Using Charge Coupled Devices Or Switched Capacitances Patents (Class 341/150)
  • Publication number: 20110148680
    Abstract: Provided is a DA conversion apparatus comprising a capacitor array DA converter that outputs to an output line an output voltage corresponding to a digital value input thereto; and a load changing section that changes a size of a load capacitance connected to the output line. The load changing section may set gain of the DA conversion apparatus with the size of the load capacitance connected to the output line being a constant capacitance unaffected by the digital value. The load changing section may include a load capacitor connected between the output line and a standard potential; a load-side switch connected in series with the load capacitor between the output line and the standard potential; and a load capacitance control section that controls the load-side switch.
    Type: Application
    Filed: December 18, 2009
    Publication date: June 23, 2011
    Applicant: ADVANTEST CORPORATION
    Inventor: Yasuhide KURAMOCHI
  • Patent number: 7916057
    Abstract: A circuit includes a digital-to-analog converter configured to produce an analog output signal (1) proportional to a reference signal and (2) as a function of a digital input signal. The converter comprises a plurality of non-trivially complex admittances configured so that each non-trivially complex admittance can be selectively switched as a function of the digital input signal so as to be coupled between a reference terminal configured to receive a reference signal and an output terminal. The method comprises selectively switching non-trivially complex admittances as a function of the digital signal between a reference terminal and an output terminal.
    Type: Grant
    Filed: April 27, 2009
    Date of Patent: March 29, 2011
    Assignee: Linear Technology Corporation
    Inventors: Andrew Joseph Thomas, Joseph Luis Sousa
  • Publication number: 20110068964
    Abstract: A digital-to-analog conversion circuit operates by selectively discharging members of a plurality of capacitors. Charging of the capacitors occurs during a reset period while digital-to-analog conversion occurs as the capacitors are discharged. Those capacitors that are discharged are selected from the plurality of capacitors based on a digital input. The analog output includes the charge discharged from the capacitors. The capacitors are optionally divided into separate capacitor banks.
    Type: Application
    Filed: September 22, 2009
    Publication date: March 24, 2011
    Inventors: Jonathan Ephraim David Hurwitz, Steven Collins
  • Patent number: 7911370
    Abstract: A pipeline analog-to-digital converter (ADC) comprises a plurality of pipeline stages is disclosed. The first pipeline stage has programmable gain function. The first pipeline stage includes a sub-analog-to-digital converter (sub-ADC) and a multiplying digital-to-analog converter (MDAC) implemented by switched capacitor (SC) circuits. Different capacitances in the sub-ADC and MDAC are provided so as to provide different gains by controlling switches in the SC circuits.
    Type: Grant
    Filed: June 25, 2009
    Date of Patent: March 22, 2011
    Assignee: Mediatek Inc.
    Inventor: Yu-kai Chou
  • Publication number: 20100321223
    Abstract: A first switched capacitor circuit is connected to the source of one MOS transistor of a current mirror pair configured by a pair of MOS transistors and a second switched capacitor circuit is connected to the source of the other MOS transistor. Each of the first and second switched capacitor circuits includes a capacitor and a switch connected in parallel with the capacitor and the switch is on/off-controlled based on a clock signal of a preset cycle. Each of the first and second switched capacitor circuits equivalently functions as a resistor with large resistance and a variation in the output current of the current mirror circuit based on a variation in the threshold voltages of the pair of MOS transistors can be reduced even if the power source voltage is reduced.
    Type: Application
    Filed: August 11, 2010
    Publication date: December 23, 2010
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Shigeo IMAI
  • Patent number: 7855670
    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: Grant
    Filed: March 29, 2010
    Date of Patent: December 21, 2010
    Assignee: Panasonic Corporation
    Inventors: Shiro Dosho, Takashi Morie, Kazuo Matsukawa
  • Publication number: 20100283651
    Abstract: Some embodiments include apparatus and methods having an amplifier, a capacitor network coupled to the amplifier, and switching circuitry coupled to the amplifier and the capacitor network. The switching circuit is configured to successively apply a selected reference voltage selected from among a first reference voltage, a second reference voltage, and a third reference voltage to the capacitor network in response to a digital input code to generate an output voltage. Additional embodiments are disclosed.
    Type: Application
    Filed: May 6, 2009
    Publication date: November 11, 2010
    Applicant: Atmel Corporation
    Inventors: Renaud Dura, Joao Pedro Carreira, Sebastien Fievet
  • Patent number: 7830290
    Abstract: A switched capacitor digital-to-analog converter (SC-DAC) is provided. The SC-DAC of the present invention can eliminate an influence of a reference voltage source caused by a signal dependent loading at each clock cycle, so as to completely solve a harmonic distortion of an analog output signal converted by a conventional SC-DAC. In addition, when the SC-DAC of the present invention has a plurality of converting channels, since the reference voltage source is not influenced by the effect of signal dependent loading of any converting channel, so that each converting channel can be regarded to have a separate state, and thus the purpose of channel separation can be achieved.
    Type: Grant
    Filed: March 12, 2009
    Date of Patent: November 9, 2010
    Assignee: Sunplus mMedia Inc.
    Inventors: Chih-Wei Chen, Lai-Ching Lin
  • Patent number: 7821438
    Abstract: A digital-to-analog converter circuit layout includes a ratiometric digital-to-analog converter. The ratiometric digital-to-analog converter includes a digital data input, a converter voltage output, a voltage controlled oscillator, and a pulse width modulation module. The a digital data input, a converter voltage output, a voltage controlled oscillator, and a pulse width modulation module is configured in a controllable manner for converting digital data received at the input to a converter output voltage at the output using a reference voltage, an adjustable current as a reference current, and an adjustable impedance value. The circuit layout is characterized in that the voltage controlled oscillator includes circuit components which multiply the reference voltage by a quotient between the adjustable impedance value and the adjustable current, and which apply the multiplication results to the pulse width modulation module.
    Type: Grant
    Filed: May 29, 2009
    Date of Patent: October 26, 2010
    Assignee: Micronas, GmbH
    Inventors: Laurent Avon, Reiner Bidenbach, Klaus Heberle
  • Publication number: 20100265113
    Abstract: A D/A converter includes plus-side and minus-side input terminals; plus-side and minus-side D/A converters each including plural plus-side or minus-side capacitors having capacitance values weighted by the powers of two, a plus-side or minus-side output terminals connected to first electrodes of the plus-side or minus-side capacitors, and plural plus-side or minus-side switches for connecting each second electrode of the plus-side or minus-side capacitors to either the plus-side or minus-side input terminal, a plus-side reference voltage terminal or a minus-side reference voltage terminal according to plus-side or minus-side control digital signals; and plural short-circuit switches provided between identically weighted plus-side and minus-side capacitors respectively.
    Type: Application
    Filed: April 9, 2010
    Publication date: October 21, 2010
    Applicant: FUJITSU LIMITED
    Inventor: Masato Yoshioka
  • Publication number: 20100253563
    Abstract: A method and system for capacitor based digital to analog converter design layout for high speed analog to digital converter are provided. The method includes arranging a plurality of metal plates to form the capacitor. Each of the plurality of metal plates includes a driven plate and a common plate. The method also includes generating a plurality of interconnects in the common plate and extending the driven plate over the plurality of interconnects. Further, the method includes shielding the common plate by the driven plate. The system includes an analog to digital converter. The analog to digital converter also includes capacitor based digital to analog converter and digital logic for controlling digital operations in the analog to digital converter. The capacitor based digital to analog converter includes a plurality of capacitors, and a comparator for comparing the analog output from the digital to analog converter with a ground potential.
    Type: Application
    Filed: March 23, 2010
    Publication date: October 7, 2010
    Applicant: Cosmic Circuits Private Limited
    Inventors: Venkatesh Teeka Srinivasa SHETTY, Govind Kulkarni, Srinivasan Chakravarthy, Sumeet Mathur
  • Patent number: 7804434
    Abstract: In a switched-capacitor circuit such as a DAC, charges are accumulated by a plurality of sampling capacitors in dependence upon input digital data during a sampling phase; then, during a sharing phase these charges are shared with a holding capacitor which is connected across an opamp. In the so-called bipolar charging type switched-capacitor DAC, the signal provided by the sampling capacitors is doubled by connecting their opposite sides to positive and negative reference voltages during the sampling phase. However, parasitic capacitances associated with the sampling capacitors then cause a disturbance to the input of the operational amplifier during the sharing phase. By equalising the input sides of the sampling capacitors to a reference voltage, prior to the sharing phase, this disturbance is avoided thereby allowing a low-power opamp to be employed in the DAC. This equalising can be achieved by adding a short equalising clock phase between the usual sampling and sharing clock phases of the DAC.
    Type: Grant
    Filed: March 30, 2009
    Date of Patent: September 28, 2010
    Assignee: Wolfson Microelectronics plc
    Inventor: Remco M. Stoutjesdijk
  • Patent number: 7800427
    Abstract: A switched capacitor circuit includes an amplifier, a charging unit, an offset unit, and an integrating unit. The charging unit is coupled between an input node and a first node, and is for accumulating charge corresponding to an input signal during a sampling mode. The offset unit is coupled between the first node and an input of the amplifier, and is for maintaining the first node to be a virtual ground during an integrating mode. The integrating unit is coupled between the first node and an output of the amplifier, and is for receiving charge from the charging unit during the integrating mode.
    Type: Grant
    Filed: November 21, 2007
    Date of Patent: September 21, 2010
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Youngcheol Chae, Gunhee Han, Seog-Heon Ham
  • Publication number: 20100231429
    Abstract: A direct capacitance-to-digital converter is provided, including a plurality of switches, an ADC, a reference voltage circuit and a trigger unit. By using trigger unit to control a plurality of switches, and combining the reference voltages outputted by the reference voltage circuit, the converter can directly sense the external to-be-measured capacitor and related stray capacitor, and directly convert the capacitance of the to-be-measured capacitor into accurate digital signal. The present invention can be integrated with other sensors into a single chip to form an integrated direct capacitance-to-digital converter.
    Type: Application
    Filed: March 11, 2009
    Publication date: September 16, 2010
    Inventor: Chih-Shiun Lu
  • Patent number: 7796074
    Abstract: In one embodiment of the present invention, a switched capacitor digital/analog converter is provided, for example providing gamma correction in liquid crystal displays. The converter includes a plurality of conversion capacitors including first plates connected to an output line and second plates connectable via electronic switches to first or second reference voltages in accordance with the values of corresponding bits of an input word. The converter also includes a plurality of terminating capacitors, at least one of which is switchable in or out of circuit depending on the value of at least one of the bits of the input word. By suitable choice of capacitance values and reference voltages, a wide range of non-linear transfer functions can be provided by the converter.
    Type: Grant
    Filed: April 3, 2006
    Date of Patent: September 14, 2010
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Harry G. Walton
  • Patent number: 7791520
    Abstract: The present patent application comprises a digital to analog converter reference circuit, comprising a capacitor connected to a current source, a positive terminal of the capacitor connected to a first switch, the first switch electrically connecting the positive terminal of the capacitor to a positive input terminal of a DAC circuit, a negative terminal of the capacitor connected to a second switch, the second switch electrically connecting the negative terminal of the capacitor to a negative input terminal of the DAC circuit. In another example, the present patent application comprises a method for converting digital code to an analog signal, comprising charging a reservoir capacitor to a reference voltage level, transferring stored charge from the reservoir capacitor to DAC feedback capacitors, and transferring the stored charge from the DAC feedback capacitors to DAC output terminals.
    Type: Grant
    Filed: February 6, 2008
    Date of Patent: September 7, 2010
    Assignee: QUALCOMM Incorporated
    Inventors: Lennart K-A Mathe, Xiaohong Quan
  • Patent number: 7786917
    Abstract: A digital-to-analog converter is disclosed for converting a digital signal into its analog equivalent. The digital-to-analog converter includes a two switches capable of coupling circuit nodes to ground, a scaling capacitor having a capacitance value that equals a unit capacitance value, a first array of capacitors coupled to the first circuit node and a first switching array which couples the first array of capacitors to either ground or a reference voltage depending on the digital values of the least significant bits of the digital word being converted, a second array of capacitors coupled to the second circuit node and a second switching array which couples the second array of capacitors to either ground or the reference voltage depending on the digital values of the most significant bits of the digital word being converted.
    Type: Grant
    Filed: July 14, 2008
    Date of Patent: August 31, 2010
    Assignee: Integrated Device Technology, Inc.
    Inventors: Pengfei Hu, JinFu Chen, Qinghua Yue
  • Patent number: 7786916
    Abstract: A multi-bit digital to analog converter is implemented by a switched-capacitor arrangement in which a reservoir capacitor (Cf) accumulates charge representing the desired analog output signal (Vout+/Vout?). An array of further capacitors (C0-CN) correspond in number at least to the number of data bits (D0-DN) to be converted. The capacitors (Cf, C0-CN) are selectively interconnected with one another and with reference voltage sources (Vmid, Vdd, Vss) in a repetitive sequence of phases including (i) a sampling phase (P2) in which the further capacitors are connected (S3, S4) to reference voltages selected in accordance with the values of the data bits, (ii) an equalization phase (P6a) in which the further capacitors are connected (S2) in parallel with one another without connecting them in parallel with the first capacitor, followed by (iii) a transfer phase (P6b) in which the parallel connected further capacitors are connected (S1, S5) in parallel with the first capacitor.
    Type: Grant
    Filed: September 3, 2008
    Date of Patent: August 31, 2010
    Assignee: Wolfson Microelectronics plc
    Inventors: Simon Kenneth Quinn, Andrew James Howlett
  • Publication number: 20100214140
    Abstract: Successive approximation register (SAR) analog-to-digital converters (ADCs) generally employ capacitive digital-to-analog converters (CDACs) to perform data conversions. In these CDACs, matching of capacitive values is important, and for conventional high resolution SAR ADCs, complex trimming or calibration procedures can be too costly. Here, however, a SAR ADC is provided that performs error correction so as to reduce the overall cost compared to conventional SAR ADCs.
    Type: Application
    Filed: February 23, 2010
    Publication date: August 26, 2010
    Applicant: Texas Instruments Deutschland GmbH
    Inventors: Michael Reinhold, Frank Ohnhaeuser, Mikael Badenius
  • Publication number: 20100201557
    Abstract: A digital-to-thermometer-code converter is disclosed for converting a digital signal into its thermometer-code equivalent. Embodiments of the digital-to-thermometer-code include a binary-to-control signal converter that generates a column control signal and a row control signal based on a binary input signal, and a control signal-to-thermometer-code decoder that includes an array of decoder circuit blocks coupled to receive the column control signal and the row control signal, wherein each of the decoder circuit blocks determine at least one bit of the thermometer-code output signal based on at least a first bit of the column control signal.
    Type: Application
    Filed: February 6, 2009
    Publication date: August 12, 2010
    Inventors: JINFU CHEN, Pengfei Hu, Qinghua Yue
  • Patent number: 7773023
    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: Grant
    Filed: November 30, 2007
    Date of Patent: August 10, 2010
    Assignee: Panasonic Corporation
    Inventors: Shiro Dosho, Takashi Morie, Kazuo Matsukawa
  • Publication number: 20100194614
    Abstract: A multiplying digital-to-analog converter includes an operational amplifier (OP-amp) operated under a first power supply voltage and a second power supply voltage; an OP-amp input switch block coupled to a common mode voltage for selectively coupling the common mode voltage to input nodes of the OP-amp, wherein the common mode voltage is substantially equal to the first power supply voltage; a capacitor block coupled to the OP-amp input switch block; a sampling switch block coupled to the input signal for selectively coupling the input signal to the capacitor block; a reference voltage switch block coupled to the capacitor block for selectively coupling the reference signal to the capacitor block; and a feedback switch block coupled between the capacitor block and output nodes of the OP-amp.
    Type: Application
    Filed: April 14, 2010
    Publication date: August 5, 2010
    Inventors: Wei-Hsuan Tu, Tzung-Hung Kang
  • Publication number: 20100182176
    Abstract: A charge corresponding to an analog signal Vi is accumulated in first and second capacitors 25, 27, respectively. A digital signal VDIGN having a digital value (D1, D0, for example) corresponding to the analog signal Vi is generated. By connecting the second capacitor 27 between an output 21c and an inversion input 21a of an operational amplifier circuit 21 and supplying a first capacitor end 25a with an analog signal VD/A corresponding to the digital signal VDIGN, a first conversion value VOUT1 is generated in the output 21c of the operational amplifier circuit 21. By connecting the first and third capacitors 25, 33 between the output 21c and inversion input 21a of the operational amplifier circuit 21 and supplying a second capacitor end 27a with the analog signal VD/A, a second conversion value VOUT2 is generated in the output 21c of the operational amplifier circuit 21.
    Type: Application
    Filed: June 8, 2007
    Publication date: July 22, 2010
    Inventor: Shoji Kawahito
  • Patent number: 7746261
    Abstract: A variable gain amplifier for amplifying an input voltage at a gain defined by a binary code includes: a signal input terminal; a signal output terminal; a charge division means that accumulates a charge, divides an accumulated charge, and accumulates a divided charge; a charge cumulation means that accumulates a charge, adds or subtracts an accumulated charge with or from the divided charge in the charge division means, and accumulates a resultant charge; and a controller that initially executes to accumulate the charge corresponding to the input voltage in the charge division means, executes to accumulate the charge corresponding to the input voltage or a predetermined voltage in the charge cumulation means, executes a charge dividing operation according to each bit of the binary code sequentially from a most significant bit, and executes a charge adding or subtracting operation according to an data value in each bit.
    Type: Grant
    Filed: July 31, 2008
    Date of Patent: June 29, 2010
    Assignee: DENSO CORPORATION
    Inventor: Masakiyo Horie
  • Patent number: 7741985
    Abstract: A digital/analogue converter for converting an input n-bit digital code, where n is an integer greater than one, has an n-bit digital input and an output for connection to a load, and includes: an array of (n?1) switched capacitors; and a switching arrangement. In one example embodiment, the switching arrangement is adapted, in a zeroing phase of operation, to connect a first reference voltage to the first plate of at least one capacitor of the array and to connect a second plate of the at least one capacitor to a voltage that, for at least one value of the input digital code, is different from the first reference voltage and is further adapted, in a decoding phase of operation, to enable, dependent on the value of the input digital code, injection of charge into the at least one capacitor. In one example embodiment, the converter may be a bufferless converter having an output for direct connection to a capacitive load.
    Type: Grant
    Filed: January 11, 2006
    Date of Patent: June 22, 2010
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yasushi Kubota, Kazuhiro Maeda, Hajime Washio, Patrick Zebedee
  • Patent number: 7733259
    Abstract: A system having a signal converter device, and a method for operating a system having a signal converter device is disclosed. One embodiment provides loading a capacitive device to a preparation voltage in a first operating phase, and loading the capacitive device to a measuring voltage in a second operating phase after the first operating phase.
    Type: Grant
    Filed: January 7, 2009
    Date of Patent: June 8, 2010
    Assignee: Infineon Technologies AG
    Inventors: Jens Barrenscheen, Patrick Leteinturier
  • Patent number: 7733258
    Abstract: A data converter for converting analog signals to digital signals, or for converting digital signals to analog signals is provided. In one embodiment, a production self-test is provided. In one embodiment, a high-speed lower-resolution method or mode for a data converter is provided. In one embodiment, a differential data converter with a more stable comparator common mode voltage is provided. In one embodiment, the input range of a digitally calibrated data converter is provided and maintained so that there is no loss in input range due to the calibration. In one embodiment, digital post-processing of an uncalibrated result using a previously stored calibration value is provided.
    Type: Grant
    Filed: September 30, 2008
    Date of Patent: June 8, 2010
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Michael T. Berens, James R. Feddeler
  • Patent number: 7729300
    Abstract: 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: Grant
    Filed: August 19, 2005
    Date of Patent: June 1, 2010
    Assignee: National Semiconductor Corporation
    Inventors: Ramsin Michael Ziazadeh, Varadarajan Devnath
  • Patent number: 7715490
    Abstract: A novel sigma delta amplitude modulator having a noise transfer function adapted to shift quantization noise outside at least one frequency band of interest. In one embodiment, the sigma delta amplitude modulator includes a programmable order low pass stage. In a second embodiment, the sigma delta amplitude modulator incorporates comb filtering wherein each comb filter comprises a plurality of fingers to permit greater programmability in the frequency location of notches. A polar transmitter incorporating the sigma delta amplitude modulator is presented that shapes the spectral emissions of the digitally-controlled power amplifier such that they are significantly and sufficiently attenuated in one or more desired frequency bands.
    Type: Grant
    Filed: March 8, 2006
    Date of Patent: May 11, 2010
    Assignee: Texas Instruments Incorporated
    Inventor: Sameh S. Rezeq
  • Publication number: 20100103014
    Abstract: A multi-bit digital-to-analog converter has a reference voltage generator generating a reference voltage with an offset voltage; a switched capacitor stage for generating a plurality of output voltages; and a switching sequencer controlling the switched capacitor stage operable to generate switching patterns for each output voltages, wherein each pattern has a charge phase and a transfer phase, and wherein for at least one output voltage the switching sequencer provides two switching patterns wherein each switching pattern contributes an offset of opposite polarity.
    Type: Application
    Filed: October 20, 2009
    Publication date: April 29, 2010
    Inventors: Vincent Quiquempoix, Philippe Deval
  • Patent number: 7683816
    Abstract: A system for displaying images is provided. A capacitor type digital-to-analog converter is coupled between a first node and a second node and generates a first analog signal according to a digital signal with N bit data. An analogue buffer is coupled between the second node and a third node and generates a second analog signal according to the first analog signal and a bias voltage. A first switch is coupled between a predetermined voltage and the second node. A second switch is coupled between the first node and the third node. A third switch is coupled between the third node and an analog output signal. The second switch is turned on and the third switch is turned off when the first switch is turned on, and the first and second switches are turned off when the third switch is turned on.
    Type: Grant
    Filed: August 21, 2008
    Date of Patent: March 23, 2010
    Assignee: TPO Displays Corp.
    Inventor: Cheng-Ho Yu
  • Publication number: 20100066707
    Abstract: In one embodiment of the present invention, a digital/analogue converter for converting an input n-bit digital code includes: a switched capacitor digital/analogue converter including a plurality of capacitors. The lower plate of each is connectable, dependent on the input digital code, to either a first reference voltage or a second reference voltage different from the first reference voltage. The converter also includes at least one further capacitor, and a switching arrangement for connecting the lower plate of the or each first further capacitor to either a third reference voltage or a fourth reference voltage different from the third reference voltage. The input to the first switching arrangement is independent of the input digital code. In the decoding phase, the output voltage floats to a voltage that depends on both the input data code and the direction and magnitude of charge injection across the further capacitor(s).
    Type: Application
    Filed: August 1, 2007
    Publication date: March 18, 2010
    Inventor: Patrick Zebedee
  • Patent number: 7679540
    Abstract: This disclosure relates to systems and methods for analog to digital conversion using delta sigma modulation. To this end, the delta sigma modulator includes a double sampling DAC and integrator and a 1-bit comparator, with reference loading insensitivity.
    Type: Grant
    Filed: November 30, 2007
    Date of Patent: March 16, 2010
    Assignee: Infineon Technologies AG
    Inventors: Jose Luis Ceballos, Michael Kropfitsch
  • Patent number: 7671776
    Abstract: Circuits, methods, and apparatus that provide sampling networks that avoid undesired transient voltages. One example provides a sampling network that includes a switch such that charge is transferred to an integrator in two separate steps instead of one. This switch connects the first side of a capacitor to an intermediate voltage after it is connected to an input voltage and before it is connected to a reference voltage, where the reference voltage is the output of a one-bit digital-to-analog converter. This intermediate switching allows charge to be transferred from a sampling capacitor to an integrating capacitor in two steps, thus avoiding undesirable transient voltages.
    Type: Grant
    Filed: June 18, 2008
    Date of Patent: March 2, 2010
    Assignee: Intersil Americas Inc.
    Inventors: Giri Rangan, Bhupendra Sharma
  • Publication number: 20100039303
    Abstract: A digital analog converter has an input terminal receiving a digital input signal, a lower-side capacitor group coupled to a lower-side common terminal in parallel, an upper-side capacitor group coupled, in parallel, to an upper-side common terminal at which an analog output signal is generated, a coupling capacitor provided between the lower-side common terminal and the upper-side common terminal, a switch group coupled to the upper-side capacitor group and the lower-side capacitor group and controlled as a conduction state and a non-conduction state in accordance with the digital input signal, and an adjusting capacitor coupled to the lower-side common terminal and having a variable capacitance value.
    Type: Application
    Filed: August 12, 2009
    Publication date: February 18, 2010
    Applicant: FUJITSU LIMITED
    Inventor: Sanroku Tsukamoto
  • Patent number: 7663525
    Abstract: A digital to analog converter including a first capacitor, a second capacitor, an operational amplifier, and a switch is disclosed. During a first period, the first capacitor stores a first voltage and the second capacitor stores a second voltage. The operational amplifier comprises an input and an output. The switch parallels the first and the second capacitors with the operational amplifier at the input and output according to a digital signal during a second period.
    Type: Grant
    Filed: July 30, 2007
    Date of Patent: February 16, 2010
    Assignee: Mediatek Inc.
    Inventor: Jen-Che Tsai
  • Patent number: 7652607
    Abstract: In a digital to analogue converter, a plurality of digital inputs are used to select one of first and second binary voltage levels as binary inputs (10) to the converter. A capacitor circuit (C, 2C, . . . , 32C) is associated with each input, and these are controlled to output an effective voltage to an output load comprising the first binary voltage level, the second binary voltage level or an average of the first and second binary voltage levels in dependence on the bits of the digital input word. The plurality of capacitor circuits can be operated in either a voltage divider mode (to provide an average output) or a resistor mode depending on the value of the digital data. Operation of the capacitor circuits in this way can result in a reduction in the currents flowing and can therefore reduce the power consumption.
    Type: Grant
    Filed: March 23, 2005
    Date of Patent: January 26, 2010
    Assignee: Chi Mei Optoelectronics Corporation
    Inventor: Martin J. Edwards
  • Publication number: 20100013690
    Abstract: Provided is a successive approximation AD conversion apparatus that outputs digital output data corresponding to an analog input signal, including a bit selecting section that selects a conversion target bit sequentially from a highest bit of the output data; a data control section that outputs comparison data determining a value of the conversion target bit, each time a conversion target bit is selected; a DA conversing section that outputs an analog comparison signal corresponding to the comparison data; a comparing section that outputs a comparison result between the input signal and the comparison signal, upon the output of the comparison signal by the DA converting section, and that is reset after outputting the comparison result; a completion detecting section that, upon detecting that the comparing section has output the comparison result, outputs a completion signal causing the bit selecting section to select a next conversion target bit, prior to the comparing section being reset; and an output secti
    Type: Application
    Filed: July 21, 2008
    Publication date: January 21, 2010
    Applicants: TOKYO INSTITUTE OF TECHNOLOGY, ADVANTEST CORPORATION
    Inventors: YASUHIDE KURAMOCHI, AKIRA MATSUZAWA
  • Publication number: 20100007539
    Abstract: A digital-to-analog converter is disclosed for converting a digital signal into its analog equivalent. The digital-to-analog converter includes a switch capable of coupling a first and a second circuit node to ground, a scaling capacitor having a capacitance value that equals a unit capacitance value coupled between the first and the second circuit node, a first array of capacitors coupled to the first circuit node, a first switching array configured to selectively couple the first array of capacitors to either ground or a reference voltage depending on the digital values of the least significant bits of the digital word being converted, a second array of capacitors coupled to the second circuit node, and a second switching array configured to selectively couple the second array of capacitors to either ground or the reference voltage depending on the digital values of the most significant bits of the digital word being converted.
    Type: Application
    Filed: July 14, 2008
    Publication date: January 14, 2010
    Inventors: Pengfei Hu, JinFu Chen, Qinghua Yue
  • Patent number: 7646325
    Abstract: An ADC, such as a CT SD-ADC, includes a clock generation circuit that produces charging and discharging clock signals such that a settling time for an integrator in the ADC is increased. The clock signals may control a feedback SD-DAC in the CT SD-ADC. The clock signals also may be asymmetric and/or may result in the settling time of the integrator being greater than half the system clock.
    Type: Grant
    Filed: August 7, 2008
    Date of Patent: January 12, 2010
    Assignee: NanoAmp Mobile, Inc.
    Inventors: Axel Schuur, David H. Shen, Ann P. Shen
  • Patent number: 7639167
    Abstract: 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: Grant
    Filed: March 11, 2008
    Date of Patent: December 29, 2009
    Assignees: NEC Corporation, NEC Electronics Corporation
    Inventor: Hiroshi Tsuchi
  • Patent number: 7623054
    Abstract: Disclosed is a differential amplifier of a multi-level output type comprising a load circuit including a diode-connected first transistor with a source thereof connected to a power supply and a second transistor with a source thereof connected to the power supply and connected to a gate of the first transistor through a capacitor, a differential pair including a third transistor and a fourth transistor with sources thereof connected in common and drains thereof connected to drains of the first and second transistors, respectively, a current source for supplying a current to the differential pair, a first switch connected between a gate of the second transistor and a drain of the fourth transistor, an amplifier with an input thereof connected to a drain of the second transistor and an output thereof connected to an output terminal, a second switch connected between a gate of the fourth transistor and a first input terminal, a third switch connected between the gate of the fourth transistor and a third input te
    Type: Grant
    Filed: September 26, 2006
    Date of Patent: November 24, 2009
    Assignee: NEC Corporation
    Inventors: Masao Iriguchi, Hiroshi Tsuchi
  • Patent number: 7619553
    Abstract: A digital-to-analogue conversion arrangement is disclosed which includes first and second groups of the same number of bi-directional bufferless digital-to-analogue converters. The output of at least one converter in each group is connected to a respective capacitive load (CLOAD, CLOAD?). During a calibration phase of operation the converter inputs receive first and second different codes representing the same output level. The arrangement also includes a respective switched capacitor network connected to each converter output, a comparator for comparing the output voltages of the first and second groups, and a control circuit. The control circuit controls the capacitor networks in response to the comparator so as to make the output voltages of the first and second groups substantially equal.
    Type: Grant
    Filed: October 21, 2005
    Date of Patent: November 17, 2009
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Patrick Zebedee, Jeremy Lock
  • Patent number: 7616145
    Abstract: A switched capacitor circuit includes a first level-crossing detector to generate a level-crossing detection signal when an input signal crosses a first predetermined level. A first waveform generator generates a first predetermined waveform and a second waveform generator generates a second predetermined waveform. A second level-crossing detector generates a second level-crossing detection signal when said second predetermined waveform crosses a voltage reference level a second time. A second switch is coupled to the second level-crossing detector, and a third switch is coupled to the first level-crossing detector. The second switch turns OFF when the second level-crossing detection signal indicates the second predetermined waveform crossed the voltage reference level a second time. The third switch turns OFF when the first level-crossing detection signal indicates the input signal crossed the first predetermined level.
    Type: Grant
    Filed: July 23, 2008
    Date of Patent: November 10, 2009
    Assignee: Cambridge Analog Technologies, Inc.
    Inventor: Hae Seung Lee
  • Patent number: 7609184
    Abstract: Provided is a D-A conversion apparatus that outputs an analog output voltage according to digital input data, which includes a capacitance array main D-A converter that supplies a main voltage according to the input data to an output terminal of the D-A conversion apparatus, a correction data output section that outputs correction data according to the input data, a capacitance array correction D-A converter that outputs a correction voltage according to the correction data, and a voltage dividing capacitor connected serially between an output end of the correction D-A converter and an output end of the main D-A converter.
    Type: Grant
    Filed: November 8, 2007
    Date of Patent: October 27, 2009
    Assignees: Advantest Corporation, Tokyo Institute of Technology
    Inventors: Yasuhide Kuramochi, Akira Matsuzawa
  • Patent number: 7592940
    Abstract: A digital-to-analog converter (DAC) can minimize the increase of an area caused by increase of number of bits. The DAC includes a coarse resistor-string digital-to-analog conversion unit for selectively outputting 2N-level analog voltages in response to upper N-bit digital data, wherein N is a natural number greater than or equal to 2, a fine resistor-string digital-to-analog conversion unit for selectively outputting 2N-level analog voltages in response to lower N-bit digital data, wherein the 2N-level analog voltages is obtained by dividing a level of unit voltage of the coarse resistor-string digital-to-analog conversion unit into 2N-levels, and a voltage combining unit for outputting 22N-level analog output signals by combining the output of the coarse resistor-string digital-to-analog conversion unit and the output of the fine resistor-string digital-to-analog conversion unit.
    Type: Grant
    Filed: December 20, 2007
    Date of Patent: September 22, 2009
    Assignee: MagnaChip Semiconductor, Ltd.
    Inventor: Yoo-Chang Sung
  • Patent number: 7593483
    Abstract: In a high-fidelity digital modulator, a mapper is provided to minimize quantization noise, jitter, and cross-talk between multiple digital-to-analog or analog-to-digital converters. The mapper receives a quantized level from a quantizer and maps the quantized level to an output sequence. The mapper includes a table defining multiple sequences corresponding to each quantized level. Each sequence includes two or more symbols, having one of multiple values. The mapper also includes a generator that selects one of the multiple sequences as the output sequence. The last symbol of a first output sequence is equal to the first symbol of the next output sequence and so on. The generator selects the output sequence by alternating between a first and a second sequence for each quantized level received. The generator selects the output sequence by alternating between sequences having a positive and a negative common mode energy for each odd valued quantized level received.
    Type: Grant
    Filed: May 9, 2005
    Date of Patent: September 22, 2009
    Assignee: Broadcom Corporation
    Inventors: Todd L. Brooks, Kevin L. Miller, Josephus A. Van Engelen
  • Publication number: 20090231176
    Abstract: A switched capacitor digital-to-analog converter (SC-DAC) is provided. The SC-DAC of the present invention can eliminate an influence of a reference voltage source caused by a signal dependent loading at each clock cycle, so as to completely solve a harmonic distortion of an analog output signal converted by a conventional SC-DAC. In addition, when the SC-DAC of the present invention has a plurality of converting channels, since the reference voltage source is not influenced by the effect of signal dependent loading of any converting channel, so that each converting channel can be regarded to have a separate state, and thus the purpose of channel separation can be achieved.
    Type: Application
    Filed: March 12, 2009
    Publication date: September 17, 2009
    Applicant: SUNPLUS mMEDIA INC.
    Inventors: Chih-Wei Chen, Lai-Ching Lin
  • Patent number: 7583217
    Abstract: A D/A converter of switched capacitor type capable of shortening the time for D/A conversion process without increasing power consumption is provided. The D/A converter comprises capacitors Cx and Cy for receiving input voltage corresponding to the digital data and charging the amount of charge corresponding to the input voltage, and an operational amplifier A21 including a first amplified output terminal To1 and a second amplified output terminal To2 for individually outputting amplified signals generated based on a signal inputted to the input terminal. During the conversion process, the amplified signal is outputted from the first amplified output terminal To1, after the conversion process is completed, the amplified signal is outputted through an output switch Sw6 from the first amplified output terminal To2.
    Type: Grant
    Filed: January 18, 2008
    Date of Patent: September 1, 2009
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Mutsuo Daito
  • Patent number: 7576675
    Abstract: A return-to-zero current-steering DAC is presented. The presented return-to-zero technique can isolate the analog output nodes of the DAC from the coupling of the control signals of the DAC without sacrificing speed. The topology uses a bank of return-to-zero circuits, which employs return-to-zero and isolation transistors to implement the presented return-to-zero technique.
    Type: Grant
    Filed: March 25, 2008
    Date of Patent: August 18, 2009
    Assignees: Megawin Technology Co., Ltd., National Cheng Kung University
    Inventors: Da-Huei Lee, Tai-Haur Kuo