Showing papers on "Bandgap voltage reference published in 1986"

Capacitor-plate bias generator for CMOS DRAM memories

Abstract: A capacitor-plate bias generator produces a voltage on the capacitor plate node which consists of a constant voltage plus the sense-level voltage. Consequently, the capacitor-plate node tracks any variations in the sense-level voltage. The constant voltage is 3VBG, or 3 times the bandgap voltage of silicon. The circuit includes a reference-voltage source which produces the sum of the sense-level voltage and VBG, and a feedback control circuit for enabling either a charge pump or a charge bleeder to regulate the capacitor-plate voltage at a level above the circuit supply voltage.

Breakpoint compensation and thermal limit circuit

Abstract: A voltage reference circuit including a Brokaw Cell band-gap reference circuit is provided with breakpoint compensation to adjust the temperature coefficient of the reference voltage provided by the Brokaw Cell as a function of temperature. The voltage reference circuit also includes a thermal limit transistor which is biased by a voltage having a positive temperature coefficient. The thermal limit transistor draws a rapidly increasing current when the operating temperature reaches a predetermined value.

Analysis, design, and performance of micropower circuits for a capacitive pressure sensor IC

Abstract: An integrated circuit has been designed, built, and testing as part of a capacitive pressure transducer. High-accuracy compact micropower circuits utilizing a standard bipolar IC process without any special components or trimming are used. The key circuits for achieving this performance are a Schmitt trigger oscillator and a bandgap voltage reference. The sensor circuits consume 200 /spl mu/W at 3.5 V, can resolve capacitance changes of 300 p.p.m., measure temperature to /spl plusmn/0.1/spl deg/C over a limited temperature range, and presently occupy 4 mm/SUP 2/ on a 2 mm/spl times/6 mm implantable monolithic silicon pressure sensor. Further scaling of the sensor is discussed showing that a reduction of area by a factor of 4 is achievable.

GaAs voltage reference generator

Abstract: In a GaAs integrated circuit, a voltage reference generator includes a pair of Schottky diodes and a first, current-source connected, depletion-mode MESFET coupled in series to conduct current from a ground node to a voltage supply node. The current-source connected FET causes a constant current to flow from the ground node through the diodes, producing a constant voltage drop which generates a constant reference voltage at a reference node between the diodes and FET. A second pair of Schottky diodes is connected in series between the source of the FET and the voltage supply node, in a loop coupling the source to the gate of the FET, to provide a voltage difference Vgs across the FET proportional to voltage drop across the second pair of diodes. This voltage difference varies with fabrication process and temperature variations and causes the first FET to modify the amount of current flow to compensate so as to maintain a constant voltage drop across the first pair of diodes. A second FET is connected between the reference node and the first, current-source connected FET and has its gate coupled to the source of the first FET, either directly or through one of the second pair of diodes. Any variations in supply voltage are transmitted to the drain of the first FET to maintain a constant voltage Vds and current Ids, thereby stabilizing the reference voltage against supply voltage variations and noise.

Voltage-insensitive and temperature-compensated delay circuit for a monolithic integrated circuit

Abstract: A delay circuit which is insensitive to variations in power supply voltage, which is temperature-compensated, and which is suitable for fabrication in a monolithic integrated circuit includes circuitry for charging a capacitive element through a resistive element from GND toward the power supply voltage. The voltage across the capacitive element is compared to a reference voltage by a voltage comparator, and the voltage comparator generates an output signal when the voltage on the capacitor becomes greater than the reference voltage. The reference voltage for the comparator is generated by a resistor divider connected between GND and the power supply voltage. Inasmuch as the reference voltage varies with changes in the power supply voltage in such a manner as to be maintained at a substantially fixed percentage of the power supply voltage, the time delay provided by the delay circuit is essentially independent of variations in power supply voltage. By utilizing resistors in the resistor divider that have differing temperature coefficients of resistance, the reference voltage for the comparator can be increased and decreased in a predetermined manner in response to increases and decreases in ambient temperature, allowing the time delay of the delay circuit to be adjusted in a predetermined manner as a function of temperature.

CMOS reference voltage generator employing separate reference circuits for each output transistor

Abstract: An internal power supply voltage generator for generating an internal power supply voltage for a semiconductor integrated device includes first and second reference voltage generators which produce first and second reference voltages having respective values a predetermined amount above and below an optimal value of the internal power supply voltage. The first and second reference voltage generators are constructed of a pair of serially connected NMOS and PMOS transistors, respectively, which transistors are connected between an external voltage supply and ground. The first and second reference voltages are applied to a CMOS output stage constructed of a NMOS and PMOS transistor serially connected between the external voltage supply and ground, the gates of the transistors being coupled to the first and second reference voltages, so as to provide said internal power supply voltage at a common node between the transistors. This voltage generator exhibits a lowered power dissipation and a lowered output impedance, as a result of providing a CMOS output stage.

Voltage regulator for generator used in automobile

Abstract: In a generator charging a battery on an automobile with output voltage thereof, a voltage regulator has a constant voltage source (20); first and second voltage dividers (91, 92 and 94, 95) dividing the voltage of the constant voltage source (20); a series circuit consisting of a thermo-sensitive element (101-103) and a resistor (93) and being connected to the middle point of the first voltage divider (91, 92); a first diode (104) having an anode connected to the middle point of the first voltage divider; a second diode (105) having an anode connected to the middle point of the second voltage divider (94, 95); and a third diode (106) having a cathode connected to both the cathodes of the first and the second diode (104 and 105) and supplying a reference voltage (V Ref ), wherein the output voltage of the generator is compared with the reference voltage (V Ref ), thereby, the output voltage of the generator is regulated to the reference voltage (V Ref ).

Noise extraction circuit

Abstract: A circuit receives either a composite voltage, which is the sum of a signal voltage and a noise voltage, or the noise voltage. A switching arrangement is used to charge a first capacitor to the composite voltage, and a second capacitor to the noise voltage. The opposite poles of the first and the second capacitors are connected after they are charged, to generate an output voltage which is proportional to the signal voltage alone.

A new bipolar reference current source

Abstract: A high-quality bipolar reference current source based on the bandgap of silicon is described that is independent of supply voltage and temperature variations. The circuit only uses identical n-p-n transistors processed in a conventional bipolar process. The circuit contains only a small number of components and needs no starting circuit.

Analog-to-digital converter and method of analog-to-digital conversion

Abstract: The system includes: a voltage conversion circuit (11a, 11b) selectively obtaining at least three kinds of conversion voltages, i.e., a first conversion voltage which is double the input voltage (AIN), a second conversion voltage which subtracts a reference voltage (VR) from the first conversion voltage, and a third conversion voltage which adds the reference voltage to the first conversion voltage; a comparison circuit (CPR1, CPR2) setting at least two decision level voltages (-¼VR, +¼/VR) and comparing the converted) voltage (VCMP) with each of the decision level voltages; then outputting a command signal as a result of a comparison to the voltage conversion circuit so that the voltage conversion circuit outputs one of the conversion voltages in response to the command signal; and a control circuit (SGT) for changing the connections of switches (S1A...S7B) provided in the voltage conversion circuit in response to the result of the comparison by the comparison circuit.

Voltage to frequency conversion circuit with a pulse width to period ratio proportional to input voltage

Abstract: A voltage to frequency converter controls the successive charge-discharge of an integrating circuit charging capacitor between low and high voltage levels to produce through a reference voltage controlled pulse generating circuit, a pulse output in which the ratio of input voltage to reference voltage equals the ratio of output pulse duration coincident with capacitor discharging, to period duration.

Nullpoint-stabilised charge amplifier

Abstract: In order to balance out the nullpoint drift in connection with piezoelectric sensors evaluated by means of a charge amplifier, a reference voltage is assigned to an arbitrary point in time in the period of the measurement signal. By means of a periodic comparison of the reference voltage with the actual voltage at this point in time, a difference voltage is determined in each case, which is used to correct the voltage level of the measurement signal in the next period.

Analog-to-digital conversion system

Abstract: In an analog-to-digital conversion system, the system includes: a voltage conversion circuit selectively obtaining at least three kinds of conversion voltages, i.e., a first conversion voltage which is double the input voltage, a second conversion voltage which subtracts a reference voltage from the first conversion voltage, and a third conversion voltage which adds the reference voltage to the first conversion voltage; a comparison circuit using at least two decision level voltages and comparing the input voltage with each of the decision level voltages, then outputting the command signal as a result of a comparisons to the voltage conversion circuit so that the voltage conversion circuit outputs one of the conversion voltages in response to the command signal; and a control circuit for changing the connections of switch contacts provided in the voltage conversion circuit in response to the result of the comparisons by the comparison circuit.

Voltage regulator circuit

Abstract: A highly stable voltage regulator circuit based on a low-voltage reference and supplying a voltage which is substantially higher than the reference voltage. The circuit is to be constructed as an integrated circuit comprising transistors of one conductivity type and without a zener diode. The reference voltage is supplied by a "band-gap reference" circuit (1). A differential circuit (T16, T17) controls the output voltage, which is applied to the base of a transistor (T16) via a resistor (R16) in which the current is maintained constant by means of an associated differential circuit (T11, T12) which comprises a resistor (R11) connected between its emitters. The bases of the transistors T11, T12 are each connected to one end of a resistor (R20) arranged in a bridge connected between the reference terminal and ground.

Precision bandgap voltage reference.

Abstract: A bandgap voltage reference circuit is described in which two sets of bipolar transistors (Q7-Q12, Q13-Q17) are connected so as to accumulate their base-emitter voltages, and currents are caused to flow through the collector-emitter circuits of each transistor (Q7-Q17). The number of transistors in each set, the geometry of each transistor and the currents transmitted through their collector-emitter circuits are selected so that the accumulated base-emitter voltages of the two sets differ by an amount corresponding to a predetermined bandgap voltage, preferably 1.23 volts. The circuitry can be implemented using either CMOS or bipolar fabrication processes, and has a lower error component than prior bandgap references. In the preferred embodiment the first set (Q7-Q12) includes one more transistor than the second set (Q13-Q17), and supports a higher current density than the second set. The bandgap voltage differential between the two transistor sets (Q7-Q12, Q13-Q17) may be reflected back across the inputs to the two sets by means of an operational amplifier circuit (A3,A4) to obtain a ground referenced output voltage which is proportional to the accumulated base-emitter voltage differential between the two transistor sets (Q7-Q12, Q13-Q17).

CML bias generator

Abstract: A bias generator for use in CML gate circuits provides an output reference voltage that is substantially independent of variations in supply voltage over a wide temperature range. The bias generator includes a temperature and voltage compensating circuit portion which is formed of an emitter resistor and a diode-connected transistor. The emitter resistor is used to control the output reference voltage for the lower temperatures and the base-emitter voltage of the transistor determines the output reference voltage for the higher temperatures.

Single-phase rectifying power unit

Abstract: PURPOSE: To prevent deterioration of a total power factor by determining a reference voltage from a sinusoidal voltage, an output voltage set point and an output voltage-detecting voltage and comparing the reference voltage with an input current-detecting voltage so as to obtain a control signal. CONSTITUTION: A control circuit 10 is composed of a sine-wave generator circuit 11, a voltage comparison circuit 13, a current comparison circuit 15 and a drive circuit 16, determines a reference voltage from a sinusoidal voltage, an output voltage-setting voltage and an output voltage-detecting voltage, and outputs a control signal by comparison between the reference voltage and input current- detecting voltage. A switching element 6 is turned ON and OFF by said control signal. The switching element 6 is connected together with a reactor 3 and a current sensing resistor 7 between positive and negative output terminals of a diode bridge 2. COPYRIGHT: (C)1987,JPO&Japio

Thermosensitive switching circuit having comparator with open collector output

Abstract: A thermosensitive switching circuit includes a first voltage divider for producing a reference voltage with a predetermined constant level and a second voltage divider for producing a detection voltage signal whose level changes in response to changes in the temperature to be detected. The reference voltage is compared with the detection voltage signal by a voltage comparator having an open-collector type output circuit, and a feedback resistor is connected between the output terminal and the input terminal of the voltage compartor to provide hysteresis for the comparing operation of the voltage comparator.

Cmos bandgap reference voltage circuits

Abstract: A CMOS bandgap voltage reference which is temperature stable is disclosed. The large temperature-dependent p-tub resistors of prior art arrangements are replaced with relatively small, temperature stable p+ diffusion resistors (32, 34). The increase in current level needed to compensate for the decrease in resistor value is provided by a simple cascode MOS circuit (36) located between the ratioing resistors and the VSS potential.

Current-regulating circuit having a bridge circuit

Abstract: In the case of current-regulating circuits having semiconductor power switches in a bridge circuit, in which circuits the magnitude and direction of a DC current is regulated by a control voltage, using pulse-duration modulation, there is frequently an interfering dead region for small positive and negative DC currents when the control voltage passes through zero, in which dead region no change in the DC current in accordance with the control voltage takes place. This dead region can be compensated for by changing the triangular reference voltage which is required for pulse-duration modulation. The change takes place in a zero region in which the reference voltage corresponds to a datum voltage. When it corresponds to this datum voltage, the reference voltage is always briefly kept constant so that there is always a small time duration with a constant voltage between each triangular amplitude. This time duration normally corresponds to the safety time period of a safety arrangement which prevents the individual half bridges turning on incorrectly.

High voltage power supply fault isolation system

Abstract: An electronics circuit for improving the fault isolation of failures between an electron tube radio frequency (RF) amplifier and its high voltage power supply is disclosed. High voltage power supplies control their output voltage by comparing a feedback voltage against a reference. This comparison is used to develop an error voltage which, in turn, drives a pulsewidth modulator that corrects the feedback voltage to the reference. The output of a digital-to-analog converter (DAC) is used as the reference voltage. The DAC is driven by a counter which would count to the correct reference voltage represented by a specific count. The final count is determined by a comparator which compares the counter output to the desired final count and stops the counter when it is reached.

Schmitt trigger circuit

Abstract: PURPOSE:To compensate the effect of a temperature characteristic of a resistive element by supplying a current from a constant current source having a characteristic entirely opposite to a temperature characteristic of a resistor setting a trigger level to an input voltage rise and a trigger level to an input voltage decrease. CONSTITUTION:TRs 21, 22 constitute a level shift-inverse level shift, a reference voltage VB equal to a band gap reference voltage VR is generated at the emitter of the TR 22 while each base-emitter voltage is cancelled and a current IB flows to a resistor 42. Nearly the same current IC as the current IB flows to the collector of the TR 22 and the current IC flows the same current ID equal to the current IC at the collector side of a TR 24 by a current mirror circuit comprising TRs 23, 24. The current ID flows currents I1-I3 each equal to the current ID by using the current mirror circuit comprising TRs 25, 27, 30 and 32. Thus, the current IB, I1-I3 are all equal. Thus, the temperature dependance of the trigger level is compensated and the waveform shaping circuit or the like is operated stably.

Wide bandwidth bandgap voltage reference circuit

Abstract: A bandgap voltage reference circuit includes an amplifier circuit (40,41,23,25,50,51) that detects imbalances in a bandgap cell (2) and transmits the imbalance signal through only high bandwidth NPN transistors to achieve very high, stable gain and very high bandwidth. The output voltage (VREF) produced thereby is sampled to provide feedback to an input (100) of the bandgap cell. Avoidance of active PNP transistors in the signal path results in a simple, yet very high bandwidth, bandgap voltage reference circuit and stable, highly predictable, highly reproducible circuit performance.

Stabilizing circuit for constant current source

Abstract: PURPOSE:To obtain the constant current stabilizing circuit which supplies a constant current circuit with electric power stable against power source variation by providing a band gap reference circuit and the constant current circuit which is supplied with the output voltage of said circuit as a source voltage. CONSTITUTION:The output voltage VCC of a power source 7 is supplied to the band gap reference (BGR) circuit 8 to supply the stable output voltage VEGR to the constant current circuit 6. The output voltage VEGR is constant even if the source voltage VCC varies, so the obtained current I2 has an invariably constant value. Consequently the constant current circuit is operated stably by supplying the stable electric power generated by the BGR circuit to the constant current circuit although the constant current varies directly before as the source voltage varies.