With Emitter Follower Patents (Class 327/491)
  • Patent number: 11431305
    Abstract: An amplifier transistor operates in two operation modes having different characteristics. A first bias circuit including a first bias supply transistor supplies an output current of the first bias supply transistor to the amplifier transistor as a bias current. A second bias circuit including a second bias supply transistor supplies a portion of an output current of the second bias supply transistor to the amplifier transistor as a bias current. At least one of the first bias circuit and the second bias circuit is selected and operates in accordance with an operation mode of the amplifier transistor by using a bias control signal input to a bias control terminal. The second bias circuit includes a current path along which a portion of the output current of the second bias supply transistor is returned to the second bias circuit.
    Type: Grant
    Filed: October 27, 2020
    Date of Patent: August 30, 2022
    Assignee: MURATA MANUFACTURING CO., LTD.
    Inventor: Yoshiaki Sukemori
  • Patent number: 10502786
    Abstract: An automotive vehicle includes a switch detection system with a hardware controller having a power supply configured to generate a supply voltage. A first switch assembly includes an input terminal configured to receive the supply voltage. The first switch assembly includes a first switch configured to operate in a first plurality of switch states. A second switch assembly is connected in series with the first switch assembly and includes an output terminal connected to a voltage reference point. The second switch assembly includes a second switch configured to operate in a second plurality of switch states. Based on a voltage potential across the input terminal and the output terminal, the hardware controller determines the first plurality of switch states independently from the second plurality of switch states, and determines the second plurality of switch states independently from the first plurality of switch states.
    Type: Grant
    Filed: November 18, 2016
    Date of Patent: December 10, 2019
    Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventors: Jeffrey R. Nowicki, Wade G. Johnson
  • Patent number: 10291187
    Abstract: A power amplifier circuit includes an amplifier transistor having a base, a collector, a bias circuit, and a first resistance element connected between the base of the amplifier transistor and the bias circuit. The bias circuit includes a voltage generation circuit, a first transistor having a base to which a first direct-current voltage is supplied, and an emitter from which the bias current or voltage is supplied, a second transistor having a base to which a second direct-current voltage is supplied, and an emitter connected to the emitter of the first transistor, a signal supply circuit disposed between the base of the amplifier transistor and the base of the second transistor, and an impedance circuit disposed between the base of the first transistor and the base of the second transistor.
    Type: Grant
    Filed: February 26, 2018
    Date of Patent: May 14, 2019
    Assignee: MURATA MANUFACTURING CO., LTD.
    Inventors: Yuri Honda, Fumio Harima, Satoshi Tanaka
  • Patent number: 7969189
    Abstract: System and method for a clock driver. An input taking circuit is used for receiving small-signal logic inputs. A voltage follower circuit is coupled to the input taking circuit and used to generate a set of voltage follower outputs. An output circuit is coupled to the voltage follower circuit to receive the set of voltage follower outputs as inputs and generate output signals. The voltage follower circuit is coupled to a switching circuit, that is connected to the set of voltage follower outputs and is deployed for reducing the phase noise level of the output signals.
    Type: Grant
    Filed: November 24, 2009
    Date of Patent: June 28, 2011
    Assignee: Linear Technology Corporation
    Inventor: Joseph Gerard Petrofsky
  • Patent number: 7649559
    Abstract: Methods, devices, and systems for offset cancellation in an amplifier are disclosed, wherein the amplifier inputs may be exposed to large loads from an array of pixel columns coupled in parallel. During a cancellation phase, an amplifier offset may be canceled by selectively coupling a first amplifier output to a first amplifier input and a second amplifier output to a second amplifier input. During a portion of the cancellation phase, a buffer may use the first amplifier input to drive a first pixel signal. During a different portion of the cancellation phase, the buffer may use the second amplifier input to drive a second pixel signal. To sense the pixel columns during an amplification phase, the first and second pixel signals are coupled to the first and second amplifier inputs, respectively, with the result that the amplifier offset and the buffer offset are cancelled from the amplifier output.
    Type: Grant
    Filed: August 30, 2006
    Date of Patent: January 19, 2010
    Assignee: Aptina Imaging Corporation
    Inventor: Alf Olsen
  • Patent number: 7545183
    Abstract: An integrated circuit comparator comprises a differential amplifier, a source follower circuit coupled to a gate terminal of a first transistor in the differential amplifier, and an output circuit. One or more source follower circuits may be utilized in connection with the differential amplifier, and one or more source follower circuits may be utilized in connection with the output circuit.
    Type: Grant
    Filed: May 23, 2007
    Date of Patent: June 9, 2009
    Assignee: Micron Technology, Inc.
    Inventor: Leonard Forbes
  • Patent number: 6784743
    Abstract: A high frequency amplifier in which a common emitter bipolar transistor is used, and in that a constant current source and a constant voltage source are switched to apply a DC bias to a base terminal of the bipolar transistor in accordance with a power level of a high frequency signal input to the bipolar transistor or a power level of a high frequency signal output therefrom, and a frequency mixer in that a DC bias is applied to a base of at least one of a bipolar transistor for the input of a high frequency signal and a bipolar transistor for the input of a local oscillation wave by using a configuration for applying the DC bias to a base of an amplifying bipolar transistor employed in the high frequency amplifier.
    Type: Grant
    Filed: July 30, 2002
    Date of Patent: August 31, 2004
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Eiji Taniguchi, Noriharu Suematsu, Chiemi Sawaumi, Kenichi Maeda, Takayuki Ikushima, Hiroyuki Joba, Tadashi Takagi
  • Patent number: 6593798
    Abstract: A voltage follower includes a follower stage including first and second bipolar junction transistors connected in cascade, and a first current generator connected to the follower stage for biasing the first and second bipolar junction transistors. A cascode stage is connected between the first current generator and the first bipolar junction transistor, and a second current generator is connected between the first bipolar junction transistor and a first voltage reference. The voltage follower dissipates less power when the output current is small.
    Type: Grant
    Filed: July 8, 2002
    Date of Patent: July 15, 2003
    Assignee: STMicroelectronics S.r.l.
    Inventor: Tiziana Mandrini
  • Patent number: 6300669
    Abstract: A semiconductor integrated circuit device comprises a multiple-stage amplifier including a plurality of transistors. The multiple-stage amplifier has a first stage comprising a plurality of bipolar transistors each having a single emitter structure. The bipolar transistors are connected parallel to each other. The semiconductor integrated circuit device can easily be designed, is of a self-aligned structure, and has a single transistor size. The semiconductor integrated circuit device may be used as a low-noise, high-power-gain high-frequency amplifier.
    Type: Grant
    Filed: September 25, 1998
    Date of Patent: October 9, 2001
    Assignee: NEC Corporation
    Inventor: Yasushi Kinoshita
  • Patent number: 6225839
    Abstract: To provide a buffer circuit that is able to achieve a reduction of the input current and a high input impedance by compensating the base current of a transistor, and to avoid a lowering of the input dynamic range by means of a current compensation circuit. By means of transistor P2, the base voltage of transistor Q2 is established in response to the signal of input node ND1 of the differential circuit, and the emitter voltage of transistor Q2 is set at virtually the same level as the reference voltage Vref. The collector current IC2 of transistor P2 is the same as the base current of transistor Q2, and is established with the amplification ratio of transistor Q2 as well as the current I2 of current source IS2.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: May 1, 2001
    Assignee: Texas Instruments Incorporated
    Inventor: Shigeki Ohtsuka
  • Patent number: 6100726
    Abstract: A buffer circuit having a high input impedance. The buffer circuit comprises an input lead, a first stage having a first emitter follower transistor and a first level shifter transistor, a second stage having a second emitter follower transistor and a second level shifter transistor, and an output lead coupled to said second stage. The first emitter follower transistor is coupled to the input lead and coupled to the first level shifter transistor. The first and second stage of the buffer circuit acts as a voltage follower. The second emitter follower transistor is coupled to the second level shifter transistor, while the second emitter follower transistor is coupled to the first emitter follower transistor. The buffer circuit has a high input impedance and very low leakage current. Hence, it is ideal for sampling filter components of a phase lock loop circuit within a high frequency clock generation circuit thereby reducing clock jitter.
    Type: Grant
    Filed: December 21, 1998
    Date of Patent: August 8, 2000
    Assignees: Sony Corporation of Japan, Sony Electronics, Inc.
    Inventors: Mehrdad Nayebi, Stephen D. Edwards, Phil Shapiro
  • Patent number: 6037891
    Abstract: A low power serial A/D converter cascades multiple stages (20) of a novel track-and-hold circuit (22) to implement a pipelined A/D converter. The track-and-hold circuit (22) is implemented using a differential structure to cancel out signal droop. This allows extremely high tracking bandwidths to be achieved while maintaining long hold times. Each stage (20) of the pipeline includes a binary quantizing circuit (24) which performs a 1-bit binary estimate of the data and a summing circuit (26) which updates the output of its track-and-hold circuit (22) to allow the next bits to be decided by the following stages.
    Type: Grant
    Filed: February 23, 1998
    Date of Patent: March 14, 2000
    Assignee: Motorola, Inc.
    Inventor: Richard Steven Griph
  • Patent number: 5952736
    Abstract: A pulse output circuit which has an output stage connected to a capacitive load capable of improving a through-rate of an input pulse signal with reduced power consumption is provided.
    Type: Grant
    Filed: September 17, 1998
    Date of Patent: September 14, 1999
    Assignee: Sony Corporation
    Inventor: Yoshiaki Matsubara
  • Patent number: 5880610
    Abstract: A device for converting a current pulse signal into a voltage pulse signal through a conversion from a current to a voltage includes a converting unit converting the current pulse signal into a first voltage signal, a voltage reducing unit generating a second voltage signal by reducing a magnitude of the first voltage signal, a delay unit generating a third voltage signal by delaying the second voltage signal, and a comparison unit generating the voltage pulse signal by comparing the first voltage signal with the third voltage signal.
    Type: Grant
    Filed: April 13, 1998
    Date of Patent: March 9, 1999
    Assignee: Fujitsu Limited
    Inventors: Kazunori Nishizono, Tetsuji Funaki, Atsushi Hayakawa
  • Patent number: 5841312
    Abstract: The gating circuit has a power transistor (T1, T2, T3) and a current measuring resistor (R5) connected with the power transistor so that a voltage drop at the measuring resistor is a measure of a current flow in the power transistor. This voltage drop is used to trigger a current regulating transistor (T5) and a temperature measuring transistor (T9). Below a predetermined temperature, the current flow is limited solely by the current regulating transistor (T5). Above this predetermined temperature the collector current is further reduced via the temperature measuring transistor (T9) and a further transistor (T10) so as to protect the power transistor from thermal overload.
    Type: Grant
    Filed: July 1, 1996
    Date of Patent: November 24, 1998
    Assignee: Robert Bosch GmbH
    Inventors: Anton Mindl, Hartmut Michel, Bernd Bireckoven, Manfred Uebele, Ulrich Nelle
  • Patent number: 5546045
    Abstract: An integrated circuit output stage is intended for use with an operational amplifier. The output is capable of driving capacitive load to within a V.sub.SAT of the power supply rails. The complementary output transistors are driven by way of a combination of buffers and complementary differential amplifiers which act to bias the stage in class AB. The quiescent current is stabilized and controlled, in part, by simple resistor rationing. The output transistor saturation is sensed and a current limit is imposed so that hard saturation is avoided. Frequency compensation is achieved in a manner that responds to output transistor saturation so as to improve the high frequency transient response. Feedforward capacitors are also included to further improve high frequency response.
    Type: Grant
    Filed: April 19, 1995
    Date of Patent: August 13, 1996
    Assignee: National Semiconductor Corp.
    Inventor: Don R. Sauer
  • Patent number: 5539350
    Abstract: A line driver switching stage includes a terminal for a reference potential, a terminal for a supply potential, and an output terminal of the line driver switching stage. A differential amplifier has a first and a second amplifier branch. The first amplifier branch has a resistor with first and second terminals. The first terminal of the resistor is the terminal for the reference potential. An emitter follower transistor has an emitter and has a base-to-emitter path connected between the second terminal of the resistor and the output terminal. A saturation prevention element has a first terminal connected to the output terminal and a second terminal connected to the second amplifier branch. A bipolar transistor has a base-to-emitter path connected between the second terminal of the saturation prevention element and the terminal for the supply potential. The bipolar transistor has a collector connected to the emitter of the emitter follower transistor.
    Type: Grant
    Filed: June 28, 1994
    Date of Patent: July 23, 1996
    Assignee: Siemens Aktiengesellschaft
    Inventor: Wilhelm Wilhelm
  • Patent number: 5485110
    Abstract: An ECL multiplexing circuit (20) includes two differential pairs (21 and 22) for receiving first and second ECL level input signals, emitter-follower output transistors (27 and 28), and a differential pair (31 and 32) for receiving differential clock signals. The differential clock signals control which of the two differential pairs (21 and 22) is coupled to the emitter-follower output transistors (27 and 28). The ECL level input signals that control a logic state of the output signals is determined by the logic state of the clock signals. The ECL multiplexing circuit (20) receives non-overlapping clock signals and is used in a quadrature frequency divide-by-two circuit (40) to divide a frequency of an input clock signal by two.
    Type: Grant
    Filed: February 1, 1994
    Date of Patent: January 16, 1996
    Assignee: Motorola Inc.
    Inventors: Kenneth W. Jones, Stephen T. Flannagan
  • Patent number: 5469104
    Abstract: An active folded cascode includes an amplifier transistor and a source follower transistor configured as a folded cascode with the drain of the amplifier transistor and the source of the follower transistor connected to form a gain node. A feedback transistor has its gate and drain connected to the source and gate of the follower transistor while bias current provided to the drain of the feedback transistor by a current source maintains the gain node at a fixed voltage with respect to a reference voltage. Coupling of the voltage at the gain node to the gate of the source follower transistor by the feedback transistor reduces the effective source impedance of the source follower transistor, providing improved gain and bandwidth properties for the active folded cascode circuit.
    Type: Grant
    Filed: March 28, 1994
    Date of Patent: November 21, 1995
    Assignee: Elantec, Inc.
    Inventors: Douglas S. Smith, Edward C. Bee
  • Patent number: 5463345
    Abstract: The circuit for converting unipolar input to bipolar output includes a differential amplifier, first and second feedback resistors; and a peak detector. The negative output of the differential amplifier is fed back to the positive input of the differential amplifier through the first feedback resistor, and the positive output of the differential amplifier is fed back to the negative input of the differential amplifier through the peak detector and the second feedback resistor. A pole of lowest frequency among feedback amplifier circuits forming the circuit for converting unipolar input to bipolar output is to be determined with cut-off frequency of an amplification stage of the differential amplifier.
    Type: Grant
    Filed: December 21, 1993
    Date of Patent: October 31, 1995
    Assignee: NEC Corporation
    Inventors: Takeshi Nagahori, Toshimasa Oami, Noriko Anzai