Multivibrator Type Patents (Class 331/113R)
  • Patent number: 6157268
    Abstract: 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: Grant
    Filed: January 19, 1999
    Date of Patent: December 5, 2000
    Assignee: Nippon Precision Circuits, Inc
    Inventor: Naoki Ueno
  • Patent number: 5994972
    Abstract: 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: Grant
    Filed: March 16, 1998
    Date of Patent: November 30, 1999
    Assignee: Fujitsu Limited
    Inventor: Noboru Katsui
  • Patent number: 5990718
    Abstract: High speed multivibrator circuits operable with lower operating voltages are disclosed. A multivibrator circuit comprises an operating voltage source, first and second nonlinear amplifier components, each comprising a first and a second main electrode and a control electrode, wherein the first main electrode of the second amplifier component is connected to control the control electrode of the first amplifier component, and the first main electrode of the first amplifier component is connected to control the control electrode of the second amplifier component. A capacitor is connected between the second main electrode of the first and second amplifier components. First and second resistors connect the first main electrode of the first and second amplifier components to a first potential of the operating voltage source. A pull-down circuit is connected between the second main electrodes of the first and second amplifier components and a second potential of the operating voltage source.
    Type: Grant
    Filed: May 18, 1998
    Date of Patent: November 23, 1999
    Inventors: Nikolay Tchamov, Petri Jarske
  • Patent number: 5942928
    Abstract: An emitter-coupled multivibrator circuit comprises two transistors (Q1, Q2), between which a positive feedback is provided by connecting each transistor base via buffer transistors (Q3, Q4) to the collector of the other transistor. In the multivibrator, the transistors (Q1, Q2, Q3, Q4) are connected to operating voltages via coils (L1, L2, L3, L4, L5, L6) instead of using conventional resistors and current sources. This lowers the necessary operating voltage, since no DC voltage loss is provided across the coils. Additionally, this improvement increases amplification during the avalanche process and thus the speed of the whole circuit. Further at high frequencies, the waveform of a signal is closer to a sinusoidal form. The speed of the circuit can be increased further by providing an electromagnetic coupling between the coils (L1, L2, L3, L4, L5, L6).
    Type: Grant
    Filed: March 27, 1998
    Date of Patent: August 24, 1999
    Inventors: Nikolay Tchamov, Petri Jarske
  • Patent number: 5914642
    Abstract: 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: Grant
    Filed: December 30, 1996
    Date of Patent: June 22, 1999
    Assignees: SGS-Thomson Microelectronics S.r.l., Consorzio per la Ricerca sulla Microelettronica nel Mezzogiorno
    Inventors: Melchiorre Bruccoleri, Gaetano Cosentino, Marco Demicheli, Valerio Pisati
  • Patent number: 5900786
    Abstract: A first capacitor is charged by a driving current. A second capacitor is charged by a driving current. A first discharging transistor discharges the first capacitor in accordance with a charged voltage of the second capacitor. A second discharging transistor discharges the second capacitor in accordance with a charged voltage of the first capacitor. The oscillation circuit generates an oscillation signal in accordance with the charged voltages of the first and second capacitors. An oscillation restarting circuit, when the first and second discharging transistors simultaneously perform discharging and thus oscillation stops, causes the discharging of the second discharging transistor to stop, and thereby, restarts the oscillation.
    Type: Grant
    Filed: July 29, 1997
    Date of Patent: May 4, 1999
    Assignee: Mitsumi Electric Company, Ltd.
    Inventors: Takashi Ito, Misao Furuya
  • Patent number: 5896070
    Abstract: 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: Grant
    Filed: May 9, 1997
    Date of Patent: April 20, 1999
    Inventors: Nikolay Tchamov, Petri Jarske
  • Patent number: 5867070
    Abstract: 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: Grant
    Filed: May 30, 1997
    Date of Patent: February 2, 1999
    Assignee: Daewoo Electronics Co., Ltd.
    Inventor: Hyun-Jin Park
  • Patent number: 5825256
    Abstract: 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: Grant
    Filed: May 9, 1997
    Date of Patent: October 20, 1998
    Inventors: Nikolay Tchamov, Petri Jarske
  • Patent number: 5821829
    Abstract: The system includes various circuit units each having a capacitor and a charging circuit for defining a quantity depending upon the ratio (I/C) between the charging current and the capacitance of the capacitors. In order to compensate automatically for deviations of the actual capacitances from the nominal capacitances due to fluctuations in the parameters of the integrated-circuit manufacturing process, the system has a phase-locked loop which uses one of the circuit units as an adjustable oscillator, and current transducer means which regulates the charging currents of the capacitors of the circuit units in dependence on the regulated charging current of the capacitor of the oscillator, or the error current of the PLL loop.
    Type: Grant
    Filed: March 4, 1997
    Date of Patent: October 13, 1998
    Assignees: SGS-Thomson Miroelectronics S.r.l., CO.RI.M.ME. Consorzio Per La Ricerca Sulla Microelettronica Nel Mezzogiorno
    Inventors: Melchiorre Bruccoleri, Gaetano Cosentino, Marco Demicheli, Valerio Pisati
  • Patent number: 5801593
    Abstract: 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: Grant
    Filed: December 16, 1996
    Date of Patent: September 1, 1998
    Assignee: Exar Corporation
    Inventor: Phong Thanh Nguyen
  • Patent number: 5712600
    Abstract: 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: Grant
    Filed: September 29, 1995
    Date of Patent: January 27, 1998
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Won-Kyum Kim, Jang-Sik Won
  • Patent number: 5699024
    Abstract: An accurate integrated oscillator circuit includes a first circuit generating a substantially temperature independent, or a linearly temperature dependent, reference current and a second circuit which is programmable to incrementally increase the reference current to a desired current level. A third circuit includes first and second capacitors and an oscillator output switchable between first and second output levels. The third circuit is responsive to a first charge value on the first capacitor, due to the reference current flowing therethrough, to switch the oscillator output to the first level while resetting the second capacitor to its uncharged state, and to a second charge value on the second capacitor, due to the reference current flowing therethrough, to switch the oscillator output to the second level while resetting the first capacitor to its uncharged state. The oscillator circuit is preferably formed of a single integrated circuit and has an adjustable center frequency.
    Type: Grant
    Filed: May 6, 1996
    Date of Patent: December 16, 1997
    Assignee: Delco Electronics Corporation
    Inventors: Gregory Jon Manlove, Mark Wendell Gose
  • Patent number: 5686862
    Abstract: An FM demodulator formed on a semiconductor chip generates a demodulated audio-frequency signal from an audio intermediate frequency signal through a phase locked loop constituted by a multiplier, a low-pass filter and a voltage-controlled oscillator. A variation of amplitude of the demodulated audio-frequency signal due to a temperature variation is compensated by a temperature compensating amplifier and a de-emphasis filter through first and second reference currents flowing out therefrom through an internal resistor fabricated on the same semiconductor chip and an external resistor.
    Type: Grant
    Filed: May 31, 1996
    Date of Patent: November 11, 1997
    Assignee: NEC Corporation
    Inventor: Toshiya Matsui
  • Patent number: 5629652
    Abstract: Both differential and single-ended band-switchable VCOs are described. The single-ended version of the voltage controlled oscillator in its most basic form includes a load, two transistors, two delay elements, and a switchable current source. The first transistor includes a collector, an emitter and a base coupled to the load to form an output terminal for providing an oscillator output signal. The first delay element is connected between the collector and the base of the first transistor. The second transistor includes a collector, an emitter and a base connected to the base of the first transistor. The second delay element is connected between the collector of the first transistor and the collector of the second transistor.
    Type: Grant
    Filed: May 9, 1996
    Date of Patent: May 13, 1997
    Assignee: Analog Devices
    Inventor: Frederick G. Weiss
  • Patent number: 5604466
    Abstract: 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: Grant
    Filed: November 28, 1994
    Date of Patent: February 18, 1997
    Assignee: International Business Machines Corporation
    Inventors: Daniel M. Dreps, Raymond P. Rizzo
  • Patent number: 5585751
    Abstract: A frequency control circuit of an FM modulator with a small number of external parts and a low number of IC pins, including a non-linear D/A converter, a current generator circuit and an emitter-coupled multivibrator. The non-linear D/A converter for giving an analog optimum resistance value depending on digital frequency control signals includes a plurality of resistors weighted by K.sup.n (1<K<2 and n is a sequential natural number). The current generator generates a current .DELTA.I depending on the output resistance value of the non-linear D/A converter. An oscillating frequency of the multivibrator is determined in proportional to I.sub.o /4CF.DELTA.I (I.sub.o represents a current value of an operational current source, C represents a capacitance of a capacitor, R represents a resistance value of a resistor and .DELTA.I represents a current flowing in the resistor). When the oscillating frequency is controlled depending on .DELTA.
    Type: Grant
    Filed: January 23, 1996
    Date of Patent: December 17, 1996
    Assignee: Sanyo Electric Co., Inc.
    Inventor: Hiroshi Iizuka
  • Patent number: 5559463
    Abstract: High-efficiency clock generator circuits having single or complementary outputs for driving capacitive loads. The clock generator has therein at least one pair of complementary FET switches, coupled between the output of the generator and power supply rails, and an inductor. The generator is operated at a frequency approximately equal the resonant frequency of the inductor combined with the capacitance of the load. Energy normally stored in the load and dissipated in the FETs as in conventional clock generators is instead stored in the inductor and returned to the loads for reuse.
    Type: Grant
    Filed: April 18, 1994
    Date of Patent: September 24, 1996
    Assignee: Lucent Technologies Inc.
    Inventors: John S. Denker, Alexander G. Dickinson, Alan H. Kramer, Thomas R. Wik
  • Patent number: 5469118
    Abstract: A stable sine wave oscillator circuit comprising two pairs of cross-coupled bipolar transistors in cascode, the collector electrodes of the transistors of each pair being interconnected by way of respective capacitors. Output signals in phase quadrature may be obtained from across these two capacitors.
    Type: Grant
    Filed: November 22, 1994
    Date of Patent: November 21, 1995
    Assignee: Plessey Semiconductors Limited
    Inventor: Rodney J. Lawton
  • Patent number: 5438299
    Abstract: A PLL circuit comprising a phase comparator unit which forms a differentiation signal based upon both edges of an external signal, outputs an early pulse only during a period in which the differentiation signal is overlapped on a period from the leading edge to the trailing edge of a reference signal, and outputs a late pulse only during a period in which the differentiation signal is overlapped on a period from the trailing edge to the leading edge thereof, a charge pump unit which calculates and compares the amounts of integration of the early pulse and the late pulse, lowers the output voltage when the amount of the late pulse is larger than the amount of the early pulse and raises the output voltage when it is smaller, and a VCO which outputs a corrected reference signal of which the frequency decreases or increases accompanying the increase or decrease in the output voltage of the charge pump unit, wherein the VCO is controlled by the output voltage of the charge pump unit and by the early pulse and the
    Type: Grant
    Filed: March 30, 1994
    Date of Patent: August 1, 1995
    Assignees: Shinko Electric Industries, Co., Ltd., Fujitsu Limited
    Inventors: Toshizi Shimada, Yasunori Kanai, Yoshio Watanabe
  • Patent number: 5430414
    Abstract: An electric circuit including a local oscillator circuit and which is adapted to prevent voltage transients. The oscillator circuit comprises two voltage sources which are alternately connected to respective electrodes of a capacitor. The capacitor electrodes are also connected, via respective load circuits, to a common reference node of the voltage sources. Thus, the respective voltage sources alternately generate mutually opposed currents in the capacitor, which currents charge and discharge the capacitor 20 to threshold levels, after which a switching control circuit interchanges the coupling of the voltage sources. In order to prevent a transient in the voltage level at the first capacitor electrode upon switching, a voltage control circuit provides a voltage difference between the voltages supplied by the voltage sources, which voltage difference corresponds to the charge voltage built up across the capacitor.
    Type: Grant
    Filed: March 19, 1993
    Date of Patent: July 4, 1995
    Assignee: U.S. Philips Corporation
    Inventors: Adrianus Sempel, Johannes Van Nieuwenburg
  • Patent number: 5412350
    Abstract: A low-frequency oscillator whose duty ratio can be simply controlled includes a charging and discharging circuit for charging a capacitor via a constant current source and then discharging the capacitor according to a discharge control signal. A voltage comparator compares the voltage across the capacitor with a reference voltage. A monostable multivibrator, triggered by the output of the voltage comparator, generates the discharge control signal. The duration of the discharge is determined according to the RC time constant of the monostable multivibrator, to thereby generate a rectangular waveform having an accurately controlled duty ratio.
    Type: Grant
    Filed: October 7, 1993
    Date of Patent: May 2, 1995
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Dong-hun Kim
  • Patent number: 5406232
    Abstract: A composite semiconductor capacitor element, applicable to various kinds of circuits to reduce the influence of parasitic capacitance therein, includes two semiconductor capacitor elements connected in parallel by connecting terminals which have parasitic capacitances to terminals which do not have parasitic capacitances. Alternatively, two such semiconductor capacitor elements are connected in series by connecting terminals which have parasitic capacitances to each other. Hence, parasitic capacitances at the respective terminals are equal to each other. In addition, as compared with a conventional structure wherein a greater number of parasitic capacitances are connected to one terminal than to the other terminal, the parasitic capacitances are smaller at each terminal side.
    Type: Grant
    Filed: July 28, 1993
    Date of Patent: April 11, 1995
    Assignee: Fujitsu Limited
    Inventors: Yasuhiro Hashimoto, Motofumi Tokuriki
  • Patent number: 5399994
    Abstract: A programmable VCO circuit (300, 700) and method of use are provided whereby a current proportional to the strength of the NMOS process used to fabricate the circuit may be subtracted from the control current derived at the circuit's input, to compensate for process variations. Also, a programmable VCO circuit (300) and method of use are provided whereby a current developed from one-half the supply voltage for the VCO circuit may be subtracted from the control current derived at the circuit's input, in order to cause programmed gain changes to occur about the center of the control voltage range, and minimize output "jitter" when the VCO is used in a phase-locked loop. A gain compensation circuit (800) is also provided to linearize the gain of the programmable VCO circuit (300) for higher control voltage levels and thereby extend the VCO's effective operating range.
    Type: Grant
    Filed: September 30, 1993
    Date of Patent: March 21, 1995
    Assignee: Texas Instruments Incorporated
    Inventors: Patrick P. Siniscalchi, William R. Krenik
  • Patent number: 5396195
    Abstract: Low-power-dissipation CMOS oscillator circuits include inductors and capacitors forming tank circuitry. Cross-connected MOS devices provide positive feedback to replenish losses in the tank circuitry and thereby sustain oscillations. Each such oscillator circuit simultaneously generates complementary output sine-wave signals.
    Type: Grant
    Filed: December 13, 1993
    Date of Patent: March 7, 1995
    Assignee: AT&T Corp.
    Inventor: Thaddeus J. Gabara
  • Patent number: 5367270
    Abstract: 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: Grant
    Filed: May 18, 1993
    Date of Patent: November 22, 1994
    Assignee: National Semiconductor Corporation
    Inventor: Perry Lorenz
  • Patent number: 5357220
    Abstract: An emitter-coupled oscillator circuit suitable for monolithic integration.
    Type: Grant
    Filed: January 21, 1993
    Date of Patent: October 18, 1994
    Assignee: Gennum Corporation
    Inventor: John R. Francis
  • Patent number: 5341113
    Abstract: 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: Grant
    Filed: June 30, 1993
    Date of Patent: August 23, 1994
    Assignee: Motorola, Inc.
    Inventors: Nathan Baron, Judah L. Adelman
  • Patent number: 5233315
    Abstract: Oscillator circuit of the regenerative type, comprising a first oscillator at least including a first feedback amplifier (Qa1, Qb1) and a first integrator (C1) in which the first oscillator has an output signal having two stable levels alternating in one oscillation cycle and an unstable or regenerative switching state between each of them, in which the loop gain is greater than unity, and has an input signal which originates from the integrator and which varies time-dependently in a positive or negative sense. A second oscillator identical to the first oscillator is provided which at least includes a second feedback amplifier (Qa2, Qb2) and a second integrator (C2) having an oscillation cycle which is equal to the said oscillation cycle or a multiple thereof and which is shifted with respect thereto.
    Type: Grant
    Filed: April 3, 1992
    Date of Patent: August 3, 1993
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventor: Christiaan J. M. Verhoeven
  • Patent number: 5231362
    Abstract: 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: Grant
    Filed: December 23, 1991
    Date of Patent: July 27, 1993
    Assignee: SGS-Thomson Microelectronics S.r.L.
    Inventors: Gianfranco Vai, Maurizio Zuffada, Fabrizio Sacchi, David Moloney, Giorgio Betti
  • Patent number: 5225972
    Abstract: A power source driving an electrical device includes a DC power supply providing a rectified and smoothed DC voltage from an AC main power, a self-oscillator energized by the DC power supply to generate a high frequency voltage, and a transformer which provides an output voltage from the high frequency voltage for driving a load circuit of the device. The characterizing feature of the power source resides in that the self-oscillator comprises a class C amplifier and includes a bias stabilizing circuit which provides a stabilized bias to the class C amplifier for assuring constant and optimum operation irrespective of possible variations in the supply voltage as well as load variations.
    Type: Grant
    Filed: March 10, 1992
    Date of Patent: July 6, 1993
    Inventor: Hiroshi Sakamoto
  • Patent number: 5216390
    Abstract: 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: Grant
    Filed: January 14, 1992
    Date of Patent: June 1, 1993
    Assignee: U.S. Philips Corporation
    Inventors: Franciscus G. Erftemeijer, Wouter M. Boeke
  • Patent number: 5187452
    Abstract: 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: Grant
    Filed: December 23, 1991
    Date of Patent: February 16, 1993
    Assignee: SGS-Thomson Microelectronics S.r.l.
    Inventors: Gianfranco Vai, Maurizio Zuffada, Fabrizio Sacchi, David Moloney, Giorgio Betti
  • Patent number: 5159540
    Abstract: A self-oscillating DC to DC voltage converter having improved efficiency. The high efficiency saturable core voltage converter 100 of the present invention provides an output voltage across an output load R.sub.L in response to the input voltage at a source node 106 of a voltage source 104. The present invention includes a transistor switching network 120, 122 coupled to the source node 106. The switching network 120, 122 generates an alternating voltage in response to oscillation of the flux within a magnetic core 116. A voltage transformer 110 then impresses an output voltage across an output load R.sub.L, thus providing a load current I.sub.L. The inventive converter 100 further includes a feedback winding 112 for providing a transistor drive current to the transistor switching network 120, 122. A portion of the transistor drive current is shunted to the source node 106 by a source feedback arrangement 126, 130.
    Type: Grant
    Filed: March 9, 1992
    Date of Patent: October 27, 1992
    Assignee: Hughes Aircraft Company
    Inventor: James Lee
  • Patent number: 5130658
    Abstract: A device for indicating the state of charge of an electrochemical cell or battery includes a regulated-voltage generating circuit having an input connectable to the cell and an output providing a regulated reference voltage, an amplifying circuit having an input connectable to the cell and an output having a predetermined relation to a voltage within a predetermined range applied to the input of the amplifying unit, and a solid state analog display unit having a reference input connected to the output of the regulated-voltage generating circuit and an address input connected to the amplifying circuit. The relation between the address voltage output of the amplifying circuit and the cell voltage input is such that the address voltage corresponds to the state of charge of the cell in the predetermined range of cell voltages and falls within the range of the most negative and most positive values of the reference voltage.
    Type: Grant
    Filed: August 29, 1990
    Date of Patent: July 14, 1992
    Assignee: Display Matrix Corporation
    Inventor: William Bohmer
  • Patent number: 5124669
    Abstract: A one-shot whose period is a fraction or multiple of the VCO period in a clock recovery circuit. In a clock recovery circuit using PLL, the one-shot is coupled to the PLL in order to enable/disable the phase detector for cases when the data stream does not consist of uniformly spaced pulses. Without a one-shot, the phase detector in the PLL generates a large error signal whenever a clock pulse occurs without a data pulse. During the times when the phase detector is enabled, a phase comparison is made between the next data edge and the next clock edge. When this comparison is completed, the phase detector is disabled again. In order for the PLL to average out the effects of noise and jitter, the phase detector is enabled one half clock period before the data edge. By doing this, the data edge can shift up to one half clock period.
    Type: Grant
    Filed: September 18, 1990
    Date of Patent: June 23, 1992
    Assignee: Silicon Systems, Inc.
    Inventors: Michael J. Palmer, Richard G. Yamasaki
  • Patent number: 5087894
    Abstract: A monolithic interface circuit for use with a linear variable differential transformer (LVDT) position transducer. The interface circuit includes a drive circuit for providing an excitation signal of selectable frequency and amplitude to the LVDT primary winding. The interface circuit further includes a decoder responsive to signals induced in the LVDT secondary windings for computing the position p of the LVDT core as a solution to the equation p=K(A-B)/(A+B), where A and B represent the signals induced in the primary winding and K is a constant scale factor. The decoder includes circuitry for rectifying and filtering the secondary signals, a charge balance loop responsive to the detected signals for providing a binary signal having a duty cycle representative of b/(A+B), and an output circuit responsive to the binary signal for providing the position output. The decoder provides excellent scale factor stability and linearity and is relatively insensitive to variations in primary drive amplitude.
    Type: Grant
    Filed: February 23, 1990
    Date of Patent: February 11, 1992
    Assignee: Analog Devices, Inc.
    Inventors: Lawrence M. DeVito, A. Paul Brokaw
  • Patent number: 5081430
    Abstract: In an overtone crystal oscillator comprising a crystal oscillator having a feedback loop and a resonance amplifier whose amplitude characteristic has an overshoot in the range of the resonant frequency of the resonance amplifier and which is arranged in the feedback loop of the crystal oscillator, the resonant frequency of the resonance amplifier is between the frequency of the overtone to be generated and the next lower oscillation frequency of the crystal oscillator, while signals in the frequency range of the next lower oscillation frequency(ies) in relation to signals in the frequency range of the overtone to be generated in the feedback loop, particularly in the resonance amplifier, have such a phase shift that the overtone crystal oscillator cannot oscillate at the frequencies of the next lower oscillation frequency(ies) and that it only oscillates at the frequency of the overtone to be generated.
    Type: Grant
    Filed: November 8, 1990
    Date of Patent: January 14, 1992
    Assignee: U.S. Philips Corporation
    Inventor: Cord H. Kohsiek
  • Patent number: 5075639
    Abstract: A PLL circuit suitable for fabrication into an integrated circuit includes: a first phase comparator for determining a phase difference between an input signal and a first feedback signal to produce a first phase difference signal in rsponse to the phase difference; a first loop filter for removing a high frequency constituent from the first phase difference signal; a first variable frequency oscillator which oscillates at a frequency which varies in response to an output of the first loop filter to produce the first feedback signal; a second phase comparator for determining a phase difference between a reference signal and a second feedback signal to produce a second phase difference signal in response to the phase difference; a second loop filter for removing a high frequency constituent from the second phase difference signal; a second variable frequency oscillator having substantially the same characteristics as those of the first variable frequency, oscillator which oscillates at a frequency which varies
    Type: Grant
    Filed: May 23, 1991
    Date of Patent: December 24, 1991
    Assignee: Oki Electric Industry Co., Ltd.
    Inventor: Takashi Taya
  • Patent number: 5061908
    Abstract: 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: Grant
    Filed: July 17, 1990
    Date of Patent: October 29, 1991
    Assignee: U.S. Philips Corporation
    Inventor: Michael Pietrzyk
  • Patent number: 5017890
    Abstract: 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: Grant
    Filed: January 23, 1990
    Date of Patent: May 21, 1991
    Assignee: U.S. Philips Corporation
    Inventor: Adrianus Sempel
  • Patent number: 4977381
    Abstract: A relaxation oscillator is disclosed which includes first and second currents for charging and discharging a capacitor wherein the slew rate of the dynamic voltages developed at the terminals of the capacitor remain substantially constant for each frequency of operation which desensitizes the oscillator to the effects of the inherent stray capacitance, and improves the accuracy of the output frequency. A circuit monitors the dynamic voltage across the capacitor and inverts a control signal at opposite polarities of a particular threshold. A bistable circuit provides first and second complementary output signals in response to the control signal from the circuit. The first and second complementary output signals drive a pair of switching transistors which alternate the direction of current flowing through the capacitor so as to provide smooth voltage transitions at the terminals of the capacitor.
    Type: Grant
    Filed: June 2, 1989
    Date of Patent: December 11, 1990
    Assignee: Motorola, Inc.
    Inventor: William E. Main
  • Patent number: 4972162
    Abstract: A high-frequency wideband relaxation oscillator utilizing parasitic capacitances of the switching transistors as charging capacitors and capable of being fabricated in both CMOS and NMOS technology. When fabricated in NMOS technology the switching transistors are implemented as charge-enhancement devices and additional charge-depletion devices are utilized to counteract detrimental parasitic capacitances.
    Type: Grant
    Filed: February 16, 1988
    Date of Patent: November 20, 1990
    Assignee: AT&T Bell Laboratories
    Inventor: Mihai Banu
  • Patent number: 4960124
    Abstract: A device for low-frequency electrotherapy wherein the output current of a low-frequency oscillator is applied to the subject's body through a pair of electrodes placed on the subject's body, comprising a first oscillator circuit that generates a low-frequency square wave voltage when the load is in connection with the electrode pair; and a second oscillator circuit that generates a therapeutic voltage when the output voltage of the first oscillator circuit is not zero.
    Type: Grant
    Filed: May 1, 1989
    Date of Patent: October 2, 1990
    Assignee: Ken Hayashibara
    Inventor: Kazumi Masaki
  • Patent number: 4960125
    Abstract: Disclosed is a novel device for low-frequency electrotherapy wherein a moisture proof variable resistor is used to control the output level of a low-frequency diphasic action potential circuit. The diphasic circuit produces a voltage having a pulse width of 0.1 to 10 seconds and a frequency off 10 to 300 Hertz superimposed on the voltage having a pulse interval of 0.1 to 10 seconds.
    Type: Grant
    Filed: October 26, 1988
    Date of Patent: October 2, 1990
    Assignee: Ken Hayashibara
    Inventor: Kazumi Masaki
  • Patent number: 4947140
    Abstract: 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: Grant
    Filed: October 2, 1989
    Date of Patent: August 7, 1990
    Assignee: NEC Corporation
    Inventor: Hisao Tateishi
  • Patent number: 4910472
    Abstract: A multivibrator circuit employing field effect transistors which operates with a high oscillation frequency and low power consumption comprises four series connections. The first series connection comprises a parallel connection including a resistor R.sub.1 and a diode D.sub.1 connected in parallel, and two field effect transistors Q.sub.1 and Q.sub.3, the first series connection being provided between the power supply V.sub.DD1 and the ground V.sub.SS. The second series connection comprises a field effect transistor Q.sub.5, diodes D.sub.3 for shifting a level and a field effect transistor Q.sub.7, the second series connection being provided between the power supply V.sub.DD2 and the ground V.sub.SS. The third series connection comprises R.sub.2, a diode D.sub.2 and two field effect transistors Q.sub.2 and Q.sub.4 in the same manner as in the first series connection. The fourth series connection comprises a field effect device Q.sub.6, diodes D.sub.4 for shifting a level and a field effect device Q.sub.
    Type: Grant
    Filed: June 6, 1988
    Date of Patent: March 20, 1990
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Noriyuki Tanino
  • Patent number: 4884042
    Abstract: A voltage controlled oscillator includes an emitter coupled multivibrator in which a capacitor determines the frequency of oscillation along with a pair of load resistors and a pair of current sources. A differential amplifier is coupled to operate in parallel with the mutlivibrator and its tail current is operated differentially, with respect to the currents in the pair of sources, in response to the input voltage at a first modulation input port. Thus, a constant current flows in the multivibrator loads even when the frequency is modulated. A second input port is coupled to vary the tail current in the differential amplifier to comprise a dual port control of the voltage controlled oscillator. The circuit can be operated at a relatively low supply voltage and can be temperature compensated. Furthermore, the input ports can include circuitry having a logarithmic response for digital signaling processing.
    Type: Grant
    Filed: February 15, 1989
    Date of Patent: November 28, 1989
    Assignee: National Semiconductor Corporation
    Inventors: Suresh Menon, Enjeti Murthi
  • Patent number: 4874966
    Abstract: A multivibrator circuit used as a delay element. A pair of complementary signals to be delayed control the transistors of a long tailed pair so as to generate charging and discharging currents for a capacitance coupled between first and second current branches of the multivibrator circuit. The delay time depends, among other parameters, on the exact values of these currents. In order to avoid the necessity of providing very accurate values of the signals for generating the proper current values, a current division is applied, to the circuit by adding in parallel to each long tailed pair transistor, a constant current source. As a result the currents in the multivibrator circuit can be switched between two exactly determined current values by alternately switching the long tailed pair transistors fully on and off. The same kind of current division is applied to the circuit in order to achieve a voltage swing at the output which is independent of the current adjustment.
    Type: Grant
    Filed: January 22, 1988
    Date of Patent: October 17, 1989
    Assignee: U.S. Philips Corporation
    Inventors: Heinz H. Gehrt, Gunter Hildebrandt, Karl-Heinz Rehfeldt
  • Patent number: 4831342
    Abstract: 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: Grant
    Filed: April 25, 1988
    Date of Patent: May 16, 1989
    Assignee: Motorola, Inc.
    Inventor: Shigeru Takehara