Using Ladder Network Patents (Class 341/154)
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Patent number: 8031093Abstract: An n bit D/A decoder is formed using P-type and N-type transistor switches, instead of convention CMOS switches. Each P-type and N-type switch may be formed of fewer transistors than those used to form a CMOS switch, thereby reducing the overall transistor count. The decoder may be used to decode digital values to non-linear GAMMA corrected analog output voltages.Type: GrantFiled: August 31, 2007Date of Patent: October 4, 2011Assignee: ATI Technologies ULCInventors: Kongning Li, Charles Leung, Grigori Temkine, Milivoje Aleksic, Steven Turner, Greg Vansickle, Kevin O'Neil
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Patent number: 8018367Abstract: An integrated circuit has a single input pin for determining a value associated with a resistor divider. First circuitry determines a resistor ratio of the resistor divider through the single input pin. A first register stores a first group of bits representing the resistor ratio. The first group of bits represents the least significant bits of the value. Second circuitry determines an equivalent resistance of the resistor divider through the single input pin. A second register stores a second group of bits representing the equivalent resistance.Type: GrantFiled: December 7, 2009Date of Patent: September 13, 2011Assignee: Intersil Americas Inc.Inventors: Chun Cheung, Weihong Qiu, Robert H. Isham, Mir Mahin
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Patent number: 8013772Abstract: One embodiment of the invention includes a digital-to-analog converter (DAC) system. A resistive ladder comprises a plurality of resistors having an approximately equal resistance and is arranged in a respective plurality of resistive rungs between first and second ends of the resistive ladder. The first end of the resistive ladder can be coupled to an output and at least a portion of the plurality of resistors between the first end and the second end of the resistive ladder can have a physical size that is descending size-scaled in a direction from the first end of the resistive ladder to the second end of the resistive ladder. A switching circuit is configured to connect each of the plurality of resistive rungs to one of a first voltage and a second voltage based on a binary value of a digital input signal to generate a corresponding analog output voltage at the output.Type: GrantFiled: December 31, 2009Date of Patent: September 6, 2011Assignee: Texas Instruments IncorporatedInventor: Qunying Li
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Patent number: 8004439Abstract: A digital to analog converter with two outputs controlled by an input signal with n-bits is disclosed. A reference voltage circuit generates (2n+1) reference voltages numbered from 1 to (2n+1). A switch array coupled to the reference voltage circuit, a first output terminal, and a second output terminal, includes a plurality of switches switching according to the input signal. The first output terminal outputs only one of odd reference voltages according to the input signal, and the second output terminal outputs one of even reference voltages according to the input signal, and the number of the switches is less than (n×2n+2n).Type: GrantFiled: November 30, 2009Date of Patent: August 23, 2011Assignee: Himax Technologies LimitedInventor: Ching-Chung Lee
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Patent number: 7999713Abstract: The invention relates to fast, high resolution, analog digital converters, and more particularly those which possess at least one conversion stage of “flash” type. The converter according to the invention uses N differential amplifiers with four inputs. The amplifier of rank j receives the input voltage to be converted Vep?Ven on two first inputs, and a reference potential difference on two other inputs. The reference potential difference is obtained between two taps of networks of resistors that are identical operating in parallel and supplied between a high voltage source and a low current source; the taps for an amplifier are respectively a tap Pj of rank j of a first network and a tap P?N?j+1 of rank N?j+1 of a second network. This reduces the first and second order non-linearity effects due to the fact that the differential amplifiers consume an input current tapped off from the networks of resistors.Type: GrantFiled: March 13, 2008Date of Patent: August 16, 2011Assignee: E2V SemiconductorsInventors: Jean-Alain Nicolas, Richard Morisson
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Patent number: 7982581Abstract: Digital potentiometer architecture is disclosed, composing of an integrated circuit containing multiple string arrays, each having a plurality of switching devices and an array of resistors. The insertion of an additional string array between the input terminals and the wiper, allows for the disconnection of a common string array and for the independent calibration of the resistance between each input terminal and the wiper.Type: GrantFiled: February 6, 2009Date of Patent: July 19, 2011Assignee: Analog Devices, Inc.Inventors: Kaushal Kumar Jha, Mrinmay Talegaonkar, Kirubakaran Ramalingam, Bhargav Vyas
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Patent number: 7973690Abstract: A gamma voltage generation circuit is provided. An offset voltage generator generates a first offset voltage by dividing a voltage difference between a first input voltage and a second input voltage based on a first code. A first voltage shifting circuit of a voltage level shifter shifts down a first reference voltage by the first offset voltage to output a first level-shifted voltage. A second voltage shifting circuit of the voltage level shifter shifts down a second reference voltage by the first offset voltage to output a second level-shifted voltage. Each of resistors of a resistor string outputs one of the gamma voltages. A first end and a second end of the resistor string are respectively coupled to a first output terminal and a second output terminal of the voltage level shifter.Type: GrantFiled: January 19, 2010Date of Patent: July 5, 2011Assignee: Himax Technologies LimitedInventor: Meng-Tse Weng
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Publication number: 20110156942Abstract: One embodiment of the invention includes a digital-to-analog converter (DAC) system. A resistive ladder comprises a plurality of resistors having an approximately equal resistance and is arranged in a respective plurality of resistive rungs between first and second ends of the resistive ladder. The first end of the resistive ladder can be coupled to an output and at least a portion of the plurality of resistors between the first end and the second end of the resistive ladder can have a physical size that is descending size-scaled in a direction from the first end of the resistive ladder to the second end of the resistive ladder. A switching circuit is configured to connect each of the plurality of resistive rungs to one of a first voltage and a second voltage based on a binary value of a digital input signal to generate a corresponding analog output voltage at the output.Type: ApplicationFiled: December 31, 2009Publication date: June 30, 2011Inventor: QUNYING LI
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Patent number: 7956786Abstract: An N-bit DAC comprises a main DAC circuit having main nodes on which analogue voltages are produced of progressively increasing values in steps of the value of one MSB value, and a sub-DAC circuit having secondary nodes on which analogue voltages are produced of progressively increasing values in steps of the value of one LSB. A main switch network couples the secondary nodes to a selected pair of main nodes as the MSB value of the digital input signal varies. A secondary switch network selectively couples one of secondary nodes to an output terminal for providing an analogue voltage output signal. The main nodes are coupled between main terminals, and a voltage reference is applied across input terminals. A first offset circuit and a first compensating circuit are selectively coupleable between the main DAC circuit and the input terminals for offsetting the main node analogue voltages downwardly.Type: GrantFiled: October 30, 2009Date of Patent: June 7, 2011Assignee: Analog Devices, Inc.Inventor: Gavin Cosgrave
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Publication number: 20110114827Abstract: A resistor-ladder voltage generator circuit is provided, which controls so that k switches among consecutive (k+1) switches out of a plurality of switches connected to the resistor ladder circuit are simultaneously set to an ON state, and which temporally switches the value of k. This allows voltage waveforms having different slopes to be arbitrarily obtained, ranging from a voltage waveform having a small slope to a voltage waveform having a large slope, thereby improving the resolution of a generated voltage waveform without increasing the numbers of resistors and switches, while A/D conversion time is not increased even if the number of bits is increased. In addition, by using this voltage generator circuit as a ramp generator circuit, and by dynamically switching the slope of the ramp wave, acceleration of an image sensor is achieved.Type: ApplicationFiled: January 24, 2011Publication date: May 19, 2011Applicant: PANASONIC CORPORATIONInventors: Yuusuke YAMAOKA, Kazuko Nishimura
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Patent number: 7945937Abstract: A programmable display device selects and displays one screen data item from one of screen data groups each constituted of a plurality of screen data items indicative of control conditions. Further, the programmable display device includes a selection information forming section and a screen data group setting section. The selection information forming section is included in a project setting processing section, and based on screen data group information concerning the screen data groups, forms selection information by which one of the screen data groups is selected. The screen data group setting section is included in the project setting processing section, and sets, as a screen data group to be used, the one of the screen data groups which is selected based on the selection information.Type: GrantFiled: November 1, 2005Date of Patent: May 17, 2011Assignee: Digital Electronics CorporationInventor: Masaki Ogawa
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Publication number: 20110102227Abstract: A resistor string digital to analog converter formed of polysilicon resistor segments to each of which is applied an electric field. The approach improves the overall accuracy.Type: ApplicationFiled: April 22, 2010Publication date: May 5, 2011Applicant: INTERSIL AMERICAS, INC.Inventor: Ali Motamed
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Patent number: 7936295Abstract: A selection section (105) selects a step voltage, among a plurality of step voltages (SV1, SV2, SV3, . . . ) each having a voltage value changing stepwise, corresponding to the digital value of digital data (D-DATA). For each of the plurality of step voltages (SV1, SV2, SV3, . . . ), different digital values are allocated to different steps of the step voltage. An amplifier section (106) amplifies the step voltage selected by the selection section (105). An output section (107) outputs the step voltage amplified by the amplifier section (106) as an output voltage (Vout) for a time period corresponding to the digital value of the digital data (D-DATA).Type: GrantFiled: June 19, 2007Date of Patent: May 3, 2011Assignee: Panasonic CorporationInventors: Yusuke Tokunaga, Shiro Sakiyama, Shiro Dosho, Yasuyuki Doi, Kurumi Nakayama
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Patent number: 7903012Abstract: A variable resistor is connected to each terminal of (2^n)?1 resistors R connected in series. The variable resistors have resistances RH and RL determined according to a digital signal containing m lower bits LoB<m?1:0>.Type: GrantFiled: June 9, 2009Date of Patent: March 8, 2011Assignee: Sharp Kabushiki KaishaInventors: Takahiro Inoue, Hideki Shioe
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Patent number: 7884747Abstract: A digital to analog converter (DAC) includes a pair of operational amplifiers each having a first input coupled to a respective high or low reference voltage. The DAC includes a plurality of switch-controlled cells, each of which includes a resistor and two force/sense switch pairs. Within each cell, all four switches are coupled to the resistor. A first force switch is coupled to an output of a first op amp and an associated sense switch is coupled to an inverting input of the first op amp. A second force switch is coupled to an output of a second op amp and an associated sense switch is coupled to an inverting input of the second op amp. Thus, the force switches provide selectively conductive paths to permit either op amp to drive a given cell.Type: GrantFiled: June 12, 2009Date of Patent: February 8, 2011Assignee: Analog Devices, Inc.Inventor: Roderick McLachlan
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Patent number: 7884783Abstract: A data driver including a first digital-to-analog converter configured to select first and second reference voltages depending on upper bits of data and supply the first and the second reference voltages to a first line and a second line, respectively, a second digital-to-analog converter having the first line and the second line to receive the first and the second reference voltages, respectively, a first group of voltage dividing resistors between the first line and the second line and configured to generate a plurality of gray scale voltages, a voltage dividing resistor unit between the first line and the second line, and at least one switch positioned between the voltage dividing resistor unit and one of the first line and the second line, and including a decoder unit configured to control on and off state of the at least one switch depending on lower bits of data.Type: GrantFiled: December 21, 2006Date of Patent: February 8, 2011Assignee: Samsung Mobile Display Co., Ltd.Inventor: Sang Moo Choi
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Patent number: 7880531Abstract: Apparatuses, systems, and methods are disclosed for generating, regulating, and modifying various voltage levels on a semiconductor device using a current mirroring digital-to-analog voltage regulator. The voltage regulator operates by mirroring a reference current onto a selectable current level and controlling the selectable current level with a digital input to a plurality of switched CMOS devices connected in parallel. The switched CMOS devices generate the selectable current level responsive to the digital input and proportional to the reference current. The selectable current level is combined with an output of a voltage divider to generate a monitor signal. The monitor signal is compared to a reference voltage and the results of the comparison controls a charge pump to generate a pumped voltage. The pumped voltage is fed back to the voltage divider, which includes a feedback resistor and a reference resistor connected in series between the pumped voltage and ground.Type: GrantFiled: January 23, 2008Date of Patent: February 1, 2011Assignee: Micron Technology, Inc.Inventor: Jae Kwan Park
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Patent number: 7868809Abstract: A resistor-based digital to analog converter (DAC) having mux fastpaths, which selectively connect a subset (or an entirety) of voltage divider nodes in a DAC to either a higher level of multiplexor hierarchy, or a DAC output node, effectively bypassing one or more levels of multiplexor devices. In addition, the fastpaths may selectively connect lower levels of multiplexor hierarchy to higher levels of multiplexor hierarchy and/or a DAC output node.Type: GrantFiled: February 20, 2009Date of Patent: January 11, 2011Assignee: International Business Machines CorporationInventors: Joseph A. Iadanza, Benjamin T Voegeli
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Patent number: 7852253Abstract: Apparatus and methods are provided for converting an analog input signal to a digital output value. A quantization circuit comprises an input node and a comparator array, wherein each comparator of the comparator array is coupled to the input node. A voltage divider arrangement is coupled to the comparator array and configured to establish a respective threshold voltage for each comparator of the comparator array. The comparator array generates a digital code based on the input signal and the respective threshold voltage for each comparator. A control node is coupled to the voltage divider arrangement, wherein the control node and the voltage divider arrangement are cooperatively configured to adjust the threshold voltage for at least one comparator of the comparator array in response to a control signal at the control node.Type: GrantFiled: February 18, 2009Date of Patent: December 14, 2010Assignee: Freescale Semiconductor, Inc.Inventors: David E. Bien, Brandt Braswell, Merit Y. Hong
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Patent number: 7847718Abstract: A digital-to-analog converter including includes a decoder which receives m (where m>=4 holds) reference voltages having voltage values that differ from one another, and selects and outputs n (where n>=3 holds) identical or different voltages from among the m reference voltages based upon a digital signal; and an amplifying circuit that outputs a voltage, which is obtained by taking the weighted mean of the selected n voltages at a ratio of 2n?1:2n?2: . . . :20, from an output terminal.Type: GrantFiled: December 5, 2006Date of Patent: December 7, 2010Assignee: NEC CorporationInventors: Junichiro Ishii, Hiroshi Tsuchi
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Patent number: 7830291Abstract: 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: GrantFiled: January 18, 2007Date of Patent: November 9, 2010Assignee: Zoran CorporationInventor: Jacob Wikner
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Patent number: 7825704Abstract: A threshold personalization circuit for a reset or supervisor chip includes personalization fuses, which shift a resistor divider to provide a variety of selectable voltage thresholds. The personalization fuses may provide hundreds of millivolts of adjustment. The threshold personalization circuit further includes trim fuses to fine tune the threshold to within a few millivolts of the target threshold voltage. The threshold personalization circuit includes a test mode to cycle through to a particular personalization trim, such that at prelaser testing the personalized value is found (the fuse blow for personalization is emulated) and then the trim fuse amount can be based on the actual final personalized voltage. This results in very accurate threshold voltages for all personalized values.Type: GrantFiled: April 9, 2007Date of Patent: November 2, 2010Assignee: STMicroelectronics, Inc.Inventor: David McClure
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Patent number: 7812754Abstract: A digital to analog converter (DAC) has a plurality of transistor-resistor units connected in a string. Each of the transistor-resistor units of the DAC has a pair of transistors that are turned on/off by a pair of complementary control signals. Since the two transistors of each transistor-resistor unit are positioned symmetrically, an equivalent resistance would be determined precisely according to received digital codes, such that an output voltage of the DAC could be adjusted precisely based on the equivalent resistance.Type: GrantFiled: December 18, 2008Date of Patent: October 12, 2010Assignee: MACRONIX International Co, Ltd.Inventors: Jer-Hau Hsu, Tien-Yen Wang, Hsin-Yi Ho
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Patent number: 7796075Abstract: A method to tune electronic devices in general using R/2R ladder networks to obtain fixed or variable accurate properties that may include, but are not limited to resistance, current, voltage, and/or timing. As a particular application, a method for internally calibrating a digital-to-analog converter is shown in detail. The DAC uses an extended R/2R ladder to improve the converting accuracy by mapping the extended bits into the original bits. A mapping matrix is maintained, which can be rewritten by an internal calibration process.Type: GrantFiled: April 30, 2007Date of Patent: September 14, 2010Inventors: Benito R. Fernandez, Zhaohong Wu
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Patent number: 7773019Abstract: A PRA-DAC is disclosed. The PRA-DAC is operable to increase its conversion speed.Type: GrantFiled: August 26, 2008Date of Patent: August 10, 2010Assignee: ATMEL CorporationInventors: Thierry Soude, Joao Pedro Antunes Carreira, Didier Davino
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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: 7767953Abstract: A ladder resistor circuit generates a plurality of different reference voltages. A plurality of switching circuits correspond to a plurality of taps of the ladder resistor circuit. Each of the plurality of switching circuits is connected at one end to a corresponding one of the taps and connected at the other end to an output node, and has a variable on-resistance value. A control circuit selects continuous n (where n is any integer equal to or greater than 2) of the plurality of switching circuits, turns the n switching circuits on, and sets the respective on-resistance values of the n switching circuits.Type: GrantFiled: May 2, 2008Date of Patent: August 3, 2010Assignee: Panasonic CorporationInventor: Yuusuke Yamaoka
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Patent number: 7764212Abstract: A driving apparatus for a display is provided. The driving apparatus for a display comprises a reference voltage generator, a digital-to-analog converter, and an output unit. The reference voltage generator generates a plurality of reference voltages, and receives a difference value between two adjacent reference voltages and generates a plurality of sub reference voltages. The digital-to-analog converter selects one of the reference voltages and outputs the selected reference voltage as a first analog signal. The digital-to-analog converter selects one of the sub reference voltages and outputs the selected reference voltage as a second analog signal. The output unit processes, by addition or subtraction, the first and second analog signals for output.Type: GrantFiled: October 31, 2007Date of Patent: July 27, 2010Assignee: Korea Advanced Institute of Science and TechnologyInventors: Hyung-Min Lee, Gyu Hyeong Cho, Young-Suk Son, Yong-Joon Jeon, Jin Yong Jeon, Seung-Chul Jung
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Publication number: 20100182175Abstract: In one embodiment, a first resistor ladder includes a first voltage across the first resistor ladder. A second resistor ladder includes a second voltage across the second resistor ladder. A third resistor ladder includes a third voltage across the third resistor ladder. The calibrator receives the first voltage and third voltage and adjusts a current through the third resistor ladder to adjust the third voltage based on the received first voltage and third voltage. A buffer is configured to provide buffering for the third resistor ladder from the second resistor ladder. The third voltage of the third resistor ladder is stable even though the second voltage of the second resistor ladder is changing.Type: ApplicationFiled: January 8, 2010Publication date: July 22, 2010Inventors: Kenneth Thet Zin Oo, Pierte Roo
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Patent number: 7737873Abstract: A flash analog-to-digital converter comprising a resistive reference ladder, a set of comparators for comparing the analog input signal with the reference voltages of the ladder to provide a digital code representing a coarse quantization of the input signal, a set of switches connected to the reference ladder and controlled by said digital code to provide an analog representation of the coarse quantization of the input signal, means to derive from said analog representation of the coarse quantization and from the input signal one or more residue signals and a fine analog-to-digital converter stage to generate a digital code representing a fine quantization of the one or more residue signals.Type: GrantFiled: March 20, 2006Date of Patent: June 15, 2010Assignee: NXP B.V.Inventors: Ben Gelissen, Hendrik Van Der Ploeg
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Publication number: 20100141498Abstract: The digital-to-analog converter in accordance with the present invention comprises an R-2R transistor-only ladder converter and a digital controller. The controller connects to the R-2R transistor-only ladder converter and comprises at least one regulating transistor and at least one shifting transistor. The at least one regulating transistor has an aspect ratio of kR(W/L). The at least one shifting transistor has an aspect ratio of kS(W/L). Setting the aspect ratios kR(W/L) and kS(W/L) of the shifting and regulating transistors adjusts a linear output current waveform to a non-linear waveform. The method to output a non-linear current comprises acts of determining an optimum non-linear output current, dividing a linear output current into multiple sections, determining slopes of the waveform of the output current, adding a controller corresponding to an R-2R transistor-only ladder converter, setting aspect ratios kR(W/L) of regulating transistors and setting an aspect ratios kS(W/L) of shifting transistors.Type: ApplicationFiled: October 1, 2009Publication date: June 10, 2010Applicant: National Taiwan UniversityInventors: Tai-Cheng LEE, Cheng-Hsiao Lin
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Patent number: 7733255Abstract: Embodiments of a digital-to-analog converter (DAC) with a logarithmic response and methods for converting digital signals to analog are generally described herein. Other embodiments may be described and claimed. In some embodiments, the DAC includes a wedge-shaped resistive array having a plurality of linearly-spaced contact nodes and a switching array to selectively couple one of the contact nodes with an analog output based on a control signal. Each of the contact nodes may provide a corresponding reference voltage that varies logarithmically with respect to the linearly-spaced contact nodes.Type: GrantFiled: February 27, 2007Date of Patent: June 8, 2010Assignee: Infineon Technologies AGInventor: Volker Christ
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Patent number: 7733257Abstract: A DAC includes a gamma voltage generator for generating a plurality of gamma voltages, and a decoder for receiving an M-bit digital value for selecting one of the gamma voltages, wherein the decoder comprises a first thermometer encoder, a first selector and a second selector. The first thermometer encoder is utilized to receive N bits of the digital value to generate a first thermometer code with 2N bits, wherein N is smaller than M, and M and N are positive integers. The first selector has a plurality of selecting groups, each selecting group having 2N switches controlled by the first thermometer code to output one gamma voltage, where the second selector receives the gamma voltages outputted by the selecting groups of the first selector and outputs one gamma voltage selected from the received gamma voltages based on the (M?N) bit of the digital value.Type: GrantFiled: December 9, 2008Date of Patent: June 8, 2010Assignee: Himax Technologies LimitedInventor: Ching-Chung Lee
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Patent number: 7729300Abstract: A method and apparatus for a Gigabit Ethernet transceiver that has a Class-B amplifier in a main transmitter for higher efficiency and power handling capabilities. The output current of the main transmitter is produced by a reference voltage applied across a resistor, where the reference voltage generator, resistor and amplifier are fabricated on the same substrate, such that the output current is constant across process voltage and temperature. The transceiver also has a replica transmitter whose signal is used to cancel the main transmitter signal at the input of the receiver section of the transceiver. The replica transmitter is fabricated on the same substrate as the main transmitter, such that its output signal reflects non-linearities in the main transmitter across process voltage and temperature.Type: GrantFiled: August 19, 2005Date of Patent: June 1, 2010Assignee: National Semiconductor CorporationInventors: Ramsin Michael Ziazadeh, Varadarajan Devnath
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Patent number: 7724172Abstract: A digital-to-analog converter, in response to a digital signal, selectively taps a resistor string to generate an analog output and selectively shunts around resistors in the string to voltage shift the analog output. If two supply voltage sets are present, two strings are provided. A mutually exclusively selection of outputs is made to select a source of the analog output. An integrated circuit temperature sensor uses the converter and includes a sensing circuit that determines exposure to one of a relatively low or high temperature. A measured voltage across the base-emitter of a bipolar transistor is selected in low temperature exposure and compared against a first reference for a too cold temperature condition. Alternatively, a measured delta voltage across the base-emitter is selected in high temperature exposure and compared against a second reference voltage for a too hot temperature condition. Through the comparisons, a temperature exposure detection is made.Type: GrantFiled: January 28, 2008Date of Patent: May 25, 2010Assignee: STMicroelectronics, Inc.Inventors: David C. McClure, Sooping Saw
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Patent number: 7714759Abstract: A resistor network digital-to-analog converter (DAC) subdivides each sampling clock cycle of the DAC into a number of phases. For at least one bit input of the DAC associated with a desired input resistor weight, the input bit value is sampled at each phase. Each of those sampled values is then applied to a respective resistor branch, the parallel set of resistor branches forming the parallel equivalent of the desired input resistor weight for that bit input. Such application may be, for example, via a slew-rate controlled driver, to smooth transient edges in the generated analog output signal. The resulting analog signal experiences reduced reconstruction errors at a higher frequency while consuming less power than a comparable oversampling DAC. Shifting reconstruction errors to higher frequencies relaxes downstream filtering requirements, which simplifies analog signal filtering and allows, for example, the use of current-mode low pass filters.Type: GrantFiled: October 20, 2008Date of Patent: May 11, 2010Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventor: Fenghao Mu
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Patent number: 7710302Abstract: A digital to analog converter (DAC) system comprising, a first segment, wherein a segment comprises, a first path including an array of resistors connected in series between a first reference voltage node and a second reference voltage node, wherein the array is connected to a first switch device disposed between nodes of the array and an output node, and a third path including a second resistor in series with a second switch device, wherein the third path is connected in parallel with the first path.Type: GrantFiled: December 21, 2007Date of Patent: May 4, 2010Assignee: International Business Machines CorporationInventors: Joseph A. Iadanza, Benjamin T. Voegeli
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Patent number: 7705762Abstract: An integrated circuit memory cell and voltage ladder design that adapts techniques typically applied to Static Random Access Memory (SRAM) circuits to implement a compact array of analog Voltage Random Access Memory (VRAM) locations. The memory cells in the VRAM each store a digital value that controls a corresponding switch. The switch couple a particular voltage from a set of voltages generated by the ladder, to be output when that location is enabled. Multiple analog output voltages are provided by simply providing additional rows of cells.Type: GrantFiled: December 10, 2008Date of Patent: April 27, 2010Assignee: Kenet IncorporatedInventors: Michael P. Anthony, Lawrence J. Kushner
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Publication number: 20100097253Abstract: A resistor network digital-to-analog converter (DAC) subdivides each sampling clock cycle of the DAC into a number of phases. For at least one bit input of the DAC associated with a desired input resistor weight, the input bit value is sampled at each phase. Each of those sampled values is then applied to a respective resistor branch, the parallel set of resistor branches forming the parallel equivalent of the desired input resistor weight for that bit input. Such application may be, for example, via a slew-rate controlled driver, to smooth transient edges in the generated analog output signal. The resulting analog signal experiences reduced reconstruction errors at a higher frequency while consuming less power than a comparable oversampling DAC. Shifting reconstruction errors to higher frequencies relaxes downstream filtering requirements, which simplifies analog signal filtering and allows, for example, the use of current-mode low pass filters.Type: ApplicationFiled: October 20, 2008Publication date: April 22, 2010Inventor: Fenghao Mu
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Publication number: 20100052966Abstract: Disclosed is a differential amplifier which includes first and second input terminals, an output terminal, first and second differential pairs, and first and second current sources for supplying currents to the first and second differential pairs. The first differential pair has first and second inputs of an input pair connected to the first input terminal and the output terminal, respectively. The second differential pair has first and second inputs of an input pair connected to the second input terminal the output terminal, respectively.Type: ApplicationFiled: November 11, 2009Publication date: March 4, 2010Inventor: Hiroshi Tsuchi
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Patent number: 7671775Abstract: A converter of 6-bit input includes a reference voltage generating circuit generating 17 reference voltages, a first switch circuit having 19 switch pairs each including MOS transistors for selecting two adjacent reference voltages in accordance with the four most significant bits, a second switch circuit including a series circuit of MOS transistors for dividing the selected two reference voltages into four to obtain three intermediate voltages, and a third switch circuit for selectively outputting the lower of the selected two reference voltages or one of the three intermediate voltages. In a second mode in which a gray level having a smaller ON-resistance of a MOS transistor than that in the first mode is selected, the number of MOS transistors used in the first and second switch circuits for voltage division is increased.Type: GrantFiled: September 23, 2008Date of Patent: March 2, 2010Assignee: Panasonic CorporationInventors: Yasuyuki Doi, Kurumi Nakayama, Makoto Hattori, Hideki Ikeda
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Publication number: 20100039304Abstract: A digital to analog converter (DAC) has a plurality of transistor-resistor units connected in a string. Each of the transistor-resistor units of the DAC has a pair of transistors that are turned on/off by a pair of complementary control signals. Since the two transistors of each transistor-resistor unit are positioned symmetrically, an equivalent resistance would be determined precisely according to received digital codes, such that an output voltage of the DAC could be adjusted precisely based on the equivalent resistance.Type: ApplicationFiled: December 18, 2008Publication date: February 18, 2010Applicant: MACRONIX International Co., Ltd.Inventors: Jer-Hau Hsu, Tien-Yen Wang, Hsin-Yi Ho
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Patent number: 7652606Abstract: A digital-analog converter including a first selection circuit of switch elements, which are coupled to each other and to a high potential power supply, and a second selection circuit of switch elements, which are coupled to each other and to a low potential power supply. First and second voltage dividing circuit each include series-connected resistor elements, each coupled between adjacent switch elements of the corresponding selection circuit. A control circuit provides a control signal to the selection circuits to activate one of the switch elements in each selection circuit and couple the activated switch element to the corresponding potential power supply. The first and second voltage dividing circuits divide voltages of the high and low potential power supplies with the resistor elements between the activated switch elements.Type: GrantFiled: March 14, 2008Date of Patent: January 26, 2010Assignee: Fujitsu Microelectronics LimitedInventors: Shogo Itoh, Hisao Suzuki
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Patent number: 7646322Abstract: A folded R-2R ladder current-steering digital-to-analog converter is disclosed. In the folded R-2R ladder current-steering digital-to-analog converter, each node in the R-2R ladder is electrically coupled with a plurality of current sources with different weights. Therefore, the numbers of the resisters and current sources can be reduced, and efficient power saving and the high-speed operation can be achieved.Type: GrantFiled: September 4, 2008Date of Patent: January 12, 2010Assignee: Chung Yuan Christian UniversityInventors: Nan-Ku Lu, Chun-Chieh Chen, Kai-Yao Lin, Yi-Zhi Zeng
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Patent number: 7646321Abstract: Provided is a digital/analog converter including a voltage dividing unit that includes a plurality of voltage dividing elements and divides a reference voltage by voltage division; a first decoder that selects a plurality of voltages among the voltages divided by the voltage dividing unit; a first voltage output unit that is connected to nodes among adjacent voltage dividing elements of the voltage dividing unit and the first decoder, and outputs a plurality of voltages selected by the first decoder; a second decoder that selects any one of the plurality of voltages output from the first voltage output unit; and a second voltage output unit that is connected to the first voltage output unit and the second decoder and outputs the voltage selected by the second decoder.Type: GrantFiled: January 31, 2008Date of Patent: January 12, 2010Assignee: Samsung Electro-Mechanics Co., LtdInventors: Byung Hoon Kim, Won Tae Choi
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Patent number: 7642946Abstract: A system and method are provided allowing for successive approximation analog to digital conversion. A first differential voltage is sampled and held during a first cycle. The first differential voltage is converted to a differential current. A second differential voltage is generated based on the differential current flowing through parallel-coupled respective first and second variable resistances. First and second portions of the second differential voltage are compared to produce a comparison result therefrom. Successive approximation is used to generate a signal based on the comparison result, the signal being an output signal and being used to control resistances of respective ones of the first and second variable resistances during subsequent cycles.Type: GrantFiled: April 7, 2008Date of Patent: January 5, 2010Assignee: Broadcom CorporationInventors: Ark-Chew Wong, Marcel L. Lugthart, Andrew R. Chen
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Patent number: 7639166Abstract: A multi-bit D/A converter circuit that prevents a bit inversion and requires a reduced layout area is offered. A first switching circuit is provided in order to select a pair of analog voltages generated across one of resistors in a first resistor string. The selected pair of analog voltages is provided as reference voltages to a second resistor string. A second switching circuit is provided in order to select a pair of analog voltages generated across one of the resistors in the second resistor string. The selected pair of analog voltages is provided as reference voltages to a third resistor string. A third switching circuit is provided in order to select one of analog voltages generated in the third resistor string.Type: GrantFiled: June 12, 2008Date of Patent: December 29, 2009Assignees: Sanyo Electric Co., Ltd., Sanyo Semiconductor Co., Ltd.Inventor: Takashi Iijima
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Patent number: 7639168Abstract: A switch signal generator circuit that may form part of a digital to analog converter is provided. The switch signal generator circuit may include a first switch that controls a high reference gate voltage. The high reference gate voltage may provide the ON state voltage for a plurality of switches that control the coupling of a high reference voltage to the digital to analog converter. The switch signal generator circuit may include a second switch that controls a low reference gate voltage. The low reference gate voltage may provide the ON state voltage for a plurality of switches that control the coupling of a low reference voltage to the digital to analog converter. The switch signal generator circuit may also include a resistor. In one embodiment of the invention, a current conducted by the first switch and/or a current conducted by the second switch may each be proportional to a current conducted by the resistor. One of the switches in the switch generator circuit may be a P channel switch.Type: GrantFiled: February 6, 2007Date of Patent: December 29, 2009Assignee: Linear Technology CorporationInventor: James Lee Brubaker
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Patent number: 7616144Abstract: A voltage interpolation circuit includes a resistive ladder connected between ground and a voltage input and having a plurality of resistors with voltage taps between the resistors. An amplifier (optionally) has first and second capacitors connected together at their respective first terminals and to an input of the amplifier. A first plurality of switches connect respective taps to a second terminal of the first capacitor. A second plurality of switches connect the respective taps to a second terminal of the second capacitor. An output voltage is interpolated by controlling the first and second pluralities of switches.Type: GrantFiled: September 18, 2007Date of Patent: November 10, 2009Assignee: Broadcom CorporationInventors: Jan Mulder, Franciscus Maria Leonardus van der Goes, Jan Westra, Rudy van der Plassche
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Patent number: 7605735Abstract: A digital-to-analog converter (DAC) includes an R-2R ladder network, switches, and an operation amplifier (OP) with a feedback resistance, for providing an analog voltage in a positive polarity and a negative polarity. Each of the switches is switched between a connection to the OP and the reference voltage.Type: GrantFiled: December 5, 2007Date of Patent: October 20, 2009Assignee: Himax Technologies LimitedInventors: Ying-Lieh Chen, Chien-Ru Chen, Chuan-Che Lee