Field Effect Transistor Patents (Class 341/136)
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Patent number: 7911366Abstract: One embodiment of the present invention is a Gray code current-mode analog to digital (ADC) converter using a Gray code current-mode ADC building block. The Gray code current-mode ADC building block can produce a Gray code bit and a current output that is sent to a next Gray code ADC building block. In one embodiment, the Gray code current-mode ADC building block does not use a voltage comparator in a signal path of the current output. In one embodiment, an 8 bit analog-to-digital converter can have a 65 ns conversion time and consume only 10 mW of power with a single +5.0V supply.Type: GrantFiled: September 17, 2008Date of Patent: March 22, 2011Assignee: Exar CorporationInventors: Richard W. Randlett, Zonggi Hu
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Patent number: 7907075Abstract: A semiconductor device includes a first switching device including a first electrode coupled with a first node, a second electrode coupled with a second node, and a first control electrode controlling connection between the first and second electrodes; a second switching device including a third electrode coupled with the second node, a fourth electrode coupled with the second node, and a second control electrode controlling the connection between the third electrode and the fourth electrode; and a first control circuit controlling a substrate voltage of the second switching device.Type: GrantFiled: November 3, 2009Date of Patent: March 15, 2011Assignee: Fujitsu LimitedInventor: Sanroku Tsukamoto
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Patent number: 7907072Abstract: A DAC unit, connected to a current supply transistor, includes first control transistors connected in parallel to each other, with each being connected in series to the current supply transistor. The first control transistors drive currents at different current values in response to a bias voltage. The DAC unit also includes second control transistors connected in parallel to each other, with each being connected in series to the current supply transistor. Each second control transistor drives the current having the same current value as one of the first control transistors in response to the single bias voltage. The first and second control transistors driving the currents having the same current value operate in a complementary manner based on part of a digital code. The DAC unit generates an output current by selectively combining at least one of the currents driven by the first control transistors.Type: GrantFiled: September 2, 2009Date of Patent: March 15, 2011Assignee: Freescale Semiconductor, Inc.Inventor: Hiroyuki Kimura
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Patent number: 7903016Abstract: A high power digital to analog converter (DAC) includes (a) an array of n bipolar transistors arranged in a binary sequence, (b) a depletion mode FET and (c) an array of n switches. The collector terminals of each bipolar transistor in the array are tied together. Furthermore, the depletion mode FET includes a source terminal which is directly connected to the collector terminals of each bipolar transistor. The FET also includes a gate terminal connected to a ground potential, and a drain terminal. Each bipolar transistor is sized to be a factor larger than its preceding transistor in the array of n bipolar transistors, for example, twice as large. The array of n switches is controlled by a digital word of n bits. Each of the n switches selectively activates a respective bipolar transistor in the array of n bipolar transistors. As the n switches are selectively activated, the array of n bipolar transistors provides n binary weighted collector currents in the source terminal of the FET.Type: GrantFiled: August 12, 2009Date of Patent: March 8, 2011Assignee: ITT Manufacturing Enterprises, Inc.Inventor: Michael A. Wyatt
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Patent number: 7903013Abstract: Operating speed as well as output accuracy of a D-A converter is enhanced. With a semiconductor device including unit current sources, and unit current source switches, plural current source elements constituting each of the unit current sources are disposed so as to be evenly dispersed, thereby reducing errors of the current source element, dependent on distance while the unit current source switches are concentratedly disposed in a small region, thereby mitigating delay in operation, attributable to parasitic capacitance. In addition, with the semiconductor device including R2R resistance ladders, the R2R resistance ladder is provided on the positive and the negative of each of the unit current source switches, and the respective R2R resistance ladders are shorted with each other at respective nodes on a unit current source switch-by-unit current source switch basis, are rendered identical in length, thereby cancelling out a nonlinearity error attributable to wiring parasitic resistance.Type: GrantFiled: July 22, 2009Date of Patent: March 8, 2011Assignee: Hitachi, Ltd.Inventors: Kenichiro Yamaguchi, Atsushi Okumura, Mitsugu Kusunoki, Tomoo Murata
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Publication number: 20110050470Abstract: A DAC unit, connected to a current supply transistor, includes first control transistors connected in parallel to each other, with each being connected in series to the current supply transistor. The first control transistors drive currents at different current values in response to a bias voltage. The DAC unit also includes second control transistors connected in parallel to each other, with each being connected in series to the current supply transistor. Each second control transistor drives the current having the same current value as one of the first control transistors in response to the single bias voltage. The first and second control transistors driving the currents having the same current value operate in a complementary manner based on part of a digital code. The DAC unit generates an output current by selectively combining at least one of the currents driven by the first control transistors.Type: ApplicationFiled: September 2, 2009Publication date: March 3, 2011Applicant: FREESCALE SEMICONDUCTOR, INC.Inventor: Hiroyuki KIMURA
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Patent number: 7889106Abstract: A first switched capacitor circuit is connected to the source of one MOS transistor of a current mirror pair configured by a pair of MOS transistors and a second switched capacitor circuit is connected to the source of the other MOS transistor. Each of the first and second switched capacitor circuits includes a capacitor and a switch connected in parallel with the capacitor and the switch is on/off-controlled based on a clock signal of a preset cycle. Each of the first and second switched capacitor circuits equivalently functions as a resistor with large resistance and a variation in the output current of the current mirror circuit based on a variation in the threshold voltages of the pair of MOS transistors can be reduced even if the power source voltage is reduced.Type: GrantFiled: August 11, 2010Date of Patent: February 15, 2011Assignee: Kabushiki Kaisha ToshibaInventor: Shigeo Imai
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Patent number: 7864074Abstract: A data driver used in a current-driving display device for receiving a digital signal and for outputting a gray-scaled current signal to a data line. The data driver includes a digital-to-analog current converter for transforming the digital signal into an analog current signal, a current-copying/reproducing module, and a control circuit. The current-copying/reproducing module is used to store a predetermined voltage for conducting the analog current signal in a transforming/storing status and to conduct a reproducing current signal to the data line in a reproducing/sustaining status. The control circuit is electrically connected between the digital-to-analog current converter and the current-copying/reproducing module for providing a switch between the transforming/storing status and the reproducing/sustaining status. The reproducing current signal is the gray-scaled current signal and is almost equivalent to the analog current signal.Type: GrantFiled: December 1, 2003Date of Patent: January 4, 2011Assignee: AU Optronics Corp.Inventor: Wein-Town Sun
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Patent number: 7843372Abstract: In an mode of this invention, a digital/analog conversion circuit, includes: a digital/analog conversion portion which outputs a first current according to an input digital signal; and a first current mirror circuit which generates a mirror current according to the first current and outputs the mirror current as an analog signal, the digital/analog conversion circuit converting the digital signal into the analog signal, and further including: a second current mirror circuit, which generates a first mirror current according to the first current; and a third current mirror circuit, which is connected to a reference voltage, and to which the first mirror current is input, and which generates a second mirror current equal to the first current, according to the first mirror current, between the digital/analog conversion portion and the second current mirror circuit.Type: GrantFiled: December 24, 2008Date of Patent: November 30, 2010Assignee: NEC Electronics CorporationInventor: Takahiro Kawano
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Patent number: 7843442Abstract: A pixel and an organic light emitting display using the pixel capable of displaying an image of uniform luminance. A pixel circuit is coupled with at least one scan line and at least one data line. The pixel circuit first charges a voltage corresponding to a first data signal across at least one capacitor when the first data signal is supplied from the data lines, and second charges the at least one capacitor when a current as a second data signal is provided. The pixel circuit controls an amount of current supplied to a second power supply from the first power supply through the organic light emitting diode according to the voltage charged in the at least one capacitor. Accordingly, an image of uniform luminescence may be displayed.Type: GrantFiled: March 17, 2006Date of Patent: November 30, 2010Assignee: Samsung Mobile Display Co., Ltd.Inventors: Sang Moo Choi, Oh Kyong Kwon
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Patent number: 7830288Abstract: Reference network embodiments are provided for use in pipelined signal converter systems. The network embodiments are fast and power efficient and they generate low-impedance reference signals through the use of at least one output transistor, a diode-coupled transistor coupled to the output transistor, and a controller. The controller is configured to provide a backgate voltage to the diode-coupled transistor to thereby establish a substantially-constant output current. The controller is further configured to provide a gate voltage to the output transistor to establish a reference voltage.Type: GrantFiled: January 25, 2010Date of Patent: November 9, 2010Assignee: Analog Devices, Inc.Inventors: Gregory W. Patterson, Ahmed Mohamed Abdelatty Ali
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Patent number: 7821438Abstract: A digital-to-analog converter circuit layout includes a ratiometric digital-to-analog converter. The ratiometric digital-to-analog converter includes a digital data input, a converter voltage output, a voltage controlled oscillator, and a pulse width modulation module. The a digital data input, a converter voltage output, a voltage controlled oscillator, and a pulse width modulation module is configured in a controllable manner for converting digital data received at the input to a converter output voltage at the output using a reference voltage, an adjustable current as a reference current, and an adjustable impedance value. The circuit layout is characterized in that the voltage controlled oscillator includes circuit components which multiply the reference voltage by a quotient between the adjustable impedance value and the adjustable current, and which apply the multiplication results to the pulse width modulation module.Type: GrantFiled: May 29, 2009Date of Patent: October 26, 2010Assignee: Micronas, GmbHInventors: Laurent Avon, Reiner Bidenbach, Klaus Heberle
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Patent number: 7812751Abstract: The invention relates to a device and a method for converting a digital signal having a plurality of data-bits into a filtered analog signal. A device according to the invention includes a delay element arranged to produce one or more differently delayed version of the digital signal and a digital-to-analog conversion circuitry arranged to convert the digital signal and the one or more differently delayed, and possibly differently scaled, versions of the digital signal into analog signals and to produce the filtered analog signal as a combination of the analog signals. Therefore, the device constitutes not only a digital-to-analog-converter but also a finite impulse response filter.Type: GrantFiled: September 26, 2007Date of Patent: October 12, 2010Assignee: Nokia CorporationInventors: Petri T. Eloranta, Pauli Seppinen, Aarno Pärssinen
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Patent number: 7808410Abstract: Provided is a current control circuit. A current control circuit may include a clock sensing unit configured to generate a control signal according to one or more frequencies based on a plurality of clock signals, and a current scaling unit configured to scale a bias current according to the control signal. The current control circuit according to example embodiments may dynamically control a bias current according to one or more frequencies based on a plurality of clock signals so that power consumption of an analog-to-digital converter (ADC) and the semiconductor device including the ADC, which require various operating frequencies, may be improved.Type: GrantFiled: March 24, 2009Date of Patent: October 5, 2010Assignee: Samsung Electronic Co., Ltd.Inventors: Sang-kyu Kim, Dae-young Chung
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Patent number: 7796073Abstract: In a current switch circuit A used for a current steering D/A converter, a current switch basic circuit 1 includes first and second transistors Tr121 and Tr122 included in a differential switch 12. A threshold voltage control circuit 5 has an output terminal Vbout controlling the substrate voltage to be outputted to the substrate terminal of each of the two transistors Tr121 and Tr122 included in the differential switch 12 for controlling the threshold voltage of the two transistors of the differential switch. Accordingly, the present invention improves the decrease in the dynamic range of the current switch basic circuit 1 dependent on the threshold of each of the two transistors in the differential switch 12 and realizes a wider output voltage range without causing deterioration in properties even in a case that the power voltage is reduced in the current switch basic circuit 1.Type: GrantFiled: October 23, 2007Date of Patent: September 14, 2010Assignee: Panasonic CorporationInventors: Tomohiro Ogawa, Heiji Ikoma
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Patent number: 7791514Abstract: A digital-to-analog converter includes MOS transistors formed in the identical configuration and arranged in a matrix array. Ones of the MOS transistors placed on the inner part of the array serve as constant current cells, while others placed around the inner MOS transistors function as dummy transistors and a MOS capacitance. Each dummy transistor has its gate, source and drain electrodes connected to a metal strip to which the gate electrode of each constant current cells is connected. Thus, the gate electrodes of the constant current cells are connected to a substrate or potential well via diodes consisting of the dummy transistors, thereby electric charges generated in metal strips due to plasma etching and like treatment being discharged through the diodes to the substrate or potential well. The digital-to-analog converter is thus able to produce even constant currents.Type: GrantFiled: January 13, 2009Date of Patent: September 7, 2010Assignee: Oki Semiconductor Co., Ltd.Inventor: Katsuyoshi Yagi
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Patent number: 7782236Abstract: Embodiments relate to a current cell circuit in a digital-analog converter. According to embodiments, a current cell circuit in a digital-analog converter may include a current source connected to a power voltage terminal to generate current having a predetermined magnitude, a first current switch transferring current provided from the current source to a first output terminal, a first current generator detecting output voltage from the first output terminal and generating the amount of reduced current from the detected voltage, and a first current supplier supplying the amount of current generated from the first current generator to the first current switch. According to embodiments, current variations at a constant output voltage may be minimized. This may make it possible to obtain more stable frequency characteristics.Type: GrantFiled: December 27, 2008Date of Patent: August 24, 2010Assignee: Dongbu HiTek Co., LtdInventor: Sang-June Kim
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Patent number: 7777655Abstract: Traditionally, constant current source circuits (and, in particular, constant current source circuits that include cascoded current sources) had numerous drawbacks due to parasitic capacitances, especially at higher switching frequencies. Here, however, a constant current source circuit is provided which uses main and replica constant current source circuitry (with buffering therebetween) to counteract the problems created by parasitic capacitances. Thus, with these new circuits, a generally constant current can be generated, regardless of switching frequency.Type: GrantFiled: October 23, 2008Date of Patent: August 17, 2010Assignee: Texas Instruments IncorporatedInventors: Ankit Seedher, Preetam Charan Anand Tadeparthy, Jomy G Joy
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Patent number: 7773013Abstract: A multiple-input follower amplifier is coupled through a configuration of switching devices to an upper reference voltage at a number of its inputs and to a lower reference voltage at the remaining number of its inputs to form a voltage interpolator. The output of the voltage interpolator is a voltage between the upper and lower reference voltages proportional to the number of inputs coupled to each reference voltage. The voltage interpolator may be constructed so that the interpolated voltage may be selected through a reduced number of signal lines, such as by a row/column selection scheme. A voltage reference circuit providing the upper and lower reference voltages may also implement a row/column selection mechanism, thereby allowing a decoding scheme common to both a voltage reference circuit and a voltage interpolator in a digital-to-analog converter.Type: GrantFiled: August 12, 2008Date of Patent: August 10, 2010Assignee: Cadence Design Systems, Inc.Inventors: Stephen Williams, Eric Naviasky, William Evans
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Patent number: 7760117Abstract: A flip-flop includes a sense amplifier stage and a latch stage. The sense amplifier includes a first P type transistor and generates a first sensed signal and a second sensed signal in a first node and a second node, respectively. When the first P type transistor is turned on, the first node is connected to the second node. The latch stage generates a first output signal and a second output signal according to the first and the second sensed signals.Type: GrantFiled: January 16, 2009Date of Patent: July 20, 2010Assignee: Mediatek Inc.Inventor: Yu-Kai Chou
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Patent number: 7750833Abstract: A D/A conversion circuit in accordance with the present invention, which is provided with a switch swD, allows a writing operation of a voltage (a true gradation voltage) to be performed at a higher speed by first applying a first voltage (a voltage close to the true gradation voltage), which is supplied without passing through a resistor element, to an output line and then applying a second voltage (the true gradation voltage), which is supplied via the resistor element, to the output line. Thus, the present invention can provide a D/A conversion circuit capable of writing display data to liquid crystal cells with higher precision at higher speed, and a semiconductor device utilizing such a D/A conversion circuit.Type: GrantFiled: August 8, 2008Date of Patent: July 6, 2010Assignee: Semiconductor Energy Laboratory Co., Ltd.Inventor: Yukio Tanaka
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Patent number: 7746259Abstract: A digital-to-analog converter, comprising: a first field-effect transistor; a second field-effect transistor; and adjusting means for adjusting a bulk voltage applied to at least one of the first and second field-effect transistors so as to tend to equalise respective switching delays of the transistors.Type: GrantFiled: July 24, 2008Date of Patent: June 29, 2010Assignee: Fujitsu Semiconductor LimitedInventors: Ian Juso Dedic, Darren Walker
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Patent number: 7719454Abstract: A method and a system are disclosed for transmitting an N-bit digital signal at a source. The N-bit digital signal representing a binary value is used to modulate an electrical current by using N discrete voltages representing each bit. The N discrete voltages are coupled to N corresponding switches to control the switches. The switches conduct a corresponding electrical current if the value of the corresponding discrete voltage is the binary value of 1. The currents from each of the closed switches are summed to form a current-encoded data signal in a single physical conductor representing the original N-bit digital signal. The current-encoded data signal is transmitted through the single physical conductor to a current decoder for decoding the current-encoded data signal and extracting the original N-bit digital signal at a destination.Type: GrantFiled: March 6, 2008Date of Patent: May 18, 2010Assignee: Embedded Engineering Services, IncInventor: Chris Minerva
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Patent number: 7714756Abstract: The present invention discloses a digital-to-analog converter (DAC), including a bias voltage generating unit, a digital-to-analog converting stage, and an operating amplifier. The bias voltage generating unit is utilized for generating a first bias voltage. The digital-to-analog converting stage is utilized for converting a digital signal into a voltage signal, the digital-to-analog converting stage includes a current source for providing a current, and a switching unit is coupled to the current source for controlling the current to pass the switching unit according to the digital signal, and a load. The current flows through the load to generate the voltage signal. The operating amplifier is coupled to the bias voltage generating unit and the digital-to-analog converting stage for controlling the current source according to the first bias voltage.Type: GrantFiled: November 1, 2007Date of Patent: May 11, 2010Assignee: Realtek Semiconductor Corp.Inventors: Chen-Chih Huang, Ming-Han Lee, Chien-Ming Wu
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Patent number: 7714755Abstract: A dynamic bias control circuit includes a current source, a first switch, a differential amplifier, and a third switch. The current source outputs a first current. The first switch is coupled to an output end of the current source for generating the first current. The differential amplifier includes a first input end for receiving a reference voltage and a second input end coupled to the first switch. The third switch is coupled to an output end of the differential amplifier and to the first end of the first switch for adjusting a voltage at the first end of the first switch according to a result outputted from the differential amplifier. A control end of the first switch is coupled to a second switch. The second switch is used for inputting a second current into the second switch, wherein the second current to the first current is a predetermined ratio.Type: GrantFiled: August 9, 2007Date of Patent: May 11, 2010Assignee: Realtek Semiconductor Corp.Inventor: Ming-Han Lee
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Patent number: 7701370Abstract: A current output circuit with bias control and a method thereof are provided. The current output circuit includes a current mirror circuit comprising a first transistor and a second transistor having respectively two drains, and a control circuit coupled to the current mirror circuit. The control circuit receives drain voltages of the first transistor and the second transistor, and adjusts a respective gate bias of the first transistor and the second transistor according to a respective drain voltage thereof.Type: GrantFiled: May 20, 2008Date of Patent: April 20, 2010Assignee: Realtek Semiconductor Corp.Inventor: Ming-Han Lee
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Patent number: 7696911Abstract: Disclosed is a digital-to-analog conversion circuit in which first and second serial DACs and an amplifier circuit for driving a data line are provided. In a first data period, the first serial DAC converts a first digital signal received in the first data period to a first signal, the second serial DAC holds a signal obtained by converting a digital signal received in a data period one period before the first data period, and the amplifier circuit amplifies and outputs the signal held in the second serial DAC, to the data line. In a second data period following after the first data period, the second serial DAC converts the second digital signal received in a second data period, the first serial DAC holds the first signal converted in the first data period, and an amplifier circuit amplifies and outputs the first signal held in the first serial DAC, to the data line.Type: GrantFiled: June 6, 2008Date of Patent: April 13, 2010Assignee: NEC Electronics CorporationInventor: Hiroshi Tsuchi
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Patent number: 7683813Abstract: A current cell matrix type of digital-to-analog (D/A) converter to prevent deterioration of a.c. characteristics on a current path for digital-to-analog conversion includes a array of current source cells arranged in a matrix configuration. Each current source cell includes a current source transistor to generate the cell current. During the regular operation, the cell current is flowed on output lines via a first transistor connected in cascode to the current source transistor. During the calibration operation, the cell current is flowed into a current comparator via a second transistor connected in cascode to the current source transistor. This prevents parasitic capacitance from being additively caused in switches for the first transistor and in another switch for the second transistor to prevent deterioration of a.c. characteristics on the current path.Type: GrantFiled: June 19, 2008Date of Patent: March 23, 2010Assignee: Oki Semiconductor Co., Ltd.Inventor: Danya Sugai
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Patent number: 7679538Abstract: A current-steering type digital-to-analog converter (DAC) is disclosed. The DAC includes a first sub-DAC, a second sub-DAC and a controlling device. Both the first sub-DAC and the second sub-DAC are configured to receive input signals. The controlling device selectively and periodically sends output signals of either the first sub-DAC or the second sub-DAC to a resistive load while sending output signals of the remaining one of the two sub-DACs to a dummy resistive load. An output of the DAC is provided at the resistive load.Type: GrantFiled: August 10, 2006Date of Patent: March 16, 2010Inventor: Robin M. Tsang
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Patent number: 7675442Abstract: This disclosure relates to a compensating for nonlinearity resulting from a capacitance feedback in current cells of a single ended digital to analog circuit.Type: GrantFiled: January 23, 2009Date of Patent: March 9, 2010Assignee: Infineon Technologies AGInventor: Franz Kuttner
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Patent number: 7659844Abstract: An analog-to-digital converter (ADC) for converting an optical signal into an electrical signal is disclosed. The ADC includes a detection module, a first P-type metal oxide semiconductor (PMOS) transistor, a first N-type metal oxide semiconductor (NMOS) transistor, a first switch unit, and an output module. The first PMOS transistor and the first NMOS transistor form an inverter. The first switch unit is disposed between the input terminal and the output terminal of the inverter and is turned on/off according to a first control signal. The output module is coupled to the output terminal of the inverter for counting the time that an input voltage is greater than a reference voltage and generating a digital signal.Type: GrantFiled: December 21, 2007Date of Patent: February 9, 2010Assignee: Au Optronics CorporationInventors: Hung-Wei Tseng, Ling-Chang Hu, Shi-Hsiang Lu, Wein-Town Sun
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Patent number: 7652601Abstract: Reference network embodiments are provided for use in pipelined signal converter systems. The network embodiments are fast and power efficient and they generate low-impedance reference signals through the use of a complimentary common-drain output stage, at least one diode-coupled transistor inserted between transistors of the output stage, and a controller. The controller is configured to provide a backgate voltage to the diode-coupled transistor to thereby establish a substantially-constant output current. The controller is further configured to provide gate voltages to the output stage to establish top and bottom reference voltages about the diode-coupled transistor that are spaced from a common-mode voltage. This reference structure maintains a constant output current as the span between the top and bottom reference voltages is selectively altered. In different embodiments, the diode-coupled transistor is replaced with a bipolar junction transistor.Type: GrantFiled: May 2, 2008Date of Patent: January 26, 2010Assignee: Analog Devices, Inc.Inventors: Gregory W. Patterson, Ahmed Mohamed Abdelatty Ali
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Publication number: 20100007537Abstract: A high-voltage metal-oxide-semiconductor (HV MOS) transistor is provided to form the decoder in a source driver of a display apparatus for substantially saving the layout area. The HV MOS transistor includes two doped regions with a first conductivity type disposed in a semiconductor substrate, and a gate region having a second conductivity type opposite to the first conductivity type on the semiconductor substrate and between the doped regions. Accordingly, the layout area could be substantially reduced.Type: ApplicationFiled: August 31, 2009Publication date: January 14, 2010Inventors: Lin-Kai Bu, Ying-Lieh Chen
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Publication number: 20090303092Abstract: An analog-to-digital (A/D) conversion device is provided and includes a first A/D conversion stage. The A/D conversion stage includes a first pre-amp unit, first and second latch units, and a first conversion unit. The first pre-amp unit amplifies the analog input data and outputs a first amplified data. The first and second latch units are enabled by first and second latch clock signals to latch the first and second amplified data and generate first and second latched data, respectively. The first pre-amp unit is reset between a time point when the first latch unit is enabled and a time point when the second latch unit is enabled. The first conversion unit receives the analog input data, and the first and second latched data and accordingly generates a first analog output data.Type: ApplicationFiled: February 17, 2009Publication date: December 10, 2009Applicant: MEDIATEK INC.Inventors: Wi-Hsuan Tu, Tzung-Hung Kang
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Patent number: 7629910Abstract: Methods and apparatus to control current steering digital to analog converters are described herein. In one example, a digital to analog converter includes a first unit cell including a positive output and a negative output, wherein the positive output of the first unit cell and the negative output of the first unit cell comprise substantially equal magnitudes and wherein the positive and negative outputs of the first unit cell are substantially one hundred eighty degrees out of phase; and a second unit cell including a positive output and a negative output, wherein the positive output of the second unit cell is substantially zero when the negative output of the second unit cell is non-zero.Type: GrantFiled: September 29, 2007Date of Patent: December 8, 2009Assignee: Texas Instruments IncorporatedInventors: Sriram Ramadoss, Sumeet Mathur
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Patent number: 7629909Abstract: In a circuit to convert a voltage range of a control signal, a first switch selectively couples, based on the control signal, an output node to a first reference voltage when the output node is to be in a first state. A second switch selectively establishes, based on the control signal, a second reference voltage when the output node is to be in a second state, the second state being a logical complement of the first state. A feedback control loop is coupled to the output node to maintain the second reference voltage in response to voltage fluctuation at the output node. The feedback control loop includes a current mirror and a transistor coupled to the current mirror. The transistor is controlled by feedback from the output node to modify a biasing current established by the current mirror to thereby counteract the voltage fluctuation.Type: GrantFiled: August 9, 2007Date of Patent: December 8, 2009Assignee: Marvell International Ltd.Inventors: Francesco Rezzi, Nicola Ghittori, Giovanni Antonio Cesura, Shafiq M. Jamal
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Patent number: 7619552Abstract: A system and method is provided for code independent switching in a digital-to-analog converter (DAC). A synchronous digital circuit is triggered by a synchronizing clocking signal and develops a digital data signal. A circuit arrangement provides the synchronizing clock a constant load at every clocking cycle, thereby assuring a data independent load. By providing a data independent load to the synchronizing clock at every clocking cycle, third harmonic distortion is advantageously reduced.Type: GrantFiled: April 24, 2008Date of Patent: November 17, 2009Assignee: Analog Devices, Inc.Inventor: William George John Schofield
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Patent number: 7609186Abstract: In a circuit to convert a first logic signal having a first range to a second logic signal having a second range, a first transistor selectively couples an output node to a first reference voltage when the output node is to be in a first state. A second transistor selectively discharges the output node toward a second reference voltage via a resistor when the output node is to transition from the first state to a second state, the second state being a logical complement of the first state. A source-follower circuit has a source follower output coupled to the output node and has a dynamic current source, the dynamic current source having a control input coupled to the resistor. A third transistor selectively couples the source follower output to the dynamic current source when the output node is to be in the second state.Type: GrantFiled: August 9, 2007Date of Patent: October 27, 2009Assignee: Marvell International Ltd.Inventors: Francesco Rezzi, Nicola Ghittori, Giovanni Antonio Cesura, Shafiq M. Jamal
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Patent number: 7609190Abstract: A current-steering digital-to-analog converter (DAC) is tested using a test component having a relaxation oscillator with an oscillation frequency based on the output current of the DAC. A series of test values is provided in sequence to the DAC for conversion to an output current with a magnitude that varies with the test values. The test component counts the number of oscillations (“the oscillation count”) of the relaxation oscillator over a fixed duration that is substantially equal for each test value. As the number of oscillations over the fixed duration depends on the oscillation frequency of the relaxation oscillator, which in turn is based on the magnitude of the output current, the oscillation count can be used as a relative measure of the magnitude of the output current for the corresponding test value. Accordingly, the oscillation counts for the test values can be used to determine operational characteristics of the DAC.Type: GrantFiled: April 22, 2008Date of Patent: October 27, 2009Assignee: Advanced Micro Devices, Inc.Inventors: Ravi Ramaswami, Michael A. Bourland, Feng Zhao
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Publication number: 20090256733Abstract: Provided is a current control circuit. A current control circuit may include a clock sensing unit configured to generate a control signal according to one or more frequencies based on a plurality of clock signals, and a current scaling unit configured to scale a bias current according to the control signal. The current control circuit according to example embodiments may dynamically control a bias current according to one or more frequencies based on a plurality of clock signals so that power consumption of an analog-to-digital converter (ADC) and the semiconductor device including the ADC, which require various operating frequencies, may be improved.Type: ApplicationFiled: March 24, 2009Publication date: October 15, 2009Inventors: Sang-kyu Kim, Dae-young Chung
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Patent number: 7595745Abstract: In a circuit to convert a first logic signal having a first range to a second logic signal having a second range, a switch selectively couples an output node to a first reference voltage when the output node is to be in a first state based on the control signal. A source-follower circuit having a current source establishes a second reference voltage. A logic circuit coupled to the switch and the source-follower circuit and having a logic gate selectively discharges, in accordance with the control signal, the output node to the second reference voltage when the output node is to transition from the first state to a second state.Type: GrantFiled: August 9, 2007Date of Patent: September 29, 2009Assignee: Marvell International Ltd.Inventors: Francesco Rezzi, Nicola Ghittori, Giovanni Antonio Cesura, Shafiq M. Jamal
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Patent number: 7583216Abstract: A digital to analog converter (DAC) includes at least one digital to analog conversion module and a gated termination. The at least one digital to analog conversion module is coupled to convert at least one bit of a digital signal into an analog signal. The gated termination is coupled to an analog output of the at least one digital to analog conversion module to provide a first termination when a termination selection signal is in a first state and to provide a second termination when the termination selection signal is in a second state.Type: GrantFiled: September 28, 2007Date of Patent: September 1, 2009Assignee: Sigmatel, Inc.Inventors: Matthew D. Felder, Marcus W. May, Michael R. May
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Publication number: 20090207059Abstract: An analog-to-digital converter (1). The analog to digital converter (1) comprises a first range-control unit (100) adapted to generate a first range-control value for controlling a size of an input range of the analog-to-digital converter (1). The analog to digital converter further comprises a second range-control unit (200) adapted to generate a second range-control value for controlling a midpoint of the input range. Further, the analog-to-digital converter (1) comprises a reference-level unit (300) operatively connected to the first range-control unit (100) and the second range-control unit (200). The reference-level unit (300) is arranged to generate a plurality of reference levels at least based on the first and the second range-control value. The analog-to-digital converter further comprises a comparison unit (400) operatively connected to the second range-control unit (200) and the reference-level unit (300).Type: ApplicationFiled: January 18, 2007Publication date: August 20, 2009Applicant: SICON SEMICONDUCTOR ABInventor: Jacob Wikner
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Patent number: 7573412Abstract: A digital to analog converter (DAC) is provided. The DAC includes a first loop unit to receive a plurality of sources and comprising a plurality of primary winding of transistors formed at a plurality of locations, and a second loop unit comprising secondary windings to correspond to the primary windings, to receive the plurality of sources through the first loop unit, and combine the plurality of sources and output the result. Accordingly, a DAC is capable of directly converting a digital signal into an RF analog signal.Type: GrantFiled: March 6, 2008Date of Patent: August 11, 2009Assignee: Samsung Electronics Co., Ltd.Inventors: Seung-woo Kim, Jae-sup Lee
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Patent number: 7545295Abstract: A digital-to-analog converter improves differential non-linearity by performing a calibration of at least one weighted cell in response to a calibration command. The digital-to-analog converter includes a group of weighted cells, a tunable cell having a tunable weight controlled by a tuning word, and a calibration cell to generate a combined output signal in response to a digital input word, the calibration command, and a calibration sequence. The digital-to-analog converter also includes a calibration circuit configured to sample and subsequently process the combined output signal to establish the tuning word in accordance with the calibration command and the calibration sequence.Type: GrantFiled: January 24, 2008Date of Patent: June 9, 2009Assignee: Realtek Semiconductor Corp.Inventor: Chia-Liang Lin
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Publication number: 20090128383Abstract: This disclosure relates to a compensating for nonlinearity resulting from a capacitance feedback in current cells of a single ended digital to analog circuit.Type: ApplicationFiled: January 23, 2009Publication date: May 21, 2009Inventor: Franz KUTTNER
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Patent number: 7528759Abstract: One embodiment of the present invention includes a pipelined analog-to-digital converter (ADC) comprising a plurality of pipeline stages. At least one of the plurality of pipeline stages comprises a feedback transistor-follower combination interconnected between a positive source voltage and a summation node and configured to set a voltage of the summation node approximately equal to a sample-and-hold voltage associated with a preceding one of the plurality of pipeline stages. The at least one of the plurality of pipeline stages also comprises a current mirror coupled to the feedback transistor-follower combination configured to provide a first current that is approximately equal to a second current that is associated with the feedback transistor-follower combination. The at least one of the plurality of pipeline stages further comprises an output resistor configured to set an output voltage of the respective at least one of the plurality of pipeline stages based on the first current.Type: GrantFiled: September 17, 2007Date of Patent: May 5, 2009Assignee: Texas Instruments IncorporatedInventors: John William Fattaruso, Marco Corsi
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Patent number: 7528754Abstract: A noise-shaped direct digital IF to RF DAC (DIF2RF) with embedded up-converter mixer is presented. The digital IF signal is noised shaped by a band-pass ?? modulator with a single bit IF output followed by a semi-digital current-mode IF filter to attenuate out-of-band quantization noise. A current steering DAC combines scaled values of local oscillator (LO) signals as current sources for performing current steering and upconversion in a single cell.Type: GrantFiled: February 8, 2007Date of Patent: May 5, 2009Assignee: Arizona Board of RegentsInventors: Bertan Bakkaloglu, Sayfe Kiaei, Shahin Taleie
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Patent number: 7515081Abstract: A digital-to-analog converter comprises a current supplier, a current divider dividing current supplied from the current supplier into certain amounts, an inverter outputting inverted signals of input signals and non-inverted signals, a switch controlling a flow of the current divided into the certain amounts by the current divider according to the inverted signals and the non-inverted signals, and a current output block adding up the current divided into the certain amounts according to the non-inverted signals to output an analog signal. The digital-to-analog converter can be implemented on a small chip area with desired resolution.Type: GrantFiled: May 29, 2007Date of Patent: April 7, 2009Assignee: Korea Advanced Institute of Science & TechnologyInventors: Gyu Hyeong Cho, Yong-Joon Jeon, Young-Suk Son, Sang Kyung Kim, Jin Yong Jeon, Gun Ho Lee
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Patent number: 7511649Abstract: In a circuit to convert a first logic signal having a first range to a second logic signal having a second range, a first metal oxide semiconductor (MOS) transistor selectively couples an output node to a first reference voltage when the output node is to be in a first state. A second MOS transistor has a source coupled to the output node and a gate coupled to a bias voltage. A current source circuit selectively biases the second MOS transistor to act as part of a source-follower circuit when the output node is to be in a second state. Additionally, a memory circuit has an input coupled to the output node, and an output. The memory circuit is configured to temporarily store a Boolean value of the output node when the output node transitions from the first state to the second state. Further, a discharging circuit is coupled to the output node and a second reference voltage.Type: GrantFiled: August 28, 2007Date of Patent: March 31, 2009Assignee: Marvell International Ltd.Inventors: Francesco Rezzi, Nicola Ghittori, Giovanni Antonio Cesura, Shafiq M. Jamal, Stefano Marchesi