14 results about "Zero temperature coefficient" patented technology

The invention discloses a composite material with a near-zero temperature coefficient. The composite material comprises composite particles with three layers of core shells, the composite particle comprises a metal organic framework serving as an inner core, a conductive carbon transition layer serving as a middle layer and a gradient doped tin oxide layer serving as a shell, and the resistance temperature coefficient symbols of materials of the inner core and the shell are opposite within the range of 0-80 DEG C. According to the composite material with the near-zero temperature coefficient, a three-layer core-shell structure of a metal organic framework core / a conductive carbon transition layer / a gradient doped SnO2 shell is adopted, mutual offset of temperature coefficients can be achieved in the material, and therefore drifting of baseline resistance generated along with fluctuation of the environment temperature is reduced.

This invention discloses an air conditioning device that determines the initial and equilibrium temperatures of a power module; controls the compressor's operating state to ensure the IGBT output current has a relative zero temperature coefficient; determines the total power module losses at the equilibrium temperature based on the IGBT's relative zero temperature coefficient parameters; acquires the thermal resistance of the inverter driver and refrigerant radiator, and determines the theoretical temperature based on the thermal resistance and total losses; determines the theoretical temperature rise based on the theoretical and initial temperatures, and determines the measured temperature rise based on the equilibrium and initial temperatures; determines the deviation value based on the theoretical and measured temperature rises; acquires the standard deviation value, and compares the deviation value with the standard deviation value to determine whether the refrigerant radiator is qualified. The air conditioning device can intelligently assess the reliability of the refrigerant radiator and its installation.

This invention provides a soft-start circuit, relating to the field of electronic and electrical technology. It includes a constant current source module that outputs a zero-temperature coefficient nA-level constant current; a constant current charging module that linearly charges a soft-start capacitor with a constant current, generating a linearly rising soft-start reference voltage; a feedback control module that clamps the output sampling voltage to the reference voltage through a negative feedback loop, ensuring a smooth rise in output voltage; a low-power logic control module that shuts down the constant current charging and feedback control modules after soft-start; and a gate drive module that drives the power devices to conduct. The advantages include using a zero-temperature coefficient nA-level current combined with negative feedback clamping to solve the problems of temperature drift, unstable charging slope, and low control accuracy in traditional RC structures; shutting down related modules after soft-start, combined with a low-current design to reduce static power consumption; and the ability to integrate the circuit on a standard process chip without external components, reducing system size and cost.

The invention discloses a front-end detection circuit of a high-precision temperature sensor. The front-end detection circuit comprises a biasing and starting module, a temperature sensing core module, an output module and a high-order temperature compensation module. The starting module activates the core temperature sensing circuit when the power supply is powered on. The temperature sensing core module takes a BJT as a temperature sensing element and generates positive and negative temperature coefficient voltage. The output module generates a zero temperature coefficient reference voltage and a positive temperature coefficient voltage. And the high-order temperature compensation module realizes temperature compensation by generating currents with different temperature characteristics, so that the measurement precision is improved.

This invention discloses a frequency converter driver testing device that determines the initial temperature and equilibrium temperature of a power module; determines the total power module loss at the equilibrium temperature based on the IGBT's relative zero temperature coefficient parameters, current, and voltage; obtains the frequency converter driver's thermal resistance and determines the theoretical temperature based on the thermal resistance and total loss; determines the theoretical temperature rise based on the theoretical temperature and initial temperature, and determines the measured temperature rise based on the equilibrium temperature and initial temperature; determines the deviation value based on the theoretical temperature rise and measured temperature rise; obtains the standard deviation value, and compares the deviation value with the standard deviation value to determine whether the heat sink and power module assembly is qualified. The testing device determines the deviation value by comparing the theoretical temperature change estimated from the power module loss under a specific state and the thermal resistance with the actual temperature change of the power module, and compares this deviation value with a pre-determined standard deviation value to determine whether the heat sink and power module assembly is qualified. This allows for intelligent assessment of the reliability of the power module and heat sink installation.

A method for generating a constant current. The method can include receiving an input voltage at a voltage input connected to a resistor pair, the resistor pair including a first resistor and a second resistor, the first resistor having a positive temperature coefficient and the second resistor having a negative temperature coefficient. The first and second resistors can be configured such that the variability of resistance over temperature of the first resistor and the variability of resistance over temperature of the second resistor cancel to produce a zero temperature coefficient for the resistor pair. The method can further include applying the input voltage to the resistor pair to generate a current with a zero temperature coefficient.

The invention provides an intermediate dielectric microwave ceramic material with a near-zero temperature coefficient and a preparation method thereof, and relates to the field of ceramic materials. The material comprises the following components in percentage by weight: 97 to 98.5 percent of main crystal phase, 0.1 to 1.0 percent of Mg-Ca-Si-O glass phase and 0.5 to 2.5 percent of modified additive (selected from BaCO3, SrCO3 and the like), the core chemical formula of the main crystal phase is (MxCaLnz) TiO3, and during preparation, Mg / Zn salt, Ca salt, rare earth and TiO2 are mixed and calcined for 1-4 h at the temperature of 1050-1250 DEG C, and the main crystal phase is obtained; melting the Mg-Ca-Si-O mixture, and performing water quenching to obtain a glass phase; the three components are mixed in proportion, molded under 10MPa, and sintered at 1280-1400 DEG C for 2-5 hours. The room temperature dielectric constant of the material is 25-33, Qf is larger than or equal to 25000GHz, tau f (-40-110 DEG C)-10-30ppm / DEG C is adjustable, the cost is low, the sintering applicability is high, the requirements of microwave devices are met, the overall preparation steps are simple, key parameters (temperature, time, pressure and the like) are definite, the repeatability is good, and the industrial stable production requirements can be met.

The application discloses a high-precision voltage stabilizing source circuit with zero temperature coefficient, and relates to the field of voltage stabilizing source circuits.The method comprises a voltage stabilizing unit, a first current source unit and a second current source unit which are adaptively connected.The first current source unit is used for generating a first current I1 with a positive temperature coefficient, and the second current source unit is used for generating a second current I2 with a negative temperature coefficient.Based on the first current I1, the second current I2 and element parameters of the voltage stabilizing unit, the voltage stabilizing unit generates a reference voltage VREF with zero temperature coefficient.The voltage stabilizing source circuit has zero temperature coefficient and higher output precision.

The invention discloses a zero-temperature-drift resistance circuit and a trimming method, relates to the technical field of integrated circuits, and aims to solve the problem that a resistance circuit in the prior art cannot realize low resistance, zero temperature drift, high precision and reduction of occupied area at the same time. The circuit comprises a main resistor network, a first trimming resistor network and a second trimming resistor network, the main resistor network is connected in parallel with the first trimming resistor network and then is connected in series with the second trimming resistor network; the trimming precision of the first trimming resistor network is smaller than that of the second trimming resistor network; trimming resistor units in the main resistor network and the first trimming resistor network are zero temperature coefficient resistor units; therefore, the main resistor network, the first trimming resistor network and the second trimming resistor network can be utilized to perform step-by-step trimming, and a resistance value adaptive to the target resistor is obtained and then output. And low resistance, zero temperature excursion and high precision are realized while the occupied area of the chip is reduced.

The invention relates to a high-precision segmented compensation band-gap reference circuit, which comprises a first-order reference core module used for enabling the voltage difference between the base electrode and the emitter electrode of a triode to act on a resistor R3, acquiring current flowing through the resistor R3, inputting the current into a self-bias current circuit, and outputting a reference voltage source VREF according to compensation current output by a temperature compensation module; the self-bias current circuit is used for generating self-bias reference current, taking the self-bias reference current as zero temperature coefficient current, taking the current flowing through the resistor R3 as positive temperature coefficient current, combining the positive temperature coefficient current and the zero temperature coefficient current in proportion, and inputting the positive temperature coefficient current and the zero temperature coefficient current into the temperature compensation module; and the temperature compensation module is used for outputting compensation current according to the combined current. According to the invention, the sensitivity of the reference voltage to process deviation and power supply fluctuation is obviously reduced.

This invention provides a porous carbon-based nanocomposite material with intrinsically zero temperature coefficient, its preparation method, and a flexible pressure sensor with intrinsically zero temperature coefficient, belonging to the field of flexible pressure-sensitive materials technology. This invention uses PDMS as a flexible matrix and carbon black and carbon nanotubes as conductive fillers. It innovatively constructs a uniform and controllable pore structure within the material through a chemical foaming method that generates gas by the in-situ reaction of sodium bicarbonate and hydrochloric acid. Unlike existing technologies that rely on circuit compensation, this invention achieves precise cancellation of the positive and negative temperature coefficient effects of the material over a wide temperature range by synergistically controlling the ratio of carbon black to carbon nanotubes and the porosity of the material, thus obtaining a porous carbon-based nanocomposite material with intrinsically zero temperature coefficient. The preparation temperature and energy consumption are low, the process is simple and controllable, and the relative change rate of the material's resistance is less than 2% in the range of 25~100℃. When used in a flexible pressure sensor, it does not rely on external compensation circuits and exhibits both excellent piezoresistive sensitivity and temperature stability.

The application discloses a CMOS voltage reference source adopting a self-elimination technology of a disordered voltage, comprising a bias circuit, an operational amplifier circuit and a zero-temperature coefficient bias circuit; the bias circuit adopts a 1uA current source to provide a bias voltage for a subsequent circuit, so that the subsequent circuit can normally work under a power supply voltage of 0.65V to 2.5V; the operational amplifier circuit locks the output voltage of the zero-temperature coefficient bias through a two-stage folded common-source common-gate operational amplifier; and the zero-temperature coefficient bias circuit realizes working at a zero-temperature coefficient point by adjusting the bias point of MN25, and realizes the output of the voltage reference source. The CMOS voltage reference source can work in a wide voltage range and is not affected by the disordered voltage of the operational amplifier.

A circuit for providing temperature compensation to sense signals in a single-ended DC resistance (DCR) sensing network for a multiphase switching power supply includes a temperature compensation calculator circuit generating a compensation adjust signal indicative of a sensed temperature; a compensating impedance network receiving the positive sense signals for all the phases and generating a correction signal for each phase in response to at least the positive sense signal for each phase and the compensation adjust signal; an average circuit coupled to average the correction signals of all phases, where copies of the average correction signal are applied to modify the positive sense signals; and an amplifier circuit receiving a summed positive sense signal being the sum of the modified positive sense signals for all the phases and a summed negative sense signal to generate an output signal having substantially zero temperature coefficient over the first frequency range.

The invention discloses a biasing circuit and electronic equipment, and relates to the technical field of power electronics. A first current and a second current with opposite temperature coefficients are set, the first current and the second current are superposed on a third resistor to generate an adjustable bias voltage, and two negative feedback loops are configured to act together to enable each branch to work stably, which is equivalent to guarantee the stable work of the circuit on the basis of an embedded temperature coefficient adjusting mechanism. The temperature characteristic of the finally output bias current is determined by the resistance value proportion of the first resistor and the second resistor which respectively determine the first current temperature coefficient and the second current temperature coefficient, and the current magnitude is jointly determined by the resistance values of the three resistors. The bias current of a zero temperature coefficient, a positive temperature coefficient or a negative temperature coefficient can be configured only by adjusting several internal resistance parameters without depending on any external additional complex compensation circuit. The technical problems of chip area increase, power consumption increase and inflexible design caused by temperature coefficient adjustment in the prior art can be solved.