Multivibrators Patents (Class 331/144)
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Patent number: 8823464Abstract: A reconfigurable element based on nonlinear (chaotic) dynamics is adapted to implement the three different multivibrator configurations. A nonlinear dynamical system, under parameter modulating control, operates as a tunable oscillator with different dynamical regimes which in turn provide the different multivibrator configurations (monostable, astable, and bistable). The reconfigurable multivibrator is realized as a tunable circuit which includes an input stage for receiving at least one input voltage signal and an output stage that produces a digital two-level electric output signal. The all-in-one reconfigurable multivibrator device consisting of a nonlinear oscillator circuit electrically coupled to the input/output circuitry is used in at least, but not limited to three basic applications, namely, an irregular width pulse generator, a rising flank trigger and a full RS flip-flop device.Type: GrantFiled: October 29, 2012Date of Patent: September 2, 2014Assignee: Instituto Potosino de Investigacion Cientifica y Tecnológica A.C.Inventors: Eric Campos Canton, Isaac Campos Canton, Juan Gonzalo Barajas Ramirez, Alejando Ricardo Femat Flores
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Publication number: 20140028408Abstract: A relaxation oscillator has a comparator that includes first through third bias current transistors coupled to a first supply rail. First and second input transistors form a pair of parallel coupled transistors connected to the first bias current transistor. A first current mirror control transistor connects the first input transistor to a second supply rail. A first current mirror output transistor is coupled to the first current mirror control transistor, and connects the second bias current transistor to the second supply rail. A second current mirror control transistor connects the second input transistor to the second supply rail. A second current mirror output transistor is coupled to the second current mirror control transistor, and connects the third bias current transistor to the second supply rail. A transition time reduction transistor, coupled across the third bias current transistor, is coupled to the second bias current transistor, and provides a comparator output.Type: ApplicationFiled: September 11, 2012Publication date: January 30, 2014Applicant: FREESCALE SEMICONDUCTOR, INCInventor: Zhengxiang WANG
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Patent number: 8570111Abstract: A single-staged balanced-output inductor-free oscillator and method thereof are provided. In one implementation an apparatus includes a first network comprising a first amplifier configured in a self feedback topology via a first feedback network for generating a first end of an output signal; a second network comprising a second amplifier configured in a self feedback topology via a second feedback network for generating a second end of the output signal; and a cross-coupling network for cross-coupling the first end and the second end of the output signal, wherein the first network and the second network share a common supply current and the first feedback network and the second feedback network are configured in a cross-controlling topology.Type: GrantFiled: November 2, 2011Date of Patent: October 29, 2013Assignee: Realtek Semiconductor Corp.Inventor: Chia-Liang Lin
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Publication number: 20130049875Abstract: A control circuit controls first and second clock generator subcircuits so that one subcircuit of the first and second clock generator subcircuits operates for a comparison voltage generating interval, then another subcircuit operates for a clock generating interval, and so that the first and second clock generator subcircuits alternately repeat processes of the comparison voltage generating interval and the clock generating interval. For the comparison voltage generating interval, each of the first and second clock generator subcircuits is controlled to generate a comparison voltage and output the same voltage to an inverted output terminal of a comparator. For the clock generating interval, each of the first and second clock generator subcircuits compares an output voltage from a current-voltage converter circuit with the comparison voltage.Type: ApplicationFiled: August 22, 2012Publication date: February 28, 2013Inventors: Seichiro SHIGA, Tetsuya Hirose, Yuji Osaki
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Patent number: 7639095Abstract: A system includes a first and second circuit electromagnetically coupled to establish a contact-less transmission, for example, between a vehicle body and a removable seat of the vehicle body. The first circuit includes a first inductor and the second circuit includes a second inductor. In order to detect in the first circuit the status of one or more input signals of the second circuit, the second circuit includes a signal generating portion including a resistor and a capacitor that generates, a time-pulsed signal. The second circuit is adapted to set a value of at least one of the resistor and the capacitor based on a sensed parameter and sets a duty cycle of the time-pulsed signal based on a value of at least one of the resistor and the capacitor. The time-pulsed signal changes a load of the second circuit over time which can be detected in the first circuit.Type: GrantFiled: August 31, 2006Date of Patent: December 29, 2009Assignee: Tyco Electronics Belgium EC N.V.Inventors: Tom Ocket, Joeri Fryns, Jan Van Cauwenberge, Michael Siotto
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Patent number: 7567071Abstract: An integrated circuit in accordance with one embodiment of the invention includes an oscillator circuit and a source circuit. The source circuit outputs a reference voltage and a bias current, wherein the reference voltage changes by substantially the same proportion as the bias current. The oscillator circuit is coupled to receive the reference voltage and the bias current from the source circuit. The oscillator circuit outputs an oscillating electrical signal.Type: GrantFiled: May 10, 2005Date of Patent: July 28, 2009Assignee: National Semiconductor CorporationInventor: Vadim Tsinker
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Patent number: 7466178Abstract: This invention relates to monostable and astable multivibrators in which the pulse width or frequency stability, respectively is increased by reducing the effect of the comparator input offset voltage. The reduction is accomplished by alternately reversing the input connections to the comparator.Type: GrantFiled: December 12, 2005Date of Patent: December 16, 2008Inventor: Fred Mirow
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Patent number: 7443256Abstract: An oscillator circuit having a relatively simple circuit structure while enabling full swing with low power consumption includes an oscillation core block, a voltage restriction block, and a differential output block. Drain terminals of first and second transistors are each connected to the voltage restriction block. The voltage restriction block restricts the amplitude of an oscillation signal to a reference voltage. Source terminals of third and fourth transistors are connected to drain terminals of fifth and sixth transistors, and source terminals of seventh and eighth transistors are connected to drain terminals of ninth and tenth transistors. This supplies the differential output block with current generated by the amplitude restriction. The differential output block converts the current into drive voltage to ground voltage to perform full swing.Type: GrantFiled: July 10, 2007Date of Patent: October 28, 2008Assignee: Freescale Semiconductor, Inc.Inventor: Hiroyuki Kimura
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Patent number: 7432771Abstract: An oscillator circuit includes a current source comprising an amplifier, a first resistor, a second resistor, and a third inverter whose input and output are connected and coupled with an input of the amplifier. The amplifier is configured to generate a first current flowing through the first resistor and the second resistor.Type: GrantFiled: June 2, 2006Date of Patent: October 7, 2008Assignee: Smartech Worldwide LimitedInventor: Martin Yeung-Kei Chui
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Patent number: 7420431Abstract: An RC oscillator integrated circuit includes: an active current mirror connected to an external resistor, for receiving a current signal corresponding to a voltage signal applied to the external resistor, performing 1/N-times division of the received current signal according to an input clock signal, and generating a 1/N-times current signal; an oscillation circuit for generating an output voltage corresponding to a charging- or discharging-operation of a capacitor via a current path formed by the active current mirror; a feedback switching circuit for controlling a charging- or discharging-path of the capacitor by a feedback of an output signal Vo of the oscillation circuit; and a divider for generating not only a first clock signal capable of driving the active current mirror according to the output signal of the oscillation circuit, but also a second output clock signal having a compensated mismatch of the active current mirror.Type: GrantFiled: December 1, 2006Date of Patent: September 2, 2008Assignee: Fairchild Korea Semiconductor, Ltd.Inventors: Jong-Tae Hwang, Dae-Ho Kim, Moon-Sang Jung, Dong-Hwan Kim
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Patent number: 7385452Abstract: A VCO is based on a capacitively emitter degenerated topology which uses a cross-coupled MOS pair as the degeneration cell. The cross-coupled MOS pair contributes additional conductance and results in a higher maximum attainable oscillation frequency and better negative resistance characteristics as compared to the other topologies at high frequencies. These properties of the disclosed VCO combined with small effective capacitance enable low-power low-noise high-frequency VCO implementations.Type: GrantFiled: February 7, 2006Date of Patent: June 10, 2008Assignee: Regents of the University of MinnesotaInventors: Ramesh Harjani, Byung-Hoo Jung
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Patent number: 7348860Abstract: There are provided relaxation oscillators and methods for controlling the same. A relaxation oscillator includes a load device, a switching device, a fine-tuning varactor, and a current source. The load device is configured to provide a variable oscillator output based on a variable input reference voltage. The switching device is connected in signal communication with the load device and is configured to become active and inactive based on the variable oscillator output. The fine-tuning varactor is connected in signal communication with the switching device and is configured to provide fine-tuning of the variable oscillator output when the switching device is active. The current source is connected in signal communication with the switching device and is configured to provide coarse-tuning of the variable oscillator output when the switching device is active.Type: GrantFiled: January 13, 2006Date of Patent: March 25, 2008Assignee: International Business Machines CorporationInventors: Woogeun Rhee, Daniel J. Friedman, Babak Soltanian
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Patent number: 7119626Abstract: An oscillation circuit has: a first MOS transistor having a gate connected to a first node and a source connected to the ground; a second MOS transistor having a gate connected to a second node and a source connected to the ground; a current supply circuit supplying a control current; a threshold correction circuit supplying a correction current; and a charge-discharge circuit which supplies a charge current which is a superposition of the control current and the correction current to the first node and the second node alternately in response to potentials of drains of the first and the second MOS transistors. The threshold correction circuit increases the correction current as threshold voltages of the first and the second MOS transistors become large.Type: GrantFiled: December 29, 2004Date of Patent: October 10, 2006Assignee: NEC Electronics CorporationInventor: Jun Yoshida
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Patent number: 6943638Abstract: A voltage controlled oscillator comprises two XOR logic units and two inverters. A first inverter inverts a first XOR result into a first output signal; a second inverter inverts a second XOR result into a second output signal; a first XOR logic unit performs an XOR logic operation based on an input signal and the second output signal and thus generating the first XOR result; and a second XOR logic unit performs an XOR logic operation based on the first output signal and a reference voltage and thus generates the second XOR result.Type: GrantFiled: January 7, 2005Date of Patent: September 13, 2005Assignee: Toppoly Optoelectronics Corp.Inventor: Yan-Liang Li
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Patent number: 6600379Abstract: A voltage-controlled variable duty-cycle oscillator includes a current generator whose current Iref mirrored in three one-shots that each include two pair of series-coupled MOS transistors and a timing capacitor. The timing capacitor is precharged to Vcc in the first two one-shots, and to a lesser voltage Vcon in the third one-shot. The oscillator also includes pre and a post-NOR-gate logic. Output signals from the two one-shots are coupled to the pre NOR-gate logic to generate an intermediate oscillator signal whose duty cycle is determined by Iref and by the first two timing capacitors. The intermediate oscillator signal and output from the third one-shot are combined in the post NOR-gate logic to yield a VCO output signal whose duty cycle is determined by the ratio of the timing capacitor in the third one-shot compared to the sum of the timing capacitors in the first and second one-shots. VCO output signal duty cycle is a fairly linear function of Vcon.Type: GrantFiled: December 21, 2001Date of Patent: July 29, 2003Assignee: Micrel, IncorporatedInventor: Douglas Anderson
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Patent number: 6587007Abstract: A VCO includes N delay stages that each contribute 180°/N phase shift at the VCO frequency of interest and provide a tunable selection of at least a fast delay and a slow delay path. Each delay stage includes a delay interpolator that smoothly interpolates between the delay paths within the stage. Each delay stage is coupled to a bandpass frequency selective network that acts as a load and helps filter phase noise. Feedback from the Nth delay stage to the first delay stage is via a phase shifter that provides a fixed phase at the frequency of interest of 180° or 0° that is required to sustain oscillation. VCO frequency is determined by the various stage delays and by the load circuit phase response. Individual stage delays are varied by interpolation such that overall VCO frequency control and phase noise performance are enhanced. Multiphase signals are available from the N delay stages.Type: GrantFiled: November 26, 2001Date of Patent: July 1, 2003Assignee: Micrel, IncorporatedInventor: George Ronald Exeter
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Publication number: 20020084861Abstract: A VCO includes a non-inverting output and an inverting output coupled to symmetrical circuitry configured to produce an oscillating output at the outputs. The symmetrical circuitry can include, for example, matched devices such as voltage-controlled resistors (VCRs) and capacitors. The symmetrical circuitry coupled to the non-inverting output and inverting output results in a stable output that operates close to the optimal 50% duty cycle independent of frequency and across a wide range of frequencies. In an alternative embodiment, the VCO further includes an output differential amplifier having its non-inverting input coupled to the non-inverting output and its inverting input coupled to the inverting output. The VCO according to this embodiment exhibits higher gain and a stable output that operates close to the optimal 50% duty cycle independent of frequency and across a wide range of frequencies.Type: ApplicationFiled: December 29, 2000Publication date: July 4, 2002Inventor: Jed D. Griffin
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Patent number: 6404296Abstract: A source-coupled oscillator contains two main MESFETs which supply current to respective loads and which have sources connected through a capacitor. Each of the main MESFETs is supplied with a constant current which can be adjusted to vary the frequency of the oscillator. The output signals are derived from the voltage across the loads. The oscillator also contains two differential pairs of MESFETs that change state as the main MESFETs are turned on and off and are connected so as to switch current into one or the other of the loads. Each of the differential pairs is supplied with a constant current. The currents supplied by the differential pairs act as compensating currents and are adjusted so that when the currents through the two main MESFETs are changed to vary the frequency of the oscillator, the total current through the loads remains constant.Type: GrantFiled: December 4, 2000Date of Patent: June 11, 2002Assignee: TriQuint Semiconductor, Inc.Inventors: William H. Davenport, Tyler Bowman
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Publication number: 20020067216Abstract: A source-coupled oscillator contains two main MESFETs which supply current to respective loads and which have sources connected through a capacitor. Each of the main MESFETs is supplied with a constant current which can be adjusted to vary the frequency of the oscillator. The output signals are derived from the voltage across the loads. The oscillator also contains two differential pairs of MESFETs that change state as the main MESFETs are turned on and off and are connected so as to switch current into one or the other of the loads. Each of the differential pairs is supplied with a constant current. The currents supplied by the differential pairs act as compensating currents and are adjusted so that when the currents through the two main MESFETs are changed to vary the frequency of the oscillator, the total current through the loads remains constant.Type: ApplicationFiled: December 4, 2000Publication date: June 6, 2002Inventors: William H. Davenport, Tyler Bowman
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Patent number: 6377129Abstract: An oscillator has a slope-fixing circuit that generates a control signal and fixes the slope of the control signal, a swing-fixing circuit that fixes the swing of the control signal, and a switching block that generates an output signal having a frequency derived from the swing and the slope of the control signal. The slope-fixing circuit comprises a fixed timing capacitor C1 in parallel with a plurality of switchable timing capacitors C2 . . . CN to provide an effective capacitance C. The slope of the control signal is determined by the ratio of a control current I to the effective capacitance C. The swing-fixing circuit comprises a replica cell that accepts a programmable reference voltage VREF and provides a fixed voltage swing VSW=VDD−VREF across a pair of load transistors. The switching block comprises a pair of switching transistors that alternate between “on” and “off” states depending on the value of the control signal to produce an oscillating output signal.Type: GrantFiled: April 30, 1999Date of Patent: April 23, 2002Assignee: Conexant Systems, Inc.Inventors: Woogeun Rhee, Akbar Ali
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Patent number: 6337605Abstract: The present invention concerns an oscillator (20) intended to supply a periodic electric voltage (Vo) at a predetermined frequency (f). This oscillator includes: a reference source (23) able to provide a reference voltage (Vref), this reference source including a resistor (R) linked to said voltage; and supply means (24) able to receive the reference voltage and to supply said periodic voltage at said predetermined frequency, the supply means having a first temperature coefficient (&agr;24) so this frequency can vary under the influence of the temperature. This oscillator is characterised in that the resistor is formed to give the reference source a second temperature coefficient (&agr;23) equal to the first temperature coefficient, so that the temperature has the same influence on the reference voltage and on the supply means, which allows the periodic voltage to be supplied independently of the temperature.Type: GrantFiled: July 24, 2000Date of Patent: January 8, 2002Assignee: EM Microelectronic-Marin SAInventor: Jean-Noël Divoux
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Patent number: 6236280Abstract: A voltage controlled oscillator has first and second complementary output terminals. A first edge delay circuit has an input terminal, an output terminal, and a control input terminal. The input terminal is coupled to the first complementary output terminal. A first comparator has a first, second and third input terminal, an output terminal, and a control input terminal. The first input terminal is coupled to the output terminal of the first edge delay circuit. The second input terminal is coupled to the first complementary output terminal. The first comparator output terminal is coupled to the second complementary output terminal. A second edge delay circuit has an input terminal, an output terminal, and a control input terminal. The input terminal is coupled to the second complementary output terminal. A second comparator has a first, second and third input terminal, an output terminal, and a control input terminal. The first input terminal is coupled to the output terminal of the second edge delay circuit.Type: GrantFiled: September 20, 1999Date of Patent: May 22, 2001Assignee: Advanced Micro Devices Inc.Inventor: Daren Allee
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Patent number: 6225872Abstract: A resonator includes a resonating device and a selection circuit for selecting a resonance mode. The selection circuit is formed by a first-order oscillator which is provided with a synchronization input and whose output is connected to the excitation input of a resonator, the output of the resonator being connected to the synchronization input of the first-order oscillator in order to synchronize the oscillator and the output signal of the resonator being derived from the oscillator.Type: GrantFiled: November 5, 1999Date of Patent: May 1, 2001Assignee: Technische Universiteit DelftInventor: Christiaan Johannes Maria Verhoeven
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Patent number: 6215369Abstract: A controllable oscillator, comprising a first (Rc,Ms1,Ms2,R′c′) and a second (R1,Mi1,Mi2,R2) amplifier which are provided with inputs (Vcc,Vee) for supply voltage and at least one controllable current source (I1,I2) for controlling the output frequency of the oscillator. Both amplifiers comprise a first (Rc,Ms1;R1,Mi1) and a second (R′c,Ms2;R2,Mi2) branch, where both the first and the second branch have an input (Ms1,Ms2;Mi1,Mi2) and an output (Vout,NVout;V′out,NV′out) for electrical signals. The output (Vout) of the first branch of the first amplifier is connected to the input (Mi2) of the second branch of the second amplifier, and the output (NVout) of the second branch of the first amplifier is connected to the input (Mi1) of the first branch of the second amplifier.Type: GrantFiled: November 22, 1999Date of Patent: April 10, 2001Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Mehran Mokhtari, Harald Jacobsson
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Patent number: 6198358Abstract: An oscillator circuit comprises two main transistors (Q1, Q2), between which is provided a positive feedback by connecting each transistor base to the collector of the other transistor via buffer transistors (Q3, Q4). A capacitor (C) is connected between the emitters of the main transistors. The frequency of the oscillator is controlled by two current sources (11, 12), which control the current (I2, I2) flowing through the capacitor (C). Additionally, a compensation current (Icom) is conducted via collector resistors (Rc1, Rc2) of the main transistors such that the current flowing through each resistor is essentially constant and independent of the control current (I1, I2), so the signal amplitude of the oscillator does not change during frequency control.Type: GrantFiled: May 18, 1998Date of Patent: March 6, 2001Inventors: Nikolay Tchamov, Petri Jarske
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Patent number: 6157268Abstract: Increase of frequency and reduction of power consumption are advanced for a voltage controlled oscillation circuit. A capacitor C1 is connected between emitters of first and second transistors Tr1, Tr2 to receive an electric current from constant current sources Cs1, Cs2. Also, emitters of third and fourth transistors Tr3, Tr4 receive an electric current from a constant current source Cs3 and have their respective collectors connected through third and fourth resistors R3, R4 to a power supply terminal VCC. The respective collectors and bases of the third and fourth transistors Tr3, Tr4 are connected to bases and collectors of the first and second transistors Tr1, Tr2. Due to this, oscillation outputs are caused at respective ends of the capacitor C1, which has a voltage amplitude equal to a voltage drop due to the third and fourth resistors R3, R4 and values of currents flowing through them. The voltage drop can be decreased to such an extent that the first and second transistors Tr1, Tr2 can be turned on.Type: GrantFiled: January 19, 1999Date of Patent: December 5, 2000Assignee: Nippon Precision Circuits, IncInventor: Naoki Ueno
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Patent number: 6091307Abstract: A crystal tank circuit is connected between the ac cross-coupled outputs of two transistors that are selectively biased to an appropriate common mode voltage to cause rapid build-up of oscillation when the circuit is turned on and in which oscillation is sustained in the desired mode regardless of battery voltage fluctuation without wasting power. The differentially driven frequency-controlling crystal tank circuit receives balanced driving voltage excursions from the circuit.Type: GrantFiled: July 29, 1998Date of Patent: July 18, 2000Assignee: Lucent Techmologies Inc.Inventor: Dale Harvey Nelson
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Patent number: 5994972Abstract: An emitter-coupled multivibrator includes two transistors, a base potential supplying circuit for maintaining the base potential of one transistor which is on at a high potential and the base potential of the other transistor which is off at a low potential, and a base potential control circuit for controlling the base potential of the transistor which is on in accordance with a frequency controlling voltage V.sub.C. A coupling capacitor is charged with a constant current which flows through the transistor which is on, and when the voltage between the base and the emitter of the transistor which is off reaches a predetermined value by charging, the transistor which is off is turned on, while the transistor which is on is turned off. The same operation is repeated so as to alternately turn on and off the transistors for the purpose of oscillating operation.Type: GrantFiled: March 16, 1998Date of Patent: November 30, 1999Assignee: Fujitsu LimitedInventor: Noboru Katsui
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Patent number: 5914642Abstract: A current-controlled multivibrator having increased accuracy independent of variations in process and temperature. The oscillator employs a bandgap voltage in combination with a current generator to ensure operational stability despite temperature and process variations.Type: GrantFiled: December 30, 1996Date of Patent: June 22, 1999Assignees: SGS-Thomson Microelectronics S.r.l., Consorzio per la Ricerca sulla Microelettronica nel MezzogiornoInventors: Melchiorre Bruccoleri, Gaetano Cosentino, Marco Demicheli, Valerio Pisati
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Patent number: 5896070Abstract: An emitter-coupled multivibrator oscillator circuit including a pair of main transistors (Q1,Q2) having a positive feedback, in which the base of each transistor is connected to the collector of the other transistor via buffer transistors (Q3,Q4). A capacitor (C) is connected between the emitters of the main transistors. The circuit further comprises pull-down transistors (Q5, Q6), cross-connected so that they are positively driven to alternate between a conducting and a non-conducting state according to the states of the main transistors. The frequency of the oscillator is adjusted by controlling the current (I1) passing through the capacitor (C). Additionally, a compensating current (Icom) is arranged to flow through the collector resistors (Rc1,Rc2) of the main transistors so that the total current passing through each resistor is essentially constant and independent of the control current (I1). This way the signal amplitude of the oscillator is not affected by the frequency control.Type: GrantFiled: May 9, 1997Date of Patent: April 20, 1999Inventors: Nikolay Tchamov, Petri Jarske
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Patent number: 5867070Abstract: A voltage controlled emitter-coupled multivibrator in which a frequency range of an oscillating signal and a frequency within the frequency range can be adjusted. An emitter-coupled multivibrator is provided with an emitter follower buffer having first and second transistors, a gain stage having third and fourth transistors which are cross-coupled through the first and second transistors, and a current source connected to emitters of the third and the fourth transistors, and generates first and second oscillating frequency signals. An outputting section compares a first voltage level of the first oscillating signal with a second voltage level of the second oscillating signal and outputs a compared signal having a predetermined voltage level. A controlling section outputs a controlling current which controls an amount of a current which flows through the current source of the emitter-coupled multivibrator.Type: GrantFiled: May 30, 1997Date of Patent: February 2, 1999Assignee: Daewoo Electronics Co., Ltd.Inventor: Hyun-Jin Park
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Patent number: 5825256Abstract: An emitter-coupled multivibrator circuit including a pair of main transistors (Q1,Q2) having a positive feedback, in which the base of each transistor is connected to the collector of the other transistor. A capacitor (C) is connected between the emitters of the main transistors. The circuit further comprises pull-down transistors (Q3,Q4), cross-connected so that they are positively driven to alternate between a conducting and a non-conducting state according to the states of the main transistors. The frequency of the oscillator is adjusted by controlling the current (Icon) passing through the capacitor (C). Additionally, a compensating current (I2) is arranged to flow through the collector resistors (Rc1,Rc2) of the main transistors so that the total current passing through each resistor is essentially constant and independent of the control current (Icon). This way the signal amplitude of the oscillator is not affected by the frequency control.Type: GrantFiled: May 9, 1997Date of Patent: October 20, 1998Inventors: Nikolay Tchamov, Petri Jarske
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Patent number: 5801593Abstract: An improved voltage controlled oscillator circuit is based on a multivibrator design with an internal gain stage to permit low voltage operation. An internal gain stage maintains a loop gain of greater than one to ensure oscillation even at power supply voltages as low as 2.7 volts. The added gain allows the use of resistors inserted on either sides of a timing capacitor for improved linearity.Type: GrantFiled: December 16, 1996Date of Patent: September 1, 1998Assignee: Exar CorporationInventor: Phong Thanh Nguyen
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Patent number: 5712600Abstract: An astable multivibrator comprising a capacitor connected between a first output signal and a third output signal, an amplification circuit connected between the first and third output signals, a delay for delaying a signal logic-converted from the first output signal and for outputting a second output signal, and a variable resistor connected between the first output signal and an output node of the delay. High frequency oscillation performance is enhanced and a larger voltage operating range is obtained by excluding the effect of feedback current.Type: GrantFiled: September 29, 1995Date of Patent: January 27, 1998Assignee: Samsung Electronics Co., Ltd.Inventors: Won-Kyum Kim, Jang-Sik Won
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Patent number: 5604466Abstract: An on-chip voltage controlled oscillator for use in an analog phase locked loop receives power from a voltage regulator which greatly reduces the noise seen by the voltage controlled oscillator. The voltage controlled oscillator has a DC bias section which supplies a relatively constant current to the multivibrator to assure a minimum operating frequency. A control signal is used to provide additional current which increases the speed of oscillation. The bias current reduces the transfer characteristics (MHz/volt) of the voltage controlled oscillator making it more immune to noise in the control signal.Type: GrantFiled: November 28, 1994Date of Patent: February 18, 1997Assignee: International Business Machines CorporationInventors: Daniel M. Dreps, Raymond P. Rizzo
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Patent number: 5367270Abstract: A voltage controlled oscillator circuit is shown in integrated circuit chip design form. The frequency range of the circuit is extended by providing switch means for isolating the off-chip frequency determining capacitor and employing a minimum-value on-chip capacitor to control circuit maximum frequency operation. The circuit is based upon a regenerative latch operation which switches a controlled current to charge a capacitor first in one polarity and then in the other polarity. A control voltage determines the charging current and hence the frequency of operation.Type: GrantFiled: May 18, 1993Date of Patent: November 22, 1994Assignee: National Semiconductor CorporationInventor: Perry Lorenz
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Patent number: 5357220Abstract: An emitter-coupled oscillator circuit suitable for monolithic integration.Type: GrantFiled: January 21, 1993Date of Patent: October 18, 1994Assignee: Gennum CorporationInventor: John R. Francis
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Patent number: 5341113Abstract: A voltage controlled oscillator (VCO) (2) provides an output signal which has a 50% duty cycle and a frequency which depends on the voltage of a control signal (V) supplied thereto. The VCO (2) comprises first (C.sub.L) and second (C.sub.R) capacitors and first (3) and second (5) circuits. Each of the first and second circuits comprises a current supply arrangement (10, 12, 14, or 18, 20, 22) coupled to a respective one of the capacitors (C.sub.L or C.sub.R) and to receive the control signal (V), and a Schmitt trigger (6 or 16) coupled to the respective current supply arrangement and to the other capacitor, which is not coupled to the respective current supply arrangement. Each current supply arrangement of the first and second circuits alternately charges and discharges the respective capacitor, in dependence on the switching of the respective Schmitt trigger, so that the VCO (2) oscillates between the charging of the first and the charging of the second capacitor.Type: GrantFiled: June 30, 1993Date of Patent: August 23, 1994Assignee: Motorola, Inc.Inventors: Nathan Baron, Judah L. Adelman
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Patent number: 5250914Abstract: In an oscillation circuit, the Schmidt circuit generates the control signal of the first level when the charge-discharge voltage inputted from the capacitor shifts to a voltage higher than the first threshold voltage and generates the control signal of the second level when the charge-discharge voltage shifts to a level lower than the second threshold voltage. The switching circuit connects the second current source circuit with the capacitor when the control signal is of the first level and connects the first current source circuit with the capacitor when the control signal is of the second level.Type: GrantFiled: June 24, 1992Date of Patent: October 5, 1993Assignee: NEC CorporationInventor: Ichiro Kondo
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Patent number: 5231362Abstract: A circuit device for phasing an oscillator, which comprises a multivibrator having a transistor pair with the emitters coupled through a capacitor, comprises a normally open electronic switch controlled by a drive signal to close and inhibit the oscillator. This switch connects a voltage divider to the base of a transistor connected to one of the emitters to interrupt the loop positive feedback of the oscillator upon the voltage across the capacitor reaching a predetermined value.Type: GrantFiled: December 23, 1991Date of Patent: July 27, 1993Assignee: SGS-Thomson Microelectronics S.r.L.Inventors: Gianfranco Vai, Maurizio Zuffada, Fabrizio Sacchi, David Moloney, Giorgio Betti
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Patent number: 5216390Abstract: An oscillator comprising a first and a second transistor having their sources interconnected via a capacitor and in which each gate is connected to the drain of the other transistor and each drain is connected to a load circuit. A load circuit in the form of a resistor produces a non-linear transfer characteristic. By arranging each load circuit in the form of a parallel combination of two transistors of which a first gate is connected to the drain of the first transistor and of which a second gate is connected to the drain of the second transistor, an oscillator presenting a more linear transfer characteristic is obtained. With different frequency adjusting circuits this transfer characteristic can be realized in a first-order approximation or can even be totally independent of the threshold voltage of the transistors used.Type: GrantFiled: January 14, 1992Date of Patent: June 1, 1993Assignee: U.S. Philips CorporationInventors: Franciscus G. Erftemeijer, Wouter M. Boeke
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Patent number: 5187452Abstract: A control circuit for an oscillator comprising a multivibrator with transistors having their emitters connected in common and being supplied corresponding currents on respective legs, comprises a circuit structure adapted to produce on output terminals, on the one side, a current which is proportional to a reference current according to a predetermined parameter, and on the other side, a second current in turn correlated to the reference current as a function of said parameter, thereby to modify the oscillator duty cycle for a given operating frequency.Type: GrantFiled: December 23, 1991Date of Patent: February 16, 1993Assignee: SGS-Thomson Microelectronics S.r.l.Inventors: Gianfranco Vai, Maurizio Zuffada, Fabrizio Sacchi, David Moloney, Giorgio Betti
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Patent number: 5061908Abstract: An emitter-coupled multivibrator circuit independent of temperature and supply voltage includes an oscillator circuit (11), a current control circuit (12) and a supply voltage circuit (13) for producing at least one reference voltage. The oscillator circuit consists of two switching transistors (15,16), each with a collector coupled to a respective collector-emitter branch of two interception transistors (37,38) for a lower threshold voltage and of two interception transistors (35,36) for a higher threshold voltage and, to respective active loads (28,29) of the current control circuit (12). The loads (28,29) are associated with a current mirror branch (31) including transistors (30,34) and a current source (32,33). The bases of the interception transistors (37,38) are connected to a reference voltage U.sub.b2 and those of the interception transistors (35,36) are connected to the emitter of the transistor (34).Type: GrantFiled: July 17, 1990Date of Patent: October 29, 1991Assignee: U.S. Philips CorporationInventor: Michael Pietrzyk
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Patent number: 5017890Abstract: A phase-controllable oscillator consists of a capacitance and an apparatus for charging and an apparatus for discharging the capacitance. In addition, feedback is provided for activating the charging and discharging apparatus in dependence on the oscillator signal. An amplifier for amplifying the capacitance voltage can be phase-controlled by providing the amplifier with a control input for adjusting the phase difference between a zero-crossing of an amplifier output signal on the one hand and a reference phase in the oscillator signal on the other hand. In order to maintain the duty cycle, a switching apparatus is provided for reversing the polarity of the control input under the control of the oscillator signal.Type: GrantFiled: January 23, 1990Date of Patent: May 21, 1991Assignee: U.S. Philips CorporationInventor: Adrianus Sempel
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Patent number: 4947140Abstract: A voltage controlled oscillator comprises a differential circuit composed of first and second MOS transistors each having a drain connected to a gate of the other MOS transistor and each having a source connected to a constant current source, a capacitor connected to couple between the sources of the first and second MOS transistors, a first current mirror circuit having an input connected to the drain of the first MOS transistor and an output connected to the second MOS transistor, and a second current mirror circuit having an input connected to the drain of the second MOS transistor and an output connected to the first MOS transistor. A current value of the constant current sources is controlled to change an oscillation frequency.Type: GrantFiled: October 2, 1989Date of Patent: August 7, 1990Assignee: NEC CorporationInventor: Hisao Tateishi
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Patent number: 4837458Abstract: A flip-flop circuit which requires only a small drive power and which operates with small power consumption, and in which the on-off transition occurs reliably. The flip-flop circuit comprises MOS field effect transistors (abbreviated as MOSFET's) and resistors. A first MOSFET and a second MOSFET, to which control signals are applied, are commonly-connected at their sources to be connected at the sources to a voltage source supplying a power supply voltage sufficiently higher than a threshold voltage of a third MOSFET and a fourth MOSFET interconnected to each other. The interconnected third and fourth MOSFET's are connected at their gates to the drains of the first and second MOSFET's, respectively, and to the drains of the fourth and third MOSFET's through resistors, respectively. The third and fourth MOSFET's are common-connected at their sources. An output terminal is led out from the drains of the first and third MOSFET's.Type: GrantFiled: August 19, 1987Date of Patent: June 6, 1989Assignee: Hitachi, Ltd.Inventors: Sigeyuki Kawahata, Yoshitaka Sugawara
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Patent number: 4831342Abstract: A variable frequency multivibrator circuit comprises first and second switching transistors having emitters coupled across a timing capacitor. First and second feedback circuits provide positive feedback to the first and second switching transistors whenever the first or second switching transistors are on. A control current controls the frequency of the multivibrator circuit and is independent of the feedback current. Additional drive is provided to the first and second switching transistors during their transitions from an off to an on state.Type: GrantFiled: April 25, 1988Date of Patent: May 16, 1989Assignee: Motorola, Inc.Inventor: Shigeru Takehara
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Patent number: 4812784Abstract: A voltage controlled oscillator (VCO) having high temperature stability and wide voltage/frequency linearity is provided. The VCO comprises a multivibrator being switched by a bipolar type device, and temperature fluctuations of the bipolar type means are compensated by a FET current source coupled thereto. To provide a linear relationship of frequency vs. voltage over wide voltage range, the bipolar device is further regulated by a plurality of resistor and diode networks.Type: GrantFiled: November 19, 1987Date of Patent: March 14, 1989Assignee: International Business Machines CorporationInventors: Paul W. Chung, Paik Saber
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Patent number: 4749961Abstract: A voltage controlled oscillator is provided which includes a pair of gain stages constituting a positive feedback path, a pair of buffer stages in cross connection with the gain stages, a pair of loads connected with the corresponding gain stages, each having a parallel connection of an active device resistor and a clamping diode, and a pair of voltage controlled current sources connected with the corresponding gain stages, for supplying constant currents to the gain stages. A timing capacitor is connected with the input sides of both voltage controlled current sources, and is charged or discharged by the constant currents from the current sources.Type: GrantFiled: March 26, 1987Date of Patent: June 7, 1988Assignee: Hitachi, Ltd.Inventors: Kazuo Kato, Takashi Sase, Hideo Sato, Kenichi Onda, Ichiro Ikushima
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Patent number: 4675617Abstract: A voltage controlled oscillator (VCO) is stabilized against variations in output frequency resulting from changes in temperature or the power supply voltage by trimming the voltage controlled oscillator from a second master VCO which is connected into a phase lock loop. Each of the two voltage controlled oscillators has an output frequency which is a function of two inputs. The signal input to one control input of each of the VCO's is the output of the low pass filter in the phase lock loop. The VCO's may both be implemented by cross-coupled NOR gates with grounded capacitor inputs.Type: GrantFiled: February 3, 1986Date of Patent: June 23, 1987Inventor: Kenneth W. Martin