Differential Amplifier Patents (Class 318/678)
  • Patent number: 10027295
    Abstract: An electrical device (e.g., an integrated circuit) includes an amplifier, a configurable common mode gain trim circuit, and a memory. The configurable common mode gain trim circuit is coupled to the amplifier. The memory is configured to include trim data that is usable during an initialization process for the electrical device to configure the impedance matching circuit.
    Type: Grant
    Filed: April 29, 2016
    Date of Patent: July 17, 2018
    Assignee: Texas Instruments Incorporated
    Inventors: Wenxiao Tan, Mayank Garg, Noble Narku-Tetteh
  • Patent number: 9117481
    Abstract: A disk drive is disclosed comprising a disk, a head, and a ramp located near an outer periphery of the disk. The disk drive further comprises control circuitry operable to load the head off the ramp over the disk, receive an unload command to perform an unload operation, evaluate a number of unloads relative to an unload limit that varies over time, and when the number of unloads exceeds the unload limit, delay the unload operation.
    Type: Grant
    Filed: May 22, 2009
    Date of Patent: August 25, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Alan T. Meyer, Kenny T. Coker, Daniel D. Reno
  • Patent number: 8531139
    Abstract: In a drive control circuit of a linear vibration motor, a differential amplifier circuit includes an operational amplifier in which an P-channel type transistor is used as a transistor that receives an input voltage, and the differential amplifier circuit detects an induced voltage occurring in a coil. Before the H-bridge circuit is controlled to a high impedance state, a drive signal generating unit turns on a first transistor and a second transistor, and delivers a regenerative current through the coil, the first transistor, the second transistor and the power supply potential.
    Type: Grant
    Filed: May 13, 2011
    Date of Patent: September 10, 2013
    Assignee: On Semiconductor Trading, Ltd.
    Inventor: Tsutomu Murata
  • Patent number: 8038619
    Abstract: A motor driver for an ultrasound system is provided. The ultrasound system includes a transmitter and receiver, both communicatively coupled to a transducer array of an ultrasound probe. The ultrasound system further includes a digital motor driver for controlling movement of the transducer array.
    Type: Grant
    Filed: April 30, 2008
    Date of Patent: October 18, 2011
    Assignee: General Electric Company
    Inventor: Franz Steinbacher
  • Patent number: 7888902
    Abstract: A method of configuring a signal for controlling a voice coil motor (VCM) is disclosed. A voltage at an error amplifier of a VCM driver is accessed. A target value at the error amplifier is accessed. A difference value between the target value and the voltage is determined. An impedance value of the variable compensation coupled with the error amplifier is adjusted, based on the difference value.
    Type: Grant
    Filed: December 28, 2007
    Date of Patent: February 15, 2011
    Assignee: Hitachi Global Storage Technologies, Netherlands, B.V.
    Inventors: Farzin Assar, Scott E. Heeren, Lee D. Nguyentran, Bryan S. Rowan
  • Patent number: 7652445
    Abstract: A disk drive controller including a differential voice coil motor control function is disclosed. The differential voice coil motor control function includes an on-chip compensation network for the inner control loop, including a resistor formed of one or more MOS transistors connected in series. The gate of the MOS transistors in the compensation network is driven with a bias voltage based on a tuning current, where the tuning current is derived so that it varies with process and temperature variations of the integrated circuit, for example with variations in an on-chip capacitor. The on-chip compensation network can be tuned with sufficient precision to properly compensate the inner control loop to provide the desired frequency response in driving the voice coil motor in the disk drive.
    Type: Grant
    Filed: April 10, 2007
    Date of Patent: January 26, 2010
    Assignee: Texas Instruments Incorporated
    Inventors: Degang Xia, Robert E. Whyte, Jr.
  • Patent number: 7619419
    Abstract: A wideband differential signal probe includes separate paths to convert a lower frequency component and a higher frequency component of a differential signal to a lower frequency single ended signal and a higher frequency single ended signal which are combined for the probe's output which is commonly input to instrumentation.
    Type: Grant
    Filed: April 28, 2006
    Date of Patent: November 17, 2009
    Assignee: Cascade Microtech, Inc.
    Inventor: Richard Campbell
  • Patent number: 7423403
    Abstract: A motor control system which can realize current detection with high accuracy by using an amplifier having an ordinary level of accuracy and can avoid deterioration of current detection accuracy even when emperature is changed.
    Type: Grant
    Filed: June 21, 2006
    Date of Patent: September 9, 2008
    Assignee: Hitachi, Ltd.
    Inventors: Mitsuhiko Watanabe, Katsuya Oyama, Shoji Sasaki
  • Publication number: 20080116837
    Abstract: The present invention relates to a circuit for detecting a functional status of an electro-motor. Typical electro-motors need additional components to identify the functional status of the motor. This means additional weight for such motors determining the functional status. According to the present invention a circuit is provided using a part of a motor as a sensor for detecting the functional status of the electro-motor.
    Type: Application
    Filed: September 17, 2004
    Publication date: May 22, 2008
    Applicants: Airbus Deutschland GmbH, Hamilton Sundstrand Corporation
    Inventors: Jurgen Kelnhofer, Thomas Scherer, Steffen Kalsow, Alvy Biccum, John Maljanian, David Leenhouts
  • Patent number: 7327103
    Abstract: A driver for a voice coil motor in a disk drive includes a sensor that provides a sense current by sensing a coil current in the voice coil motor, a comparator that provides an error current by determining a difference between a command current and the sense current, an integrator that provides an integrated error current by integrating the error current, and an amplifier that provides the coil current by amplifying the integrated error current.
    Type: Grant
    Filed: August 31, 2001
    Date of Patent: February 5, 2008
    Assignee: Maxtor Corporation
    Inventor: Ashraf El-Sadi
  • Patent number: 7311081
    Abstract: One embodiment includes an apparatus comprising a closed loop feedback controller and a power output stage to couple to the closed loop feedback controller. The closed loop feedback controller and the power output stage are combined to form a single element.
    Type: Grant
    Filed: July 8, 2005
    Date of Patent: December 25, 2007
    Assignee: Infineon Technologies AG
    Inventors: Kyle Shawn Williams, Joseph Funyak
  • Patent number: 7285930
    Abstract: A method is specified for controlling a multiphase motor that is commutated by an inverter-side bridge circuit, in the course of which a particularly precise and technically simple detection of a control-relevant variable of a considered motor phase, in particular of a motor phase current and/or a back EMF voltage and/or a variable derived therefrom, takes place. It is provided here to determine the control-relevant variable with the aid of the current state of a freewheeling diode that is disposed in a phase half bridge, assigned to the respective motor phase, of the bridge circuit, the current state being detected during an on time in which a power switch, connected in parallel with the freewheeling diode, of the phase half bridge exhibits a conducting state, and a power switch connected in series with the freewheeling diode exhibits a blocking state.
    Type: Grant
    Filed: February 22, 2006
    Date of Patent: October 23, 2007
    Assignee: Diehl AKO Stiftung & Co. KG
    Inventors: Martin Weinmann, Alexander Müller, Stefan Zeh
  • Patent number: 7283596
    Abstract: A PAM-4 data slicer includes first, second, and third comparators which provide first, second, and third thresholds, respectively. Each of the comparators has an offset. The first and third comparators have an offset generating arrangement at their outputs to provide the first and third comparator circuits with symmetrical offsets.
    Type: Grant
    Filed: July 8, 2003
    Date of Patent: October 16, 2007
    Assignee: Avago Technologies General IP (Singapore) Pte Ltd
    Inventor: William W. Brown
  • Patent number: 7230989
    Abstract: A digital communication system for transmitting and receiving Digital Visual Interface (DVI) communication data signals and Display Data Channel (DDC) communication signals over a transmission line comprises an open-loop equalizer circuit and a DDC extension circuit. The open-loop equalizer circuit is operable to receive DVI communication signals transmitted over the transmission line and output equalized DVI communication data signals. The DDC extension circuit is operable to inject a boost current at the receive end of the transmission line during a positive transition in the DDC communication signal, and clamp the receive end of the transmission line during a negative transition of the DDC communication signal.
    Type: Grant
    Filed: March 14, 2003
    Date of Patent: June 12, 2007
    Assignee: Gennum Corporation
    Inventors: Aapoolcoyuz Biman, John Hudson, Eliyahu D. Zamir, Stephen P. Webster
  • Patent number: 6943514
    Abstract: For applying a driving current to a motor, an H-bridge circuit is constructed by a first and a second switching unit and a first and a second linear unit. An error amplifier generates an error signal representative of a difference between the driving current detected by a current detecting circuit and a command current signal. A state control circuit synchronously controls the first and second switching units and a feedback circuit. Through the feedback circuit, the error signal is selectively applied to the first or second linear unit such that one is operated in a linear mode and the other is operated in a nonconductive mode, thereby controlling the driving current to become proportional to the command current signal. The state control circuit further controls a brake circuit for transforming the error signal into a brake signal to operate the first and second linear units simultaneously in a conductive mode.
    Type: Grant
    Filed: April 6, 2004
    Date of Patent: September 13, 2005
    Assignee: Aimtron Technology Corp.
    Inventors: Chi-Yang Chen, Li-Cheng Chen
  • Patent number: 6611167
    Abstract: A balanced bi-directional current source is provided, which includes first and second current output terminals, a current control circuit, first and second amplifiers and first and second sense impedances. The current control circuit has a reference input, a feedback input, and a control output, which is based on the reference input and the feedback input. The first amplifier has a first amplifier input, which is coupled to the control output, and a first amplified output. The second amplifier has a second amplifier input, which is coupled to the control output, and a second amplified output, which is inverted relative to the first amplified output. The first sense impedance is coupled in series between the first amplified output and the first current output terminal and has a feedback output which is coupled to the feedback input. The second sense impedance is matched with the first impedance and is coupled in series between the second amplified output and the second current output terminal.
    Type: Grant
    Filed: September 23, 2002
    Date of Patent: August 26, 2003
    Assignee: Seagate Technology LLC
    Inventors: Terrence A. McMahon, Ray V. Rigles, David M. Gray, William P. Wood
  • Patent number: 6184665
    Abstract: In a current mode pulse width modulation (PWM) integrated drive system having an external load, a switched-capacitor amplifier and a sample & hold stage connected in cascade form a current sensing amplifier for a control loop. The current sensing amplifier overcomes resistive mismatchings, thus permitting a scaling down of the supply voltage with high precision for the integrated drive system.
    Type: Grant
    Filed: October 19, 1998
    Date of Patent: February 6, 2001
    Assignee: STMicroelectronics S.r.l.
    Inventors: Alberto Salina, Donatella Brambilla
  • Patent number: 6154001
    Abstract: A circuit to pull down a driver circuit of a motor, including a circuit to monitor the input signal to a driver amplifier to compare the input signal with the output signal from the motor and to output a difference signal when the input signal and the output signal are different, and a circuit to pull down the driver circuit in response to the difference signal.
    Type: Grant
    Filed: November 23, 1999
    Date of Patent: November 28, 2000
    Assignee: Texas Instruments Incorporated
    Inventor: Dennis Vernon Hahn
  • Patent number: 6060858
    Abstract: A circuit and method for controlling a switched reluctance motor are provided. The circuit includes a phase coil and a switch that controls a current in the phase coil responsive to a hysteresis control signal. The circuit also includes a current sensor that measures the level of current in the phase coil and a comparator that compares the measured current level to a predetermined upper hysteresis current level. The circuit further includes a hysteresis control signal generating circuit that generates the hysteresis control signal responsive to the comparison signal and a timing signal that comprises a series of timing pulses. The hysteresis control signal assumes a first logic level whenever the measured level of current in the phase coil exceeds the predetermined upper hysteresis current level, thereby opening the switch and allowing current to dissipate from the phase coil.
    Type: Grant
    Filed: August 18, 1998
    Date of Patent: May 9, 2000
    Assignee: Dana Corporation
    Inventors: Scott E. Blackburn, Ramani R. Kalpathi
  • Patent number: 5920163
    Abstract: A differential amplifier amplifies a PG reproduction signal to a level permitting signal processing. A low-pass filter makes the signal waveform of a PG detection signal generated by the differential amplifier substantially uniform irrespectively of the rotational speed of a rotating drum. A comparator outputs a PG pulse by comparing an output of the low-pass filter with a threshold. A magnetic recording and reproducing apparatus having such a structure can detect the PG pulse with accuracy over a rotational speed range requiring a precision control of the rotating drum.
    Type: Grant
    Filed: May 27, 1997
    Date of Patent: July 6, 1999
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hiroshi Tatsumi, Chiaki Yamawaki
  • Patent number: 5861775
    Abstract: A cost-effective conditioning circuit for extracting a weak, floating, wide-band signal with a low common-mode voltage from noisy environments is proposed that includes a high gain single ended operational amplifier to increase the amplitude of the signal. A simple, cost-effective approximately unity gain differential amplifier stage is used to level-shift the signal down to the desired reference potential. A typical application is a motor drive system, where the signals to be measured are bi-directional motor currents.
    Type: Grant
    Filed: January 16, 1997
    Date of Patent: January 19, 1999
    Assignee: Ford Global Technologies, Inc.
    Inventors: Chingchi Chen, Venkateswara Anand Sankaran
  • Patent number: 5781068
    Abstract: A transadmittance amplifier provides an output current that is proportional to an input voltage level. The output current drives a coil of an electric motor (the load) through a sense resistor, the voltage drop across the sense resistor providing an indication of the amount of current flowing through the coil. The indication provided by the sense resistor is applied across the differential input terminals of a feedback amplifier, which responds by outputting a feedback signal proportional to the output current. In one embodiment, the maximum output current is increased by providing a pair of complementary drive amplifiers.
    Type: Grant
    Filed: March 14, 1996
    Date of Patent: July 14, 1998
    Assignee: Nikon Corporation
    Inventor: Mark K. Takita
  • Patent number: 5736826
    Abstract: A control circuit, in particular for a direct current control in positioning systems, comprising a differential circuit (1), a control logic (2) and a full bridge (3) connected between a supply voltage V.sub.S and a reference potential GND. The differential circuit (1) has a first hysteresis comparator (HC1) and a second hysteresis comparator (HC2). The two comparator inputs (HC1-, HC1+, HC2-, HC2+) of the two hysteresis comparators (HC1, HC2) are connected each to one of two input terminals (IN1, IN2) of the control circuit and crosswise to a comparator input of the respective other comparator (HC1, HC2). The inverting input of each comparator (HC1, HC2) is connected to the non-inverting input of the respective other comparator. (FIG.
    Type: Grant
    Filed: July 19, 1996
    Date of Patent: April 7, 1998
    Assignee: SGS-Thomson Microelectronics GmbH
    Inventor: Petr Hrassky
  • Patent number: 5659230
    Abstract: A brushless motor drive circuit which can suppress switching pulses without using capacitors or other external components is provided. The brushless motor drive circuit has a hall element for generating two sinusoidal signals of opposite phase and a switching circuit which separates the two sinusoidal signals and cuts off the negative portion to produce two half cycle signals. The two half cycle signals are combined in the switching circuit, and the combined signal is applied to an automatic gain control circuit for providing a stable current to the hall element.
    Type: Grant
    Filed: September 30, 1994
    Date of Patent: August 19, 1997
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Toshiaki Fukuoka
  • Patent number: 5587640
    Abstract: A servomotor control system is set forth that assists in overcoming the problem of servomotor shut down during a failure of the programmable control system and/or servo-amplifier. The presently disclosed servomotor control system includes a programmable control system having one or more output signals connected to control a servo-amplifier. The system further includes a servomotor that is connected for control by the servo-amplifier. A safety switch is connected for detection by the programmable control system, the programmable control system controlling the servo-amplifier to brake the servomotor upon detection of the actuation of the safety switch. A delayed braking apparatus is disposed between the servo-amplifier and the servomotor. The delayed braking mechanism is also connected to detect the actuation of the safety switch, and acts to brake the servomotor after a predetermined time period from the detection of such actuation has lapsed.
    Type: Grant
    Filed: September 28, 1994
    Date of Patent: December 24, 1996
    Assignee: Tetra Laval Holdings & Finance S.A.
    Inventors: Anders Ek, Johan Hegardt
  • Patent number: 5559416
    Abstract: A control circuit, in particular for a direct current control in positioning systems, comprising a differential circuit (1), a control logic (2) and a full bridge (3) connected between a supply voltage V.sub.S and a reference potential GND. The differential circuit (1) has a first hysteresis comparator (HC1) and a second hysteresis comparator (HC2). The two comparator inputs (HC1-, HC1+, HC2-, HC2+) of the two hysteresis comparators (HC1, HC2) are connected each to one of two input terminals (IN1, IN2) of the control circuit and crosswise to a comparator input of the respective other comparator (HC1, HC2). The inverting input of each comparator (HC1, HC2) is connected to the non-inverting input of the respective other comparator.
    Type: Grant
    Filed: January 31, 1995
    Date of Patent: September 24, 1996
    Assignee: SGS-Thomson Microelectronics GmbH
    Inventor: Petr Hrassky
  • Patent number: 5495156
    Abstract: Method and apparatus for retracting an actuator comprising determining back emf voltage generated by the actuator motor; applying the determined voltage to a capacitor-resistor network; applying a holding voltage to the capacitor-resistor network. The application of the determined voltage and the holding voltage together charges a capacitor in the capacitor-resistor network to develop a charged capacitor voltage. The method and apparatus further comprises terminating application of the determined voltage to the capacitor-resistor network upon charging of the capacitor, and discharging the capacitor through the capacitor-resistor network to provide a forcing voltage to the actuator for retract operation. The forcing voltage initially forces a high deceleration current in the actuator. Further, the forcing voltage decays with time to a predetermined holding voltage to complete the retract operation.
    Type: Grant
    Filed: June 24, 1994
    Date of Patent: February 27, 1996
    Assignee: Quantum Corporation
    Inventors: Dean Wilson, Brian Molloy
  • Patent number: 4885517
    Abstract: A signal amplifier including a bridge output stage, a comparator stage arranged to control a first part of the output stage in accordance with the polarity of an input signal, and a modulating stage arranged to control a second part of the output stage in accordance with the magnitude and polarity of the input signal. The signal amplifier is particularly suitable for fabrication as an integrated circuit.
    Type: Grant
    Filed: June 20, 1988
    Date of Patent: December 5, 1989
    Assignee: Seagate Technology, Inc.
    Inventor: John L. Pennock
  • Patent number: 4851753
    Abstract: A proportional control circuit for the direction and precise speed control of D.C. electric motors such as those used to drive camera tilt/pan mountings. The circuit applies current to D.C. motors in a push/pull proportional scheme whereby slewing speed is smoothly and precisely controlled and electromotive force provides motor braking. A single current source powers the motors through an "H" bridge switching amplifier arrangement responsive to the balance between two voltage dividers, one of which includes a controlling potentiometer that regulates both direction and speed.
    Type: Grant
    Filed: June 15, 1988
    Date of Patent: July 25, 1989
    Inventor: Mark L. Hamilton
  • Patent number: 4812778
    Abstract: An isolator for connection between an informational signal source and a high voltage controlled load may be used with numerous combinations of different input signal type and magnitude and output signal requirements. The compensation for input and output signal variation is accomplished by changing a minimum number of easily accessible plug-in passive circuit components.
    Type: Grant
    Filed: January 25, 1988
    Date of Patent: March 14, 1989
    Assignee: Electro-Mechanics, Inc.
    Inventor: Leon Gryk
  • Patent number: 4777382
    Abstract: A circuit is disclosed which provides power isolation between the initializing and driven circuit, allowing the logic of a wide pulse width signal to be effectively transmitted across pulse transformers and faithfully reproduced.
    Type: Grant
    Filed: June 19, 1987
    Date of Patent: October 11, 1988
    Assignee: Allied-Signal, Inc.
    Inventor: Phillip S. Reingold
  • Patent number: 4644239
    Abstract: A motor actuator, responsive to conditions such as temperature, and to the position of a mechanism which the motor moves during operation, such as a damper which separates a refrigerating chamber from a cold storage area. The motor actuator is a capable of controlling the operation of more than one mechanism from a single motor, and can operate one or more mechanisms simultaneously (with or without a predetermined delay,) or with a relative predetermined delay.
    Type: Grant
    Filed: June 7, 1985
    Date of Patent: February 17, 1987
    Assignee: Kabushiki Kaisha Sankyo Seiki Seisakusho
    Inventors: Shinichi Yoshikawa, Shigeru Nishiwaki, Toshiro Shimodaira
  • Patent number: 4588937
    Abstract: A position control apparatus has a variable gain-type velocity amplifier (115) provided within a servo control circuit, and a low velocity sensing circuit (114) for sensing a predetermined low velocity of a motor (100) immediately before the motor is stopped. When the rotational velocity of the motor (100) drops to the predetermined low velocity immediately before stoppage during orientation control, the velocity amplifier is changed over in response to a signal from the gain of the low velocity sensing circuit (114), thereby raising servo loop gain.
    Type: Grant
    Filed: December 13, 1984
    Date of Patent: May 13, 1986
    Assignee: Fanuc Ltd.
    Inventors: Yoshiki Fujioka, Naoto Ota, Mitsuhiko Hirota
  • Patent number: 4556835
    Abstract: An operating system for movable parts for the selective closing or exposing of openings, especially for sliding roofs and sliding/lifting roofs of motor vehicles. The operating mechanism has a motor drive for the movable part and an actuating member for starting the drive, if required. In order to facilitate, especially, the bringing of the movable part into intermediate positions, the actuating member is developed as a desired-value transmitter for the position of the movable part, and the drive is part of a control circuit which compares the position selected at the desired-value transmitter with the actual position of the movable part and adjusts the movable part until the deviation has become zero.
    Type: Grant
    Filed: September 9, 1983
    Date of Patent: December 3, 1985
    Assignee: Webasto-Werk W. Baier GmbH & Co.
    Inventors: Wolfgang Vogel, Albert Zintler
  • Patent number: 4549124
    Abstract: A circuit arrangement for controlling the action of an adjusting device, in particular of a patient chair, which comprises, as target value indicator, a digital-analog converter (1) and, as actual value indicator controllable by the adjusting device, a potentiometer (2), which receives an equalized feed voltage which serves to operate the digital-analog converter, and which is connected via a branch (13) to a comparator unit (12), whose other input is connected to output (8) of the digital-analog converter (1), and which controls the adjusting device (31, 32, 33). According to this circuit design, the digital-analog converter (1), and the potentiometer (2), form a Wheatstone bridge of which one diagonal is supplied with a single feed voltage, while the other diagonal contains the comparator unit (12).
    Type: Grant
    Filed: February 14, 1983
    Date of Patent: October 22, 1985
    Assignee: Kaltenbach & Voigt GmbH & Co.
    Inventor: Stefan Beier
  • Patent number: 4538099
    Abstract: A driver amplifier circuit for an electromechanical position translator having two coils of substantially equal inductance and resistance is disclosed. The circuit includes an input for a control voltage representing desired translator position and a reference voltage, a very low value reference resistor series connected between the two coils, differentially driven push pull amplifiers connected to drive the coils, and two equal value feedback resistors connected from the reference resistor to inverting inputs of the amplifiers, whereby absolute magnitude of output voltage equals the input voltage plus twice the reference voltage, and wherein zero differential input volts yields zero current flow through the coils.
    Type: Grant
    Filed: January 17, 1983
    Date of Patent: August 27, 1985
    Assignee: Quantum Corporation
    Inventor: Ronald R. Moon
  • Patent number: 4506203
    Abstract: A circuit for controlling the position of a driven member is disclosed which includes a control circuit for controlling the application of electrical power to a motor and a circuit element operable for generating position error signals corresponding to the position of the load which may in one embodiment constitute a rotor element of the motor. A comparator section is provided for comparing the position error signals with position reference signals and for generating control signals to effect rotation of the load in a desired direction. In one embodiment, the error signal is generated by a feedback loop including a potentiometer having a movable element coupled to the load or motor rotor, wherein the voltage magnitude of the error signal is varied in accordance with the rotational position of the load or rotor element. In a preferred embodiment, the comparator section includes first and second comparators respectively responsive to position deviations of the rotor in first and second rotational directions.
    Type: Grant
    Filed: October 13, 1982
    Date of Patent: March 19, 1985
    Assignee: LTV Aerospace and Defense Company
    Inventor: William G. Redmond, Jr.
  • Patent number: 4496886
    Abstract: A three state driver for an inductive load, e.g., a stator winding of a variable reluctance motor, allows the use of charge, idle, and discharge states in which a positive voltage, a short, and a reverse voltage are connected across the inductive load, respectively. An H-bridge comprising two electronic switches and two diodes is used to switch the inductive load voltages as commanded by a comparator circuit which compares the load current to a desired load current.
    Type: Grant
    Filed: November 8, 1982
    Date of Patent: January 29, 1985
    Assignee: Hewlett-Packard Company
    Inventors: Gary B. Gordon, Robert Joy, Michael J. Lee
  • Patent number: 4492908
    Abstract: This invention relates to a circuit arrangement and the associated mechanism for slaving the angles of rotation of the slats of a plurality of centrally controlled sun or window blinds. The driving motor of each blind is provided with current via a corresponding operational amplifier and related circuit. The motor operates the slats to achieve balance between an input control voltage and a voltage depending on the angular position of the slats. An automatic version in which the control voltage is generated by a photoelectric sensor and several circuit variations are shown.
    Type: Grant
    Filed: February 17, 1983
    Date of Patent: January 8, 1985
    Assignee: International Standard Electric Corporation
    Inventors: Bernd Stockle, Klaus Pfendler
  • Patent number: 4481452
    Abstract: In a control circuit, which has a current switching-over circuit including at least four switching transistors for controlling a current flowing through an electromagnetic device, the control circuit has driving circuits each of which drives the switching transistors in such a way that a short circuit does not occur during the switching-over operation thereof.
    Type: Grant
    Filed: May 28, 1982
    Date of Patent: November 6, 1984
    Assignee: Diesel Kiki Co., Ltd.
    Inventors: Yuichi Kitano, Yoshiharu Tada
  • Patent number: 4463296
    Abstract: A driving circuit for use in controlling a motor for controlling an air mixing door, an inner and surrounding air change-over door and a mode setting door and the like used in a vehicle air conditioning device, or a motor used in opening or closing of window panes of a vehicle or in opening or closing the door which includes a control transistor for use in controlling a transistor circuit having a transistor to cause both normal and reverse directed currents to flow in a vehicle motor, the control transistor being operated until a specified period of time has elapsed after the power supply switch is turned on, the motor input being shut off by the control transistor so as to prevent erroneous operation of the motor just after the power supply switch is turned on or to prevent the production of a chattering sound caused by the operation of gear trains with the motor.
    Type: Grant
    Filed: March 1, 1982
    Date of Patent: July 31, 1984
    Assignee: Diesel Kiki Kabushiki Kaisha
    Inventors: Yoshiharu Tada, Yuichi Kitano
  • Patent number: 4446410
    Abstract: A control circuit comprises a switching element connected in series with the coil of an actuator for generating a drive current when rendered conductive. A drive current sensing resistor is coupled in a circuit with the switching element and the coil to develop a first voltage in response to the switching element being rendered conductive. A surge current sensing resistor is coupled in a circuit with the coil through a unidirectionally conducting element to develop a second voltage in response to the switching element being rendered nonconductive. The first and second voltage are amplified and fed to a differential integrator to which an actuator control signal is also applied. The output of the differential integrator is compared with the instantaneous value of a ramp voltage to generate gating pulses applied to the switching element.
    Type: Grant
    Filed: January 21, 1982
    Date of Patent: May 1, 1984
    Assignee: Nippondenso Co., Ltd.
    Inventors: Toshiaki Yagura, Kenichiro Satoyama, Kazutoshi Morisada, Ryoichi Yamamoto, Seietsu Yoshida
  • Patent number: 4441081
    Abstract: This dual operating mode switching power driving circuit arrangement comprises an amplifying circuit of conventional form which is operated substantially as a Class A feedback amplifier in a servosystem "following" mode and is switched to operate as a Class D amplifier in the "seeking" mode under program control calling for the latter mode and reswitched to the "following" mode only at the succeeding transition of the Class D waveform whereby transients are avoided. For operating in Class D mode, the Class A feedback loop is opened and the amplifier circuit is arranged so that the input wave now overdrives the input circuit and drives the output circuit between .+-. values of the energy potential, whereby the efficiency is very high.
    Type: Grant
    Filed: December 22, 1981
    Date of Patent: April 3, 1984
    Assignee: International Business Machines
    Inventor: Michael O. Jenkins
  • Patent number: 4358724
    Abstract: A linear solid state servo amplifier operated from a low voltage source and which develops a voltage across the servo motor equal to the source voltage diminished only by the saturation voltages of two of its output transistors has a bridge output stage of complementary transistors and a bridge driver stage of complementary Darlington transistors having as its load a preselected resistor.
    Type: Grant
    Filed: December 8, 1980
    Date of Patent: November 9, 1982
    Assignee: Commercial Shearing, Inc.
    Inventor: Lambert Haner
  • Patent number: 4303875
    Abstract: A device for the remote control of the angular position of an aerial rotor comprising a d.c. motor for the rotation of the rotor and a drive circuit adapted to cause the rotation of the motor in one direction when it receives as input a d.c. voltage higher than a reference value and in the opposite direction when it receives as input a d.c. voltage lower than the reference value. The device provides for a feeder, in proximity of the receiver, for generating at least one d.c. control voltage and comprising a regulator of the value of the voltage as a function of the desired angular position of the rotor of the aerial, and a regulator and stabilizor of the d.c. control voltage, located in proximity of the drive circuit of the motor, to obtain from the d.c. control voltage a stabilized constant voltage of a value lower than the minimum value of the d.c. control voltage, for the feeding of the drive circuit and the motor.
    Type: Grant
    Filed: May 24, 1979
    Date of Patent: December 1, 1981
    Inventor: Salvatore Montorio
  • Patent number: 4274039
    Abstract: A circuit for a servo-amplifier saves power when the position servo has reached balance. The servo input is a high frequency differential transformer having its armature positioned by mechanical means driven by a servo motor controlled through amplifier circuitry. The power to the amplifier is turned off in the vicinity of the servo null point.
    Type: Grant
    Filed: February 25, 1980
    Date of Patent: June 16, 1981
    Assignee: Fluid Data Systems
    Inventors: Gene Glassey, Aldan D. Gomez
  • Patent number: 4242560
    Abstract: The servo circuit is operable both in a dual and in a single mode and includes an analog gate for multiple gap inputs. Dual operation is required where more than one gap is involved such as in the situation where multiple electrodes are carried by a common machine tool ram. In the servo operation, the unwanted information over a relatively wide voltage range is eliminated and the more significant voltage excursions around the 30 volt or gap breakdown voltage level are employed. This compensates for the non-linearity that is inherent in the electrical discharge machining gap.
    Type: Grant
    Filed: March 26, 1979
    Date of Patent: December 30, 1980
    Assignee: Colt Industries Operating Corp.
    Inventors: Oliver A. Bell, Jr., Randall C. Gilleland, Davey J. Chance
  • Patent number: 4236106
    Abstract: A control system for the automatic adjustment of controlling elements. The ystem includes a pulse controlled servo follow-up circuit, a signal generating circuit, a sensing circuit, a system controller and a switching circuit. The system controller is either a special or small general purpose digital device which transmits a control signal to the switching circuit in response to the output of the sensing circuit. The switching circuit provides either of two variable time duration pulse control signals to the pulse-controlled follow-up circuit. One control signal will cause the follow-up circuit to provide a positive control and the other control signal will cause negative control. The amount of positive or negative control is determined by the time duration of the pulse. The signal generating device will be controlled by the output of the follow-up circuit and the sensing circuit will measure the condition of the signal generating circuit.
    Type: Grant
    Filed: October 16, 1978
    Date of Patent: November 25, 1980
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Doxie M. Davis, John B. Gehman
  • Patent number: 4232259
    Abstract: A servo-system includes a high-gain direct-coupled direct current (dc) differential amplifier to which a dc input signal is fed. An adder adds the dc amplifier output to a comparison voltage, and the adder output is applied through a filter circuit to a second input of the differential dc amplifier. A servo-amplifier drives a servo-motor in accordance with the dc amplifier output. Means are provided for zero-balancing the dc amplifier output while varying the comparison voltage by the servo-motor.
    Type: Grant
    Filed: December 27, 1977
    Date of Patent: November 4, 1980
    Assignee: Yokogawa Electric Works, Ltd.
    Inventors: Nobuo Kaieda, Yoshihiro Okano
  • Patent number: RE42291
    Abstract: A digital communication system for transmitting and receiving Digital Visual Interface (DVI) communication data signals and Display Data Channel (DDC) communication signals over a transmission line comprises an open-loop equalizer circuit and a DDC extension circuit. The open-loop equalizer circuit is operable to receive DVI communication signals transmitted over the transmission line and output equalized DVI communication data signals. The DDC extension circuit is operable to inject a boost current at the receive end of the transmission line during a positive transition in the DDC communication signal, and clamp the receive end of the transmission line during a negative transition of the DDC communication signal.
    Type: Grant
    Filed: June 4, 2009
    Date of Patent: April 12, 2011
    Assignee: Gennum Corporation
    Inventors: Aapoolcoyuz Biman, Birubi Ram Biman, John Hudson, Eliyahu D. Zamir, Stephen P. Webster