Showing papers on "Bandgap voltage reference published in 1988"

Bandgap voltage reference including a process and temperature insensitive start-up circuit and power-down capability

Abstract: A bandgap voltage reference start-up circuit configured to initiate bandgap reference operation over an extended temperature range while being relatively insensitive to the effects of fabrication process variables. The circuit as preferably implemented includes a differential amplifier in the bandgap voltage reference stage which controls the source of current to contrasted bipolar devices situated in parallel paths. A comparator monitors the activities of the current source drive signal and compares that to an internally generated reference, which reference is configured to the matched in temperature and process variable effect the corresponding bandgap reference bipolar device and the current source device. During start-up the comparator initiates an injection of current into one bipolar device of the bandgap reference circuit to drive the bandgap loop into the appropriate of two potential operating states. The preferred embodiment also includes a power-down mode capability.

High voltage semiconductor with integrated low voltage circuitry

Abstract: Low voltage semiconductor devices (2′,3′) are integrated monolithially with a high voltage semiconductor device (1′) on an electrically conductive substrate. The substrate forms an electrode (4′ of the high voltage device (1′) and is connected in use to the high voltage terminal (5′) of a power supply. The low voltage devices (2′,3′) operate from a regulated low voltage supply (12′,13′), which is regulated with reference to the high voltage supply voltage, and not with reference to earth. This reduces the need to isolate the low voltage devices from the conductive substrate. An intelligent power switch circuit constructed in accordance with the invention is suitable for example for use in a motor vehicle.

High voltage booster circuit for use in EEPROMs

Abstract: A semiconductor integrated circuit includes a CMOS circuit operated on a voltage of a first voltage level to set an output node thereof to a voltage of the first voltage level or a reference voltage; an output circuit for controlling supply of a voltage of a second voltage level which is higher than the first voltage level to a signal output node; and an isolation MOS transistor having a current path connected between the output node of the CMOS circuit and the signal output node and a gate connected to receive a control signal. The output node of the CMOS circuit is set to the reference voltage with the conduction resistance of the isolation MOS transistor kept high after the lapse of period in which the voltage of the second voltage level is kept supplied to the signal output node. After this, the conduction resistance of the isolation MOS transistor is reduced in response to the control signal.

MOS bandgap voltage reference circuit

Abstract: A bandgap voltage reference circuit manufactured with a MOS process is provided which is stable over temperature variations as well as variations in threshold voltage that does not require an operational amplifier. The reference is generated by a MOS current source two sourcing current to substrate bipolar transistors operating at different current densities and operated as emitter followers having a pair MOS current mirrors sinking current therefrom. A start-up circuit initializes the circuit upon application of supply voltages. An output stage multiplies the bandgap reference voltage to the desired output voltage level. A feedback stage improves the accuracy of the output voltage by adjusting the current in the reference circuit.

CMOS bandgap voltage reference apparatus and method

Abstract: An improved CMOS bandgap voltage reference in which a magnified current derived from a thermal voltage reference produces a voltage drop across a resistor. The resistor in turn couples to a single bipolar transistor which is part of the thermal voltage reference. The bandgap voltage is the sum of the voltage across the resistor and the voltage across the bipolar transistor. In addition, the immunity of a bandgap voltage reference to variations in power supply variations is improved by having a differential amplifier sense the voltages at the control current input and the output of a current mirror in the thermal voltage reference portion of the bandgap voltage reference and adjusting the power supply voltage to the thermal voltage reference until the sensed voltages are substantially the same.

ESD protection circuit for MOS integrated circuits

Abstract: An ESD protection circuit, suitable for use as part of an integrated circuit, limits the voltage potential at the contacts of the integrated circuit to a voltage potential difference range relative to, though extending beyond the voltage source potentials of the circuit protected. The ESD protection is effective regardless of whether the integrated circuit is powered. The ESD protection circuit includes a clamp subcircuit for limiting the voltage potential at a clamp point to a first voltage range approximately defined by the voltage source potentials and a voltage offset subcircuit, coupled between the clamp point and an integrated circuit contact, to establish a second voltage range encompassing the first voltage range. The voltage offset subcircuit conducts current between the clamp point and the contact to limit the voltage potential at the contact to the second voltage range.

Temperature and power supply compensation circuit for integrated circuits

Abstract: A monolithic integrated circuit generates a programmable time delay under control of a digital work. The delay is generated by comparing a ramp signal to a threshold determined by the value of the digital word and appears as a time difference between a trigger pulse and a pulse generated when the value of the ramp voltage equals the value of the threshold voltage. The ramp voltage is generated by a simple resistance/capacitance charging circuit whose time constant can be adjusted by the user. The threshold voltage is set by a digital-to-analog converter (DAC) and resistor circuit which converts the digital control word into a variable voltage. In order to stabilize the device against changes in temperature and power supply variations, a voltage coupling circuit forces the threshold voltage to track changes in the ramp voltage caused by temperature and power supply variations. The coupling circuit obviates the need for percision voltage sources or current mirrors conventionally used to compensate for temperature and power supply changes. Without the need for the latter device, the integrated circuit can be easily and inexpensively fabricated of transistors of a single bipolar type.

CMOS input buffer with switched capacitor reference voltage generator

Abstract: An input buffer circuit for providing corresponding CMOS compatible signals to an input signal. The input buffer circuit is comprised of a switched-capacitor voltage division network for providing a reference voltage to a comparator. The comparator accepts an input voltage and determines if the input voltage is greater or less than the reference voltage and generates a CMOS compatible output, which is determined by the value of the input signal in reference to the reference voltage. The reference voltage generator is comprised of two capacitive devices, wherein the first capacitive device is charged and the second capacitive device is discharged during a first time period and the charges on the two capacitive devices are shared during a second time period. A ratio of the capacitances of these two capacitive devices determines the voltage value at the junction of the two capacitors, which then determines the reference voltage. The two capacitors are comprised of an n-type device and a p-type device to provide immunity to variations in process and temperature.

AFT circuit for CATV receiver system

Abstract: An automatic fine tuning (AFT) circuit for a CATV receiver system of a double conversion type having a first local oscillator and a second local oscillator and a first mixer and a second mixer respectively supplied with oscillation outputs from the first and second local oscillators is disclosed. A reception signal is sequentially subjected to frequency conversation by use of the first and second mixers so as to attain an intermediate frequency signal of a predetermined value. The AFT circuit includes a control voltage generator for outputting a control voltage which is a function of a frequency fluctuation of the intermediate frequency signal; a selector for selecting either the control voltage or a constant voltage and for supplying the selected voltage as an oscillation frequency control voltage controlling the oscillation frequency of the second local oscillator; an integration unit for integrating the oscillation frequency control voltage so as to produce an integrated control voltage; and a voltage comparator for comparing the integrated control voltage with a reference voltage so as to supply a result of the comparison to the selector. In response to the compare result from the voltage comparator, the selector supplies the control voltage to the second local oscillator when the integrated voltage is higher than the reference voltage and supplies the constant voltage to the second local oscillator when the integrated voltage is lower than the reference voltage.

Power on reset circuit for a MOS technology integrated circuit

Abstract: A powering circuit to start up a MOS technology integrated circuit consists of first means made up of an oscillator and a voltage-increasing device to generate, from a supply voltage, a voltage greater than said supply voltage, and second means to measure the difference between the supply voltage and the generated voltage and to generate a powering signal when the difference reaches a given threshold.

Voltage comparator having hysteresis characteristics

Abstract: A voltage comparator circuit with hysteresis characteristics includes a voltage comparator circuit for comparing an input signal voltage with a comparison reference voltage and outputting a comparison result, a resistor element connected between the reference potential terminal and the comparison reference voltage input terminal of the voltage comparator circuit, a first constant current source for supplying current into the comparison reference voltage terminal and a second constant current source for deriving current out of the comparison reference voltage input terminal, and a control circuit for selectively activating one of the first and second current sources, in accordance with the logic level of an output of the voltage comparator circuit.

Wide range power supply BiCMOS band-gap reference voltage circuit

Abstract: A BiCMOS bandgap reference voltage circuit is disclosed wherein substantial independence from a specified variation in supply voltage is accomplished through establishing a feedback loop between the output of the circuit and the input of the circuit such that the input is a function of the output.

Temperature controller and method of temperature control for use in a refrigerating device

Abstract: A temperature controller and method of controlling a refrigerating device includes a temperature sensor for detecting temperature, a conversion circuit, a refrigerating cycle driving circuit, a comparison circuit, a failure decision circuit, and a memory circuit The conversion circuit converts the temperature detected by the temperature sensor into a voltage value The refrigerating cycle driving circuit operates a refrigerating cycle to cool a compartment in accordance with the voltage value The comparison circuit compares the voltage value with a reference voltage range The reference voltage range is changed by the failure decision circuit to two different states The reference voltage range in the first state includes an ordinary voltage range corresponding to an ordinary operating temperature range of the refrigerating device The reference voltage range in the second state includes the first state reference voltage range When the voltage value is outside the reference voltage range in the second state, it is decided that a failure has occurred in the temperature sensor When the voltage value is outside the reference voltage range in the first state but inside the second state reference voltage range, it is decided that a failure has occurred in the refrigerating cycle or the refrigerating cycle driving circuit The failures of the refrigerating device are memorized in the memory circuit

Bandgap voltage reference circuit with an NPN current bypass circuit

Abstract: A temperature compensated bandgap voltage reference circuit employs an npn transistor based bypass circuit to maintain a constant collector current within the reference circuit. This bypass circuit draws a nominal current from the bandgap voltage reference circuit. The value of this current is set by a bias circuit responsive to changes in the supply voltage. As the supply voltage changes, the bias circuit varies the conductance of a bypass transistor to draw more or less current and thereby maintain the collector current within the reference circuit constant.

An analog front end for v.22bis modems

Abstract: An analog front end for the 2400-b/s v.22bis modem has been implemented in a 3- mu m CMOS process. A high level of integration in the front end results in a low-cost, high-performance modem system. A mix of analog switched-capacitor and digital circuits is used throughout the chip. Some of the major functional blocks are a modulator, tone generator, band-split filters, programmable receive gain stage, 8-bit ADC (analog-to-digital converters), bandgap voltage reference, and special signal detectors. Features are included to support a number of lower-speed, split-band modem standards. The chip occupies 59000 mils/sup 2/ and dissipates 200 mW. System and circuit aspects of the design are discussed; measured performance of the IC and of the complete modem system are given. >

CMOS input buffer stable for the variation of a power supplying voltage

Abstract: A CMOS input buffer for converting the TTL level signals to the CMOS level signals, thereby being capable of stably operating within all allowable range of the power supply voltage, is disclosed. Said CMOS input buffer includes an inverter, a reference voltage generating circuit, a power supply voltage tracer circuit and an input circuit. The input circuit includes P-channel MOS transistors and N-channel MOS transistors so as to supply a stable logic output in response to the input signal of TTL level, regardless of variation of the power supply voltage Vcc, under the control of a voltage that is approximately proportional to the difference between the reference voltage and the power supply voltage within a fixed range of the power supply voltage.

Pulse generator output voltage calibration circuit

Abstract: A calibration circuit for a pulse generator which produces pulse rise and pulse fall times by charging and discharging a capacitor at selected currents and clamps the pulse high voltage output and pulse low voltage output at selectable voltage levels. An output voltage error is developed by comparing each output voltage to a reference clamping voltage. The output voltage error is converted to digital form for storage and then reconverted back into a voltage where it effectively compensates the reference clamping voltage, thereby removing the error from the output voltage. The pulse generator output can be calibrated for any combination of currents and voltages and also for any amplification factor selected for the output amplifier.

Charge transfer device with reset voltage generating circuit

Abstract: In a charge transfer device, a voltage generating cirucit generates a voltage amounting to a potential lower by "α" (α: a predetermined potential) than a potential formed under a reset gate electrode when stored charges of a floating diffusion region are discharged into a drain region. A voltage step-up circuit steps up a predetermined voltage and supplies the stepped-up voltage as a reset voltage to the drain region. A comparison/control circuit generates an error voltage amounting to a difference between the output voltage of the voltage generating circuit and the stepped-up voltage, and controls the voltage step-up operation by the step-up circuit according to the error voltage. With the structure of the device, the stepped-up voltage from the voltage step-up circuit, which is supplied as a reset voltage to the drain region, is controlled according to the process parameter variations. The result is that the reset voltage well follows up the process parameter variations, the dynamic range of the output signal is always kept wide, and the output signal of good linearity and good S/N performance can be obtained.

Voltage regulator circuit for use in a programmable message display

Abstract: A voltage regulator circuit provides an economical approach for maintaining the RMS filament voltage of vacuum fluorescent tubes within an acceptable voltage range during input supply voltage variations. The regulator circuit includes substantially identical upper and lower clipper circuits which clip the AC voltage of a step-down transformer secondary. The supply voltage is allowed to vary so that the secondary voltage is outside of the acceptable range of voltage defined by substantially identical voltage reference circuits. Each of the voltage reference circuits is coupled to its respective clipper circuit and to the center tap of the secondary winding of the transformer so that the regulator circuit and the clipped output voltage are symmetrical about the center tap. Th regulator circuit is simple and power-efficient while keeping the filament voltage within the acceptable range of voltages.

Cmos reference voltage generator device

Abstract: of EP0282725The reference voltage generator device implemented in CMOS technology, comprises a first circuit (10) for generating a differential voltage; a second circuit (12) for amplifying and shifting the differential voltage to provide a single ended voltage; and a third circuit (14) for selectively removing unwanted components from said single ended voltage and to provide a reference voltage that is supply and temperature independent.

Regulated power supply for MOS Transistors with short channel length

Abstract: This semiconductor device has power source terminals for receiving a power source voltage and a voltage converting circuit for generating an output voltage lower than the power source voltage on a semiconductor chip. In particular, the voltage converting circuit has a constant voltage circuit for generating a reference voltage lower than the power source voltage, a voltage drop circuit which is connected to the power source terminal, and a differential amplifying circuit for controlling the conductivity of the voltage drop circuit in accordance with a difference between the output voltage of the voltage drop circuit and the reference voltage from the constant voltage circuit. This differential amplifying circuit generates a control voltage which linearly varies at a gentle slope in response to a change in feedback voltage near the reference voltage.

Bandgap startup circuit

Abstract: A bandgap reference circuit has first and second bipolar transistors 2, 4 of similar type but with different current density emitter paths, the first transistor 2 providing a base-emitter voltage to the base of the second transistor 4 to fix its operating point. The collectors of the first and second transistors are coupled to third and fourth transistors 6, 8, respectively, the third and fourth transistors being connected in current mirror configuration to form an active load which forms part of an output load of the circuit across which an output reference voltage is developed. The output reference voltage is sensed by a transistor 24 which controls a current source 20, 26 coupled to the first transistor 2 whereby, should the circuit go towards a collapsed condition, the reduced output reference voltage is sensed, causing increased flow of current from the current source to the first and second transistors, whereby to maintain the circuit in an operative condition.

Voltage multiplier circuit

Abstract: An EEPROM includes a voltage multiplier (100) for generating an erase voltage and a voltage regulator circuit (108) for controlling the magnitude of the erase voltage. The voltage regulator circuit includes means for providing a first voltage proportional to the erase voltage, means for providing a reference voltage on a reference voltage lead, and means for controlling the voltage multiplier circuit so that if the first voltage is less than the reference voltage, the voltage multiplier circuit will increase the erase voltage, but if the first voltage is greater than the reference voltage, the voltage multiplier will not continue to increase the erase voltage. The voltage multiplier (100) includes capacitors (103) and transistors (101;105) constructed using standard EEPROM processing to withstand high voltages without breaking down.

Temperature detection method and apparatus

Abstract: A temperature detector including a temperature sensor to generate an analog voltage corresponding to a temperature detected thereby. The temperature detector is provided with an A/D conversion device to generate digital temperature data corresponding to the analog voltage input thereto, a reference voltage range setting device to set the reference voltage range to the A/D conversion device, and a reference voltage range changing device. The A/D conversion device compares the analog voltage with the reference voltage which varies within the set reference voltage range. The reference voltage range is automatically changed by the reference voltage range changing device not only to obtain a desired resolution of temperature in a normal operating mode, but also to detect a malfunction of the temperature sensor in a malfunction detection mode.

A CMOS Bandgap Reference with Reduced Offset Sensitivity

Abstract: A new circuit technique to realize a voltage reference in a CMOS process based on the bandgap reference principle is discussed. The reference voltage can be chosen freely as long as it is greater than or equal to the silicon bandgap voltage. The circuit combines a reduced sensitivity for MOS amplifier offset with a reduction of chip area occupied by resistors. The validity of the circuit technique has been demonstrated on silicon.

Semiconductor integrated circuits

Abstract: A semiconductor integrated circuit, comprises a semiconductor integrated circuit chip; a standard voltage generating means for generating standard voltage other than a supply voltage and a ground voltage, at least one, standard voltage wire for supplying the standard voltage to at least one circuit of said semiconductor integrated circuit chip; at least one first capacitor extending along the standard voltage wire, the first capacitor having the standard voltage wire as one electrode thereof, and the other electrode connected to the supply voltage; and at least one second capacitor extending along the standard voltage wire, the second capacitor having the standard voltage wire as one electrode thereof, and the other electrode connected to the ground voltage.

A 1-Mbit BiCMOS DRAM using Temperature Compensation Circuit Techniques

Abstract: A temperature-compensation circuit technique for a dynamic random-access memory (DRAM) with an on-chip voltage limiter is evaluated using a 1-Mb BiCMOS DRAM. It was found that a BiCMOS bandgap reference generator scheme yields an internal voltage immune from temperature and V/sub cc/ variation. Also, bipolar-transistor-oriented memory circuits, such as a static BiCMOS word driver, improve delay time at high temperatures. Furthermore, the BiCMOS driver proves to have better temperature characteristics than the CMOS driver. Finally, a 1-Mb BiCMOS DRAM using the proposed technique was found to have better temperature characteristics than the 1-Mb CMOS DRAM which uses similar techniques, as was expected. Thus, BiCMOS DRAMs have improved access time at high temperatures compared with CMOS DRAMs. >

Constant current circuit

Abstract: PURPOSE:To obtain a constant current with high accuracy, by utilizing a band gap reference type reference voltage source. CONSTITUTION:When a voltage is impressed on a power source voltage line VCC, the base and the collector potentials of an NPN transistor NTr15 form a one diode voltage drop part. On the collector of an NTr14, the current smaller than that of the NTr15 flows. Also, on a PNP transistor PTr11, the same current as the collector current of the NTr14 flows, then, the voltage between the base and the emitter of the PTr11 is decided. The current of the PTr11 is shifted to a PTr10, then, it flows into an NTr16. The base and the collector potential of the NTr16 goes to a value higher by one diode voltage than the voltage V of the reference voltage source 9, and is impressed on the base of an NTr13, and since it is higher than the NTr14, the NTr14 is switched to a cut off state, and the current with the value in which the emitter potential of the NTr13 is divided by a resistor 17 flows on the collector of the NTr13, and the collector current of the PTr11 goes to the constant current similarly as the PTr12. In such a way, it is possible to obtain the constant current with high accuracy.

Low-loss voltage comparator

Abstract: The invention relates to a circuit arrangement for a voltage comparator, particularly for digital telephone terminals fed via the subscriber line, subsequent circuit sections only being connected in the case of a minimum feed voltage. It is the object to create such a circuit arrangement as inexpensively as possible and with the lowest possible losses. This is achieved by the fact that, with the aid of a voltage divider, a part voltage of the direct voltage to be tested is obtained and is evaluated together with a reference voltage via a transistor network in such a manner that, when the minimum direct feed voltage is present, a corresponding output signal is formed, the transistor network at the same time going into the blocked state and the circuit arrangement thus becoming a low-loss arrangement.