range of applications. The most design intensive component of the dll is the digitally controlled delay line. A synchronous digital delay line that can be programmed by variable delay increments to independently delay the leading and trailing edges of a digital signal and that can be utilized to provide a wide range of digital delaying requirements. Like many modern forms of electronic computer memory, delay line memory was a refreshable memory, but as opposed to modern randomaccess memory, delay line memory was sequentialaccess analog delay line technology had been used since the 1920s to delay the. The proposed designs have a wide frequency range and high frequency. Tunable nanophotonic delay lines using linearly chirped. Glitchfree nandbased digitally controlled delaylines ieee. A digitally controlled line with switched reference sections is introduced. Nand based digitally controlled delay lines dcdl are used in wide range of. Random read latency is one of the fundamental differences between parallel nor and slc nand. Synthesizable delay line architectures for digitally.
Path a is composed of a 32 to 1 mux, a 19bit adder, a 19bit register, 5bit register, an and, and a lap selector ls. Dear all, i have a project where i need to delay a signal with about tens of microseconds max. From a practical point of view, nowadays, dcdl is a key block in the many applications like all. First delay line with short delay times is designed for high frequencies, and second delay line with long delay times is designed for low frequencies. Programmable delay lines are programmable devices are designed to delay rf input signals up to 200ns maximum with a minimum step size starting at 10 ps. Single flipflop driving circuit for glitchfree nand. This paper presents a glitchfree nandbased dcdl which overcame this limitation by opening the employ of nandbased dcdls in a wide range of applications. In digitally controlled switching converters, this precise voltage regulation is achieved by high resolution digital pulse width modulators dpwm. The proposed modulator uses a pathshared tapped delay line tdl and a dynamical pseudo clockgating control technique. A glitchless delay line using a gray code multiplexer is provided. Glitch reduction in combinational logic circuits by using nand.
A glitch free dcdl behavior is often a strict requirement e. Currently a glitch free nandbased dcdl is used to overcome the limitation of glitching problem. These proposed dros include of 5 stages, and each stage contains 10 parallel delay cells. It has been accepted for inclusion in retrospective theses and dissertations by an authorized administrator of iowa state university digital repository.
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