263 results about "Zero temperature coefficient" patented technology

The invention provides a circuit for outputting adjustable positive, negative or zero temperature coefficient current and voltage reference, including: a start-up circuit, a positive and negative temperature coefficient current generation circuit, a feedback stable and negative temperature coefficient current derivation circuit, and the temperature coefficient can be Adjusted current reference, voltage reference synthesis circuit. The invention is realized under the standard CMOS technology, has simple structure, low input voltage, and can generate current reference and voltage (VREF) reference with adjustable temperature coefficient, which can be positive, negative or zero temperature coefficient.

A constant-temperature piezoelectric oscillator includes: a piezoelectric vibrator; an oscillation circuit; a frequency voltage control circuit; a temperature control section; and an arithmetic circuit, wherein the temperature control section includes a temperature-sensitive element, a heating element, and a temperature control circuit, the frequency voltage control circuit includes a voltage-controlled capacitance circuit capable of varying the capacitance value in accordance with the voltage, and a compensation voltage generation circuit, and the arithmetic circuit makes the compensation voltage generation circuit generate a voltage for compensating a frequency deviation due to a temperature difference between zero temperature coefficient temperature Tp of the piezoelectric vibrator and setting temperature Tov of the temperature control section based on a frequency-temperature characteristic compensation amount approximate formula adapted to compensate the frequency deviation, and then applies the voltage to the voltage-controlled capacitance circuit to compensate the frequency.

A bandgap reference voltage generator includes, in part, a first closed-loop circuit having a first operational amplifier and adapted to generate a first current with a positive temperature coefficient and a second closed-loop circuit having a second operational amplifier and adapted to generate a second current with a negative temperature coefficient. The bandgap reference voltage generator is further adapted to include a multitude of output stages. Each output stage may be independently scaled to sum any selected multiple of the first current to any selected multiple of the second current to generate an output voltage having either a nearly zero, a positive or a negative temperature coefficient. For example, the first output stage may be scaled to generate a reference output voltage with a nearly zero temperature coefficient. Similarly, the second output stage may be scaled to generate a reference output voltage with a negative temperature coefficient.

A high shunt regulator provides precise voltage over process, temperature, power supply, and foundries. The HV level is settable by a digital control bits such as fuse bits. A filter network filters out the ripple noise and charge transient. A tracking capacitor divider network speeds up response time. A fractional band gap reference provides fractional bandgap voltage and current, and operates at low power supply and has superior power supply rejection. It is unsusceptible to substrate hot carrier effect. It exposes very little to drain induced barrier lowering effect. The bandgap core has better than conventional transient response and stability. One embodiment has adjustable level control. Complementary TC (temperature coefficient) trimming allows efficient realization of zero temperature coefficients of current and voltage. Higher order curvature correction of voltage and current is integrated. Replica bias for the control loop is presented. A Binary and Approximation Complementary TC search trimming is described. A zero TC fractional voltage less than the theoretical bandgap voltage (<<−1.2. Volt) is realizable. The bandgap core has a filtering mechanism to reject high frequency noise. A low power startup circuit powers up the band gap. The band gap also has variable impedance.

The invention discloses a lower-power-consumption reference source circuit. The lower-power-consumption reference source circuit comprises a starting circuit unit, a current generation circuit unit and an output load circuit unit, wherein the starting circuit unit, the current generation circuit unit and the output load circuit unit are connected in sequence, the starting circuit unit is used for providing starting voltage, and preventing operation in a zero state area, the current generation circuit unit is used for generating microcurrent for the output load circuit unit, and reducing power consumption of the lower-power-consumption reference source circuit, and the output load circuit unit is used for achieving output of a zero-temperature coefficient and low-output voltage. The lower-power-consumption reference source circuit has the advantages of being low in power consumption, low in temperature coefficient, large in range of operating voltage and small in area.

The invention relates to an integrated circuit and discloses a current reference source circuit and a method for generating a current reference source. The method comprises the following steps of: generating a linear positive temperature coefficient current, a nonlinear negative temperature coefficient current and a nonlinear positive temperature coefficient current through three circuits respectively; superimposing the three currents; and taking the superimposed output currents as the current reference source. The linear positive temperature coefficient current is used for effectively offsetting linear components in the nonlinear negative temperature coefficient current, and the nonlinear positive temperature coefficient current is used for compensating residual nonlinear negative temperature coefficients, so that the sensitivity of the acquired currents to temperature changes is further reduced, and the current reference source which approximates to a zero temperature coefficient can be realized.

The invention provides a voltage reference source circuit with ultra-low power consumption and a high power supply rejection ratio.The voltage reference source circuit comprises a starting circuit unit, a current generation circuit unit and an output voltage reference circuit unit which are electrically connected in sequence.The staring circuit unit is used for providing starting voltage and preventing the voltage reference source circuit from working in a zero-state zone.The current generation circuit unit is used for generating working current for the output voltage reference circuit unit and lowering the power consumption of the voltage reference source circuit at the same time.The output voltage reference circuit unit is used for achieving voltage reference output at a zero temperature coefficient and a high power supply rejection ratio.The voltage reference source circuit has the advantages of being ultra-low in power consumption, low in temperature coefficient, high in power supply rejection ratio, wide in working voltage range and small in size.

A bandgap circuit is provided, which includes a current source, a voltage boost circuit, a voltage input circuit, a voltage equalizer circuit, and a voltage output circuit. The current source provides a first current, a second current, and a third current, which are equal to one another. The voltage boost circuit provides a boost voltage by a single current path. The voltage input circuit receives the first and the second currents, and provides a first input voltage and a second input voltage based on the boost voltage. The voltage equalizer circuit receives the first and the second input voltages and equalize the two input voltages. The voltage output circuit provides a bandgap reference voltage according to the third current.

The invention discloses a high-precision and low-maladjustment reference voltage source realized by utilizing a triode emitter current compensation technique. The high-precision and low-maladjustment reference voltage source comprises four circuits: a start-up circuit (1), a bias voltage generating circuit (2), a reference voltage generating circuit (3) and an emitter current compensation circuit (4), wherein the start-up circuit is mainly used for relieving a circuit deadlock state possibly generated when the circuit is powered on; the bias voltage generating circuit generates bias voltage required by reference; the reference voltage generating circuit outputs reference voltage close to a zero-temperature coefficient by utilizing a method of mutually offsetting the negative temperature coefficient and the positive temperature coefficient of a triode; and the emitter current compensation circuit is used for compensating the emitter current of the triode, thereby reducing the influence of operational amplification on reference output. The invention can effectively restrain the influence of the temperature and power voltage changes on the reference output voltage and simultaneously reduces the influence of the operational amplification on the reference output; moreover, the circuit is completely compatible with a common CMOS (Complementary Metal Oxide Semiconductors) process, and simultaneously, the invention has big output range, high precision and wide application range.

A current reference circuit is disclosed. A small startup current is defined as the base current into a bipolar transistor with its collector-emitter path connected in series with a resistor between the power supply voltage and ground. This startup current is conducted via a diode-connected MOS transistor in a first leg of a current mirror. Temperature compensation is maintained by a reference leg in the current mirror that includes a bipolar transistor having an emitter area N times larger than that of a bipolar transistor in a second leg of the current mirror, to establish a temperature-compensated current in the reference leg. A compensation capacitor connected between the collector and base of a bipolar transistor in the first leg suppresses oscillation, and can be modest in size due to the Miller effect.

A differential voltage controlled current source generating one or more output currents is based upon a single external resistor. The differential voltage controlled current source may generate an output current that is proportional to a received differential voltage and a bias current with the use of a single external resistor. The technique may be used to generate multiple accurate and process independent current sources. The current sources may be a zero temperature coefficient (ZTC) current, a proportional to absolute temperature (PTAT) current, or an inversely proportional to absolute temperature (NTAT) current. The output of the current sources may be inversely proportional to the resistance of the external resistor.

The invention relates to an integrated circuit and discloses a voltage reference source circuit and a method for generating a voltage reference source. The method comprises the following steps of: generating a self-adaption nonlinear PTAT (positive temperature coefficient) current through a high-order temperature coefficient compensation circuit; converting the current into a self-adaption nonlinear PTAT voltage and then superposing the voltage with a first-order reference voltage; and generating the reference voltage approximate to zero-temperature coefficient, as the voltage reference source. The self-adaption nonlinear PTAT voltage counteracts the nonlinear negative temperature coefficient in the first-order reference voltage, so the voltage reference source has lower temperature coefficient. In addition, the structure is simple, the compensation branch stability is better and the influence on the initial precision of the voltage reference source is small.

The invention relates to the field of design of an integrated circuit and discloses a low temperature coefficient bandgap voltage reference circuit. In the circuit, a temperature compensation circuit is introduced to perform feedback correction on a temperature coefficient of output reference voltage based on the traditional current mode bandgap reference circuit structure, and due to a nonlinear temperature coefficient compensation mode, the temperature coefficient of the output reference voltage can be greatly reduced, and the reference circuit has high compensation stability and slight influence on initial accuracy of the preference voltage. By a nonlinear temperature sensing unit, the base-emitter (BE) junction voltage of a crystal triode is subjected to temperature detection, and a nonlinear current is generated and is superposed with two circuits with opposite temperature coefficients in the reference circuit, so that zero temperature coefficient reference voltage which is hardly related to the temperature is generated.

Disclosed is a digital signal conditioning chip of a full-bridge and piezoresistive pressure sensor, which mainly comprises a bandgap reference voltage module, an adjustable gain calculation amplifier module and a digital control unit module. The invention is characterized in that a positive temperature coefficient voltage is generated in the bandgap reference voltage module to provide an energizing voltage for the full-bridge and piezoresistive pressure sensor, the digital control unit module is equipped with a memory and an inner clock circuit, the gain in the adjustable gain switch capacity calculation amplifier is confirmed by the digital control unit module according to the parameter of positive temperature coefficient, zero temperature coefficient and zero output value. The digital signal conditioning chip of a full-bridge and piezoresistive pressure sensor has the advantages that the conditioning chip realizes effect compensation of sensitivity, zero drift compensation and adjustment of zero output, and is high in conditioning accuracy and low in cost.

The invention belongs to the field of integrated circuits, and specifically relates to a temperature compensation circuit for a crystal oscillator. The temperature compensation circuit generates reference voltage Vref of a third power function for temperature, and controls the magnitude, monomial coefficient, quadratic coefficient and ternary coefficient of the output reference voltage under the actions of control signals Cont-Rm1, Cont-Rm2, Cont-Rm3 and Cont-NL, so as to change the temperature coefficient and the zero temperature coefficient point of the reference voltage according to the temperature-frequency characteristics of different crystals. The reference voltage controls the capacitance of a variable capacitance diode, so as to accurately compensate the offset of the oscillation frequency of the crystal oscillator due to temperature changes and improve the temperature stability of the frequency. The temperature compensation circuit generates the reference voltage with different temperature coefficients and zero temperature coefficient points for crystals with different temperature characteristics, is high in flexibility, high in compensation precision, simple in structure and low in cost, and facilities miniaturization and integration.

A constant-temperature piezoelectric oscillator includes: a piezoelectric vibrator; an oscillation circuit; a frequency voltage control circuit; a temperature control section; and an arithmetic circuit, wherein the temperature control section includes a temperature-sensitive element, a heating element, and a temperature control circuit, the frequency voltage control circuit includes a voltage-controlled capacitance circuit capable of varying the capacitance value in accordance with the voltage, and a compensation voltage generation circuit, and the arithmetic circuit makes the compensation voltage generation circuit generate a voltage for compensating a frequency deviation due to a temperature difference between zero temperature coefficient temperature Tp of the piezoelectric vibrator and setting temperature Tov of the temperature control section based on a frequency-temperature characteristic compensation amount approximate formula adapted to compensate the frequency deviation, and then applies the voltage to the voltage-controlled capacitance circuit to compensate the frequency.

The Ku frequency band environment friendly microwave dielectric ceramic is prepared with CaO, Ln2O3, TiO2 and Al2O3, where Ln is La, Nd and Sm, as material and has the chemical expression of xCaO-y(mNd2O3-nLa2O3-pSm2O3)-z(aTiO2+bAl2O3), where x is 20-45 mol%, y is 5-20 mol%, z is 45-60 mol%, x+y+z=100 mol%, m+n+p=1, a+b=1. The Ku frequency band environment friendly microwave dielectric ceramic contains no components harmful to environment and human health, and has the microwave dielectric performance including dielectric constant of 30-70, high of value of 16,000-47,000 GHz and near zero temperature coefficient of resonant frequency. It may be used in resonator, filter, capacitor and other key electronic elements and devices for Ku frequency band satellite communication and has important industrial application value.

The invention relates to an asymmetric band-gap reference circuit which is characterized by comprising a positive temperature coefficient current generation unit, a negative temperature coefficient current generation unit, a zero temperature coefficient reference voltage VREF generation unit, a switch tube control unit and a start circuit Start-up; and the asymmetric band-gap reference circuit has the advantages that: (1) a unilateral resistor R2 serves as a low-voltage bandgap reference circuit for temperature compensation; (2) the obtained bandgap reference voltage VREF has low-power supply voltage action, extremely low temperature drift and better power supply features; (3) the circuit can still work normally when the op amp as quite high offset voltage; and (4) the structure is simple, the operation is convenient, and the circuit can provide precise and stable reference voltage for any system.

The invention relates to a microwave medium ceramic and a preparation method thereof. The structural formula of the microwave medium ceramic is a(MgxMyTizO3)-b[(La0.5Li0.5)TiO3], wherein M refers to Co, Zn, Zr or Sb; x=0.9-1, y=0.01-0.1, z=0.9-0.1, and x+y+z=2; and a=0.9-0.99, b=0.1-0.01, and a+b=1. The preparation method comprises the following steps: weighing raw materials in a chemical ratio of MgxMyTizO3 to (La0.5Li0.5)TiO3, and ball-milling and drying to obtain powder with uniform particles; and pre-sintering the powder, mixing in a ratio of a:b of (0.9-0.99):(0.1-0.01), performing secondary ball milling, drying the mixed powder, adding an adhesive, granulating and grinding, sieving and pressing into a green body, and sintering the green body at high temperature to obtain the microwave medium ceramic. The magnesium titanate system microwave medium ceramic material has the dielectric constant of 15-25, the quality factor (Qf) of more than 200,000GHz and the near-zero temperature coefficient of resonance frequency tau f of -2ppm / DEG C, and the dielectric property of magnesium titanate ceramics is greatly improved.

The invention discloses a low-power-consumption full-CMOS reference source circuit based on a subthreshold value. The low-power-consumption full-CMOS reference source circuit based on the subthreshold value comprises a start circuit unit, a current generating circuit unit and an active load circuit unit. The start circuit unit is used for providing a start current to enable the current to get into a normal work state. The current generating circuit unit is used for generating a current irrelevant to input power voltages. Due to the fact that part of MOS transistors work in a subthreshold state, the work current is low, and the power consumption of the circuit can be reduced. The output active load circuit unit outputs a zero temperature coefficient and low output voltages through the body polarization technology. The circuit has the advantages of being low in power consumption, low in temperature coefficient, wide in work voltage range, small in area and the like.

The invention provides an LTCC (low-temperature co-fired ceramic) material with a low dielectric constant, low loss and a near-zero-temperature coefficient and a preparation method. According to the LTCC material, on the basis of a BaSO4 ceramic powder, glass of a BaO-B2O3-SiO2-Al2O3 system is adopted for assisted combustion to reduce sintering temperature, and TiO2 is adopted for adjusting a resonance frequency temperature coefficient, so that 900 DEG C low-temperature sintering can be realized. Under 60GHz, the dielectric constant of the LTCC material is 5.5-9, the low dielectric loss is smaller than 2*10<3>, and the near-zero-temperature coefficient is tua f-+ / -10ppm / DEG C. In addition, the preparation method has the advantages of cheap production raw material, low production cost and simple preparation process. The LTCC material can be applied to manufacture of microwave devices such as low-temperature co-fired ceramic systems, multilayer dielectric resonators, microwave antennas and filters, and has high application value in industry.

The invention discloses a band gap reference circuit, which comprises a first double-carrier transistor, a first resistor, a second double-carrier transistor, a second resistor, a first operational amplifier, a second operational amplifier and a zero temperature coefficient current generator, wherein the first resistor is used for generating positive temperature coefficient current; the second resistor is used for generating negative temperature coefficient current; the first operational amplifier is coupled to the first double-carrier transistor and the first resistor; the second operational amplifier is coupled to the first double-carrier transistor and the second resistor; and the zero temperature coefficient current generator is used for totaling the positive temperature coefficient current and the negative temperature coefficient current so as to generate zero temperature coefficient current.

The invention discloses a reset circuit with a high response speed and a low temperature coefficient, and relates to the technical field of integrated circuits. The reset circuit includes a voltage sampling circuit, a voltage detection circuit and an output circuit, one connected with another in sequence, wherein the voltage sampling circuit includes a first resistor, a first NMOS transistor and a second NMOS transistor; the voltage detection circuit includes a first CMOS inverter and a first capacitor; the first CMOS inverter includes a first PMOS transistor and a third NMOS transistor; the output circuit includes a first Schmitt trigger, a second CMOS inverter and a third CMOS inverter, one connected with another in sequence; the output end of the output circuit is connected to the input end of a time-delay circuit; the time-delay circuit adjusts the time for outputting reset signals and shapes the reset signals according to reset requirements of the circuit system. The reset circuit provided by the invention is high in response speed with a near-zero temperature coefficient, and can fully ensure the reliability of the operations.

General speaking, a resistor of high resistivity has a negative-temperature-coefficient and a resistor of low resistivity has a positive-temperature-coefficient. Utilizing this characteristic, an appropriate proportion between the above resistors can be found to make a combined resistor with an approximate zero-temperature-coefficient. The combined resistor can be used to design a circuit for generating voltage and current with approximate zero-temperature-coefficients.

The invention discloses a non-bandgap high-precision reference voltage source realized by utilizing a principle that the changes of electron mobility and MOS tube threshold voltage to temperature are in a reverse trend. The reference voltage source consists of three circuits: (1) a start-up circuit which is mainly used for removing circuit deadlock states possibly occurring in the process of electrifying the circuit; (2) a reference-current generating circuit which generates a reference current that does not change with power-supply voltage; and (3) a reference-voltage generating circuit which utilizes the reference current produced by mirror images, adopts a method of mutually regulating positive temperature coefficients of the electron mobility and negative temperature coefficients of the MOS tube threshold voltage, and realizes the reference voltage output with zero-temperature coefficients. The reference voltage source can effectively inhibit output from changing with the changes of temperature and the power-supply voltage, can be completely compatible with the common CMOS process, and has the advantages of simple structure, small chip area, large output range and high precision at the same time, thereby greatly reducing system cost.

The invention belongs to an electronic ceramic material and the manufacturing field thereof, and in particular relates to a Ti-based LTCC microwave dielectric ceramic material and a preparation method thereof. The preparation method comprises the following steps: firstly, compounding (Mg0.95Co0.05)2TiO4 and Li2TiO3; then realizing low-temperature sintering at 900-950 DEG C of a whole material system by means of LMZBS glass doped fluxing; and finally, realizing the optimum properties under the low-temperature sintering at 900 DEG C: the dielectric constant: epsilonr=16.6, Q*f=125800GHz and tauf=1.4ppm / DEG C. The Ti-based LTCC microwave dielectric ceramic material provided by the invention has high properties of ultra-low-loss, near-zero temperature coefficient of resonance frequency and low-temperature sintering. The dielectric constant of the material epsilonr is 16.6-17.1, the Q*f value is 88400-125800GHz, and the temperature coefficient of resonance frequency tauf is 1.3-5.1ppm / DEG C. The material can be widely applied to an LTCC microwave substrate, a laminated microwave apparatus and a module.

The invention discloses an operational amplifier circuit. The operational amplifier circuit comprises an operational amplifier and a chopping offset elimination circuit for eliminating an offset signal and flicker noise of the operational amplifier. The invention further discloses a reference voltage generating circuit module. The reference voltage generating circuit module comprises a reference voltage generating circuit, an operational amplifier, a chopping offset elimination circuit and a filtering circuit, wherein the reference voltage generating circuit is used for generating voltage with a zero temperature coefficient and current with a zero temperature coefficient; the operational amplifier is used for providing feedback for the reference voltage generating circuit in order that the output of the reference voltage generating circuit is stabilized at a required working point; the chopping offset elimination circuit is used for modulating the inherent offset voltage and the low-frequency flicker noise of the operational amplifier in order to modulate the influence of the offset of the operational amplifier on a reference voltage generated by the reference voltage generating circuit; and the filtering circuit is used for filtering the offset signal modulated by the offset elimination circuit and keeping a useful reference voltage signal. Through adoption of the operational amplifier circuit and the reference voltage generating circuit module, the offset and the flicker noise of the operational amplifier can be eliminated, and the accuracy is increased.

The invention discloses a reference current source comprising a current source core circuit, a current bias circuit, an offset voltage circuit and an output stage unit. The reference current source is characterized in that a fifth end and a sixth end of the current source core circuit are respectively connected to a first relative voltage and second relative voltage outside, and the difference between the first relative voltage and the second relative voltage serves as offset voltage which maintains constantly while the temperature changes and which is reserved to carrier mobility along the process changing tendency. According to the reference current source, the temperature coefficient of the voltage of two end of an MOS (metal oxide semiconductor) resistor can be changed by guiding in the offset voltage in the current source core circuit and can compensate mutually with that of the carrier mobility, and output current with zero temperature coefficient can be realized. The reference current source further has the advantages of process compensation, and influences on current source accuracy by process variations can be reduced.

The invention discloses a low temperature drift band-gap reference voltage source based on VBE linearization. Circuits comprise a PTAT current generation circuit, a high-order compensation band-gap reference circuit, a first starting circuit and a second starting circuit. The reference circuit builds a nonlinear term through the difference between two VBEs with different collector current temperature characteristics, then is overlaid with the VBEs to counteract the nonlinear term, and achieves the high-order compensation effect. The collector current of the zero temperature characteristic is formed by overlaying the two VBEs, subtracting voltage of one VBE and adding on the negative temperature coefficient current generated at two ends of a resistor R3 and the positive temperature coefficient current of delta VBE generated on a resistor R1, the temperature characteristic is not affected by output voltage precision, and the high-order compensation precision is ensured. Compared with a traditional VBE linearization method, the circuits adopt the voltage-mode output VREF, influence of current mirror mismatching and output resistor temperature characteristics on compensation precision is avoided, and therefore the reference voltage of the high precision and zero temperature coefficient is obtained, and the problems of low conversion precision and the like are solved.

A resistorless CMOS low power voltage reference circuit is provided. The start-up circuit is used to prevent the circuit to stay in the zero state and stop working when the circuit gets out of the zero state. The self-biased VPTAT generating circuit generate the voltage VPTAT which has positive temperature coefficient. The square-law current generating circuit generates a square-law current which is proportional to μT2 through the VPTAT. Finally, the reference voltage VREF is obtained by introducing the square-law current into the reference voltage output circuit. The reference voltage VREF of this application can realize approximative zero temperature coefficient in the temperature range of −40° C.˜ 100° C. This application improves temperature characteristic which may be poorer due to temperature nonlinearity of carrier mobility based on the traditional subthreshold reference. This application can reduce the power consumption from μW level to nW level and realize low power consumption.