Showing papers on "Bandgap voltage reference published in 1983"

A precision curvature-compensated CMOS bandgap reference

Abstract: A precision curvature-compensated switched-capacitor bandgap reference is described which uses a standard digital CMOS process and achieves temperature stability significantly lower than has previously been reported for CMOS circuits. The theoretically achievable temperature coefficient approaches 10 ppm//spl deg/C over the commercial temperature range and uses a straightforward room temperature trim procedure. Experimental data from monolithic prototype samples are presented which are consistent with theoretical predictions. The experimental prototype circuit occupies 3500 mil/SUP 2/ and dissipates 12 mW with /spl plusmn/5 V power supplies. The proposed reference is believed to be suited for use in monolithic data acquisition systems with resolutions of 10 to 12 bits.

MOS transistors operated in the lateral bipolar mode and their application in CMOS technology

Abstract: Operation of an MOS transistor as a lateral bipolar is described and analyzed qualitatively. It yields a good bipolar transistor that is fully compatible with any bulk CMOS technology. Experimental results show that high /spl beta/-gain can be achieved and that matching and 1/f noise properties are much better than in MOS operation. Examples of experimental circuits in CMOS technology illustrate the major advantages that this device offers. A multiple current mirror achieves higher accuracy, especially at low currents. An operational transconductance amplifier has an equivalent input noise density below 0.1 /spl mu/V//spl radic/Hz for frequencies as low as 1 Hz and a total current of 10 /spl mu/A. A bandgap reference yields a voltage stable within 3 mV from -40 to +80/spl deg/C after digital adjustment at ambient temperature. Other possible applications are suggested.

Electronic clutch for electric tools of selectable speed

Abstract: An electronic clutch for a multispeed electric tool includes a voltage sensor having a D.C. voltage output proportional to the current absorbed by the tool's motor and dependent on the motor operating temperature. A comparator compares this D.C. voltage with a suitably generated reference voltage, and if the former exceeds the latter it blocks the oscillation of an oscillator which via a power circuit controls a triac provided in the motor power supply circuit. Blocking the oscillator causes the deactivation of the triac, and thus stops the motor. The proportionality constant of the D.C. voltage, or that of the reference voltage, can be varied as a function of the tool operating speed. For this purpose, the voltage sensor or, respectively, the reference voltage generator includes a voltage divider in which resistors are provided which can be cut in or out by means of electric contacts controlled by the tool's speed change mechanism.

Photovoltaic device with increased open circuit voltage

Abstract: A photovoltaic device having an increased open circuit voltage includes a body of semiconductor material between layers of opposite conductivity type, one of which has a wide bandgap energy and through which light enters the device. The body includes a first region closest to the wide bandgap layer and a second region with the bandgap energy of the first region being greater than that of the second region and less than or equal to that of the wide bandgap layer.

Reference voltage producing circuit

Abstract: A reference voltage producing circuit includes a voltage signal producing circuit, a differential amplifier and an emitter follower circuit. The voltage signal producing circuit includes a first series circuit for producing a first voltage signal, a second series circuit for producing a second voltage signal and a constant current source for controlling the first and second series circuits. The differential amplifier operates so as to make the levels of the first and second voltage signals equal to each other, and controls the transistor forming the emitter follower circuit. The emitter of the transistor forming the emitter follower circuit produces a reference voltage.

CMOS power-on reset pulse generating circuit with extended reset pulse duration

Abstract: A source voltage buildup detecting circuit which detects, after the source is switched on, whether the source voltage is higher than a predetermined voltage and outputs a detecting signal. The source voltage buildup detecting circuit includes a complementary metal-oxide semiconductor (CMOS) inverter, a level shifting element connected between the power source and the CMOS inverter, and a voltage generating circuit connected to an input of the CMOS inverter. The level shifting element supplies a voltage lower than the source voltage to the CMOS inverter as a working voltage, and when the source voltage becomes greater than the predetermined voltage after the source voltage is switched on, the voltage generating circuit outputs a voltage higher than the threshold voltage of the CMOS inverter. When the source voltage becomes higher than the predetermined voltage, the voltage generating circuit outputs a voltage lower than the threshold voltage of the CMOS inverter.

Comparator circuit having hysteresis voltage substantially independent of variation in power supply voltage

Abstract: A comparator circuit provided with a hysteresis characteristic comprises an amplifier comparing an input voltage with a reference voltage, a voltage-clamping circuit clamping the output voltage of the amplifier at a first stabilized voltage or at a second stabilized voltage in response to the comparison output of the amplifier, and a feedback circuit generating a first feedback voltage or a second feedback voltage as the reference voltage in response to the output voltage level of the amplifier, whereby the hysteresis voltage of the comparator circuit is substantially independent of the variation in a power supply voltage for actuating the comparator circuit.

Reference frequency and low voltage detector circuit

Abstract: A reference frequency and low voltage detector circuit for use with a constant frequency A.C. voltage source is disclosed in which a first supply circuit supplies a first voltage wave form having a repetition rate and magnitude proportional to the A.C. source voltage. A second supply circuit supplies a regulated D.C. voltage of a fixed magnitude as long as the amplitude of the A.C. source voltage is normal. The voltages produced by the first and second supply circuits are supplied to noninverting and inverting input terminals of a differential amplifier which produces a rectangular wave output signal only when the A.C. source voltage is normal. The differential amplifier output signal provides a frequency reference under normal conditions and signals a user device to switch to a secondary mode of operation when the repetition rate of the rectangular wave form changes.

Trimless bandgap reference voltage generator

Abstract: A voltage generator circuit consists essentially of two separate groups of serially connected semiconductor junctions with one group having one more junction than the other, two groups of constant current sources, and a differential operational amplifier. The circuit generates a reference voltage which in one embodiment is close to the bandgap voltage of silicon and is essentially constant over an operating temperature range of 25-85 degrees C. and does not require the trimming (adjusting) of resistor values. This circuit is particularly useful in CMOS CODECs. The circuit is designed such that the input offset voltage of an operational amplifier is not multiplied by the gain of the amplifier.

EL panel drive system

Abstract: A drive system for a thin-film EL matrix display panel includes first and second voltage doubler circuits and a DC booster circuit. A 1/4V M voltage, which has the 1/4 voltage level of the modulation voltage, is applied to the first voltage doubler circuit of which an output voltage is applied to a modulation voltage applying circuit. The 1/4V M voltage is further applied to the DC booster circuit which develops an output voltage having a voltage level of 1/2V W . The thus obtained 1/2V W voltage is applied to the second voltage doubler circuit of which an output voltage is applied to a write voltage applying circuit.

Floating back-up power supply

Abstract: A back-up voltage source useful over a comparatively long time interval during a power outage or voltage fluctuation is described. A circuit for adjusting the position of a voltage difference available at the back-up supply outputs is described. A potential difference appearing at the terminals of a floating voltage source is connected to a reference circuit for generating a voltage reference from the difference of potential. A voltage follower connected to the reference and to a second voltage source is employed to cause the voltage follower to reposition the potential difference of the supply so as to force the voltage reference to a level equal to the second voltage source.

Level detecting apparatus

Abstract: PURPOSE: To detect an absolute level with high accuracy by compensating the temp. characteristics of a logarithm conversion type detector circuit, by changing the reference voltage of an AD converter circuit so as to follow the temp. change of the output voltage from a detector circuit by utilizing the voltage current characteristics of a diode. CONSTITUTION: An AC input signal 2 is detected by a logarithm conversion type detector circuit 3 and an AD converter 5 compares input voltage with individual reference voltage obtained by dividing the reference voltages V + ref, V - ref from a reference voltage generating circuit 6 to take out the same as a digital value 7. The current source 20 of the reference voltage generating circuit 6 generates a DC current corresponding to the reference level of the output voltage 4 of the detector circuit 3 and a current source Q 26 is constituted so as to flow a current proportional to the temp. voltage of a diode while the voltage at the connection point of resistors R 11 , R 12 is equal to the terminal voltage of a diode 21 and high voltage and low voltage corresponding to voltage falling of the resistors R 11 , R 12 are obtained centering around the terminal voltage of the diode 21 at both terminals 28, 29 of a resistor R 13 as reference voltages V + ref, V - ref. COPYRIGHT: (C)1984,JPO&Japio

Voltage detection circuit using threshold as reference voltage for detecting input voltage

Abstract: A voltage detection circuit for comparing an input voltage against a reference voltage, the reference voltage being derived from the threshold voltage of a semiconductor active device which forms a portion of the voltage detection circuit. To make the detection circuit substantially independent of ambient temperature changes, it is constructed as an integrated circuit and includes devices for producing a temperature dependent voltage equal to but of opposite sign to the temperature sensitive voltage component of the reference voltage. The two temperature sensitive voltages cancel each other to thereby permit a temperature independent voltage comparison.

Stabilized power supply device

Abstract: PURPOSE:To attain low cost by obtaining a reference voltage from a voltage dividing circuit so as to switch is thereby obtaining an optional voltage. CONSTITUTION:An AC power 2 is subjected to phase control by a triac 11 and applied to an exposure lamp 1. A lamp voltage V2 is converted into an effective voltage V4 via a transformer T1, a full wave rectifier circuit 3 and an effective value detecting circuit 4. The voltage V4 is compared with a reference voltage Vr from a reference voltage generating circuit 12 at a differential amplifier circuit 5 and its output V5 and a sawtooth wave voltage V8 by a zero cross pulse V7 from a zero cross detecting circuit 8 control the triac 11 via a phase shift circuit 6 or the like. In this case, the reference voltage generating circuit 12 consists of a constant voltage power supply circuit, a voltage division circuit, and a switch element forming the voltage division control means. A prescribed voltage dividing ratio is changed by means of the on/off state of the switch element so as to change the output reference voltage Vr.

Signal translator with supply voltage compensation

Abstract: A signal translator for converting an input voltage (V1) into an output voltage (Vo) at a different level contains a primary element stack (10) and a similarly-configured image element stack (12), both coupled between the sources of a potentially variable supply voltage (Vcc) and a substantially constant supply voltage (VEE). A reference voltage (VR) is supplied to both a primary-stack transistor (02) which provides the output voltage and an image-stack transistor (04) which provides a feedback signal (VF). A feedback circuit (14) responsive to the feedback signal supplies the reference voltage at such a value as to compensate the output voltage for changes in the variable supply voltage.

Method for compensation of the switching threshold voltage in a voltage-injection converter circuit, and a converter circuit for this purpose

Abstract: In pulse-controlled invertors, direct converters or other voltage-injection converter circuits, in which the changeover commands of a switch (7.R) are derived from a reference voltage (Uref.R) for an output voltage (U.R), when the switching threshold voltage (Uv.R) control setting is low, the output voltage has a magnitude error and a phase error with respect to the reference voltage. In order to compensate for this error, the magnitude of the threshold voltage is applied as an additional signal (Uz.R) of the reference voltage corresponding to the mathematical sign of the current flowing through the switch.

Detection circuit for converting a mechanical adjustment into a rectified signal

Abstract: An electrostatically-capacitively acting detection circuit is used for converting a mechanical adjustment into a rectified signal. For this purpose, a series circuit consisting of a capacitor (12) changing its capacitance as a function of the adjustment, a voltage of an oscillator (11), and a resistor (13) and a reference voltage source (15) is provided. The alternating voltage occurring across the resistor (13) is converted into a direct voltage by means of a rectifier circuit (14) and then compared with the reference voltage (15) by means of a comparator circuit (16). The output variable of the comparator circuit (16) is supplied to the oscillator (11) to keep the direct voltage at the same amplitude as the reference voltage (15). Furthermore, the oscillator (11) has another output for an output variable which, after rectification, forms the signal corresponding to the adjustment.

Voltage limit protection circuit for phase controlled rectifiers

Abstract: A voltage limit circuit for phase controlled rectifiers avoids shoot-through and limit cycling conditions by limiting the d.c. output voltage of the rectifier bridge. The circuitry follows a voltage reference signal as long as the reference signal is less than an input derived from the a.c. voltage applied to the bridge, reduced by the volt-seconds required for commutation. Should the reference signal exceed the a.c. derived input, the a.c. derived input limits the maximum available d.c. voltage. To this end, a voltage reference signal provides an output signal corresponding to the desired output voltage of the bridge. A slew limit circuit limits the rate by which the output signal may be changed. A magnitude limit circuit is coupled to the output of the slew limit circuit and provides a reference signal for the firing circuit of the rectifier bridge. The magnitude limit circuit receives the a.c. voltage derived limiting signal for limiting the reference signal to a magnitude not greater than that established by the limiting signal. The limiting signal is obtained in a commutating volt-seconds subtraction circuit that reduces an appropriately scaled a.c. voltage by an amount necessary to establish the volt-seconds required for commutation of the controlled rectifiers.

FET Power supply for MOS memories

Abstract: The invention applies a reference voltage to a responsive means for producing a signal of one type in the absence of a semi-conductor at the addressed memory location, and applies a voltage less than the reference voltage to the responsive means for producing a signal of another type if a semi-conductor is present at the addressed memory location. The reference voltage is produced by a novel constant low voltage variable current source. The responsive means comprises inverter amplifier means. The reference voltage centers the small voltage swing on the bit line to the trigger point of the inverter amplifier. The means for determining the magnitude of voltage applied to the inverter is a pull up FET in series with the memory FET at the addressed location. If the electrical resistance of the FETs is similar, one half of the reference voltage will be applied to the inverter and it produces an off, or nearly off, type signal indicating presence; otherwise in the absence of a memory FET, full reference voltage is applied to the inverter to produce an on type signal indicating absence. Thus, the sense amplifier is independent of any reference voltage tracking the midpoint of the small bit line swing, and it is faster, requires less die area and restores full MOS output from a one volt signal swing.