Abstract: A differential amplifying circuit 11 includes a current mirror circuit having first and second current ends to which drains of MOS transistors M8 and M9 are respectively connected, and a pair of differential MOS transistors M1 and M2 having gates between which a switch SW1 is connected. A reference potential Vref is applied to the gate of the MOS transistors M9. A switch SW2 is connected between the output VO of an output buffer circuit 12 and the gate of a MOS transistor M1, and a switch SW3 is connected between the output VO and the gate of the MOS transistor M8. During the offset-cancel preparation period, the switches SW1 and SW3 are on and the switch SW2 is off. Next, the switches SW1 to SW3 are turned over, consequently outputting offset-canceled potential VO.

Abstract: A semiconductor device is provided in which power consumption can be reduced in a data cascading system required to always operate. If a data signal captured by a data capturing circuit is to be latched by a latch circuit, a clock transfer blocking circuit and an external data transfer blocking circuit blocks a clock signal and a data signal from being transferred to a data output circuit. Thus, power consumed in semiconductor devices to later stages can be reduced. If the data signal captured is necessary for a later stage of semiconductor device, an internal data transfer blocking circuit blocks the data signal from being latched in the latch circuit, while the clock transfer blocking circuit and the external data transfer blocking circuit cause the captured clock signal and data signal to be output to the data output circuit. Thus, the semiconductor device of interest stops capturing the data signal so that power consumption can be reduced.

Abstract: A semiconductor device carries out a test utilizing contact with a probe needle without being affected by narrowing of the pitch at which output pads are arranged. The device is equipped with test circuits provided between a plurality of output buffers via which signals are output and output pads corresponding thereto. The test circuit includes output switches caused to sequentially make connections by a controller in test and interpad switches involved in making connections of the output pads with a test pad by the controller in test. In test, probe needles are brought into contact with the test pad. The output pads are not used in test, and can be arranged at a narrowed pitch. Thus, the chip area can be reduced and are therefore so that the pitch for the output pads can be narrowed and the chip area can be decreased.

Abstract: A selector circuit comprises four 2-input selectors 50 to 53 each selecting in response to the complementary selection signals D2 and *D2 of MSB and a 4-input selector 24A selecting in response to complementary selection signals D1, *D1, D0 and *D0 of the lower 2 bit. In each of the 2-input selectors 50 to 53, one ends of two switching transistors are commonly connected to each other and the two switching transistors are adjacently arranged in the same row. In the 4-input selector 24A, 4 analogue switch circuits, each of which has two switching transistors arranged in the same row and serially connected, are arranged in parallel to one another and each is arranged in the same row as that of a corresponding 2-input selector. Same selectors are arranged in a row on a substrate and trunk lines for providing two families of gradation potentials V0 to V7 to the circuits are laid above the circuits. Upper/lower trunk line pairs are in the third and second wiring layer, respectively.

Abstract: An operational amplifier, which generates an output voltage at an output terminal that is equal to an input voltage, comprises: a differential circuit, which compares the input voltage and the output voltage; first and second output transistors, which are controlled by the output of the differential circuit to drive the output terminal; and an offset cancel circuit, connected with the differential circuit, for storing an offset amount of this differential circuit, wherein, in the offset cancel period in which the offset amount is stored by the offset cancel circuit, the output terminal is driven by the second output transistor, and in the operational amplifier operation period following the offset cancel period, the output terminal is driven by the first output transistor.

Abstract: The invention relates to an X-Y address type solid-state image pickup device manufactured by a CMOS process, and has an object to provide an X-Y address type solid-state image pickup device which has a small element size and a wide opening ratio, and can reduce a kTC noise. A photodiode 10, a reset transistor 12, a source follower amplifier 14, and a horizontal selection transistor 16 are formed in each of pixel regions Pmn. A kTC noise reduction circuit 6VR1 for reducing a kTC noise and a CDS circuit 6CL1 are formed outside of the pixel regions Pmn. A differential amplifier is constituted by a first differential transistor 62 of the kTC noise reduction circuit 6VR1 and the source follower amplifier 14 in each of the pixel regions Pmn.

Abstract: The invention relates to an X-Y address type solid-state image pickup device manufactured by a CMOS process, and has an object to provide an X-Y address type solid-state image pickup device in which a chip area is not increased, manufacturing costs are suppressed, and an image averaging processing can be carried out. Pixel regions Pmn are arranged in a matrix form in regions defined by horizontal selection lines RWm and vertical selection lines CLn. Each of the pixel regions Pmn includes a photodiode 10, a source follower amplifier 14 for converting an electric charge of the photodiode 10 into a voltage and amplifying it to output image data, and a horizontal selection transistor 16 for outputting the image data to a predetermined one of the vertical selection lines CLn. An amplifier/noise cancel circuit 6 has a built-in image averaging circuit for carrying out an averaging processing of the image data outputted from at least two of the plurality of the pixel regions Pmn.

Abstract: An offset cancel circuit for an operational amplifier comprises a capacitive element for storing a voltage to be amplified by an operational amplifier section and containing an offset, and for feedback-controlling a voltage value of the operational amplifier section based on the stored voltage, and switching elements for switching operation between the storage of the voltage in the capacitive element and the feedback control based on the value of the voltage stored in the capacitive element. The capacitive element and the switching elements can be used to cancel accurately an offset in the operational amplifier section without increasing the gate areas of transistors in the operational amplifier section.

Abstract: In a data driver 10A of a dot-inversion driving type, the outputs of voltage buffer amplifiers B1 to B12 are connected to respective data bus lines D1 to D12 of a LCD panel, short-circuiting switches S1, S3, S5, S7, S9 and S11 are connected between ones of every other adjacent data bus lines concerned with the same display color, and interconnecting lines on first and second rows are arranged in a staggered configuration. These short-circuiting switches are formed at one sides of every other data bus lines, and turned on by a control circuit 13 when the outputs of the voltage buffer amplifier are in a high impedance state.

Abstract: An offset cancel circuit for an operational amplifier comprises a capacitive element for storing a voltage to be amplified by an operational amplifier section and containing an offset, and for feedback-controlling a voltage value of the operational amplifier section based on the stored voltage, and switching elements for switching operation between the storage of the voltage in the capacitive element and the feedback control based on the value of the voltage stored in the capacitive element. The capacitive element and the switching elements can be used to cancel accurately an offset in the operational amplifier section without increasing the gate areas of transistors in the operational amplifier section.

Abstract: The present invention provides a data driver on which an operation test can be easily and reliably conducted at the stage of manufacture and for which the testing time can be reduced and a display utilizing the same. A select switch portion 60 is provided for electrically connecting and disconnecting a ladder resistor portion 56 and selector portions 58. At the ends of wiring of grayscale voltage lines l1 through l64 opposite to the ladder resistor portion 56, there is provided a state setting circuit 62 which sets each of the grayscale lines l1 through l64 at a “High” level or a “Low” level or which sets the ends of the grayscale voltage lines l1 through l64 in a high impedance state. The state setting circuit 62 is further connected to a testing control portion 64 incorporating a shift register which operates in synchronism with a test clock TST-CLK.

Abstract: A liquid crystal display panel includes a driver having pairs of first and second D/A converters, corresponding pairs of first and second polarity changeover switches, and plural switching elements. Each of the first D/A converters receives a picture signal and outputs a positive-polarity voltage and each of the second D/A converters receives the picture signal and outputs a negative-polarity voltage. The first polarity changeover switches are connected to the outputs of the first and second D/A converters and alternately output the positive and negative polarity voltages. The second polarity changeover switches are also connected to the outputs of the first and second D/A converters and output a reverse polarity voltages. The switching elements are connected between the outputs of the first D/A converters and the first polarity switch and the output of the second D/A converters and the second polarity changeover switch.

Abstract: Lower level of data latch holding a digital image data and a positive selector arranged immediately above positive gradation voltage line, for selecting positive analog gradation voltage of positive gradation levels are take as a set, and upper level of data latch holding a digital image data and a negative selector arranged immediately above negative gradation voltage line, for selecting negative analog gradation voltage of negative gradation levels are take as a set. Two sets are arranged in alignment in vertical direction. A plurality of sets of vertically aligned sets are arranged horizontally to shorten a length in horizontal direction with respect to gradation voltage lines.

Abstract: A voltage selector for a D/A converter compensates for varying output response times for different value input signals due to variations in signal line lengths. The voltage selector includes a plurality of first stage transfer gates, including first and second groups of transfer gates, and a plurality of second stage transfer gates, including a first transfer gate connected to the first group of transfer gates and a second transfer gate connected to the second group of transfer gates. The number of the first group of transfer gates is greater than the number of the second group of transfer gates and the number of the second group of transfer gates is set such that a load of the second transfer gate is smaller than a load of the first transfer gate.

Abstract: A first level converter is provided with an input transistor circuit and an output transistor circuit. The input transistor circuit is supplied with power from a first power source and outputs a complementary signal on the basis of an input signal. The output transistor circuit is supplied with power from a second power source, and amplifies and outputs the complementary signal. A second level converter is provided with a pulse generating circuit and a signal output circuit. The pulse generating circuit is supplied with power from the first driving power source, and generates a one-shot pulse signal. The signal output circuit is supplied with power from the second driving power source, latches the one-shot pulse signal and outputs the signal. The semiconductor integrated circuit is provided with a first circuit system, a level conversion circuit and a second circuit system. The first circuit system is driven by being supplied with power from the first driving power source.

Abstract: A constant voltage supplying circuit is disposed between a voltage output terminal of a voltage generation circuit for outputting a voltage having the same polarity as that of a reference voltage, which can be arbitrarily set, and having a greater absolute value than the reference voltage, and a load. This constant voltage supplying circuit includes a first field effect transistor a gate of which is connected to its drain, and to a source of which the reference voltage is supplied, and a second field effect transistor which has the same conductivity type as the first field effect transistor, a gate of which is connected to the drain of the first field effect transistor, a source of which is connected to the voltage output terminal of the voltage generation circuit, and a drain of which is connected to the ground. According to the circuit constitution, the output voltage of the voltage generation circuit can be stabilized to a desired voltage value (the same voltage value as the reference voltage).

Abstract: A flip-flop circuit includes a first switch for controlling passing of input data in response to a single clock signal, a first inverter for inverting the data passed through the first switch, a second inverter for inverting the data output from the first inverter into inverted data and for inputting the inverted data to the first inverter, a second switch for controlling passing of the data output from the first inverter in response to the single clock signal, a third inverter for inverting the data passed through the second switch, and a fourth inverter for inverting the data output from the third inverter into inverted data and for inputting the inverted data to the third inverter, where the first inverter has a driving capability larger than that of the second inverter, and the third inverter has a driving capability larger than that of the fourth inverter.

Abstract: A semiconductor delay circuit device comprises a pair of transistors of the same conduction type having source regions that are arranged adjacent to each other and facing each other, and a substrate contact diffusion region whose conduction type is opposite to that of the source regions. The substrate contact diffusion region extends between the source regions. Therefore, the source regions of the transistors do not influence each other.