Coarse And Fine Conversions Patents (Class 341/145)
  • Publication number: 20110227770
    Abstract: A system having: a digital pre-distortion circuit fed by a digital signal for distorting the digital signal; a digital to analog converter (DAC) core section coupled to an output of the calibration circuit for converting the distorted digital signal into a corresponding analog signal, the DAC core section performing the conversion in accordance with a control signal fed to the DAC core section; a power amplifier (PA) section coupled to an output of the DAC core section for amplifying power in the analog signal; and a calibration circuit coupled to the output of the power amplifier for producing, in response to the power in the power amplified analog signal, the control signal for the DAC core section.
    Type: Application
    Filed: March 22, 2010
    Publication date: September 22, 2011
    Applicant: Raytheon Company
    Inventors: Valery S. Kaper, John P. Bettencourt
  • Patent number: 8022971
    Abstract: A data driver, including a first digital-to-analog converter configured to select two reference voltages of a plurality of reference voltages depending on upper bits of data, and a second digital-to-analog converter configured to divide the two reference voltages into a plurality of voltages and supply any one voltage of the two reference voltages and the divided voltages to an output terminal as a data signal depending on lower bits of the data, wherein the second digital-to-analog converter is configured to supply an intermediate gray scale voltage to the output terminal prior to supplying the data signal, the intermediate gray scale voltage having a voltage between the two reference voltages.
    Type: Grant
    Filed: November 29, 2006
    Date of Patent: September 20, 2011
    Assignee: Samsung Mobile Display Co., Ltd.
    Inventor: Sang Moo Choi
  • Patent number: 8022851
    Abstract: A current-steered DAC has first and second differential outputs for providing an analog output signal under control of a digital input signal. In operational use of the DAC, the output signal has a differential component, which is representative of the digital input signal, and also has a first common-mode component. The DAC has circuitry operative to add an extra common-mode component to both the first and second differential outputs so as to make a sum of the first common-mode component and the extra common-mode component substantially independent of a state change of the digital input signal.
    Type: Grant
    Filed: June 5, 2008
    Date of Patent: September 20, 2011
    Assignee: NXP B.V.
    Inventor: Briaire Joseph
  • Patent number: 8013769
    Abstract: In one embodiment, the DAC includes an analog gray voltage generation unit configured to generate a plurality of analog gray voltages, and a first decoder configured to select two different voltages of the plurality of the gray voltages as a first level voltage and a second level voltage, respectively, in response to an upper K-bits of N-bit input image data. Here, N may be an integer not less than two, and K may be an integer less than N. A second decoder may be configured to repeatedly distribute the first level voltage and the second level voltage to output a plurality of distributed voltages in response to a lower L-bits of the N-bit input image data. Here, L may be equal to N subtracted by K, and L may be less than K. An interpolated voltage generation unit may be configured to generate an interpolated voltage based on the plurality of distributed voltages.
    Type: Grant
    Filed: March 7, 2007
    Date of Patent: September 6, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventor: Hyung-Tae Kim
  • Patent number: 8013770
    Abstract: A digital-to-analog converter (DAC) for converting a digital signal to an analog signal includes a first thermometer decoder and a second thermometer decoder. The first thermometer decoder is configured to decode most-significant bits (MSBs) of the digital signal to generate a first thermometer code. The second thermometer decoder is configured to decode middle bits of the digital signal to generate a second thermometer code. The DAC further includes a plurality of macro cells with each controlled by one bit of the first thermometer code. The plurality of macro cells is configured to provide a first analog signal according to the first thermometer code. The DAC further includes a macro cell configured to provide a second analog signal according to the second thermometer code. The macro cell is further configured to provide a third analog signal according to least-significant bits (LSBs) of the digital signal.
    Type: Grant
    Filed: December 9, 2008
    Date of Patent: September 6, 2011
    Assignee: Taiwan Semiconductor Manufacturing Company, Ltd.
    Inventors: Robit Yang, Ying-Chi Hsu, You-Cheng Xiao, Wen-Shen Chou
  • Publication number: 20110205097
    Abstract: A DA conversion device includes the following elements. A higher-bit current source cell portion includes uniformly weighted higher-bit current source cells to generate an identical constant current. A lower-bit current source cell portion includes a lower-bit current source cells that are weighted to generate 1/two-to-the-power-of-certain-numbers constant currents. A constant current source selection controller includes a lower-bit controller having a scaler that uses clocks scaled down to 1/two-to-the-power-of-certain-numbers to select the lower-bit current source cells, and a higher-bit controller having shift registers and using a signal indicating a carry bit or a borrow bit used in the lower-bit controller to sequentially activate shift outputs of the shift registers, and uses the shift outputs to select the higher-bit current source cells. Constant current outputs of the selected current source cells are added and output so that an output current corresponding to the digital input signal is obtained.
    Type: Application
    Filed: April 29, 2011
    Publication date: August 25, 2011
    Applicant: SONY CORPORATION
    Inventors: Go ASAYAMA, Noriyuki FUKUSHIMA, Yoshikazu NITTA, Yoshinori MURAMATSU, Kiyotaka AMANO
  • Patent number: 8004439
    Abstract: 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 (nĂ—2n+2n).
    Type: Grant
    Filed: November 30, 2009
    Date of Patent: August 23, 2011
    Assignee: Himax Technologies Limited
    Inventor: Ching-Chung Lee
  • Patent number: 7990300
    Abstract: DAC includes a reference current setting unit (RCSU) that sets reference current, and current cell output unit (CCOU) including plurality of current sources, the current sources being configured to output currents corresponding to the reference current, the CCOU being configured to generate analog voltage signal according to an input digital signal, wherein the RCSU includes, reference current source (RCS) that generates the reference current, first and second resistance through which the reference current flows, selection control circuit that, when amplitude level of the analog voltage signal is to be changed, selects at least one of the first and second resistances and connect the selected resistance to the RCS, and reference current control circuit that controls current amount of reference current of the RCS according to voltage generated by resistance selected from among the first and second resistances.
    Type: Grant
    Filed: December 7, 2009
    Date of Patent: August 2, 2011
    Assignee: Renesas Electronics Corporation
    Inventor: Tomio Takiguchi
  • Patent number: 7986255
    Abstract: A controller receives an M-bit input and generates, in response, an S-bit upper range binary data feeding S-bit high range DAC and an R-bit lower range data feeding an R-bit low range DAC. The controller detects transition points in the M-bit input and in response, adds a transition data to the S-bit data equal to at least one least significant bit of the S-bit data and subtracts a value from the R-bit data equal to the transition data. The transition points and the transition data are detected and added at points avoiding such transitions at a full scale value of the R-bit data.
    Type: Grant
    Filed: November 24, 2009
    Date of Patent: July 26, 2011
    Assignee: NXP B.V.
    Inventors: Kevin Mahooti, He Bo, Meng Hao, Johnny Chuang-Li Lee, Rui Yang, Tian Jie Feng
  • Patent number: 7978110
    Abstract: A system for converting a digital signal to an analog signal is provided. The present invention provides a digital-to-analog converter (DAC) that can convert a large bit value digital signal to a corresponding analog signal. The digital-to-analog converter includes a bias regeneration circuit, and three sub-DACs. The bias regeneration circuit provides biasing to the three sub-DACs allowing the DAC to be implemented with smaller circuit area. In addition, the three sub-DACs may be digitally calibrated during the conversion process to increase the linearity of the DAC.
    Type: Grant
    Filed: February 18, 2010
    Date of Patent: July 12, 2011
    Assignee: Taiwan Semiconductor Manufacturing Company, Ltd.
    Inventors: Yu-Jen Lai, Mei-Chen Chuang, Wen-Shen Chou
  • Publication number: 20110156942
    Abstract: 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: Application
    Filed: December 31, 2009
    Publication date: June 30, 2011
    Inventor: QUNYING LI
  • Patent number: 7965212
    Abstract: Techniques are disclosed for improving the dynamic performance of digital-to-analog converters (DAC), by compensating for the unique delay characteristics of each bit in the DAC summing junction to equalize the delays. In one example case, a DAC device is provided that includes a plurality of current sources and a plurality of switches, each switch operatively coupled between a corresponding one of the current sources and a summing junction that is operatively coupled to an analog output. The device further includes a plurality of switch control lines configured to receive a digital input, each switch control line for controlling a corresponding one of the switches. The device further includes a plurality of compensation delay elements, each associated with a corresponding one of the switch control lines and providing a different delay value.
    Type: Grant
    Filed: February 12, 2010
    Date of Patent: June 21, 2011
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Steven E. Turner
  • Publication number: 20110140943
    Abstract: In order to reduce a current mismatch by laying-out the bias circuit of current cells adjacent to each other in a common current centroid manner or connecting the output lines of the current cells in a tournament manner, there is provided a digital-analog converter in which a plurality of current cells are two dimensionally and symmetrically disposed according to a previously determined order, the digital-analog converter including: a first current cell group including a portion of the plurality of current cells; and a second current cell group including the rest of the plurality of current cells, not included in the first current cell group, the outputs of each current cell of the first current cell group being connected to the outputs of each current cell of the second current cell group in a tournament manner, wherein each of the plurality of current cells includes: a switch circuit switching the output and block of a unit current according to an input signal; and a bias circuit mirroring current supplied
    Type: Application
    Filed: August 3, 2010
    Publication date: June 16, 2011
    Applicant: SAMSUNG ELECTRO-MECHANICS CO., LTD.
    Inventor: Sang Hoon Hwang
  • Publication number: 20110140944
    Abstract: A resistor string digital-to-analog converter includes a high-order resistor string, first high-order switches, a high-order decoder, a low-order decoder, and a conversion unit. The high-order resistor string includes a plurality of voltage acquisition points that are coupled through unit resistors. The high-order decoder generates a first high-order control signal in accordance with a high-order bit value, and operates in accordance with the first high-order control signal to bring into conduction a first high-order switch coupled to a pair of voltage acquisition points adjacent to each other through one or more voltage acquisition points. The low-order decoder generates a low-order control signal for controlling the conversion unit. The conversion unit divides a pair of high-order analog voltages output from a pair of voltage acquisition points.
    Type: Application
    Filed: December 14, 2010
    Publication date: June 16, 2011
    Applicant: RENESAS ELECTRONICS CORPORATION
    Inventor: Koji HIRAI
  • Patent number: 7956786
    Abstract: 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: Grant
    Filed: October 30, 2009
    Date of Patent: June 7, 2011
    Assignee: Analog Devices, Inc.
    Inventor: Gavin Cosgrave
  • Publication number: 20110122008
    Abstract: A controller receives an M-bit input and generates, in response, an S-bit upper range binary data feeding S-bit high range DAC and an R-bit lower range data feeding an R-bit low range DAC. The controller detects transition points in the M-bit input and in response, adds a transition data to the S-bit data equal to at least one least significant bit of the S-bit data and subtracts a value from the R-bit data equal to the transition data. The transition points and the transition data are detected and added at points avoiding such transitions at a full scale value of the R-bit data.
    Type: Application
    Filed: November 24, 2009
    Publication date: May 26, 2011
    Applicant: NXP B.V.
    Inventors: Kevin Mahooti, He Bo, Meng Hao, Johnny Chuang-Li Lee, Rui Yang, Tian Jie Feng
  • Patent number: 7948418
    Abstract: A digital-to-analog conversion circuit includes a digital-to-analog converter and a buffer amplifier. The digital-to-analog converter receives upper bits of digital data and a plurality of analog voltages and is configured to output two adjacent analog voltages of the plurality of analog voltages based on the upper bits. The buffer amplifier includes two input terminals. One of the input terminals receives one of the two adjacent analog voltages and the other input terminal receives the other adjacent analog voltage. The buffer amplifier is configured to generate a current offset by controlling a current flowing into each of the two input terminals based on lower bits of the digital bits.
    Type: Grant
    Filed: December 4, 2009
    Date of Patent: May 24, 2011
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Gyu Hyeong Cho, Yoon Kyung Choi, Hyoung Rae Kim, Yong Joon Jeon, Hyung Min Lee, Sung Woo Lee
  • Publication number: 20110102226
    Abstract: An N-bit DAC (1) comprises a main DAC circuit (5) having a main impedance string (8) of series connected main resistors, which define 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 (6) having a secondary impedance string (19) of series connected secondary resistors, which define secondary nodes on which analogue voltages are produced of progressively increasing values in steps of the value of one LSB. A main switch network (12) is provided for coupling the secondary impedance string (19) to a selected pair of main nodes of the main impedance string (8) for moving the secondary impedance string (19) upwardly and downwardly along the main impedance string (8) as the MSB value of the digital input signal varies.
    Type: Application
    Filed: October 30, 2009
    Publication date: May 5, 2011
    Applicant: ANALOG DEVICES, INC.
    Inventor: Gavin COSGRAVE
  • Patent number: 7936294
    Abstract: A DA conversion device includes the following elements. A higher-bit current source cell portion includes uniformly weighted higher-bit current source cells to generate an identical constant current. A lower-bit current source cell portion includes a lower-bit current source cells that are weighted to generate 1/two-to-the-power-of-certain-numbers constant currents. A constant current source selection controller includes a lower-bit controller having a scaler that uses clocks scaled down to 1/two-to-the-power-of-certain-numbers to select the lower-bit current source cells, and a higher-bit controller having shift registers and using a signal indicating a carry bit or a borrow bit used in the lower-bit controller to sequentially activate shift outputs of the shift registers, and uses the shift outputs to select the higher-bit current source cells. Constant current outputs of the selected current source cells are added and output so that an output current corresponding to the digital input signal is obtained.
    Type: Grant
    Filed: April 20, 2009
    Date of Patent: May 3, 2011
    Assignee: Sony Corporation
    Inventors: Go Asayama, Noriyuki Fukushima, Yoshikazu Nitta, Yoshinori Muramatsu, Kiyotaka Amano
  • Patent number: 7936295
    Abstract: 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: Grant
    Filed: June 19, 2007
    Date of Patent: May 3, 2011
    Assignee: Panasonic Corporation
    Inventors: Yusuke Tokunaga, Shiro Sakiyama, Shiro Dosho, Yasuyuki Doi, Kurumi Nakayama
  • Publication number: 20110090106
    Abstract: A 12-bit DAC includes a resistor string, three 16-to-1 selectors and an adder. The 12-bit DAC receives a 12-bit digital input data and provides a corresponding analog output voltage with 3-segmented conversion. The resistor string includes a plurality of voltage-dividing units for providing a plurality of reference voltages corresponding to each segment of conversion. After receiving the plurality of reference voltages generated by the resistor string, the three 16-to-1 selectors output 3 reference voltages corresponding to the three segments of conversion according to the 4 most significant bits, 4 least significant bits and the other 4 bits in the 12-bit digital input data, respectively. The adder can then generate the corresponding output analog voltage by summing the 3 reference voltages.
    Type: Application
    Filed: November 26, 2009
    Publication date: April 21, 2011
    Inventors: Shu-Chuan Huang, Chun-Hsien Chou, Chih-Cheng Wang, Shih-Meng Chang, Chi-Neng Mo
  • Patent number: 7928881
    Abstract: The present invention relates to a direct digital frequency synthesizer using a variable sine wave-weighted digital to analog converter with improved size and efficiency and a synthesizing method thereof. The direct digital frequency synthesizer and the synthesizing method thereof are capable of simplifying a configuration for matching output data of a phase accumulator to sine wave amplitude without increase in complexity of a DAC by applying a nonlinear DAC for directly generating a current corresponding to base points with sine weights and a variable sine wave-weighted DAC for generating fine currents to be combined with variable weights based on the base points. Accordingly, it is possible to provide a high quality output, reduce a size and power consumption, and increase a speed.
    Type: Grant
    Filed: December 27, 2009
    Date of Patent: April 19, 2011
    Assignees: Chung-Ang University Industry—Academy Cooperation Foundation, ZARAMTECHNOLOGY Co. Ltd.
    Inventors: Kwang-Hyun Baek, Hong Chang Yeoh, Jae-Hun Jung, Yun-Hwan Jung, Joon Hyun Baek
  • Patent number: 7924198
    Abstract: A digital-to-analog converter is disclosed. The digital-to-analog converter includes a decoder that receives a plurality of digital input signals to output a plurality of thermometer decode signals, a current supply part including a plurality of current sources, each of which operates in one of a sleeping mode and an operating mode under the control of the thermometer decode signals, and a switching part including a plurality of switching units, each of which operates in one of a sleeping mode and an operating mode under the control of the thermometer decode signals. The current supply part selectively outputs a plurality of switching power signals. The switching part outputs an analog signal under the control of the thermometer decode signals.
    Type: Grant
    Filed: December 23, 2009
    Date of Patent: April 12, 2011
    Assignee: LG Display Co., Ltd.
    Inventors: Zhiyuan Cui, Injae Chung, Namsoo Kim
  • Patent number: 7916059
    Abstract: A digital-analog conversion circuit, a method for the digital-analog conversion and a source driver are disclosed. A digital-analog conversion circuit may include a latch for storing N bit digital data therein, and a digital-analog converter, for performing a first digital-analog conversion on predetermined bits out of the N bit data stored in the latch by using R-string conversion, and for performing a second digital-analog conversion based on a result of the first digital-analog conversion and all remaining bits of the N bit data, excluding the predetermined bits.
    Type: Grant
    Filed: December 18, 2009
    Date of Patent: March 29, 2011
    Assignee: Dongbu HiTek Co., Ltd.
    Inventors: Tae-Woon Kim, Shin-Young Yi, Sang-Hoon Lim, Jin-Seok Koh
  • Patent number: 7903013
    Abstract: 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: Grant
    Filed: July 22, 2009
    Date of Patent: March 8, 2011
    Assignee: Hitachi, Ltd.
    Inventors: Kenichiro Yamaguchi, Atsushi Okumura, Mitsugu Kusunoki, Tomoo Murata
  • Publication number: 20110050474
    Abstract: A method for calibrating a phase include comparing a phase of an in-phase output signal and a phase of a quadrature-phase output signal and generating a digital code corresponding to a comparison result, and controlling the phase of the in-phase output signal in response to quadrature-phase differential input signals and the digital code, and controlling the phase of the quadrature-phase output signal in response to in-phase differential input signals and the digital code, to make a phase difference between the in-phase output signal and the quadrature-phase output signal 90°.
    Type: Application
    Filed: July 14, 2010
    Publication date: March 3, 2011
    Inventor: Byoung Joong Kang
  • Patent number: 7893853
    Abstract: A method of calibrating a digital-to-analog converter (DAC) is provided. The DAC includes a least-significant bit (LSB) block, and dummy LSB block adjacent to the LSB block. The DAC has a most-significant bit (MSB) block, which includes MSB thermometer macros. The method includes measuring the dummy LSB block to obtain a dummy LSB sum; and calibrating the MSB block so that each of the MSB thermometer macros provides a substantially same current as the dummy LSB sum.
    Type: Grant
    Filed: December 31, 2008
    Date of Patent: February 22, 2011
    Assignee: Taiwan Semiconductor Manufacturing Company, Ltd.
    Inventors: Fang-Shi Jordan Lai, Kuo-Ming Wang, Hsu-Feng Hsueh, Cheng Yen Weng, Yung-Fu Lin
  • Patent number: 7893856
    Abstract: A digital-to-analog conversion circuit includes a first digital-to-analog converter (DAC), a second DAC, and a control circuit to select which DAC to use for digital-to-analog conversion of a digital signal. Concerned with the noise level produced at a given out-of-band frequency, the control circuit bases its selection of DACs, at least in part, on a frequency distance between the given out-of-band frequency and the digital signal's frequency. The control circuit, for example, may select the DAC producing the lowest noise level at that frequency distance, or, if both DACs are able to reduce noise to a level below a noise tolerance specified for the frequency distance, the DAC consuming the least power. To reduce the chip area required for the digital-to-analog conversion circuit, the first and second DACs advantageously have topologies that permit them to share common components (e.g., DAC unit elements).
    Type: Grant
    Filed: April 15, 2009
    Date of Patent: February 22, 2011
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Staffan Ek, Stefan Andersson
  • Patent number: 7884783
    Abstract: 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: Grant
    Filed: December 21, 2006
    Date of Patent: February 8, 2011
    Assignee: Samsung Mobile Display Co., Ltd.
    Inventor: Sang Moo Choi
  • Publication number: 20110006939
    Abstract: A resistor string type D/A converter in accordance with an exemplary aspect of the present invention includes a resistor string, switches, a higher-order decoder, a lower-order decoder, and a conversion unit. The resistor string generates a plurality of analog voltages by dividing a voltage between a first reference voltage and a second reference voltage. Each of the switches is provided for a respective one of a plurality of voltage drawing points. The higher-order decoder generates a higher-order control signal according to the value of higher bits of an input digital signal. The lower-order decoder generates a lower-order control signal corresponding to the value of lower bits of the input digital signal. The conversion unit outputs a voltage between a pair of the analog voltage values obtained through a pair of switches based on the lower-order control signal.
    Type: Application
    Filed: June 9, 2010
    Publication date: January 13, 2011
    Applicant: NEC Electronics Corporation
    Inventor: Koji Hirai
  • Patent number: 7868809
    Abstract: 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: Grant
    Filed: February 20, 2009
    Date of Patent: January 11, 2011
    Assignee: International Business Machines Corporation
    Inventors: Joseph A. Iadanza, Benjamin T Voegeli
  • Patent number: 7868805
    Abstract: A Digital-Analog (D/A) converter, a data driver and a flat panel display using the D/A converter and data driver includes a controller to generate a first control signal or a second control signal according to a bit value of data supplied thereto. A voltage generator is disposed between a first voltage and a second voltage, and includes a plurality of resistors for dividing the first voltage and the second voltage. First switches are coupled to respective nodes of the resistors. Capacitors are respectively coupled to the first switches, and are charged with turning-on or turning-off the first switches. Second switches are respectively coupled to the first switches, and transfer the first control signal or the second control signal to the first switches. Shift registers are respectively coupled to the second switches, and supply reset signals or shift signals.
    Type: Grant
    Filed: January 30, 2008
    Date of Patent: January 11, 2011
    Assignee: Samsung Mobile Display Co., Ltd.
    Inventor: Byong Deok Choi
  • Publication number: 20110001692
    Abstract: An integrated circuit for converting digital signals to analog signals is provided. The integrated circuit includes a decoder coupled with at least one digital-to-analog converter (DAC). The decoder is capable of receiving at least one n-bit digital signal, decoding m bits of the at least one n-bit digital signal, and outputting at least one (n?m)-bit digital signal and at least one decoded digital signal. The at least one digital-to-analog converter (DAC) is capable of converting the at least one (n?m)-bit digital signal and the at least one decoded digital signal to at least one analog signal.
    Type: Application
    Filed: April 19, 2010
    Publication date: January 6, 2011
    Applicant: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD.
    Inventor: N. P. TU
  • Patent number: 7859445
    Abstract: An embodiment of a digital to analog converter (DAC) with two outputs is provided. The DAC is controlled by an n-bits input signal and comprises a reference voltage circuit generating (2n+1) reference voltages, a first switch array and a second switch array. The first switch array receives and outputs 2n selected reference voltages among the (2n+1) reference voltages to the second switch array. The second switch array outputs a first voltage via a first output terminal and a second voltage via a second output terminal according to the input signal, wherein the (2i+1)th reference voltages are directly transmitted to the second switch array, and when the first bit of the input signal is at a first voltage level, the first voltage is transmitted to the second output terminal, and the second voltage is transmitted to the first output terminal.
    Type: Grant
    Filed: June 25, 2009
    Date of Patent: December 28, 2010
    Assignee: Himax Technologies Limited
    Inventor: Ching-Chung Lee
  • Patent number: 7852250
    Abstract: This invention discloses a digital to analog converter (DAC) for converting a digital signal with a predetermined number of bits to a corresponding analog signal, the DAC comprises a first current source element having a first control signal, the first control signal controlling the conduction current provided by the first current source element, and a second current source element having a second control signal, the second control signal controlling the conduction current provided by the second current source element, wherein the first and the second control signals have different voltages during operation of the DAC.
    Type: Grant
    Filed: December 19, 2008
    Date of Patent: December 14, 2010
    Assignee: Taiwan Semiconductor Manufacturing Co., Ltd.
    Inventors: Mei-Chen Chuang, Wen-Shen Chou
  • Patent number: 7847718
    Abstract: 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: Grant
    Filed: December 5, 2006
    Date of Patent: December 7, 2010
    Assignee: NEC Corporation
    Inventors: Junichiro Ishii, Hiroshi Tsuchi
  • Publication number: 20100302085
    Abstract: A field device having an analog output, i.e., a measuring transducer, for process instrumentation having a 4-20 mA interface as the analog output. For digital-to-analog conversion, a digital value is split into a digital coarse portion and a digital fine portion. Depending on the digital coarse portion, a first analog signal is generated using a pulse width modulator having a downstream mounted low path filter and a signal above the analog output signal, and a second output signal using a pulse width modulator also having a downstream mounted low path filter with a signal below the analog output signal. The analog signals are supplied to a third pulse width modulator controlled with the digital fine portion, where a low-pass filter (TP3) is downstream mounted. As a result, an analog output signal is provided having a high resolution and good dynamic properties. In addition, the field device is provided with a digital-to-analog converter that can be produced having minimal complexity.
    Type: Application
    Filed: September 26, 2008
    Publication date: December 2, 2010
    Applicant: Siemens AG
    Inventors: Eric Chemisky, Michael Geppert, Ulrich Hahn, Simon Rohrbach
  • Publication number: 20100297965
    Abstract: Apparatus for generating a modulation signal for use in modulating the power supply of a power amplifier uses coarse and fine control for controlling the amplitude of the modulation signal, and thereby controlling the output power of the power amplifier. The modulation signal may be generated in the digital domain and converted to the analog domain by a digital-to-analog converter, with the digital-to-analog converter providing the fine control and a variable gain amplifier providing the coarse control of the analog signal.
    Type: Application
    Filed: May 21, 2010
    Publication date: November 25, 2010
    Applicant: ST-ERICSSON SA
    Inventor: Roland Ryter
  • Publication number: 20100289680
    Abstract: A background self-calibrated DAC is presented. In the present invention, a virtual-short theory, applicable to input/output terminals of an operational amplifier, is periodically employed so as to self-calibrate a current source serially connected with an equivalent resistor, and the DAC using the same. The aforesaid DAC does not require an additional self-calibration period, and digital-to-analog conversion thereof can be realized in merely a small amount of die area. Correspondingly, a compact and high-speed current steering DAC can be realized.
    Type: Application
    Filed: May 13, 2010
    Publication date: November 18, 2010
    Applicant: REALTEK SEMICONDUCTOR CORP.
    Inventors: Chun-Ta Ho, Chuan-Ping Tu
  • Patent number: 7821431
    Abstract: A multiphase hybrid digital pulse width modulator can comprise a counter that is selectable between at least two different numbers of states to indicate a first portion of a switching period. Unclocked logic can indicate a second portion of the switching period. The unclocked logic can include a delay line.
    Type: Grant
    Filed: February 16, 2010
    Date of Patent: October 26, 2010
    Assignee: Exar Corporation
    Inventors: Aleksandar Prodic, Zdravko Lukic
  • Patent number: 7808416
    Abstract: A selection circuit receives a plural number (m) of respective different values of voltages as reference voltages to select and output two voltages. An amplifier receives at two input terminals the two reference voltages output from the selection circuit to output an output voltage extrapolated.
    Type: Grant
    Filed: October 10, 2006
    Date of Patent: October 5, 2010
    Assignees: Nec Corporation
    Inventor: Hiroshi Tsuchi
  • Patent number: 7773013
    Abstract: 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: Grant
    Filed: August 12, 2008
    Date of Patent: August 10, 2010
    Assignee: Cadence Design Systems, Inc.
    Inventors: Stephen Williams, Eric Naviasky, William Evans
  • Patent number: 7764212
    Abstract: 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: Grant
    Filed: October 31, 2007
    Date of Patent: July 27, 2010
    Assignee: Korea Advanced Institute of Science and Technology
    Inventors: Hyung-Min Lee, Gyu Hyeong Cho, Young-Suk Son, Yong-Joon Jeon, Jin Yong Jeon, Seung-Chul Jung
  • Publication number: 20100182181
    Abstract: A successive approximation type A-to-D converter includes a cyclic D-to-A converter (11), a comparator (12) for comparing an analog value with an output value of the D-to-A converter (11), and memory means (13) for sequentially storing an output value of the comparator (12) and supplying the stored value to the D-to-A converter (11) in a reverse order.
    Type: Application
    Filed: March 29, 2010
    Publication date: July 22, 2010
    Applicant: Panasonic Corporation
    Inventors: Shiro Dosho, Takashi Morie, Kazuo Matsukawa
  • Publication number: 20100182175
    Abstract: 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: Application
    Filed: January 8, 2010
    Publication date: July 22, 2010
    Inventors: Kenneth Thet Zin Oo, Pierte Roo
  • Publication number: 20100164777
    Abstract: A digital-to-analog converter is disclosed. The digital-to-analog converter includes a decoder that receives a plurality of digital input signals to output a plurality of thermometer decode signals, a current supply part including a plurality of current sources, each of which operates in one of a sleeping mode and an operating mode under the control of the thermometer decode signals, and a switching part including a plurality of switching units, each of which operates in one of a sleeping mode and an operating mode under the control of the thermometer decode signals. The current supply part selectively outputs a plurality of switching power signals. The switching part outputs an analog signal under the control of the thermometer decode signals.
    Type: Application
    Filed: December 23, 2009
    Publication date: July 1, 2010
    Inventors: Zhiyuan CUI, Injae Chung, Namsoo Kim
  • Patent number: 7746258
    Abstract: Disclosed are a digital-analog converter and a camera module having the same. The digital-analog converter includes a plurality of decoders for receiving bits of a digital input signal by dividing the bits in a predetermined bit unit except for lower bits of the digital input signal, and decoding the bits into thermometer code signals, a delay unit for delaying output of the lower bits of the digital input signal, a latch unit for synchronizing output signals of the decoders with an output signal of the delay unit, and a current source for converting a digital signal output from the latch unit into an analog signal.
    Type: Grant
    Filed: August 14, 2007
    Date of Patent: June 29, 2010
    Assignee: LG Innotek Co., Ltd.
    Inventor: Cheong Yong Park
  • Publication number: 20100156867
    Abstract: A digital-to-analog converter includes a voltage-to-current converter, a current-mode digital-to-analog converter and an operational amplifier. The voltage-to-current converter generates a first current signal, and the current-mode digital-to-analog converter generates a second current signal. The operational amplifier modulates a drain current in response to the second current signal and generates an output signal having an offset.
    Type: Application
    Filed: December 16, 2009
    Publication date: June 24, 2010
    Applicant: SAMSUNG ELECTRONICS CO., LTD.
    Inventors: Hyoung-Rae Kim, Yong-Joon Jeon, Gyu-Hyeong Cho, Sung-Woo Lee, Hyung-Min Lee, Yoon-Kyung Choi
  • Publication number: 20100141493
    Abstract: A digital-to-analog conversion circuit includes a digital-to-analog converter and a buffer amplifier. The digital-to-analog converter receives upper bits of digital data and a plurality of analog voltages and is configured to output two adjacent analog voltages of the plurality of analog voltages based on the upper bits. The buffer amplifier includes two input terminals. One of the input terminals receives one of the two adjacent analog voltages and the other input terminal receives the other adjacent analog voltage. The buffer amplifier is configured to generate a current offset by controlling a current flowing into each of the two input terminals based on lower bits of the digital bits.
    Type: Application
    Filed: December 4, 2009
    Publication date: June 10, 2010
    Inventors: Gyu Hyeong CHO, Yoon Kyung Choi, Hyoung Rae Kim, Yong Joon Jeon, Hyung Min Lee, Sung Woo Lee
  • Publication number: 20100141497
    Abstract: A digital-to-analog converter (DAC) for converting a digital signal to an analog signal includes a first thermometer decoder and a second thermometer decoder. The first thermometer decoder is configured to decode most-significant bits (MSBs) of the digital signal to generate a first thermometer code. The second thermometer decoder is configured to decode middle bits of the digital signal to generate a second thermometer code. The DAC further includes a plurality of macro cells with each controlled by one bit of the first thermometer code. The plurality of macro cells is configured to provide a first analog signal according to the first thermometer code. The DAC further includes a macro cell configured to provide a second analog signal according to the second thermometer code. The macro cell is further configured to provide a third analog signal according to least-significant bits (LSBs) of the digital signal.
    Type: Application
    Filed: December 9, 2008
    Publication date: June 10, 2010
    Inventors: Robit Yang, Ying-Chi Hsu, You-Cheng Xiao, Wen-Shen Chou