Abstract: Integrated circuit devices are provided that include power detection circuits that indicate whether power supplies have reached functional voltage levels. The power detection circuits include latches coupled to power supplies that can detect whether all the power supplies have reached functional voltage levels, logic circuits to provide appropriate output signals, and well bias circuits that supply current to the power detection circuits. Well bias circuits provide current from first power supplies to reach functional voltage levels so that indication may be provided from the power detection circuit without requiring functional voltage levels of all power supplies. Outputs from power detection circuits can be combined with control signals, for various applications. Applications include holding an integrated circuit device in reset until power supplies have reached functional voltage levels.

Abstract: An input buffer having a stable trip point over at least process skew and supply voltage variations includes a first inverter stage; a second inverter stage; and an arrangement for compensating for process skew and supply voltage variations. The compensating arrangement is disposed both in the pull-up and pull-down paths, and increases the conductivity of the pull-up path and decreases the conductivity of the pull-down path when the DC trip point of the input buffer falls below nominal. The compensating arrangement also decreases the conductivity of the pull-up path and increases the conductivity of the pull-down path when the DC trip point rises above nominal. The compensating arrangement may include at least one device disposed in each of the pull-up and pull-down paths. The conductivity of these devices may then be controlled by a reference signal that swings about the DC trip point responsive to at least process skew corners and variations in supply voltage.

Abstract: An evaluation circuit 16 repeats processing in which an output VD thereof is reset, there is obtained repeatedly given times a difference between sampled output voltages Vo of a replica circuit 11R when respective times t1 and t2 have elapsed after a voltage Vi is step-inputted to the replica circuit 11R, and the differences are successively summed. A comparator circuit 20 compares a difference cumulation voltage VD with a reference voltage VS. A bias adjustment circuit 15 steps up the bias currents of the replica circuit 11R and an adjusted circuit 11 at every this given times if VD>VS, and ceases the adjustment if VD<VS.

Abstract: A device for reducing the electromagnetic emission in integrated circuits having driver stages reduces the electromagnetic emission of an integrated circuit without requiring an increase in the blocking capacitance in the process. This is achieved by combining driver stages which do not switch simultaneously to form driver groups, and special wiring of a plurality of blocking capacitors.

Abstract: A semiconductor integrated circuit device has a hierarchical power supply system for a logic circuit. Inverters are provided with power supply from a main power supply line and a sub-power supply line of a higher potential and a main ground line and a sub-ground line of a lower potential. An internal power supply voltage-down converter is placed to set the voltage of the main power supply line higher than a normal operation voltage of the higher potential. An internal supply voltage boosting circuit is placed to set the voltage of the main ground line lower than a normal operation voltage of the lower potential. When respective power supply lines are short-circuited by a switching transistor, the voltage of each power supply line can be maintained at an operation supply voltage.

Abstract: A logic circuit has two internal voltage lines and includes additional upper and lower MOS transistors for coupling the external voltage supplies to the internal voltage nodes instead of using a single diode or transistor. These additional devices serve to clamp the internal voltages to a level that minimizes leakage current and maintains the data in the logic circuits.

Abstract: An apparatus having a latch core, where the latch core has a plurality of devices and at least one of the devices has a back gate bias net. A bias voltage circuit is coupled to the back gate bias net. The apparatus may further comprise back to back inverters where each inverter output is coupled to the other inverter input. The inverters may further comprise a PFET transistor and an NFET transistor, where the PFET transistors have a back gate bias net. The inverters may further comprise a PFET transistor and an NFET transistor, the NFET transistors having a back gate bias net. The inverters may further comprise a PFET transistor and an NFET transistor, the NFET transistors and the PFET transistors having a back gate bias net. The bias voltage circuit may be further configured to apply a bias voltage when a metastability may occur. The bias voltage circuit may further comprise a NAND gate.

Abstract: A semiconductor integrated circuit device has a hierarchical power supply system for a logic circuit. Inverters are provided with power supply from a main power supply line and a sub-power supply line of a higher potential and a main ground line and a sub-ground line of a lower potential. An internal power supply voltage-down converter is placed to set the voltage of the main power supply line higher than a normal operation voltage of the higher potential. An internal supply voltage boosting circuit is placed to set the voltage of the main ground line lower than a normal operation voltage of the lower potential. When respective power supply lines are short-circuited by a switching transistor, the voltage of each power supply line can be maintained at an operation supply voltage.

Abstract: A low-voltage differential dual receiver for a SCSI bus uses a symmetrical driver by doing without a termination bias voltage. The data phase and protocol phase of SCSI communication are separated by using two receivers and optimizing each receiver for its particular function. A high-speed receiver is used when transmitting data at high-speeds, and a lower performance, low-speed receiver is used for other SCSI phases. A built-in offset allows the low-speed receiver to operate correctly during bus arbitration. The built-in offset in the low-speed receiver takes the place of the termination bias voltage in a traditional SCSI bus and is implemented in a variety of ways.

Abstract: A low power consuming circuit is provided which is capable of reducing power consumption by using a Vt (threshold voltage) characteristic of a MIS (Metal Insulator Semiconductor) transistor for generating a source voltage. N-channel transistors making up an inverter is configured by being stacked vertically. An N-channel transistor source voltage control circuit controls voltages so that a gate voltage of an N-channel transistor source voltage bias transistor existing in a lower state is transferred to a drain voltage terminal of the N-channel transistor source voltage bias transistor or to a supply voltage terminal.

Abstract: A hybrid power supply circuit for supplying a power to a logic circuit performing a digital logic process and for controlling the charging/discharging of the logic circuit. The power supply circuit has an adiabatic power supply portion for charging/discharging the logic circuit in such a manner to suppress a sudden current change during initial time after the input signal changes, and a CMOS power supply portion for quickly charging/discharging the logic circuit to supply power level/ground level after the charging/discharging by the adiabatic power supply portion. The energy consumption of the circuit decreases even in a digital system having a plurality of logic circuits.

Abstract: In a semiconductor integrated circuit device, for realizing high speed, as well as superior product yield rate and usability, while reducing circuit scale and improving on product yield rate and reliability thereof, a main circuit, constructed with CMOS elements, is coupled to a speed monitor circuit for forming a speed signal corresponding to an operating speed thereof and to a substrate bias controller for supplying corresponding substrate bias voltages to the main circuit in response to the speed monitor circuit.

Abstract: An apparatus comprising a pullup circuit, a pulldown circuit, and a control circuit. The pullup circuit may be configured to receive a first and second control signal. The pulldown circuit may be configured to receive a third and fourth control signal. The control circuit may be configured to generate the first, second, third and fourth control signals. The control circuit may comprise (i) a first and second control device coupled between the first and second control signals and a supply and (ii) a third and fourth control device coupled between the third and fourth control signals and the supply.

Abstract: A method and apparatus in which the switching of a field-effect transistor is effected by the application of a control voltage suitable for switching to an RC element connected upstream of the gate terminal. The method and apparatus are distinguished by the fact that switching of the field-effect transistor is carried out using a control voltage that at least temporarily only slightly exceeds the threshold voltage via an attenuation circuit which has to be applied to the gate terminal of the field-effect transistor in order to be able to effect switching of the transistor.

Abstract: A transistor output circuit featuring a low power consumption, high speed and stabilized operation is realized.

Abstract: A method and apparatus are provided for tri-state dynamic body charge modulation for sensing devices in silicon-on-insulator (SOI) complementary metal oxide semiconductor (CMOS) applications. A sense amplifier includes a silicon-on-insulator (SOI) field effect transistor. A tri-state body charge modulation circuit is coupled to a body of the silicon-on-insulator (SOI) field effect transistor. The body charge modulation circuit provides a high body bias preparatory state; a floating body state and a low body bias stand-by state enabling high performance operation, good matching characteristics, and low stand-by leakage suitable for low-power applications. The tri-state body charge modulation circuit includes a P-channel field effect transistor (PFET) and an N-channel field effect transistor (NFET) connected between a high voltage potential and ground.

Abstract: A semiconductor device includes a PMOS transistor and an NMOS transistor. In a standby state, a potential of Vcc level is applied to the substrate of the PMOS transistor and a potential of Vss level is applied to the substrate of the NMOS transistor. Therefore, the voltage between the source and substrate of the P and NMOS transistors becomes 0 V. In an active state, potentials that render the voltage between the source and substrate lower than the built-in potential are applied to respective substrates of the P and NMOS transistors. Therefore, the threshold voltage of the transistor is lowered in an active state than in a standby state, and almost no leakage current flows between the source and substrate.

Abstract: A semiconductor integrated circuit device has a hierarchical power supply system for a logic circuit. Inverters are provided with power supply from a main power supply line and a sub-power supply line of a higher potential and a main ground line and a sub-ground line of a lower potential. An internal power supply voltage-down converter is placed to set the voltage of the main power supply line higher than a normal operation voltage of the higher potential. An internal supply voltage boosting circuit is placed to set the voltage of the main ground line lower than a normal operation voltage of the lower potential. When respective power supply lines are short-circuited by a switching transistor, the voltage of each power supply line can be maintained at an operation supply voltage.

Abstract: A driver for an EL lamp includes a source of high voltage coupled to a first voltage rail and a second voltage rail and a transistor bridge output coupled to the rails, wherein the bridge output has no current mirrors for the high side transistors in the bridge output.

Abstract: A semiconductor integrated circuit device has a hierarchical power supply system for a logic circuit. Inverters are provided with power supply from a main power supply line and a sub-power supply line of a higher potential and a main ground line and a sub-ground line of a lower potential. An internal power supply voltage-down converter is placed to set the voltage of the main power supply line higher than a normal operation voltage of the higher potential. An internal supply voltage boosting circuit is placed to set the voltage of the main ground line lower than a normal operation voltage of the lower potential. When respective power supply lines are short-circuited by a switching transistor, the voltage of each power supply line can be maintained at an operation supply voltage.

Abstract: An input buffer having a stable trip point over at least process skew and supply voltage variations includes a first inverter stage; a second inverter stage; and an arrangement for compensating for process skew and supply voltage variations. The compensating arrangement is disposed both in the pull-up and pull-down paths, and increases the conductivity of the pull-up path and decreases the conductivity of the pull-down path when the DC trip point of the input buffer falls below nominal. The compensating arrangement also decreases the conductivity of the pull-up path and increases the conductivity of the pull-down path when the DC trip point rises above nominal. The compensating arrangement may include at least one device disposed in each of the pull-up and pull-down paths. The conductivity of these devices may then be controlled by a reference signal that swings about the DC trip point responsive to at least process skew corners and variations in supply voltage.

Abstract: Commonly clocked digital storage elements are provided with mutually different clock-to-output delays in order to timewise stagger their respective switching current spikes from one another, thereby “smearing” the aggregate current spike over time.

Abstract: Circuits with SOI devices are coupled to a body bias voltage via a switch for selectively connecting the body bias voltage signals to the SOI device body. NMOS or PMOS SOI devices are used for the switched body SOI device and a FET is used for the switch and the gate terminal of the SOI device is connected to the FET device. The gate of the SOI device controls the FET switch connection of the body bias voltage signals to the SOI device to adjust the threshold value of the SOI device. Logic circuits incorporating the SOI devices are also disclosed, and the fabrication process for the SOI devices as well.

Abstract: A circuit that provides a termination resistance to a transmission line includes a controllable termination resistor coupled between the transmission line and a termination voltage node. The circuit also includes a control circuit coupled to the controllable termination resistor and to a reference resistor. The control circuit matches the resistance of the controllable termination resistor to the resistance of the reference resistor.

Abstract: An output buffer includes a p-channel transistor, and first and second n-channel transistors. The p-channel transistor has one of a source and drain which is connected to power supply and the other which is connected to an output node connected to an output terminal. The first n-channel transistor has one of a source and drain which is grounded and the other which is connected to the output node. The second n-channel transistor is series-connected to the p-channel transistor between a power supply and the output node and receives at a gate a power supply potential level which rises at substantially the same time as the power supply upon ON operation.

Abstract: A CMOS-based bus-hold circuit having overvoltage tolerance. The bus-hold circuit of the present invention includes, in addition to conventional input and latching inverters, a sense circuit and an arbiter circuit designed in combination to block overvoltage events from powering the latching inverter. The sense circuit includes a comparator designed to compare the potential of a standard high-potential power supply rail to the potential associated with a signal applied to the bus-hold circuit's input node. The higher of those two potentials is used to activate the arbiter circuit that in turn couples the higher of those two signals to a pseudo high-potential power rail. The pseudo high-potential power rail is used to supply power to the latching inverter such that the latching inverter will not be activated during overvoltage conditions, particularly when the circuit is in its high-impedance state. The bus-hold circuit may be similarly designed to establish an undervoltage tolerance as well.

Abstract: An analog process/voltage/temperature (PVT) compensated buffer includes a differential amplifier providing a first output signal indicative of a difference between an input signal and a reference signal. The input signal is compatible with a first type of logic. An active gain stage is coupled to translate the first output signal to a second output signal. The second output signal is compatible with a second type of logic. The differential amplifier and the active gain stage are coupled to receive a process/voltage/temperature (PVT) compensation signal. In one embodiment, the first type of logic is Gunning Transceiver Logic (GTL) and the second type of logic is complementary metal oxide semiconductor (CMOS) logic.

Abstract: An isolation mechanism serves to isolate digital signal processor outputs from a dynamic random access memory controller upon the occurrence of a low power condition. The isolation prevents corruption of dynamic random access memory due to low power. The isolation mechanism receives inputs of a first low power indicator and a second low power indicator. The first low power indicator pulls low and the second low power indicator is forced high when a low power condition exists. One embodiment of the isolation mechanism includes a NAND gate connected to a first low power indicator signal and to a second low power indicator signal as inputs, a NOR gate connected with a NAND gate output as input, and a flip flop connected with a NOR gate output and the first low power indicator as inputs. The flip flop output is input to the NOR gate.

Abstract: A semiconductor integrated circuit including an input circuit constituted as a single-input differential circuit which has a first MOSFET to whose gate a reception signal with a small amplitude with respect to a power supply voltage is supplied and a second MOSFET to whose gate a reference voltage corresponding to an intermediate value of the reception signal is supplied. A dummy circuit is provided and transmits substantially the same power supply noise as the power supply noise transmitted to the gate of the first MOSFET through a electrostatic protection circuit provided to an external terminal which receives the reception signal.

Abstract: A tristate circuit for driving three signal levels to a pin of a device-under-test is disclosed. The tristate circuit includes a driver having an output at a first signal level and adapted for coupling to the pin. A first switching unit couples to the output and responds to a programmed signal. The first switching unit operates to selectively alter the first signal level to a second signal level. A second switching unit connects serially to the first switch. The second switching unit responds to a second programmed signal and operates to cooperate with the first switch to alter the second signal level to a third signal level.

Abstract: A programmable variable impedance output driver circuit uses analog biases to match driver output impedance to load input impedance. A current mirror is used to obtain a measurement of an external resistance value for matching the impedance of a driven load. The mirrored current generates the voltage "NBIAS" when passed through the resistively connected NFET. Similarly, the current is again mirrored and passed through a resistively connected PFET resulting in the voltage "PBIAS". The analog bias voltages, NBIAS and PBIAS are used to vary the impedance of complementary FETs in an impedance matched driver for a high degree of dI/dt control. The driver provides a high degree of flexibility because its turn-on and turn-off characteristics do not depend on a combination of digital control signals connected directly to the driving FETs as in the prior art.

Abstract: An input buffer includes a first CMOS inverter (400) made up of a PMOS transistor (602) connecting Vdd to the buffer output and an NMOS transistor (604) connecting the buffer output to Vss. NMOS transistors (404) and (414) have with series connected source to drain paths to connect the buffer output to Vss in conjunction with transistor (604) of inverter (400). PMOS transistors (402) and (412) have series connected source to drain paths connecting Vdd to the buffer output in conjunction with transistor (602). To control transistors (402, 404, 412 and 414) an inverter (420) is connected from the buffer output to the gates of transistors (402 and 404), and inverters (431, 432, 433, and 440) are connected between the buffer input and the gates of transistors (412 and 414).

Abstract: A bias compensator circuit for significantly reducing an offset produced by a termination bias that is associated with a differential pair bus. The differential pair bus is connected to a driver. The bias compensator circuit includes: (a) a signal source connected to a first line of the differential pair; (b) a first switch for switching ON the signal source while the driver is driving; (c) a signal sink connected to a second line of the differential pair; and (d) a second switch for switching ON the signal sink while the driver is driving.

Abstract: A differential clock receiver for a SynchLink-type Synchronous Dynamic Random Access Memory (SLDRAM) includes a differential amplifier with a novel method for biasing its NMOS and PMOS current sources. A differential clock received and amplified by the differential amplifier switches a set of multiplexers, which respond by outputting a differential output clock. The multiplexers can be "disabled" by an inactive enable signal so they output a constant "0" level for the differential output clock. This disabling feature of the differential clock receiver is particularly useful with the intermittent data clocks found in SLDRAMs. Also, the novel biasing method for the current sources of the differential amplifier gives the clock receiver very low skew.

Abstract: An integrated circuit such as an ASIC device having partitioned functional units with independent threshold voltage control. A first partition is always operated in a normal mode, while subsequent partitions are maintained in a standby mode until a transition is detected at the input of the first partition. The subsequent partitions are switched to the normal mode by lowering the body voltage applied to the devices with each partition. A pulse stretcher is used to keep a partition in a normal mode for a predetermined period of time after the transition is detected.

Abstract: A small amplitude signal output circuit comprises an output section, for receiving a logic signal to output a small amplitude signal, having first and second transistors connected in series between a first source line and a second source line, and voltage control sections connected between each of the source lines and the output section for reducing the output voltage supplied from the output node, thereby allowing ON-resistance of the transistors of the output section to be smaller. The small ON-resistance of the transistors in turn allows variations in the output voltage of the output circuit caused by variations in the fabrication process to be smaller. The voltage control sections may have a function for reducing variations in the output circuit due to temperature variation.

Abstract: A voltage compensating CMOS input buffer converts input TTL signals to CMOS logic levels, and compensates for changing supply voltage by using a n-channel transistor to vary the effective size ratio of pairs p-channel to n-channel transistors making up an input inverter. The compensating transistor becomes operable with increasing supply voltage to help the n-channel input inverter transistors offset the p-channel input inverter transistors whose trip points would otherwise have been increased by increasing power supply voltage. As the power supply voltage decreases, the compensating transistor turns off, returning the input inverter to its original size ratio. The gate of the compensating transistor is coupled to the supply voltage through two diodes to control the amount of current flowing through the compensating transistor. Further trip point transistors in series with the compensating transistor have their gates coupled to the input signals to help stabilize the trip points.

Abstract: An input circuit (20) and a method for protecting the input circuit (20) from positive and negative overvoltages. The input circuit (20) includes an N-channel Metal Oxide Semiconductor Field Effect Transistor (MOSFET) (12), a P-channel MOSFET (13), a Zener diode (21), and a diode-connected transistor (22). The P-channel MOSFET (13) protects the N-channel MOSFET (12) from negative overvoltages. The Zener diode (21) and the diode-connected transistor (22) protect the N-channel MOSFET (12) from positive overvoltages. In addition, the Zener diode (21) protects the P-channel MOSFET (13) from positive overvoltages.

Abstract: The present invention provides digital integrated circuits, buffers, digital devices and methods for buffering data. One embodiment of the digital integrated circuit comprises: a data input configured to receive an input signal at a first voltage; a data output configured to output an output signal at a second voltage; a controller coupled with the data input and the controller being configured to generate an internal control signal and an external control signal responsive to the input signal; the controller having a first voltage regulator configured to maintain the external control signal above a threshold and a feedback voltage regulator configured to maintain the internal control signal above a threshold; and an output driver coupled with the data output and the controller, the output driver being configured to apply the output signal to the data output responsive to the external control signal.

Abstract: A driver circuit drives a digital signal onto a differential digital data transmission bus nominally biased to a negative data state during bus idle intervals by a weak negation bias current. The driver circuit overcomes the negation bias current during an active signaling sequence and comprises a signal current source and sink pair for selectively sourcing and sinking current onto positive and negative lines of the transmission bus in accordance with internally-supplied binary data levels during the active signaling sequence, and a bias override current source and sink pair for applying an override bias current to the positive and negative lines of the transmission line without interruption during the signaling sequence.

Abstract: Various methods and circuitry for implementing output buffers with low voltage CMOS transistors capable of handling signal overshoot and undershoot conditions at an external terminal are disclosed. The present invention detects the level of the signal at the external terminal and adjusts the voltage at the gate terminals of the output transistors connecting to the external terminal in response thereto, such that oxide stress conditions are alleviated. In one embodiment, dynamic biasing techniques are developed by the present invention to ensure that the circuitry protecting the output devices is itself protected against voltage stress caused by overshoot and undershoot at the external terminal.

Abstract: According to one embodiment of the present invention, an output buffer (200) includes a first output driver (86) having a gate oxide protected from voltage changes on an output (16). A second output driver (88) also has a gate oxide protected from voltage changes on the output (16). A level shifter (60) includes at least one cascode device (66, 68, 70, 72) and switches the first output driver (86) according to the values of a data input (12) and an enable input (14). A bias-generation circuit (300) generates a quasi-failsafe voltage that is approximately equal to a chip core voltage when a power supply (4) is supplying the chip core voltage and equal to a portion of the chip core voltage when the power supply (4) is not supplying the chip core voltage. The bias-generation circuit (300) is coupled to a first output cascode (80) coupled to the first output driver (86), to a second output cascode (84) coupled to the second output driver (88), or to the cascode device (66, 68, 70, 72) of the level shifter (60).

Abstract: A constant slew rate amplifier has a precision internal slew rate control reference, that generates respective positive-going and negative-going voltages, associated with corresponding excursions in the input signal. These slew rate-defining voltages are decoupled from the line, making it possible to drive the line with an amplified output signal that faithfully follows the input signal and conforms with prescribed slew rate and rise/fall time specifications, irrespective of the capacitance of the line. In addition, the constant slew rate amplifier of the present invention is configured to minimize power dissipation during non-transitional signal conditions, while providing substantial current to rapidly drive the line from one state to another in accordance with the input signal.

Abstract: A driver circuit has first and second output drivers, monitor circuitry for deriving control signals related to driven signal levels, and supply circuitry responsive to the control signals for controlling the supply voltage to the output drivers. The monitor circuitry can be connected to monitor the voltage at the supply inputs of the output drivers for deriving the control signals. Alternatively, the monitor circuitry can be connected directly to monitor driven output levels from the drivers. In the latter case, the output levels to be monitored are rectified. The monitor circuitry can comprise first and second operational amplifiers for comparing a monitored voltage from first and second output drivers, respectively, to a first and second reference voltages, respectively. The supply circuitry can comprise first and second constant current sources, for example field effect transistors.

Abstract: A low voltage CMOS circuit and method provide output current ability meeting multimode requirements of high voltage off-chip drivers while protecting the CMOS devices from various breakdown mechanisms. The circuit and method utilize intermediate voltages between two power rails and voltage division techniques to limit the voltages to acceptable limits for drain-to-source, gate-to-drain, and gate-to-source of CMOS devices in any chosen technology. The circuit comprises first and second CMOS cascode chains connected between a high voltage power rail, e.g 5 volt and a reference potential power rail, e.g. ground. Each CMOS cascode chain comprises first and second p-type MOS devices in series with first and second n-type MOS devices. An input circuit is coupled to a node at the midpoint of the first CMOS cascode chain. A bias voltage, typically 3.3 volts is connected to the NMOS devices in the first and CMOS cascode chains.

Abstract: In an input circuit of a semiconductor device, a CMOS inverter has first and second transistors connected in series between an external power supply and ground and complementarily operating in accordance with an input signal. The first and second transistors have a connection point connected to an output terminal. A first switching device is connected in parallel to the second transistor and turned on/off. A comparator compares a voltage from the external power supply with a predetermined reference voltage and outputs a reference signal representing a comparison result. A logic circuit performs a logical operation between the reference signal from the comparator and the input signal supplied to an input terminal of the CMOS inverter and ON/OFF-controls the first switching device on the basis of a logical operation result.

Abstract: A bootstrap logic driver circuit operable from a low voltage power supply includes first and second bipolar transistors coupled between positive and negative voltage supplies and having a collector load comprising a first diode structure. A further transistor coupled between the voltage supplies has a collector load comprising a second diode structure. A bootstrap capacitor coupled between the diode structures stores charge when the circuit is in a first condition and is discharged when the circuit is in a second condition to provide an enhanced drive voltage for an output transistor.

Abstract: A microcomputer includes an operation circuit for performing an operation using a reference voltage. A reference voltage input terminal receives the reference voltage from an external device. An output circuit outputs an output signal from the microcomputer to an external destination. The level of the output signal depends on the reference voltage input through the reference voltage input terminal.

Abstract: A transistor output circuit comprises a first insulated gate transistor having a control electrode connected to an input terminal, one main electrode connected to a first diode, and the other main electrode connected to a reference voltage source, and a second insulated gate transistor having a control electrode connected to the input terminal, one main electrode connected to an output terminal, and the other main electrode connected to the reference voltage source. A ratio (W.sub.1 /L.sub.1) of a gate width (W.sub.1) to a gate length (L.sub.1) of the first insulated gate transistor is larger than a ratio (W.sub.2 /L.sub.2) of a gate width (W.sub.2) to a gate length (L.sub.2) of the second insulated gate transistor.

Abstract: The control voltage .phi.1 outputted by the control voltage generating circuit 1 is at a low level in a range where an external supply voltage Vcc is lower than the threshold value of the transistor P1, but increases continuously in analog manner when the external supply voltage Vcc rises. After having matched the external supply voltage Vcc, the control voltage .phi.1 increases in the same way as the external supply voltage Vcc. By use of the control voltage provided with the characteristics as described above for an output circuit, controlled is the gate of a transistor P4 of a low-voltage operating output section 6 operative only at a voltage lower than a predetermined value. The transistor P2 of a full-voltage operating output section 5 of the output circuit is always operative on the basis of the control signal .phi.H of the data output control circuit 3.