Showing papers on "Bandgap voltage reference published in 1990"

High voltage generating circuit for a semiconductor memory circuit

Abstract: There is provided a high voltage generating circuit including a circuit for sensing a voltage level of a high voltage for erasing and programming operations, a circuit for generating a given reference voltage, a circuit for comparing the sensed high voltage with the reference voltage, a circuit for applying or blocking a pump signal to a high voltage pump circuit according to the compared signal, a circuit for raising the voltage up to a given level under the control of the pump signal, and an EEPROM fuse circuit connected to the circuit for sensing the voltage level of the high voltage or the circuit for generating the given reference voltage and having stored data, whereby the voltage level of the high voltage finally output may be properly maintained and controlled according to the state of the stored data.

Integrated circuit system for analog signal recording and playback

Abstract: Integrated circuit system for analog signal recording and playback having improved performance and a very high level of integration. The integrated circuit is complete with preamplifier, automatic gain control, filter, fixed references including a band gap reference, trimming, power output amplifier, memory array, multiple closed loop sample and hold circuits, column decoder, column driver, row decoder, address counters, master oscillator and chip function timing circuits including sample clock, charge pumps, high voltage regulator and waveshapers, low VCC detector, power-on reset and recording reference circuits on a single chip. The system uses a writable analog reference scheme to put many error sources in the common mode, and provides a double ended output for maximum power output in a limited voltage range, and to allow direct connection to a speaker. Trim bits are provided for trimming the oscillator and filter so that the filter characteristics match and track the oscillator frequency and provision is made for absolute addressing and digital end of message markers. Programming is by way of a multi level iterative write process for high resolution.

Source voltage control circuit

Abstract: There is provided a source voltage control circuit including a reference voltage generating circuit with a negative feedback circuit, a source voltage level sensing circuit for increasing the internal source voltage when the external voltage exceeds a given voltage, a first differential amplifying circuit for active operation, and a second differential amplifying circuit for stand-by operation, whereby a stable internal source voltage is produced and the slope of the internal source voltage is readily adjusted when the external source voltage exceeds the given value. The first differential amplifying circuit receives the reference voltage and the internal source voltage, controlled by a first control signal and the output of the source voltage level sensing circuit. The second differential amplifying circuit receives the reference voltage and the internal source voltage, controlled by a second control signal.

Laser driver with temperature compensation

Abstract: A laser driver includes a reference circuit, which may be a bandgap reference, mounted in thermal contact with the laser. The reference produces a current component Iptat that is proportional to the absolute temperature. The modulation current is proportional to Iptat, which slowly with temperature, up to a certain junction temperature (e.g., 65 to 70 degrees C.). Above that temperature, the modulation current increases more rapidly by adding an additional current component Icomp. This provides for the required increase in modulation current to compensate for temperature variations in the laser output. This technique allows the laser to be operated without cooling (as by a thermoelectric cooler) in many applications. The laser driver may optionally include circuitry to provide a bias current, which may be controlled by a backface monitor or threshold detector.

Buffer circuit including comparison of voltage-shifted references

Abstract: An integrated circuit that is useful as a buffer is disclosed. The integrated circuit has an input voltage shifter circuit for shifting an input voltage and an output voltage shifter circuit for shifting an output voltage. It has a first comparator circuit for comparing the input voltage to the output voltage and a second comparator circuit for comparing the shifted input voltage to the shifted output voltage. The first comparator circuit produces a first control signal and the second comparator circuit produces a second control signal. A voltage driver circuit receives the control signals and produces the output voltage. A capacitor to compensate the output voltage can be connected to the output voltage before it is applied to the first comparator circuit and to the output voltage shifter circuit.

Switched capacitor bandgap reference circuit having a time multiplexed bipolar transistor

Abstract: Time multiplexing two or more current sources to source current to a single bipolar transistor achieves a more stable Vbe input for a switched capacitor bandgap reference circuit. With the proper selection of switched capacitor sizes and current sources values to establish a Vbe voltage at the input of a differential amplifier, an output reference voltage can be achieved that is substantially independent of processing and temperature variations as well as circuit aging characteristics. The invention reduces, and in some cases, eliminates the need for trimming values of capacitance or resistance to achieve the desired output reference voltage.

Signal delay circuit for minimizing the delay time dependence on power supply voltage variation

Abstract: A signal delay circuit includes a driving circuit for driving an output signal with a voltage swing voltage between a supply voltage and a ground voltage. The signal delay circuit further includes a varactor load which is coupled to the output signal and has a capacitance which increases according to the supply voltage within a variation range of the supply voltage. The varactor load keeps the delay characteristic of the signal propagation circuit independent of the change of the supply voltage, thereby ensuring high speed operation and improved reliability of the CMOS semiconductor integrated circuit.

Voltage reference circuit with power supply compensation

Abstract: A BiMOS voltage reference circuit which includes a bandgap circuit for providing a predetermined voltage at an output of the circuit that is independent of temperature. A start-up and bias circuit coupled to the bandgap circuit for providing a start-up current to the bandgap circuit during power-up and for providing a bias current to the bandgap circuit after power-up. A feedback circuit coupled to the bandgap circuit for maintaining the bias current to the bandgap circuit independent of power supply variations wherein the predetermined voltage at the output of the circuit is also independent of power supply variations as well as temperature.

Integrated circuit two-cycle test mode activation circuit

Abstract: In an integrated circuit memory chip an improved test mode activation circuit that utilizes a two-cycle voltage level input in conjunction with a first and second voltage pulse. The first and second voltage level inputs are different from the normal power supply voltage level and are compared with each other to see that a significant voltage transition has occurred and, if so, then a test mode output signal is initiated.

A composite high-voltage device using low-voltage SOI MOSFETs

Abstract: A circuit is described that uses low-voltage transistors to form a high-voltage composite device. The circuit is a series string of SOI (silicon-on-insulator) MOSFETs and associated biasing elements fabricated using a modified nMOS process on a SIMOX (separation by implantation of oxygen) substrate. The circuit voltages higher than the breakdown voltage of a single transistor by dividing the applied voltage among the transistors in the string. MOSFET-like characteristics with breakdown voltage up to 60 V are demonstrated using a string of 25 SOI MOSFETs, each with a breakdown voltage of 6-7 V. >

Controlled voltage or current source, and logic gate with same

Abstract: A controlled voltage or current source comprises a first CMOS active voltage divider, which generates a first reference voltage at a first reference node as a first function of temperature, and a second CMOS active voltage divider, which generates a second reference voltage at a second reference node as a second function of temperature. A CMOS difference amplifier, generates the controlled voltage as a function of the difference between the first reference voltage and the second voltage reference, and of a third function of temperature. A final amplifier stage offsets changes in the source voltage. In another aspect, temperature compensated NAND and NOR gates are provided using the controlled voltage source.

Bandgap voltage reference using a power supply independent current source

Abstract: A voltage reference circuit is provided for developing an output voltage operating independent of temperature and power supply variation. A current reference circit provides a current reference signal operating independent of power supply variation and having a predetermined temperature coefficient and flowing through a first transistor and a first resistor each having opposite temperature coefficients. The output voltage is established as the sum of the base-emitter junction potential of the first transistor and the potential developed across the first resistor. The temperature coefficient of the potential developed across the first resistor substantially cancels the temperature coefficient across the base-emitter junction of the first transistor thereby providing the output voltage operating independent of temperature and power supply variation.

High accuracy analog-to-digital converter with rail-to-rail reference and input voltage ranges

Abstract: An analog-to-digital inverter includes successive approximation control logic for generating ten-bit binary numbers, a digital-to-analog converter (DAC) having a resistor string and a weighted-capacitor array for converting the ten-bit binary output of the control logic to a known analog voltage, and an analog comparator for comparing the output of the DAC to a reference voltage provided via a tap to the mid-point of the DAC resistor string. The unknown analog voltage input to the ADC and the reference voltage are provided to the capacitor array to precharge the array to a voltage equal to the reference voltage minus the unknown analog voltage. The output of the DAC is therefore equal to the known analog voltage plus the reference voltage minus the unknown analog voltage.

Band-gap reference

Abstract: A band-gap reference having a differential amplifier with first and second inputs and an output, and a voltage divider coupled to the differential amplifier output. A first transistor having a base, emitter and collector, has its base coupled to the voltage divider, the first transistor having an emitter current density of x. A second transistor having a base, emitter and collector, has its base coupled to the voltage divider, the second transistor having an emitter current density of nx, where n is fixed. A third transistor having a base, emitter and collector, has its base coupled to the emitter of the first transistor, and its collector coupled to the first input of the differential amplifier. A fourth transistor having a base, emitter and collector, has its base coupled to the emitter of the second transistor, and its collector coupled to the second input of the differential amplifier, and the emitter of the fourth transistor being coupled to the emitter of the third transistor. The threshold voltage term for the band-gap reference is derived by setting the emitter current density for the input transistors of the differential amplifier at a fixed ratio, so that there is only one stable operating point, thereby eliminating the need for additional start-up circuitry and allowing the band-gap reference to be used in transient radiation environments.

Bandgap threshold circuit with hysteresis

Abstract: A combined CMOS/linear circuit employs a voltage reference circuit to provide a temperature compensated V REF output. The circuit includes means for switching the reference circuit off and on in response to the signal on an enable terminal. The voltage reference circuit includes a current mirror feedback which is positive in nature to provide a controlled hysteresis action. This provides noise immunity for the enable input. A digital output indicator is included to indicate the state of the reference circuit.

Quick response CMOS voltage reference circuit

Abstract: A CMOS reference voltage generation circuit having a reference stage and a drive stage. Feedback is provided from the generated reference voltage to the reference stage. The inventive circuit is characterized by low standby current requirements, quick correction to deviations in the output voltage due to load variations, and quick response in generation of a new reference voltage when supply voltage transitions.

High-side switch with overcurrent protecting circuit

Abstract: A switching circuit providing detection circuit for detecting a current which flows through a main P-channel MOSFET detection of a floating voltage dependent upon a power supply potential, a reference-voltage generating circuit for generating a reference voltage which is a floating voltage dependent upon the power supply potential and has a constant value independently of variations in power supply potential, a comparator circuit operated on a supply voltage which is a floating voltage dependent upon the power supply potential, for comparing a detected voltage from the detection circuit with the reference voltage from the reference-voltage generating means, to convert the detected voltage into a logic voltage signal (i.e., a bi-level voltage signal and a conversion circuit for converting the logic voltage outputted by the comparator circuit into a voltage measured from a ground potential.

Precision reference-voltage source

Abstract: Proposed is a monolithic-integrated precision reference-voltage source based on the bandgap principle and suitable for use over a wide temperature range. The parabolic temperature/reference-voltage curve produced by the source is made linear using the processing means available in the monolithic integration without the need for additional active components such as transistors and diodes. The precision voltage-reference source includes two resistors (21, 22) represented by the n-doped emitter diffusion zone.

Bandgap voltage reference

Abstract: A bandgap voltage reference of a unique design is disclosed. The reference utilizes a pair of transistors operating at different current densities to provide a current component through a resistor at the ΔV BE of the two transistors. A second current component through the resistor is provided through another resistor connected to the common emitter connection of another pair of transistors, the collectors of the last named pair of transistors each being connected to one input of a operational amplifier, the output of which is the output of the circuit. In operation, the base of one of the last named pair of transistors is connected to a resistor divider on the circuit output and held at the bandgap voltage, the base of the other of the last named pair of transistors also being held at the bandgap voltage by being connected to a resistor divider between the collector of one of the two transistors operating at different current densities and the emitter of a fifth transistor, the base of the fifth transistor being connected to the resistor divider on the circuit output at a point corresponding to a voltage of two bandgap voltages. By proper selection of transistor size ratios and resistor ratios, a high degree of symmetry can be achieved.

Voltage as a function of temperature stabilization circuit and method of operation

Abstract: There is disclosed a circuit and method for providing bias voltage levels which are precisely controlled as a function of temperature. The circuit is arranged to mix a precise bandgap regulated voltage with a temperature compensated circuit to provide the required output. The temperature compensated circuit is in turn arranged to mimic the temperature sensitive components in the output circuit. A reduced voltage level is created which introduces no temperature related voltage changes.

Voltage regulator and method for submicron CMOS circuits

Abstract: A circuit is provided that generates a predetermined regulated voltage between first and second terminals that is positioned between first and second power supply voltage rails wherein the predetermined regulated voltage is substantially independent of temperature and power supply variation. The circuit includes a bandgap circuit for providing a predetermined reference potential that is substantially independent of temperature and power supply variation. A resistive circuit provides first and second voltages which are referenced with respect to the first supply voltage rail. A level translator circuit translates the second voltage provided by the resistive circuit to a third voltage which is referenced with respect to the second supply voltage rail. First and second operational amplifier circuits are provided for respectively transferring the first and third voltages respectively to first and second terminals wherein a voltage developed between the first and second terminals is substantially equal to the predetermined reference voltage of the bandgap circuit.

Semiconductor integrated circuit including an intrinsic MOS transistor for generating a reference voltage

Abstract: A semiconductor integrated circuit for generating a reference voltage, including a semiconductor substrate, a first voltage terminal connected to a first voltage source, a resistor(5) connected to the first voltage terminal, a second voltage terminal connected to a second voltage source, an intrinsic MOS transistor(6) formed in the semiconductor substrate and having a source, a drain, a gate and a channel having no ion-implantation for threshold control, a first wiring connected to the resistor(5) and the source, a second wiring connected to the second voltage terminal and the drain, a third wiring connected to the drain and the gate, and an output terminal(7) connected to the first wiring for connecting the resistor to the source. In addition, in one embodiment, there is further provided a power source voltage generating circuit(36) formed in the semiconductor substrate, wherein a reference voltage input terminal of the semiconductor integrated circuit for generating the reference voltage is connected to the reference voltage output terminal(7), and a predetermined operation is performed in accordance with the potential of the reference voltage input terminal.

Circuit for generating a high voltage for a semiconductor memory circuit

Abstract: Circuit for producing a high voltage comprising a circuit (200) for detecting the level of the high voltage serving in erasure and programming, a circuit (300) for producing a given reference voltage, a circuit (400) for comparing the high voltage detected with the reference voltage, a circuit (500) for applying or blocking pumping signals (17, 18) in voltage pumping circuits (100) depending on the signal resulting from the comparison (410), a circuit for raising the voltage to a given level under the control of the pumping signals, and a fusable circuit of an EEPROM (210, 220) which is connected to the circuit (200) for detecting the level of the high voltage or to the circuit (300) for producing a reference voltage and which has already memorized the information, whereby the level of the high voltage finally output can be maintained appropriately and controlled as a function of the state of the memorized information.

Method and device for converting voltage to frequency

Abstract: A method for converting voltage to frequency and a device for implementing the method where an extremely rapid and highly accurate digitization of an input signal at a great freqency deviation is achieved using simple means. An input voltage which is raised into the positive range, is integrated, and as an integrated voltage is compared with a reference voltage which is variable in constant voltage steps. The resulting differential voltage acts upon a voltage controlled oscillator through a control element. The voltage controlled oscillator emits a pulse repetition frequency which is proportional to the output voltage of the controlling element. The reference voltage is incremented with each pulse so that this voltage follows the integrated voltage in a step-like manner. The pulse repetition frequency of the pulses, which are generated by the voltage controlled oscillator, is therefore proportional to the input voltage.

Speed/position sensor based upon magnetoresistive effect

Abstract: A measuring circuit comprising a transducer (MR), a comparator (33) controlled by the transducer, a bandgap reference circuit (51) with current compensation, a first current mirror, a second current mirror controlled by the comparator and bandgap reference to control the total current. The transducer is a magnetoresistive transducer.

A complete 18-bit audio D/A converter

Abstract: A voltage-output digital-to-analog converter (DAC) for digital audio applications, which combines several conventional circuit architectures, is described It uses high-resolution laser-trimming techniques to achieve total full-scale harmonic distortion plus noise of -94 dB, without external components or adjustments The single-chip converter is integrated with an advanced high-density bipolar/CMOS process, resulting in a 62-mm/sup 2/ chip area, and is assembled in a 16-pin plastic package The logic section includes TTL/CMOS translators for the three-input serial interface, an 18-b shift register, thermometer decoder for segmentation of the four MSBs, and an edge-triggered holding register for minimizing bit skew The analog section consists of an 18-b binary-weighted current source DAC, bipolar offset circuitry, low-noise bandgap reference, and a low-distortion amplifier to provide voltage output The core of the chip is a combination of three different DAC structures The four most significant bits are segmented into 15 equally weighted current cells Segmentation was chosen to decrease the component matching needed for good differential linearity and to decrease sensitivity to component drift over time, temperature, and packaging stress >

Voltage reference having steep temperature coefficient and method of operation

Abstract: There is disclosed a temperature compensated reference voltage generation circuit and method adapted to maintain a specific temperature/voltage relationship. The circuit is designed such that it can easily be adapted to switch between different voltage temperature requirements simply by adjusting the parameters of a few circuit elements. The circuit relies upon three different current generators, each performing a different function.

Reference voltage circuit having low temperature coefficient suitable for use in a GaAs IC

Abstract: A solid-state electrical circuit (10) includes a reference diode (D1) and multiple diodes (D3-D14) connected in electrical series to produce a substantially temperature-invariant output reference voltage. The reference diode is characterized by a forward voltage drop (VD1) that changes in accordance with a temperature coefficient. The multiple diodes, which have selected junction areas (A1 and A2) and receive one of two different forward-bias currents (I1 and I2), are electrically interconnected to establish a net voltage (ΔVDi) that equals the forward voltage drop across the reference diode and changes in accordance with a net temperature coefficient of substantially equal magnitude but of opposite sign to the temperature coefficient of the reference diode. The output reference voltage equals the sum of the forward voltage drop across the reference diode and the net voltage established by the multiple diodes. The output reference voltage is substantially unaffected by changes in temperature because voltage changes resulting from the two temperature coefficients of opposite sign effectively offset each other. The invention is particularly suitable for implementation in GaAs IC technology.

BICMOS positive supply voltage reference

Abstract: The present invention provides a voltage reference level using a bipolar output transistor to provide a reference voltage on a reference output line. A control circuit is used for varying the current to the base of the output transistor in response to the load on the reference output line. In addition, the control circuit provides the reference level to the output transistor. The MOS control circuit and the bipolar output transistor are fabricated on the same chip using a BICMOS process. The voltage reference provided by the control circuit is derived from a voltage level provided by a resistor coupled between the positive voltage supply and a current source.

ISDN U transceiver analog front-end

Abstract: The transmit and receive analog sections of a single-chip U transceiver implemented in a 1.2- mu m CMOS process are presented. A sigma-delta A/D converter achieves 87 dB S/(N+D) pk/rms. A bandgap reference, D/A, switched-capacitor filter, buffer, and line driver implement the transmit path that meets the pulse, spectral, and linearity requirements specified by T1E1. All analog circuits are implemented using fully differential techniques and are designed to meet performance specifications without any production trimming or calibration. >