Showing papers on "Bandgap voltage reference published in 1999"

A CMOS bandgap reference circuit with sub-1-V operation

Abstract: This paper proposes a CMOS bandgap reference (BGR) circuit, which can successfully operate with sub-1-V supply, In the conventional BGR circuit, the output voltage V/sub ref/ is the sum of the built-in voltage of the diode V/sub f/ and the thermal voltage V/sub T/ of kT/q multiplied by a constant. Therefore, V/sub ref/ is about 1.25 V, which limits a low supply-voltage operation below 1 V. Conversely, in the proposed BGR circuit, V/sub ref/ has been converted from the sum of two currents; one is proportional to V/sub f/ and the other is proportional to V/sub T/. An experimental BGR circuit, which is simply composed of a CMOS op-amp, diodes, and resistors, has been fabricated in a conventional 0.4-/spl mu/m flash memory process. Measured V/sub ref/ is 518/spl plusmn/15 mV (3/spl sigma/) for 23 samples on the same wafer at 27-125/spl deg/C.

Low-power bandgap references featuring DTMOSTs

Abstract: This paper describes two CMOS bandgap reference circuits featuring dynamic-threshold MOS transistors. The first bandgap reference circuit aims at application in low-voltage, low-power ICs that tolerate medium accuracy. The circuit runs at supply voltages down to 0.85 V while consuming only 1 /spl mu/W; the die area is 0.063 mm/sup 2/ in a standard digital 0.35-/spl mu/m CMOS process. The second bandgap reference circuit aims at high accuracy operation (/spl sigma/=0.3%) without trimming. It consumes approximately 5 /spl mu/W from a 1.8-V supply voltage and occupies 0.06 mm/sup 2/ in a standard 0.35-/spl mu/m CMOS process.

Charge pump circuit adjustable in response to an external voltage source

Abstract: An integrated circuit detects the voltage level of the supply voltage to the integrated circuit. Circuity on the integrated circuit including the charge pump circuity adjusts to operate more effectively or efficiently at the voltage level of the supply voltage.

Band gap reference using a low voltage power supply

Abstract: A band gap reference includes an operational amplifier with an output (n23) driving the gate of three current source transistors (501-503). The first current source (501) drives the (+) opamp input (n20) and a transistor (511) functioning as a diode. The second current source (502) drives the (-) opamp input and a series resistor (R 1 ) and a transistor (512) functioning as a diode. The third current source (503) drives a series resistor (R 2 ) and diode connected transistor (513). The opamp includes first series transistors (521) and (524) connected between V DD and V SS , and second series transistors (522) and (525) connected between V DD and V SS . With only two series transistors between V DD and V SS at any point, only two times a CMOS transistor threshold drop (less than 1.8 volts) will occur enabling V DD to range from 1.8-3.6 volts without altering the band gap reference output voltage (V DIODE ). Further, CMOS transistors in the circuit may operate with a 2.7 volt maximum gate to source, or gate to drain voltage.

Small capacitance change detection device

Abstract: A small capacitance change detection device includes a capacitance detection element, signal generation circuit, signal amplification circuit, and output circuit. The signal amplification circuit includes a first transistor and first to third voltage sources. The second or third voltage source is connected to the other output terminal of the first transistor via a first switch. A voltage to be applied from the second voltage source to the other output terminal is set to have a value equal to or larger than a value obtained by subtracting a threshold voltage of the first transistor from a voltage of the first voltage source while a voltage to be applied from the third voltage source to the other output terminal is set to have a value equal to or smaller than a value obtained by subtracting the threshold voltage from the voltage of the first voltage source. The output circuit is connected to a connection point between the other output terminal of the first transistor and the first switch and, after a voltage of the second or third voltage source is applied to the connection point in an ON state of the first switch, receives the voltage at the connection point on the basis of an OFF state of the first switch and charge control by the signal generation circuit after the first switch is turned off.

Internal oscillator circuit including a ring oscillator controlled by a voltage regulator circuit

Abstract: An oscillator circuit residing internally to a semiconductor device for generating a clock signal for use by digital circuits. The oscillator circuit includes a voltage regulator circuit responsive to frequency selection signals for selecting a predetermined frequency and a supply voltage. The voltage regulator circuit is operative to generate a voltage reference signal having a voltage level being adjusted to compensate for variations due to temperature, process and supply voltage variations. The oscillator circuit further includes a ring oscillator circuit responsive to the voltage reference signal for generating a clock out signal having a particular frequency based upon the voltage level of the voltage reference signal. Wherein the frequency of the clock out signal remains substantially constant despite temperature, process and supply voltage variations in the semiconductor circuit.

Exact curvature-correcting method for bandgap circuits

Abstract: A curvature corrected bandgap reference voltage circuit, the output voltage of which is substantially linear and independent of the operating temperature of the circuit. The circuit includes a voltage divider network comprised of a first resistor and a second resistor connected in series. A first compensating circuit provides a first, linear, operating temperature-dependent current, and a second compensating circuit provides a second, logarithmic, operating temperature-dependent current. The first current is supplied to the first resistor of said voltage divider network, while the second current is supplied to the second resistor of the voltage divider network.

Switching bandgap reference circuit with compounded DELTA V beta EPSILON

Abstract: A switching bandgap reference circuit with compounded DELTA VBE includes an amplifier having an output, an inverting input and a non-inverting input; a first PN junction connected to the non-inverting input; a second PN junction connected to the inverting input through an input capacitor; a low current source and a high current source; a switching device for applying in the auto zero mode the low current source to a first terminal of the first PN junction and the high current source to a first terminal of the second PN junction for establishing the VBE, of the first junction at both the inputs of the amplifier and for applying in the valid reference mode the high current source to the first terminal of the first PN junction and the low current source to the first terminal of the second PN junction for establishing the positive DELTA VBE, of the first PN junction to both the inputs of the amplifier and applying the negative DELTA VBE2 of the second PN junction to the input capacitor to produce a voltage of DELTA VBE1 plus (- DELTA VBE2) across the input capacitor; a feedback capacitor connected between the output and inverting input of the amplifier to define the gain on the combined DELTA VBE voltages to produce a temperature stabilized voltage at the output of the amplifier and a reset switching device for discharging the feedback capacitor and enabling the amplifier to equalize its inputs in the auto zero mode.

Method of curvature compensation, offset compensation, and capacitance trimming of a switched capacitor band gap reference

Abstract: Curvature in a reference voltage produced by a switched capacitor band gap reference circuit is compensated by producing a first ΔV BE voltage by causing first and second PTAT/R currents to flow through a first ΔV BE -generating circuit. The first ΔV BE voltage is applied to a first terminal of a first capacitor having a second terminal coupled to a summing conductor of an operational amplifier producing the reference voltage. A second ΔV BE voltage is produced by causing a third PTAT/R current and a fourth current to flow through a second ΔV BE -generating circuit. The second ΔV BE voltage is applied to a first terminal or a second capacitor having a second terminal coupled to the summing conductor. First and second charges are transferred from the first and second capacitors through the summing conductor into a feedback capacitor coupled between the summing conductor and an output of the operational amplifier to produce the compensated reference voltage on the output of the operational amplifier. A technique of storing a voltage on the feedback capacitor equal to a V BE voltage minus a voltage on the summing conductor during a charging phase, and then connecting the feedback capacitor between the summing conductor and the output of the operational amplifier cancels the offset voltage of the amplifier.

Drive circuit of light emitting element

Abstract: A drive circuit of a light emitting element capable of setting a desired constant current and capable of operating stably at a high speed while holding a forward direction voltage required for the emission of light even under a low power supply voltage, wherein there is provided an input circuit which receives differential drive signals and outputs differential signals of levels in accordance with the level of a supplied drive voltage, a differential output circuit in which an emitter-connection portion of transistors is grounded via a resistor, the differential signals and are supplied to bases, and a laser diode is connected to a collector of the transistor, a reference voltage generation circuit which generates a reference voltage, a comparison circuit which compares the voltage of the emitter-connection portion with the reference voltage and outputs a signal of the level in accordance with the result of comparison, and a variable voltage supply circuit which generates a voltage in accordance with the input level of the output signal and supplies the same as the drive voltage of the input circuit.

Digitally calibrated bandgap reference

Abstract: A system and method for compensating for a voltage offset between an inverting input and a noninverting input of an op amp to provide a stable bandgap reference. The method including measuring the voltage offset between the inverting input and the noninverting input of the op amp and searching for a compensating current input to the op amp that compensates for the voltage offset. A programmable current source is set to output the compensating current to the op amp.

Any value, temperature independent, voltage reference utilizing band gap voltage reference and cascode current mirror circuits

Abstract: A voltage reference circuit for generating various selectable voltage reference values with temperature independence is disclosed wherein a band-gap voltage reference circuit portion, that produces a temperature independent band-gap voltage reference VBG output, has a cascode current mirror circuit portion coupled thereto in such manner that a selectable voltage reference VREF is output with the temperature coefficient of the selected voltage reference canceled.

Precision voltage reference circuit with temperature compensation

Abstract: A precision voltage reference circuit for generating a constant reference voltage over a range of operating temperatures uses a bandgap voltage generator which is compensated with replicated currents fed back from the bandgap stage as control currents. These currents are attenuated and fed back in proper proportions to correct for bias conditions which would otherwise vary with temperature.

Low power voltage reference circuit

Abstract: A bandgap voltage reference circuit according to the present invention generates a constant reference voltage and is not affected by variations in a power supply voltage and in a manufacturing process. In the bandgap voltage reference circuit, a constant voltage supply unit supplies a constant voltage, a first current mirror mirrors a first current flowing through the constant voltage supply unit to generate a second current, and a second current mirror controlled by the constant voltage from the constant voltage supply unit mirrors the second current to generate a third current and outputs the third current to an output node. A voltage reference unit is connected to the output node to provide a reference voltage to the output node. The voltage reference unit includes at least one PMOS transistor and at least one NMOS transistor which are connected to each other in series or in parallel. Ion implantation processes for determining threshold voltages of the PMOS transistor and the NMOS transistor are simultaneously performed.

Bandgap-based reference voltage generator circuit with reduced temperature coefficient

Abstract: A bandgap-based reference voltage generator circuit with an increased output reference voltage and a reduced temperature coefficient uses a curvature correction bias voltage to significantly reduce the degree of variation of the bandgap-based reference voltage over temperature. A current having a negative temperature coefficient is conducted by a resistor having a positive temperature coefficient. The resultant voltage across the resistor has an arcuate voltage-versus-temperature characteristic with a direction of incurvature that is substantially opposite the direction of incurvature of the corresponding arcuate voltage-versus-temperature characteristic of the voltage generated by a conventional bandgap reference voltage generator circuit. These voltages are summed together to produce a bandgap-based reference voltage which is greater in magnitude than a conventional bandgap reference voltage and has a significantly reduced temperature coefficient.

Dual current source circuit with temperature coefficients of equal and opposite magnitude

Abstract: A dual current source circuit provides dual currents of the same magnitude and having coefficients of temperature compensation that are also equal but opposite. The core of the circuit is a degenerated differential pair of bipolar junction transistors wherein the base of a first transistor of the pair is connected to a bandgap voltage reference. The base of the second transistor of the pair is connected to a PTAT current source having only one of a positive or a negative coefficient of temperature compensation and a resistor which generates a voltage difference between the bases of the two transistors. This voltage difference generates dual currents, each having equal but opposite coefficients of temperature compensation. A temperature independent stable tail current is provided to the transistors and can be generated by summing the current output of a negative PTAT current source and a positive PTAT current source.

Low-power start-up circuit for a reference voltage generator

Abstract: A reference voltage generation circuit has a start-up circuit that will force the reference voltage generation circuit to assume a normal operation mode producing the desired reference voltage level and will reduce noise coupled from a power supply voltage source. The start-up circuit for reference voltage generation circuit will be disabled when a sensing circuit has determined that the reference voltage generation circuit has attained the desired reference voltage level.

Bandgap voltage reference circuit with an increased difference voltage

Abstract: A reference voltage output by a bandgap voltage reference circuit is formed by summing an amplified voltage that has a positive temperature coefficient with a base-to-emitter voltage that has a negative temperature coefficient. The amplified voltage is formed by amplifying a difference voltage ΔVBE. Variations over temperature of the reference voltage are reduced by increasing the magnitude of the difference voltage ΔVBE. By increasing the magnitude of the difference voltage ΔVBE, a smaller gain can be used to form the amplified voltage. By utilizing a smaller gain, less of the error associated with the difference voltage ΔVBE is present in the amplified voltage.

Low voltage pvt insensitive mosfet based voltage reference circuit

Abstract: Methods and apparatus for generating a MOSFET based voltage reference circuit with automatic trimming of resistors to compensate for process and supply voltage variations and to improve the accuracy of a MOSFET based reference voltage circuit, a temperature compensated MOSFET based reference voltage, and arbitrary translation of the MOSFET based reference voltage with or without trimming are provided.

High voltage detector to control a power supply voltage pump for a 2.5 volt semiconductor process device

Abstract: A high voltage detector circuit (FIG. 2) maintains a voltage (V 2 ) on a reference line driven by a charge pump by turning the charge pump on with a signal (PUMPON) when the reference line voltage (V 2 ) drops below a reference voltage (V 1 ) plus a CMOS transistor threshold voltage. The high voltage detector is further configured to use transistors which have a maximum gate to drain, or gate to source voltage which exceeds the pin supply voltage to the chip. The high voltage detector includes comparators made up of a series of current mirrors driven by weak current sources enabling the circuit to use a minimum amount of power.

Bandgap start-up circuit

Abstract: A circuit and a method for starting a bandgap circuit which is in a “non-start” mode. The circuit incorporates an inverter circuit with hysterysis and sharp transitions caused by a positive feedback loop. The inverter circuit, which is connected at its input to a bandgap voltage node of the bandgap circuit, activates a switching transistor when voltage (Vbg) at the bandgap voltage node is low and deactivates the switching transistor when Vbg is high. The switching transistor draws current from a critical node of the bandgap circuit, such as the drain of a current mirror PMOS transistor, when it is activated, starting the bandgap circuit.

Switching circuit having an output voltage varying between a reference voltage and a negative voltage

Abstract: Switching circuit that receives a supply voltage, a reference voltage, a line adapted to carry a negative voltage and a control signal, the switching circuit capable of providing at an output a voltage alternatively equal to the reference voltage or to the voltage of the line in response to the control signal. The circuit includes a first MOSFET with a first electrode operationally connected to the line, a second electrode operationally connected to the output, and a control electrode, a second MOSFET with a first electrode operationally connected to the reference voltage, a second electrode operationally connected to the output, and a control electrode, and driving circuitry adapted to bring the control electrodes of the first and second MOSFETs respectively to the supply voltage and to the voltage of the line or, alternatively, to the voltage of the line and to the supply voltage, in response to the control signal.

Circuit for the regulation of an output voltage of a charge pump device

Abstract: A regulation circuit for regulating an output voltage of a positive charge pump for an integrated circuit includes a comparison circuit receiving a reference voltage at an input, and delivering an enabling signal at an output to the positive charge pump. The regulation circuit further includes a first switching circuit controlled by a first control signal for the application of a first voltage level as a reference voltage when the integrated circuit is in an operational mode, and the application of a second voltage level as the reference voltage when the integrated circuit is in a standby mode.

Dual regeneration bandgap reference voltage generator

Abstract: A dual regeneration bandgap voltage generator circuit includes both CMOS and bipolar regeneration bandgap voltage generator circuits. Each of the regeneration bandgap voltage generator circuits is formed by cross-coupling current mirror circuits of opposite conductivity types. Upon initial application of power, the CMOS circuit becomes active first due to its higher leakage current. The "on" current from the CMOS circuit is then used to initiate current conduction within the bipolar circuit. Once the bipolar circuit begins operating, it turns the CMOS circuit off.

Band-gap regulator circuit for producing a voltage reference

Abstract: A band-gap regulator circuit produces a voltage reference having a temperature compensation for second order effects. The regulator circuit includes: a Brokaw cell for producing a first band-gap voltage reference Vbg; a circuit portion including a comparator connected to the Brokaw cell output for providing a compensation voltage value Vcorr; and a summing circuit that sums together the compensation voltage value Vcorr and the first band-gap voltage reference Vbg.

Bandgap reference circuit for charge balance circuits

Abstract: A method and circuit for providing a reference voltage to a charge balance circuit. The method includes transferring charge corresponding to VBE and charge corresponding to ΔVBE to a summing node of the charge balance circuit, where VBE is a voltage produced across a p-n junction and where ΔVBE is a difference between two VBE voltages. With such method, instead of forming a bandgap reference circuit which produces a bandgap reference voltage and applying such voltage to the reference sampling and charge transfer circuit, charge corresponding to VBE and charge corresponding to ΔVBE are transferred to the input summing node of the modulator in correct proportion and with a polarity corresponding to the modulator output. Thus, the reference sampling and charge transfer circuit delivers VBE and ΔVBE charge samples to the summing node having the correct proportion and polarity, that in aggregate over a modulator cycle, equal the charge that sampling the reference voltage VREF produced by the explicit bandgap reference circuits would deliver.

Surface potential sensor and processing circuit having improved noise reduction

Abstract: A surface potential sensor which is less affected by noise superposed on a reference source voltage than prior sensors, and hence can improve measurement accuracy with ease, and which also has higher stability against extraneous noise. The sensor includes an initial-stage input circuit comprising an FET, and a succeeding-stage amplifier circuit mainly comprising an operational amplifier for amplifying a difference between an AC component from the initial-stage input circuit and a reference source voltage. A resistor is connected between a drain of the FET constituting the initial-stage input circuit and a source voltage line to take out a signal from the FET drain. The source voltage supplied to the FET is the reference source voltage.

Temperature compensated, zero bias RF detector circuit

Abstract: A temperature compensated zero bias RF detector circuit includes a zero biased diode detector circuit feeding the positive input of a differential amplifier circuit. The negative input of the same differential amplifier circuit is a temperature compensation voltage. The temperature compensation voltage is produced by current flow from a bias source through a reference diode and through the resistor back to ground. The bias supply remains constant over temperature, whereas the temperature compensation voltage changes with temperature as the forward voltage across the reference diode changes with temperature. The differential amplifier outputs a temperature compensated detection voltage. The differential amplifier is followed by a voltage level shifter, which adjusts the output temperature compensated voltage to a suitable level for measuring equipment or for use by other processing circuits.

CMOS level shift circuit for integrated circuits

Abstract: There is provided a level shift circuit which includes an input terminal for receiving a logic input signal changing between a first voltage and a reference voltage. An output terminal provides a logic output signal changing between a second voltage and the reference voltage. A pull-up transistor has a control electrode and a pair of controlled electrodes. The controlled electrodes are coupled between the second voltage and the output terminal. A pull-down transistor has a control electrode and a pair of controlled electrodes. The control electrode of the pull-down transistor is coupled to the input terminal, and the controlled electrodes of the pull-down transistor are coupled between the reference voltage and the output terminal. A charge/discharge circuit charges the control electrode of the pull-up transistor with the second voltage when the logic input signal is changed from the reference voltage to the first voltage. The charge/discharge circuit discharges the control electrode of the pull-up transistor to the reference voltage when the logic input signal is changed from the first voltage to the reference voltage.