Ring Oscillators Patents (Class 331/57)
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Patent number: 7394328Abstract: An oscillator circuit that generates an oscillation signal is provided. The oscillator circuit includes an oscillator that generates the oscillation signal based on positive feedback of a signal, a synchronization signal generating section that generates a compulsory synchronization signal having an edge that (i) crosses a zero cross point at an ideal timing of an edge of the oscillation signal every predetermined number of cycles of the oscillation signal and (ii) has a gradient in the same direction as the edge of the oscillation signal, and a combining section that injects the compulsory synchronization signal into a positive feedback path of the oscillator.Type: GrantFiled: January 22, 2007Date of Patent: July 1, 2008Assignee: Advantest CorporationInventors: Daisuke Watanabe, Toshiyuki Okayasu
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Patent number: 7394325Abstract: A differential type voltage-controlled oscillator circuit including: a plurality of VCO cells each having one pair of switching elements, the switching elements having one terminal side connected to a voltage source via a load and another terminal side connected to a common current source via a common node, the switching elements being supplied with differential signals, the plurality of VCO cells outputting differential signals different in phase from the differential signals; and a vibration canceling section connecting the plurality of VCO cells such that vibration at each node is cancelled.Type: GrantFiled: July 7, 2006Date of Patent: July 1, 2008Assignee: Sony CorporationInventor: Yosuke Ueno
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Patent number: 7391274Abstract: Methods and circuits for chain ring oscillators having a constant delay time over variations of temperature and variations of semiconductor manufacturing process while requiring low operating voltage only have been disclosed. A system current source includes a constant voltage circuit generating a constant voltage and hence a constant current via a resistance element. Main parts of the constant voltage circuit are an operational amplifier and a bandgap reference circuit. Using a series of current mirrors the constant currents are mirrored to current sources contained in each of n-inverter stages of the chain ring oscillator.Type: GrantFiled: March 30, 2005Date of Patent: June 24, 2008Assignee: Etron Technology, IncInventor: Jenshou Hsu
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Patent number: 7391276Abstract: In an oscillation apparatus formed by a ring oscillator including an odd number of inverters (more than two inverters) connected in a ring, each of the inverters having one drive MOS transistor and one load MOS transistor, a constant voltage generating circuit is adapted to generate a constant voltage corresponding to a threshold voltage of the drive MOS transistor, and a voltage-to-current converting circuit is adapted to convert the constant voltage into load currents. Each of the load currents flows through the load MOS transistor of one of the inverters.Type: GrantFiled: October 12, 2005Date of Patent: June 24, 2008Assignee: NEC Electronics CorporationInventor: Makoto Sakaguchi
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Patent number: 7391275Abstract: Circuits and methods for generating an oscillator output. The circuit generally includes a ring oscillator, with a series of inverters connected in series and an LC resonator tank (or a variable resistance) coupled to the input and output of the inverter series. The method generally includes the steps of applying an operating voltage to such a circuit and generating an oscillator signal. The circuits and methods may be employed as a VCO component of a phase-locked loop. The upper limit of the oscillator signal frequency may be configured by altering or controlling the variable resistance and/or one or more parameters of the LC resonator tank. The circuit design demonstrates a high tolerance to variations in circuit or circuit component values.Type: GrantFiled: July 18, 2005Date of Patent: June 24, 2008Assignee: Seiko Epson CorporationInventor: George Jordy
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Patent number: 7391277Abstract: An interleaved voltage-controlled oscillator (VCO) is disclosed. The VCO includes a ring circuit comprising a series connection of main logic inverter gates, a plurality of delay elements connected in parallel with a selected sequence of the main logic inverter gates, at least one temperature compensation circuit comprising a logic inverter gate in series connection with one or more field effect transistors, the field effect transistor responsive to a compensating voltage input that is proportional to temperature, and an electronic circuit in signal communication with the at least one temperature compensation circuit and configured to provide a voltage signal responsive to temperature. Each delay element includes a feedforward section, comprising controls for regulating signal transmission through feedforward elements responsive to one or more control voltages, and a proportional section, comprising controls for regulating signal transmission through at least one logic inverter gate.Type: GrantFiled: July 20, 2006Date of Patent: June 24, 2008Assignee: International Business Machines CorporationInventors: David W. Boerstler, Eskinder Hailu, Jieming Qi, Mike Shen
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Publication number: 20080143415Abstract: A circuit, method, and system are disclosed. In one embodiment the circuit comprises a ring oscillator circuit having a plurality of delay elements, the ring oscillator circuit to generate a clock signal frequency, a checker circuit to compare a count of clock signal oscillations observed per complete loop of the ring oscillator circuit to a reference count, and to set a flag signal if the clock signal oscillation count is above a high threshold amount or below a low threshold amount.Type: ApplicationFiled: December 18, 2006Publication date: June 19, 2008Inventor: David I. Poisner
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Patent number: 7388442Abstract: This disclosure relates to a cell-placeable variable-frequency digitally controlled oscillator (DCO) that consumes approximately the same current in a fast process corner as in the case of a slow process corner. By modulating the effective channel length of transistors in inverters, a fast process DCO may be slowed down to a desired frequency at nearly the same current consumption as that of a slow process DCO.Type: GrantFiled: June 18, 2005Date of Patent: June 17, 2008Assignee: Agere Systems Inc.Inventor: Dale H. Nelson
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Patent number: 7388443Abstract: An integrated circuit (IC) includes a ring oscillator. One may tune the ring oscillator by controlling a power supply of the ring oscillator. One may further tune ring oscillator by varying a capacitance of at least one varactor. Using the tuning techniques, one may tune the output frequency of the ring oscillator to a desired frequency.Type: GrantFiled: April 25, 2006Date of Patent: June 17, 2008Assignee: Altera CorporationInventors: Mashkoor Baig, Shoujun Wang, Haitao Mei, Bill Bereza, Tad Kwasniewski
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Patent number: 7388447Abstract: A method and circuit for stabilizing a frequency of a clock generator comprising a ring oscillator with respect to manufacturing process variations and a circuit temperature. A bias circuit comprising a current mirror and cascade circuits provides a compensated bias current based on a gate source voltage and drain source voltage of an output transistor, where the two voltages are independent of transistor parameters and circuit temperature. As a result, the ring oscillator frequency is stabilized with respect to those parameters.Type: GrantFiled: June 21, 2006Date of Patent: June 17, 2008Assignee: National Semiconductor CorporationInventors: Vladislav Potanin, Elena Potanina
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Publication number: 20080136400Abstract: This invention discloses a system and method for dynamically managing voltage and frequency in an integrated circuit (IC), comprising a plurality of ring oscillators for generating a plurality of continuous pulses with frequencies reflecting the process parameter, operating voltage and temperature effects in the IC, a period generator for generating at least one gating period with a predetermined duration, a plurality of counters coupling to the plurality of ring oscillators as well as the period generator for counting the number of the continuous pulses in the gating period, at least one selector for selecting a predetermined number counted by the plurality of counters, and at least one voltage-and-frequency adjustment circuitry for adjusting one or more operating voltages or one or more clock frequencies in the IC based on the predetermined number selected by the selector, wherein the IC operating voltage or clock frequency correlates with the ring oscillator frequencies.Type: ApplicationFiled: December 7, 2006Publication date: June 12, 2008Inventors: Shyh-An Chi, Chih-Hung Chung
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Publication number: 20080136539Abstract: In a voltage controlled oscillation circuit including a cascade connection of a voltage-to-current conversion circuit (310) for generating an input voltage converted current which is a current corresponding to an input voltage and a current controlled oscillation circuit (120) of which an oscillation frequency varies according to the input voltage converted current, the voltage-to-current conversion circuit (310) includes a first current source for outputting a current in proportion to the input voltage and a plurality of second current sources for outputting a current in proportion to a voltage obtained by shifting the input voltage. Then, a current obtained by adding a current output from the first current source and currents output from the plurality of current sources is output as the input voltage converted current to the current controlled oscillation circuit (120).Type: ApplicationFiled: March 12, 2007Publication date: June 12, 2008Inventors: Takashi Oka, Seiji Watanabe
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Publication number: 20080129393Abstract: A ring oscillator based voltage controlled oscillator (VCO) is disclosed. The VCO includes a set of delay cells connected to each other in a ring configuration. Each of the delay cells includes a source-coupled input transistor pair, a current-steering transistor pair and a pair of load resistors. The source-coupled input transistor pair receives a pair of differential voltage inputs. The load resistors, which are connected to the source-coupled input transistor pair, provide a pair of differential voltage outputs. The current-steering transistor pair, which is connected to the source-coupled input transistor pair, receives a pair of differential bias voltage inputs. The output frequency of the VCO is directly proportional to the differential bias voltages at the pair of differential bias voltage inputs.Type: ApplicationFiled: November 29, 2007Publication date: June 5, 2008Inventors: Giri N.K. Rangan, Earl E. Swartzlander
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Publication number: 20080130816Abstract: A phase lockedcircuit comprising a phase detector for comparing an incoming serial data signal with a feedback clock signal and generating a digital phase detector output signal representing a phase difference between the incoming data signal and the feedback clock signal; a dual path filter for receiving the phase detector output signal, the dual path filter including a first path for generating a digital proportional output signal that is proportional to the phase detector output signal and a second path having an integral digital filter for generating a digital integral output signal that is proportional to an integral of the phase detector output signal; and a digitally controlled oscillator for receiving the proportional output signal and the integral output signal as tuning inputs and generating in dependence thereon an output clock signal from which the feedback clock signal is obtained. The circuit can be implemented in a receive path of a serializer/deserializer.Type: ApplicationFiled: November 30, 2007Publication date: June 5, 2008Inventors: Kenneth W. Martin, Jonathan E. Rogers, Tony Pialis, Mehrdad Ramezani
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Patent number: 7382165Abstract: A selection circuit and method. The selection circuit comprises a logic circuit, an array of sub-circuits and a switching circuit electrically coupled to each other. The selection circuit is subjected to a first operating condition. The switching circuit selects a group of sub-circuits from the array. The selection circuit generates a first frequency. The selection circuit is subjected to a second operating condition that is different from the first operating condition and generates a second frequency. A first frequency differential between the first frequency and the second frequency is compared to a predetermined frequency differential to determine if the first frequency differential is about equal to the predetermined frequency differential.Type: GrantFiled: August 23, 2006Date of Patent: June 3, 2008Assignee: International Business Machines CorporationInventors: Christopher Gonzalez, Vinod Ramadurai, Norman Jay Rohrer
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Patent number: 7382203Abstract: A delay circuit, which is included in a ring oscillator, comprises a current source for providing a current; a first circuit coupled to the current source for receiving an input signal and producing an output signal; a second circuit coupled to the current source and the first circuit; a first adjustable impedance element coupled to the first circuit; a second adjustable impedance element coupled to the second circuit; and a control circuit coupled to the first adjustable impedance element and the second adjustable impedance element for producing a first control signal to control a first resistance of the first adjustable impedance element and producing a second control signal to control a second resistance of the second adjustable impedance element; wherein the first adjustable impedance element includes at least one transistor operated in linear region, and the second adjustable impedance element also includes at least one transistor operated in linear region.Type: GrantFiled: March 21, 2006Date of Patent: June 3, 2008Assignee: Realtek Semiconductor Corp.Inventor: Han-Chang Kang
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Patent number: 7382202Abstract: An apparatus provides a local oscillator signal based on a selected channel of an RF input signal. For example, the apparatus can set a frequency of the local oscillator signal based on the selected channel. Digital circuitry can be used to generate the local oscillator signal. For instance, the digital circuitry can provide a digital representation of the local oscillator signal. A DAC can convert the digital representation to an analog signal. Other circuitry can provide first and second quadrature components of the local oscillator signal, based on the analog signal.Type: GrantFiled: October 2, 2006Date of Patent: June 3, 2008Assignee: Broadcom CorporationInventors: Steven Jaffe, Donald McMullin, Ramon Gomez
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Publication number: 20080122545Abstract: A phase locked loop with a voltage controlled oscillator, where the voltage controlled oscillator includes a feedback loop and delay cells connected in a ring. Each delay cell has a biased pMOSFET to provide pull-up current and a biased nMOSFET to provide pull-down current. For each delay cell, the gate of the biased nMOSFET is biased by the control voltage provided by the phase locked loop, and the gate of the biased pMOSFET is biased at a bias voltage provided by the feedback loop. The biasing of the pMOSFETs is adjusted so that the pull-up and pull-down currents for each delay cell are matched, thereby providing a 50% duty cycle and good jitter performance over process, supply voltage variations, and temperature variations. Because only the feedback loop has non-zero static current, low power is expected. Other embodiments are described and claimed.Type: ApplicationFiled: November 3, 2006Publication date: May 29, 2008Inventors: Yongping Fan, Ian Young
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Publication number: 20080122546Abstract: In a variable frequency oscillator in a semiconductor device, as the variation of an oscillation frequency caused by the variation of temperature and supply voltage and process variation is large, it is difficult to reduce the conversion ratio of control voltage dependent upon phase noise and the oscillation frequency and therefore, phase noise is large. The variation of the oscillation frequency is suppressed and phase noise is reduced by connecting a voltage-to-current conversion circuit that converts input control voltage to control current of a ring oscillator to the ring oscillator where delay circuits a delay time of which increases and decreases according to the amplitude of input control current are cascade-connected by a plurality of stages in a ring and increasing/decreasing current dependent upon any of temperature, supply voltage and the threshold voltage of a transistor inside the voltage-to-current conversion circuit.Type: ApplicationFiled: June 29, 2007Publication date: May 29, 2008Inventors: Nobuhiro SHIRAMIZU, Toru Masuda
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Publication number: 20080116961Abstract: The invention is mainly directed to providing a charge pump circuit which realizes low power consumption. A first clock signal is supplied from an oscillator circuit to capacitor elements forming a charge pump circuit. A current generation circuit controls a current flowing through each of inverters by controlling operation of PMOS and NMOS, and as a result controls the frequency of the first clock signal. A gate and a drain of PMOS are short-circuited, and between the node thereof and a ground terminal a constant current generation circuit and a resistor are connected in parallel. The constant current generation circuit serves to keep the current flowing through the inverters constant against a change of a power supply voltage. Therefore, the frequency of the clock signal is reduced according to the increase of the power supply voltage.Type: ApplicationFiled: November 13, 2007Publication date: May 22, 2008Applicants: Sanyo Electric Co., Ltd., Sanyo Semiconductor Co., Ltd.Inventors: Sadao Yoshikawa, Toshiki Rai
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Publication number: 20080111638Abstract: A delay stage for a semiconductor device includes at least one delay branch and at least one controllable switching apparatus. The at least one controllable switching apparatus is configured to connect a predefined amount of the at least one delay branch to a supply voltage.Type: ApplicationFiled: October 27, 2006Publication date: May 15, 2008Applicant: Infineon Technologies AGInventor: Edwin Thaller
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Publication number: 20080111637Abstract: A Voltage Controlled Oscillator (VCO) includes a plurality of oscillation units connected in cascade to form a chain; and a plurality of current source sections operatively connected to the oscillation units, the current source sections each being configured to control current provided to the oscillation units, wherein each of the current source sections includes: at least one fixed current source configured to perform a current control of a corresponding oscillation unit by using a fixed voltage; and at least one variable current source configured to perform a current control of the corresponding oscillation unit by using a variable voltage.Type: ApplicationFiled: June 27, 2007Publication date: May 15, 2008Applicant: SAMSUNG ELECTRONICS CO., LTD.Inventors: Jung SUNWOO, Young-Don CHOI
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Patent number: 7372340Abstract: A clock synthesis circuit) including a phase-locked loop and one or more frequency synthesis circuits is disclosed. The phase-locked loop includes a voltage-controlled oscillator (VCO) having a sequence differential stages o produce equally spaced clock phases. The frequency synthesis circuit includes a sequence of adder-and-register units that select one of the VCO clock phases. An output multiplexer receives each of the selected clock phases, and selects among these clock phases in sequence; the output of the multiplexer is applied to a first toggle flip-flop that changes state in response to rising edge transitions at the output of the multiplexer. A second toggle flip-flop is clocked by the output of the first toggle flip-flop, itself toggling in response to rising edge transitions at the output of the first toggle flip-flop. One or more additional flip-flops can be similarly connected in sequence.Type: GrantFiled: October 14, 2005Date of Patent: May 13, 2008Assignee: Texas Instruments IncorporatedInventors: Liming Xiu, Zhihong You
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Publication number: 20080106345Abstract: A voltage controlled oscillator includes at least one input port for receiving a control voltage and at least one voltage-to-current coupled to the input port for generating a control current in response to the control voltage. At least one current controlled oscillator generates an oscillating frequency output in response to the control current. At least one compensation branch is coupled to the voltage-to-current converter for generating a compensation current that increases the control current when the control voltage exceeds a predetermined value.Type: ApplicationFiled: November 3, 2006Publication date: May 8, 2008Inventor: Mu-Jen Huang
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Patent number: 7369600Abstract: A communications apparatus and method use tapped delay lines as multiplexers and demultiplexers. In one embodiment, a receiver (100) uses a tapped delay line (110) as a demultiplexer to acquire a burst communication at very high data rates in the range of 2.5 to 80 Gbps with low preamble overhead. A sliding window correlator (114) continually samples the delay line (110) to determine when a PN encoded word is contained therein. The transmission frequency is pre-acquired before any data is present through the use of a ring oscillator frequency calibration loop (130) that is imbedded within the tapped delay line (110).Type: GrantFiled: December 22, 2003Date of Patent: May 6, 2008Assignee: Northrop Grumman CorporationInventors: Eric L. Upton, James M. Anderson, Edward M. Garber
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Patent number: 7362189Abstract: A voltage controlled current source outputs oscillator drive current and oscillator equivalent current. A signal oscillator outputs first source oscillation signal and second source oscillation signal. A differential amplifier outputs first amplification oscillation signal and second amplification oscillation signal. First switch circuit and second switch circuit output first current oscillation signal and second current oscillation signal, respectively. A first current value converter-amplifier circuit converts a value of the first current oscillation signal whereas a second current value converter-amplifier circuit converts a value of the second current oscillation signal, so that the thus converted values become output current finally. An adder outputs to the differential amplifier a differential amplifier drive current in which equivalent current for use with conversion is added up with the oscillator equivalent current outputted from the voltage controlled current source.Type: GrantFiled: May 28, 2004Date of Patent: April 22, 2008Assignee: Rohm Co., Ltd.Inventors: Takao Kakiuchi, Takeshi Wakii, Sho Maruyama
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Patent number: 7362187Abstract: Circuits, methods, and apparatus that provide a sequential start-up of outputs of an oscillator following a power-up or restart. The outputs are gated by enable signals. These enable signals are derived sequentially, the first in a series being triggered by a specific output of the oscillator.Type: GrantFiled: October 25, 2005Date of Patent: April 22, 2008Assignee: Altera CorporationInventors: Kang-Wei Lai, Greg Starr
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Publication number: 20080088379Abstract: A current device capable of process, voltage and temperature compensation for phase-locked loop (PLL) is disclosed. The current device can adjust the central frequency of oscillation of a voltage-controlled oscillator (VCO), making a compensated central oscillating frequency not affected by all process, voltage and temperature (PVT) variations. Meanwhile, the VCO having lower KVCO can operate in the same range of operating frequencies. Further, the current device of the invention can also be applied to a charge pump circuit, causing the charge pump current Icp to vary according to KVCO and therefore making the product of (Icp*KVCO) substantially independent of the PVT conditions.Type: ApplicationFiled: October 16, 2007Publication date: April 17, 2008Inventor: Yi-Kuang Chen
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Publication number: 20080084250Abstract: In a DPLL circuit, when the size of a data value which is output from a data latch circuit and should be naturally set in a 11-bit down-counter becomes equal to or more than 12 bits, an overflow preventing circuit substitutes the 11-bit data for the data value.Type: ApplicationFiled: July 31, 2007Publication date: April 10, 2008Applicant: DENSO CORPORATIONInventors: Yasuyuki Ishikawa, Yoshinori Teshima, Hideaki Ishihara
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Patent number: 7355488Abstract: A differential amplifier circuit for use in a ring oscillator includes first and second MOS transistors to each source of which an operating power source voltage is applied, and which individually respond to first and second input signals with mutually contrary phases applied to gates thereof; cross-coupled first and second-stage transistors of which each drain-source channel is connected between each drain of the first and second MOS transistors and a ground voltage level; a first variable resistance, which is connected between a drain of the first MOS transistor cross-connected to a second gate of the cross-coupled second-stage transistors, and a first gate of the cross-coupled first-stage transistors, and which is controlled by the operating power source voltage applied to a gate thereof; and a second variable resistance, which is connected between a drain of the second MOS transistor cross-connected to a second gate of the cross-coupled first-stage transistors, and a first gate of the cross-coupled secondType: GrantFiled: June 15, 2006Date of Patent: April 8, 2008Assignee: Samsung Electronics Co., Ltd.Inventor: Kwang-Il Park
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Patent number: 7352253Abstract: The invention discloses an oscillator circuit (100, 200, 300, 400), comprising an oscillating element (110, 210, 310, 410) and output means (115, 215, 315, 415) for outputting an oscillation frequency from the oscillating circuit. The circuit further comprises a signal delay means (120, 220, 320, 420) which is arranged in series with the oscillating element and feeds the output signal back to the oscillating element. The delay means is (120, 220, 320, 420) tuneable with respect to the delay it provides. The oscillating element can be an amplifier or a VCO, and the delay means can be a Delay Locked Loop or a tuneable delay line, depending on the embodiment of the invention.Type: GrantFiled: December 10, 2003Date of Patent: April 1, 2008Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Harald Jacobsson, Spartak Gevorgian, Thomas Lewin
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Patent number: 7352213Abstract: The use of an alternating current (ac) source to power logic circuitry can support satisfactory device performance for a variety of applications, while enhancing long-term stability of the circuitry. For example, when organic thin film transistor (OTFT)-based logic circuitry is powered by an ac power source, the logic circuitry exhibits stable performance characteristics over an extended period of operation. Enhanced stability may permit the use of OTFT logic circuitry to form a variety of circuit devices, including inverters, oscillators, logic gates, registers and the like. Such circuit devices may find application in a variety of applications, including integrated circuits, printed circuit boards, flat panel displays, smart cards, cell phones, and RFID tags. In some applications, the ac-powered logic circuitry may eliminate the need for ac-dc rectification components, thereby reducing the manufacturing time, expense, cost, complexity, and size of the component carrying the circuitry.Type: GrantFiled: May 31, 2006Date of Patent: April 1, 2008Assignee: 3M Innovative Properties CompanyInventors: Paul F. Baude, Michael A. Haase
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Patent number: 7352252Abstract: A circuit for inline testing of memory devices which provides information on the variation of the threshold voltage. The circuit includes an array of ring oscillators with a series of inverters, which already exist in the memory device. A control logic systematically steps through all of the ring oscillators by enabling each inverter and toggling the input. The mean frequency and its distribution is measured and recorded in an output circuit. The threshold voltage variation in the memory device is deduced from the ring oscillators. The circuit additionally includes two inverters place external of the memory device. Each ring oscillator is coupled to an inverter. The inverter preconditions the elements of the ring oscillator to prevent a resistive divider between the two transistors.Type: GrantFiled: July 11, 2006Date of Patent: April 1, 2008Assignee: International Business Machines CorporationInventors: Christopher J. Gonzalez, Vinod Ramadurai, Norman J. Rohrer
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Publication number: 20080074170Abstract: The invention discloses a charge pump circuit control system comprising a level detector, a ring oscillator, and a charge pump circuit. The level detector detects the variation of the output voltage of the charge pump circuit for generating a control signal. The ring oscillator generates a plurality of clocksignals according to the control signal. And the charge pump circuit generates the output voltage according to the plurality of clock signals.Type: ApplicationFiled: April 30, 2007Publication date: March 27, 2008Inventor: Jen Shou Hsu
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Publication number: 20080068100Abstract: A method and system for modulating logic clock oscillator frequency based on voltage supply. The system comprises a logic unit having a logic operation and a device to produce self-adjusting clocks to match the logic operation. The device is configured to use supply voltage as an independent variable to optimize device parameters for voltage variations.Type: ApplicationFiled: September 12, 2006Publication date: March 20, 2008Inventors: Kenneth J. Goodnow, Clarence R. Ogilvie, Christopher B. Reynolds, Sebastian T. Ventrone, Keith R. Williams
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Methods and apparatus for inline measurement of switching delay history effects in PD-SOI technology
Publication number: 20080068099Abstract: Techniques for inline measurement of switching delay history effects in an integrated circuit device are provided. A pulse is launched down a delay chain. The pulse is substantially synchronized with a signal of a ring oscillator. The delay chain and the ring oscillator comprise substantially identical gates to a defined point on the ring oscillator corresponding to a far end of the delay chain. At least one difference in a number of gates traversed by an edge of the signal in the ring oscillator and a number of gates traversed by a corresponding edge of the pulse in the delay chain is measured when the pulse reaches the far end of the delay chain. One or more switching histories in the integrated circuit device are determined in accordance with the at least one measured difference in the number of gates traversed by an edge of the signal and a corresponding edge of the pulse.Type: ApplicationFiled: September 6, 2006Publication date: March 20, 2008Inventors: Manjul Bhushan, Mark B. Ketchen -
Publication number: 20080069292Abstract: Described is a compact, lower power gated ring oscillator time-to-digital converter that achieves first order noise shaping of quantization noise using a digital implementation. The gated ring oscillator time-to-digital converter includes a plurality of delay stages configured to enable propagation of a transitioning signal through the delay stages during an enabled state and configured to inhibit propagation of the transitioning signal through the delay stages during a disabled state. Delay stages are interconnected to allow sustained transitions to propagate through the delay stages during the enabled state and to preserve a state of the gated ring oscillator time-to-digital converter during the disabled state. The state represents a time resolution that is finer than the delay of at least one of the delay stages. A measurement module determines the number of transitions of the delay stages.Type: ApplicationFiled: September 13, 2007Publication date: March 20, 2008Applicant: MASSACHUSETTS INSTITUTE OF TECHNOLOGYInventors: Matthew Straayer, Michael Perrott
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Publication number: 20080063044Abstract: A burst control pulse generating circuit which generates a pulse signal used to provide communication includes a timing generating circuit containing a ring oscillation circuit which oscillates a periodic signal based on a burst signal for controlling the ON and OFF condition of the communication to output a plurality of timing signals based on the periodic signal, and a pulse generating logic circuit which generates the pulse signal based on the plural timing signals. The burst control pulse generating circuit generates the pulse signal one or more times when the burst signal is in an ON condition, and stops generation of the pulse signal when the burst signal is in an OFF condition.Type: ApplicationFiled: September 6, 2007Publication date: March 13, 2008Applicant: Seiko Epson CorporationInventor: Izumi Iida
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Publication number: 20080061893Abstract: Systems and methods for implementing a temperature compensated two-stage ring oscillator are described. At least one embodiment includes a system for generating a clock signal comprising a self-starting oscillator comprising two delay stages in a ring configuration. The two-stage ring oscillator is configured to generate the clock signal, wherein the delay stages are configured such that the two-stage ring oscillator has a single right-half plane (RHP) pole in each of the two delay stages where feedback is always positive. For some embodiments, the system further comprises a compensation module configured to sense temperature and process variations and adjust a supply voltage for the two-stage ring oscillator to compensate for temperature and process variations in order to maintain a constant frequency clock signal. For such embodiments, the compensation module comprises a replica circuit configured to mirror operation of the n-channel devices within the two-stage ring oscillator.Type: ApplicationFiled: September 11, 2007Publication date: March 13, 2008Applicant: CONEXANT SYSTEMS, INC.Inventors: Kadaba Lakshmikumar, Vinod Mukundagiri
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Patent number: 7339439Abstract: A multi-phase realigned voltage-controlled oscillator (MRVCO) achieves phase realignment based on charge injection in the VCO stages. The individual VCO stages provide an oscillating output signals having an asymmetric waveform with substantially different rise and fall times. This ensures that the VCO as a whole has a multiphase impulse response to the charge injection that is strictly positive or strictly negative, and substantially constant so as to be independent of the VCO phase or timing of charge injection. The MRVCO may form a component part of an implementation of a multi-phase realigned phase-locked loop (MRPLL).Type: GrantFiled: July 11, 2006Date of Patent: March 4, 2008Assignee: Atmel CorporationInventors: Regis Roubadia, Sami Ajram
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Publication number: 20080048790Abstract: A configurable ring oscillator is operated in a first configuration so that an oscillating signal passes from a first node to a second node through a first signal path. A first measurement of an operational characteristic is made. The ring oscillator is operated in a second configuration where an oscillating signal passes from the first node to the second node through a second signal path. A second measurement is made. The first and second measurements are used to determine a circuit simulator parameter. If the first path has little interconnect and the second path has substantial interconnect, then the effect on circuit operation due to interconnect loading can be isolated from the effects on circuit operation due to variations in transistor performance. If the first and second paths are laid out to be identical, then the first and second measurements are usable to determine a circuit simulator mismatch parameter.Type: ApplicationFiled: March 23, 2007Publication date: February 28, 2008Applicant: QUALCOMM INCORPORATEDInventors: David Bang, Jayakannan Jayapalan
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Patent number: 7336134Abstract: A tunable oscillator suitable for use in a frequency synthesizer of a transceiver is controlled by varying one or more parameters associated with the oscillator. In particular, a digital control signal affects one or more of the capacitances of the oscillator, the bias voltage of the oscillator, the supply voltage, or the bias current of the oscillator. Changes to one or more of these parameters allows the frequency of the oscillator to be controlled as desired.Type: GrantFiled: June 25, 2004Date of Patent: February 26, 2008Assignee: RF Micro Devices, Inc.Inventors: Stephen T. Janesch, Paul G. Martyniuk
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Patent number: 7332978Abstract: A glitch free controlled ring oscillator may comprise a programmable delay chain connected to a gating and inverter stage or means. A latch or latching means may be provided between the delay chain and the gating and inverter stage or means for registering the clock state at the time of disabling the oscillator and setting the output of the oscillator to the registered clock state.Type: GrantFiled: December 16, 2005Date of Patent: February 19, 2008Assignee: STMicroelectronics Pvt Ltd.Inventors: Naveen Tiwari, Balwant Singh
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Patent number: 7330081Abstract: A digitally controlled oscillator circuit is provided that comprises a ring oscillator including multiple inverters; multiple digitally controlled capacitors (DCCs), each coupled to apply a digitally controllable amount of capacitance to an output of a different one of the inverters; and control circuitry operable to change an amount of capacitance applied to each inverter during operation of the ring oscillator and to cause the multiple DCCs to apply substantially the same amounts of capacitance to each of the inverter throughout operation of the ring oscillator.Type: GrantFiled: July 7, 2005Date of Patent: February 12, 2008Assignee: Marvell Semiconductor Israel Ltd.Inventors: Gil Asa, David Moshe, Ido Bourstein
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Patent number: 7330080Abstract: One embodiment in accordance with the invention is a method that can include utilizing a ring oscillator module to determine a process corner of an integrated circuit as fabricated that includes the ring oscillator module. The impedance of an output driver of the integrated circuit can be altered based on the process corner of the integrated circuit as fabricated.Type: GrantFiled: November 4, 2004Date of Patent: February 12, 2008Assignee: Transmeta CorporationInventors: Steven T. Stoiber, Stuart Siu
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Patent number: 7328115Abstract: A quality assurance integrated circuit for a print controller is provided. The IC has a memory, a system clock having a ring oscillator for generating a clock signal, clock trim circuitry for trimming the clock signal generated by the system clock and a processor. The processor is arranged to, in response to receiving an external signal, determine the number of cycles of the clock or external signal during a predetermined number of cycles of the external or clock signal, respectively and to output the determined number of cycles to an external circuit, and, in response to receiving a trim value based on the determined number of cycles from the external circuit, store the trim value in the memory and control the clock trim circuitry to trim the frequency of the clock signal generated by the ring oscillator using the trim value.Type: GrantFiled: July 19, 2006Date of Patent: February 5, 2008Assignee: Silverbrook Research Pty LtdInventors: Gary Shipton, Simon Robert Walmsley
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Publication number: 20080024232Abstract: A circuit for inline testing of memory devices which provides information on the variation of the threshold voltage. The circuit includes an array of ring oscillators with a series of inverters, which already exist in the memory device. A control logic systematically steps through all of the ring oscillators by enabling each inverter and toggling the input. The mean frequency and its distribution is measured and recorded in an output circuit. The threshold voltage variation in the memory device is deduced from the ring oscillators. The circuit additionally includes two inverters place external of the memory device. Each ring oscillator is coupled to an inverter. The inverter preconditions the elements of the ring oscillator to prevent a resistive divider between the two transistors.Type: ApplicationFiled: July 11, 2006Publication date: January 31, 2008Inventors: Christopher J. Gonzalez, Vinod Ramadurai, Norman J. Rohrer
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Patent number: 7323908Abstract: A cascaded pass-gate test circuit including interposed split-output drive devices provides accurate measurement of critical timing parameters of pass gates. The rise time and fall time of signals passed through the pass gate can be separately measured in a ring oscillator or one-shot delay line configuration. Inverters or other buffer circuits are provided as drive devices to couple the pass gates in cascade. The final complementary tree in each drive device is split so that the only one of the output pull-down transistor or pull-up transistor is connected to the next pass gate input, while the other transistor is connected to the output of the pass gate. The result is that the state transition associated with the device connected to the pass gate input is dominant in the delay, while the other state transition is propagated directly to the output of the pass gate, bypassing the pass gate.Type: GrantFiled: October 27, 2005Date of Patent: January 29, 2008Assignee: International Business Machines CorporationInventors: Ching-Te Chuang, Jente B. Kuang, Hung C. Ngo
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Publication number: 20080018408Abstract: An interleaved voltage-controlled oscillator (VCO) is disclosed. The VCO includes a ring circuit comprising a series connection of main logic inverter gates, a plurality of delay elements connected in parallel with a selected sequence of the main logic inverter gates, at least one temperature compensation circuit comprising a logic inverter gate in series connection with one or more field effect transistors, the field effect transistor responsive to a compensating voltage input that is proportional to temperature, and an electronic circuit in signal communication with the at least one temperature compensation circuit and configured to provide a voltage signal responsive to temperature. Each delay element includes a feedforward section, comprising controls for regulating signal transmission through feedforward elements responsive to one or more control voltages, and a proportional section, comprising controls for regulating signal transmission through at least one logic inverter gate.Type: ApplicationFiled: July 20, 2006Publication date: January 24, 2008Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: David W. Boerstler, Eskinder Hailu, Jieming Qi, Mike Shen
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Patent number: 7321269Abstract: An inverting circuit comprises a first inverter in a main path having a first input and a common ouput. A second inverter receives the first input and is coupled with a first voltage controlled pass gate to the common output. A third inverter couples a second input to the common output using a second voltage controlled pass gate. A fourth inverter couples the second input to the common output using the first voltage controlled pass gate. A ring oscillator is formed using a number N of the inverting circuits with each common output coupled to the first inputs forming a main ring of a ring oscillator. The second inputs are coupled to feed-forward signals from selected outputs. The resulting signals at the common outputs are an interpolation of the first and second input signals modulated by a control voltage coupled to the first and second pass gates.Type: GrantFiled: July 19, 2005Date of Patent: January 22, 2008Assignee: International Business Machines CorporationInventors: Alan J. Drake, Fadi H. Gebara, Jeremy D. Schaub