Abstract: A digital-to-analog conversion circuit of charge distribution type includes a plurality of capacitors having respective capacitances that increase in a sequential order, one end of the capacitors being commonly connected electrically. The circuit also includes a plurality of analog switches each for electrically connecting a reference potential corresponding to a digital signal inputted from outside to the other end of the corresponding capacitor. These analog switches have respective driving capacities that increase in a sequential order.

Abstract: A sequential comparison type AD converter comprising series resistors for generating at respective connection portions reference values to convert an analog value to an m-bit digital value; a comparator for sequentially comparing the analog value and one of the reference value and outputting a digital value; a plurality of capacitive elements for distributing any one of the reference values by capacitance ratio; and a control unit for switching a value compared to the analog value by the comparator from a reference value to a distribution value of the plurality of capacitive elements when the comparator outputs an m-bit digital value, wherein the analog value is converted to an (m+n) bit digital value.

Abstract: A multiplying digital-to-analog converter (MDAC) stage includes a plurality of second capacitances in parallel selectively connected between an input node and an amplifier input and between a corresponding plurality of digital reference signals, which can include a pseudo-random first calibration signal, and the amplifier input. A pipelined ADC incorporating a series of such MDAC stages includes a multiplier connected to the last MDAC stage of the series, a low-pass filter for filtering output of the multiplier and outputting a DC component, and an encoder for receiving output of the MDAC stages and generating a digital output signal and for compensating the digital output signal with the DC component. Background calibration of the ADC includes applying the first calibration signal to a second capacitance of the MDAC stage during a hold phase, and filtering the first calibration signal from the digital output of the pipelined analog-to-digital converter.

Abstract: Improved methods for the calibration, in particular for self-calibration, of an A/D or D/A converter with weighted network (CN) are proposed. Only a relevant part of the weights (C0, C1, C2, Cn) is calibrated by measurement. In addition, by iterative repetition of measurements used for the calibration a noise is used for increasing a resolution. Finally, possibilities for dealing with the offset are illustrated. Complementary equations are set up and the offset is eliminated by subtraction. If an equation necessary for calibration cannot be directly set up because of an overflow, this is resolved by using special binary codes which indicate which weights are enabled and/or disenabled, and their conversion.

Abstract: An interleaving A/D conversion type waveform digitizer module comprising a means for eliminating spurious components resulting from phase errors according to N A/D converters, wherein the digitizer samples signals continually with a predetermined timing corresponding to a interleaving configuration of the A/D converters, receives signals outputted by a tested device to be tested, converts the signals into digital signals, performs Fourier-transform of the digital signals and performs interleaving.

Abstract: A method and apparatus for analog-to-digital pipeline conversion are described. The apparatus includes a sample/hold circuit having an input to receive an analog input voltage, a comparator device coupled to the input of the sample/hold circuit to receive the analog input voltage, and a separate gain circuit coupled to an output of the sample/hold circuit and to the comparator device. The sample/hold circuit and the comparator device sample the analog input voltage and the separate gain circuit amplifies an analog residue voltage obtained from the analog input voltage to obtain an amplified analog residue voltage in a first phase of a non-overlapping clock. The analog residue voltage is obtained in a second phase of the non-overlapping clock, when the sample/hold circuit holds the analog input voltage sampled in the first phase, and the comparator device compares the analog input voltage sampled in the first phase with a reference voltage value.

Abstract: A switched capacitor digital/analog converter is provided for performing non-linear conversion. An input receives an n bit digital word for conversion. The individual bits of the input word control electronic switches which switch the plates of n capacitors between upper and lower reference voltages. The capacitors have values C0, . . . Cn−1 such that Cx<Cx+1 for each integer x greater than −1 and less than (n−1) and such that Cy+1 is different from 2·Cy for at least one integer y greater than −1 and less than (n−1). The other electrodes of the capacitors are connected together and to the output of the converter.

Abstract: A digital-to-analog converter (DAC) with high linearity includes a switched capacitor amplifier removably coupled to a capacitor array. The result of the conversion by the capacitor array is sampled by the switched capacitor amplifier directly from the capacitor in the most significant cell in the array. The switched capacitor amplifier includes a memory capacitor and a feedback capacitor. The memory capacitor provides the initial output voltage corresponding to the result of the conversion when coupled to the capacitor array and stores the output voltage while the feedback capacitor is reset.

Abstract: A digital-to-analog converter (DAC) converts a digital signal into an analog signal. The DAC comprises a first capacitor network, a second capacitor network, a first amplifier, and a second amplifier. The first capacitor network includes at least one capacitor that has a weighted capacitance value. Similarly, the second capacitor network includes at least one capacitor that has a weighted capacitance value. The first amplifier has an input that couples to the first capacitor network. The first amplifier also has an output that couples to, and drives, the second capacitor network. The second amplifier has an input that couples to the second capacitor network. The output of the second amplifier constitutes the analog signal.

Abstract: An object of the present invention is to obtain a high A/D or D/A conversion accuracy, even when there exists a slope in the insulating layer film thickness distribution of the capacitors. The DAC comprises: a capacitor array for storing electric charges in accordance with a digital voltage signal; and an operational amplifier of which input terminal is connected with the capacitor array and amplifies a voltage which corresponds to the electric charges. Here, the capacitor array comprises a plurality of unit capacitors which comprises 2n divisional capacitors which are of the same shape and are connected in parallel. The divisional capacitors are linearly disposed in mirror symmetry about a center line of the capacitor array and one half of the divisional capacitors every unit capacitor is disposed at one side of the center line and another half is disposed at the another side of the center line.

Abstract: A pseudo-differential amplifier circuit 1 is constructed from two equivalent amplifiers 2 and 3 that amplify a pair of input signals without using a differential pair. This pseudo-differential amplifier circuit 1 is used in an arithmetic unit in each of the A-D converter circuits AD1 through ADm in a parallel pipeline A-D converter 10.

Abstract: A digital-to-analog converter (DAC) output stage has an operational amplifier, an integrating path, a direct or data path, and a differentiated path. The integrating path is coupled in parallel to the operational amplifier. Each of the ends of the integrating path is respectively coupled to an input and an output of the operational amplifier. The direct or data path samples data during a first time sampling phase and is coupled in parallel with the integrating path during a second time sampling phase. The differentiated path is coupled in series with a data input voltage to the input of the operational amplifier.

Abstract: In a method and apparatus for digital-to-analog signal conversion, each of a plurality of first capacitors is charged during a first time period in accordance with an associated data bit of an input data byte. During a second time period that follows the first time period, the first capacitors are connected to a second capacitor for charge redistribution. During a third time period that follows the second time period, the second capacitor is connected to an operational amplifier to generate an analog output corresponding to the input data byte.

Abstract: A digital to analog converter augmented with Direct Charge Transfer (DCT) techniques. A digital to analog converter augmented with DCT and CDS techniques. A digital to analog converter augmented with Postfilter Droop Compensation.

Abstract: When a clock &phgr;1 is in high state, based on a digital signal, capacitive elements C11 to C1i are connected between a reference voltage Vr+ or Vr− and a sampling ground V1 to hold a charge corresponding to difference between the reference voltage and sampling ground V1 while capacitive elements C21 to C2i are connected between a reference voltage Vr+ or Vr− and a sampling ground V2 to hold a charge corresponding to difference between the reference voltage and sampling ground V2. When a clock &phgr;2 is in high state, the capacitive elements C11 to C1i and C21 to C2i are connected, in parallel with a feedback capacitive element Cfb, between an input terminal and output terminal of an operational amplifier 100. To obtain a D/A converter which operates at a lower supply voltage and produces output signals low in harmonic components and noise components.

Abstract: A digital-to-analog converter (DAC) with high linearity includes a switched capacitor amplifier removably coupled to a capacitor array. The result of the conversion by the capacitor array is sampled by the switched capacitor amplifier directly from the capacitor in the most significant cell in the array. The switched capacitor amplifier includes a memory capacitor and a feedback capacitor. The memory capacitor provides the initial output voltage corresponding to the result of the conversion when coupled to the capacitor array and stores the output voltage while the feedback capacitor is reset.

Abstract: A switched capacitor digital/analog converter is provided for performing non-linear conversion. An input receives an n bit digital word for conversion. The individual bits of the input word control electronic switches which switch the plates of n capacitors between upper and lower reference voltages. The capacitors have values C0, . . . Cn−1 such that Cx<Cx+1 for each integer x greater than −1 and less than (n−1) and such that Cy+1 is different from 2·Cy for at least one integer y greater than −1 and less than (n−1). The other electrodes of the capacitors are connected together and to the output of the converter.

Abstract: Line drivers are provided that are suitable for driving communication cables (e.g., in Data Over Cable Service Interface Specification (DOCSIS) certified systems) without the need for output drivers and their size, power-consumption, noise and signal-distortion penalities. These line drivers directly couple switched current mirrors to a transformer's input winding to simultaneously provide currents in response to a differential input signal and a digital command signal and drive the load impedance to thereby realize a corresponding signal gain.

Abstract: An integrator stage for use in a delta sigma modulator includes an operational amplifier, an integration capacitor coupling an output of the operational amplifier and a summing node at an input of the operational amplifier, and a feedback path. The feedback path includes first and second capacitors having first plates coupled electrically in common at a common plate node and switching circuitry for sampling selected reference voltages onto second plates of the capacitors during a sampling phase. The integrator stage further includes a switch for selectively coupling the common plate node and the summing node during an integration phase.

Abstract: A successive approximation routine analog-to-digital converter includes a switched-capacitor circuit that samples an input voltage into a plurality of capacitors without the need for power to be dissipated by the analog-to-digital converter. A comparator, coupled to the switched-capacitor circuit, compares a voltage across the capacitors with another voltage during each of a number of iterations. A common mode voltage of the switched-capacitor circuit is boosted during at least some of the iterations. The boost may be accomplished in many different ways and may be different for each of a single-ended, a quasi-differential and fully differential versions of the analog-to-digital converter.

Abstract: In a method and apparatus for digital-to-analog signal conversion, each of a plurality of first capacitors is charged during a first time period in accordance with an associated data bit of an input data byte. During a second time period that follows the first time period, the first capacitors are connected to a second capacitor for charge redistribution. During a third time period that follows the second time period, the second capacitor is connected to an operational amplifier to generate an analog output corresponding to the input data byte.

Abstract: D/A converter of this invention including n+1 capacitors in total consisting of one terminating capacitor (C0) and n binary-weighted capacitors (C1-4) that are subjected to binary weighting ratio of 1:2:4: . . . :2(n−1), and, an inverting amplifier (INV1), further comprising: a feedback switching means (SWR5) provided between the input and output of the inverting amplifier (INV1); a switching means for terminating operation (SWR0) supplies one of two main reference voltages (VB,VT) to the terminating capacitor (C0), and then, makes connection of the terminating capacitor (C0) to the output of the inverting amplifier (INV1); a plurality of switching means for input operation (SWD1-4,SWR1-4) makes selection of one of the two main reference voltages (VB,VT) to be provided for the n binary-weighted capacitors (C1-4) depending on digital data (D1-4), and then, makes connection of the second terminal side of the n binary-weighted capacitors (C1-4) to the output of the inverting amplifier (INV1).

Abstract: When a clock &phgr;1 is in high state, based on a digital signal, capacitive elements C11 to C1i are connected between a reference voltage Vr+ or Vr− and a sampling ground V1 to hold a charge corresponding to difference between the reference voltage and sampling ground V1 while capacitive elements C21 to C2i are connected between a reference voltage Vr+ or Vr− and a sampling ground V2 to hold a charge corresponding to difference between the reference voltage and sampling ground V2. When a clock &phgr;2 is in high state, the capacitive elements C11 to C1i and C21 to C2i are connected, in parallel with a feedback capacitive element Cfb, between an input terminal and output terminal of an operational amplifier 100.

Abstract: A D/A converter circuit capable of handling a high bit number digital signal, having good linearity, and having a small occupied surface area is provided. The D/A converter circuit has n−m+1 capacitors (where m is a natural number, and smaller than n), and the supply and discharge of electric charge to one of the capacitors from among the n−m+1 capacitors are controlled by the lower m bits of a digital video signal. The supply and discharge of electric charge to the remaining n−m capacitors, from among the n−m+1 capacitors, are controlled by the upper n−m bits, from among the n bits, of the digital video signal.

Abstract: A machine used for multi-stage analog-to-digital (A/D) conversion accepts as a stage input an unknown analog input signal and produces as a stage output a residue signal which is negatively scaled with respect to the unknown analog input signal. Combination of the unknown analog input signal and adjustment signals and scaling are accomplished using a circuit requiring only a single op-amp and corresponding output settling delay. The negatively scaled residue signal is passed as input to the following stage. The effects of negative scaling are compensated for in the following stage with proper connection of desired pre-generated reference signals to the second stage's comparators. The invention has a much lower implementation cost than full flash A/D conversion, particularly for high-precision conversions. The invention is also faster than successive approximation (SA) A/D conversion. With proper design, the implementation cost of the present invention can be less than that of prior art SA A/D converters.

Abstract: Provided is a D/A converter circuit which copes with high-bit digital signals and has favorable linearity and small occupation area. In a capacitive divider type DAC, capacitances are simply provided in a one-to-one relationship correspondingly to lower order bit digital signals instead of providing capacitances one-to-one correspondingly to bits. In a reset period, voltages having a height corresponding to higher order bit digital signals are provided to one electrodes (first electrodes) of the capacitances thereby charging the capacitances. In a write period, voltages having a height corresponding to lower order bit digital signals are provided to the other electrodes (second electrodes) of the capacitances thereby charging the capacitances.

Abstract: A switched capacitor digital to analog converter includes first and second converter segments having respective first and second arrays of binary weighted capacitors. Each capacitor of the first segment has a first electrode connected to a first common node and a second electrode connected through respective switches to one of first and second reference voltage terminals. Each capacitor of the second segment has a first electrode connected to a second common node and a second electrode connected through respective switches to one of the first and second reference voltage terminals. The converter includes a coupling capacitor connected between the first and second common nodes and capacitance means connected between the first common node and a reference voltage terminal.

Abstract: A switched capacitor digital-to-analogue converter (DAC) 400 for reducing signal dependent loading of a reference voltage source used by the converter comprises an active circuit (102) with a feedback element. The feedback element comprises a feedback capacitor (104), a second capacitor (106) and switches (402, 110) to connect the second capacitor to one of first and second reference sources to store charge on the second capacitor and to connect the second capacitor in parallel with the feedback capacitor to share said stored charge with the feedback capacitor. The switch is further configured to connect the second capacitor to a substantially signal-independent reference prior to connection of the second capacitor to said one of said first and second references. Connecting the second capacitor to a substantially signal-independent reference source prior to the selected first or second reference gives a linear signal-dependent loading of the first and second reference sources.

Abstract: The successive comparison analog-to-digital (A-D) converter includes a plurality of capacitors, a plurality of first analog switches, a plurality of second analog switches, a plurality of third analog switches, a voltage comparator, and a state controller. Each of the plurality of capacitors has a capacitance weighted with a prescribed weighting factor. Each of the plurality of first analog switches has an on-state resistance weighted with a prescribed weighting factor. In the successive comparison A-D converter, a first analog switch corresponding to a capacitor having a capacitance weighted with a larger weighting factor has an on-state resistance weighted with a smaller weighting factor, whereby a time constant for this capacitor can be reduced. As a result, the difference in time constant between the capacitors is reduced. This enables reduction in time required to precharge (sample and hold) an analog input, improving the A-D conversion speed.

Abstract: A digital to analog converter for converting a multi bit digital input signal into an analog output signal. The converter includes a plurality of substantially equal conversion elements on a semiconductor chip and which are selected in accordance with a dynamic element matching algorithm. The dynamic element matching algorithm is adapted to the position of the conversion elements on the semiconductor chip so as to improve the shaping of the noise caused by the systematic, i.e. position dependent, errors of the conversion elements.

Abstract: A digital-to-analog converter includes a first converter stage 1 for converting the m most significant bits of a k bit input signal to upper and lower voltage limits VL and VH by selecting the appropriate low impedance reference voltages. A second converter stage 2 performs a linear conversion of the n least significant bits of the k bit input within the voltage range defined by the voltage limits VL and VH. A precharging circuit including switches SW1 and SW2 disconnects the stage 2 from the load CLOAD, which is charged to the voltage limit VL during the precharge phase. The load is subsequently disconnected from the voltage limit VL and connected to the output of the stage 2 to complete charging of the load CLOAD to the converter output voltage.

Abstract: A circuit includes a switched current source having a switching transistor coupled in series to a bias transistor. An isolation transistor is coupled in series to an output of the switched current source. The width of the switching transistor is greater than the width of the isolation transistor.

Abstract: Briefly, in accordance with an embodiment of the invention, a method and circuit to perform an analog-to-digital conversion is provided. The method may include generating and storing a combined charge which is generated by combining an input charge and a reference charge.

Abstract: A signal to be produced, which represents a digital data stream, is generated using the currents or voltages from current or voltage sources selected from multiple current or voltage sources. The current or voltage sources whose currents or voltages are used to generate the signal which is to be produced are selected based on the contents of the elements of a shift register whose input connection has the signal which is to be filtered applied to it.

Abstract: A circuit, system, and method are provided for imparting improved randomness into the selection of components or elements of a data converter, such as a D/A converter. The elements are intended to be of equal value, however, regardless of whether they are or not. A circuit is used to randomly select subsets of elements according to a bi-directional selection technique in order to effectively rending the elements or components of equal value. Associated with each component is a switch, and a subset of the plurality of components are correspondingly switched in successive order progressing in a first direction and, subsequently, in successive order progressing in a second direction opposite the first direction. Connecting components in a first direction from left-to-right follows by selecting components in a second direction from right-to-left, and then again selecting components in the first direction from left-to-right, and so forth.

Abstract: A circuit includes an analog-to-digital (A/D) converter for multiplexing between a number of analog input signals and converting the selected analog input signals to a digital code representation. The A/D converter includes a comparator having a first input terminal connected to receive the first signal having a number of levels, a second input terminal connected to receive a multiple number of analog input signals, and a third input terminal for receiving a multiple number of input select signals. The comparator includes a multiplexer coupling the multiple number of analog input signals to a multiple number of corresponding input signal paths. The multiplexer selects one of the multiple number of input signal paths based on the multiple number of input select signals. In one embodiment, the A/D converter is applied in a digital image sensor for performing pixel-level analog-to-digital conversion using a multi-channel bit serial ADC technique.

Abstract: A method and apparatus for performing gain calibration of an analog to digital converter is provided. During a calibration mode, an input sampling circuit comprised of multiple branches can be configured to provide a calibration mode gain of one. The analog-to-digital converter selects one of the parallel capacitor input sampling branches and repetitively samples the whole charge associated with the calibration voltage signal. This sampling step is repeated for each input sampling branch that is used during normal operation mode. The results of the sampling of the branches may be suitably averaged to create a gain calibration coefficient that is representative of and accounts for sampling variations between the input branches.

Abstract: In a sigma-delta modulator the feedback circuit (4, 5) has an adjustable feedback factor controlled by an adjusting member (6) for adjusting the feedback factor of the feedback circuit.

Abstract: A segmented digital-to-analog converter circuit employs a tri-level technique to provide an output current in response to a bit code. DAC slice circuits are activated in unary fashion in response to their respective control signal, which are provided by a decoder circuit in response to the high-order bits. Each DAC slice circuit provides a binary weighted current to a summing node in response to the middle-order bits. One of the DAC slice circuits is selected to direct a portion of its total current to the input of a DAC_LOW circuit, where the input current is divided to provide a divided current to the summing node in response to the low-order bits. At certain code transitions a different DAC slice circuit is selected to provide the input current, and the previously selected DAC slice circuit redirects its total current to the summing node such that differential non-linearity errors are minimized.

Abstract: A circuit includes a switched-capacitor array for converting a digital signal into a corresponding amount of electric charge, a switching circuit, and a continuous-time reconstruction filter circuit. The switched-capacitor array includes a plurality of capacitors and a summing node to which the plurality of capacitors are connected. The switching circuit is coupled between the summing node and the continuous-time reconstruction filter circuit, and supplies a pulsed current signal to the continuous-time reconstruction filter circuit. The circuit may further include a gain stage coupled between the summing node and the switching circuit, for controlling a gain of the pulsed current signal. The gain stage may include a coupling capacitor. A digital signal is supplied to the switched capacitor array and converted into a corresponding amount of electric charge. The electric charge is supplied as a pulsed current signal to the continuous-time reconstruction filter circuit without converting into a voltage signal.

Abstract: A driving circuit of a display device like liquid crystal display, which is small in circuit size, ensures good quality images, and can freely change the display gradation, is configured to execute digital-analog conversion by reallocating charges between a primary-side capacitor and a secondary-side capacitor and includes a plurality of such capacitors in the primary side or the secondary side to enable both quick conversion and reliable potential output to signal lines. Also in an output circuit, output of signal potentials not affected by fluctuation of properties of TFT and inverters can be realized.

Abstract: The successive comparison analog-to-digital (A-D) converter includes a plurality of capacitors, a plurality of first analog switches, a plurality of second analog switches, a plurality of third analog switches, a voltage comparator, and a state controller. Each of the plurality of capacitors has a capacitance weighted with a prescribed weighting factor. Each of the plurality of first analog switches has an on-state resistance weighted with a prescribed weighting factor. In the successive comparison A-D converter, a first analog switch corresponding to a capacitor having a capacitance weighted with a larger weighting factor has an on-state resistance weighted with a smaller weighting factor, whereby a time constant for this capacitor can be reduced. As a result, the difference in time constant between the capacitors is reduced. This enables reduction in time required to precharge (sample and hold) an analog input, improving the A-D conversion speed.

Abstract: In a capacitor-array D/A converter which includes a thermometer decoder (103) for thermometer-decoding a decoder input signal having first through m-th (m is an integer not less than two) input bits to produce an output signal having first through n-th (n=2m−1) output bits, where m is an integer not less than two and where n is equal to (2m−1), first through n-th switches (SU1 to SU31) corresponding to the first through the n-th output bits of the thermometer decoder, and a capacitor array (104) including first through n-th capacitors (8C1 through 8C31) corresponding to the first through the n-th switches, the first through the n-th capacitors are arranged in a main area of the capacitor array and in a row direction of the capacitor array consecutively from the center outward to the left and the right to be symmetrical. Each of the first through the n-th switches are supplied with a corresponding bit of the first through the n-th output bits from the thermometer decoder.

Abstract: Provided is a D/A converter circuit which copes with high-bit digital signals and has favorable linearity and small occupation area. In a capacitive divider type DAC, capacitances are simply provided in a one-to-one relationship correspondingly to lower order bit digital signals instead of providing capacitances one-to-one correspondingly to bits. In a reset period, voltages having a height corresponding to higher order bit digital signals are provided to one electrodes (first electrodes) of the capacitances thereby charging the capacitances. In a write period, voltages having a height corresponding to lower order bit digital signals are provided to the other electrodes (second electrodes) of the capacitances thereby charging the capacitances.

Abstract: A CDAC circuit is provided that can operate at low supply voltages, for example, at supply voltages of 2.5 volts or less. To accomplish low voltage operation, switches in the CDAC circuit, such as sampling bit switches, mid-point switches or auto-zero switches, are gate-boosted to permit the voltage at the transmission gates to exceed the threshold voltage and thus permit the transmission gates to effectively operate. As a result, the CDAC can continue to operate, even with the existence of lower power supply voltages. In accordance with an exemplary embodiment, a gate-boosting circuit comprises a pair of N-channel transistor devices and a charging capacitor configured to provide a gate-boosting voltage to the transmission gates. In addition, the gate boosting circuit can comprise conventional CMOS devices, rather than more expensive low threshold MOSFET devices.

Abstract: A digital-to-analog converter comprises capacitor stack (61, 62), the common point of which is the output of the converter. Digitally controlled switches (66-70), which may be discrete outputs from a microcontroller, selectively apply first or second potentials to points in the capacitor stack, either directly (66, 70) or through resistors (63-65).

Abstract: An algorithmic procedure automatically generates layout of matched capacitor arrays used in A/D converters, D/A converters and programmable gain amplifiers, among other types of devices, using templates to define the style of the layout. Since each array can be generated from a particular template, multiple arrays associated with an IC can be optimized for different purposes to preserve silicon area. The automated technique allows fast and easy migration of an array layout from one process to another and eliminates the manual design work generally associated with capacitor array layout.

Abstract: The present invention relates to a D/A converter circuit which is capable of independently controlling the output voltage amplitude VOUT and the reference voltage. The D/A converter circuit converts “n” bit digital data (“n”: natural number) to analog signals, wherein the respective bits of said “n” bit digital data control a switch, control charge and discharge of electric charges in the capacitance connected to said switch, and output analog signals with the offset potential used as a reference potential.

Abstract: A capacitor digital-to-analog converter for N-bit digital-to-analog conversion comprises a converter capacitor network comprising 2N capacitors and 2N+1 MOS switches and an output buffer. The MOS switches are connected in a series chain at their respective source/drain, and each of the capacitors has a first electrode connected to a corresponding joining node between two consecutive MOS switches in the series chain and a second electrode connected together to a common node. The output buffer comprises a differential amplifier and an output amplifier, the differential amplifier has 2N discrete inputs each connected to a corresponding one of the first electrodes of the capacitors in the converter capacitor network.

Abstract: In a D/A conversion apparatus capable of achieving high accuracy formation of output voltage of an analog signal, when data D7 through D0 of 8 bits are inputted to a decoder 4, by a control signal from the decoder 4, a pair of switches connected to both ends of predetermined resistor R0 are selected from respective switches S0A through S255A, S0B through S255B of respective switch groups 3A, 3B of a voltage selecting circuit 3 and simultaneously operated to make ON and the other respective switches are operated to make OFF. Further, voltage across both sides of resistor R0 of a voltage generating circuit 2 connected with the pair of switches operated to make ON is inputted to a differential amplifier 5 and average voltage of the voltage across the both ends of the resistor R0 connected with the switches operated to make ON is outputted from an output terminal 6 as an analog signal.