634 results about "Digital potentiometer" patented technology

The present invention discloses an electromagnetic sensing touch screen, which includes a display panel, a sensing capacitor matrix, select units, voltage controlled oscillators (VCOs), digital potentiometers, EM (electromagnetic) wave receive / detection units, a standard EM wave transmit unit and a control unit. A single detection unit consists of a corresponding select unit, VCO, digital potentiometer and EM wave receive / detection unit. The control unit drives the standard EM wave transmit unit to transmit standard EM wave, and further controls the EM wave receive / detection units to receive sensed capacitance values from the sensing capacitor matrix in a scanning manner. As a result, each EM wave receive / detection unit generates a respective detection signal for determining the location of the finger(s) and checking how the finger(s) approaches to or actually touches the sensing capacitor matrix, thereby generating finger location information and implementing the multipoint touch and display function.

A patient temperature repeating system and a method of repeating patient temperature information from a resistive-type patient temperature sensor allow one or more medical instruments to utilize a single patient temperature sensor. In one embodiment, the patient temperature repeating system (10) includes input and output connectors (12, 14), a microprocessor (20), optical isolators (22), a coarse digital potentiometer (24) in parallel with a fine digital potentiometer (26), a current sense resistor (28), amplifiers (30A, 30B), analog-to-digital converters (32A, 32B), a filter (34), fuses (36), a non-volatile memory device (38), and a relay (40). In operation, the microprocessor (20) reads the resistance level of a resistive-type patient temperature sensor (16) connected to the input connector (12) and provides the appropriate control signals through the optical isolators (22) to the coarse and fine digital potentiometers (24, 26) in order to set the resistance seen by a medical device (18) connected to the output connector (14) to match that of the patient temperature sensor (16).

The present invention discloses an electrical servo steering controller, which comprises a PID controller, a triangular wave generating circuit, a comparator, a motor current detecting circuit, a motor drive circuit, a microprocessor and a motor current setting circuit. Wherein, the PID controller outputs an adjusting voltage to the comparator according to a difference between a motor current setting signal output by the motor current setting circuit and a motor current detecting signal output by the motor current detecting circuit. The comparator compares a triangular wave signal output by the triangular wave generating circuit to output a pulse width modulation signal to the motor drive circuit to control the motor current. The microprocessor works out and controls a resistance value of a digital potential device in the motor current setting circuit to modify a servo characteristic. An analog circuit is adopted to complete main functions. Besides, a special motor drive chip can provide a higher servo force and ensure a larger applicable scope, simple circuit control, wonderful steering feeling and higher reliability.

A system for measuring the velocity of a fluid can comprise a temperature sensor, for measuring the ambient temperature of the fluid, an RTD placed in the flow path of a fluid, the RTD being included as part of a Wheatstone bridge circuit, a digital potentiometer, the digital potentiometer also being included as part of a Wheatstone bridge circuit, and a controller coupled to the temperature sensor, the RTD and the digital potentiometer. In the system, the controller adjusts the digital potentiometer in response to an ambient fluid temperature signal from the temperature sensor such that the temperature of the RTD remains at a constant differential temperature above the ambient fluid temperature.

A system for measuring the velocity of a fluid can comprise a temperature sensor, for measuring the ambient temperature of the fluid, an RTD placed in the flow path of a fluid, the RTD being included as part of a Wheatstone bridge circuit, a digital potentiometer, the digital potentiometer also being included as part of a Wheatstone bridge circuit, and a controller coupled to the temperature sensor, the RTD and the digital potentiometer. In the system, the controller adjusts the digital potentiometer in response to an ambient fluid temperature signal from the temperature sensor such that the temperature of the RTD remains at a constant differential temperature above the ambient fluid temperature.

A light transmission module of tunable positive-governing type consists of tunable positive-governing laser, positive-governing control circuit, automatic light power control circuit, automatic temperature control circuit, laser switch control and performance detection circuit. It is featured as enabling to realize parameter calibration, on-line regulation and performance parameter diagnosis of digitalization module by leading in micro control unit and nonvolatile digital potentiometer.

The invention discloses an intelligent integrated power supply device for Internet of Things. The intelligent integrated power supply device comprises a front public power supply module, a single chip microcomputer core control module, a DC voltage grade conversion module and a communication interface module, wherein the front public power supply module comprises an AC / DC front base voltage stabilizing circuit and an auxiliary power supply circuit; the single chip microcomputer core control module completes collecting and monitoring of voltage and current of various paths of output modules, and achieves a programmable presetting function on output voltage and over-voltage, over-current and over-temperature protection functions of various output loops of a complete machine through digital potentiometers; the DC voltage grade conversion module comprises four paths of identical modules; each module comprises a DC / DC converter circuit, a current / voltage sampling circuit and the digital potentiometer; and the communication interface module is connected with serial communication pins of a single chip microcomputer, completes the function of connecting different forms of actual transmission interfaces and forms connection with a network from an upper node to a monitoring center.

The invention discloses a method and optimization for adjusting an XFP optical module which adopts a distributed feedback (DFB) semiconductor laser by the gradual change of a digital potentiometer DAC and making the XFP optical module work at the best working point. The method and the optimization are suitable for a high-speed low-power consumption long-distance transmission optical fiber communication system; a microcontroller adjusts an APC control circuit through lookup tables (LUTs) to compensate bias current Ibias so as to make the set output light power of the DFB laser component the set output light power value which corresponds to the temperature range, and stabilizes the temperature of the DFB laser within the set output light power range through the APC control circuit; and the invention discloses a method for testing through two LUTs and three temperature points, and makes the XFP optical module which adopts the distributed feedback (DFB) semiconductor laser work under the best condition.

A magnetic field sensor with a plurality of magnetic field sensing elements is presented. The magnetic field sensor includes a sequences switches circuit to sequentially select from among the plurality of magnetic field signals. The magnetic field sensor further includes a memory device to store a plurality of potentiometer control values. Also included is a variable potentiometer to attenuate an offset of each one of the plurality of magnetic field signals by using a respective plurality of offset attenuation factors responsive to one or more of the plurality of potentiometer control values. A corresponding method is also described.

The invention relates to a simulation test method for the active thermal control circuit of a space optical remote sensor. A test system consisting of a voltage conditioning circuit, an analog to digital conversion circuit, a computer PCI bus driving circuit, an FPGA, a digital potentiometer synthesis conversion processing circuit and a microcomputer is connected to the active thermal control circuit of the optical remote sensor being tested, which forms an optical remote sensor active thermal control circuit closed loop simulation test system and realizes the aim of simulation test. At first, the heating information of a control circuit is collected, the validity of the information is judged, and then according to a pre-constructed thermal network mathematical model, temperature information after changing is fed back to the active thermal control circuit, therefore, the effect of maintaining heating is simulated. The test method can satisfy the long-term, rapid, convenient and clear test and monitor need of the active thermal control circuit of the optical remote sensor.

The invention discloses a digital adjusting method for an optical receiver module, and the method implements real-time monitor of parameters, on-line adjustment and non-linear compensation. The digital optical receiver module includes elements as follow: a voltage output circuit of optical power detection 24, a DC / DC voltage boost circuit 22 and a bias voltage adjusting unit which is consisted of an optical-electronic conversion circuit 21; a digital adjusting unit 25, an analog-digital converter (A / D converter) 26 and a memory 27. The digital adjusting unit 25, which is a D / A converter or a digital potentiometer, is used to make on-line adjustment and to implement temperature compensation and dark current compensation of the optical receiver module. The A / D converter 26 is used to monitor the optical power, the working temperature and the bias voltage of the optical detector in real time. The memory 27 is used to store parameters of the optical receiver module for comparison with a detected optical power and measured temperature etc. and for on-line interrogation.

This invention relates to one rotation device fault test machine based on sound emission technique, which comprises sound emission sensor, signal adjust and automatic gain amplifier module and digital signal process module, wherein, the digital signal process module comprises DSP digital signal processor, Flash data memory, RAM data memory, RS232 series chip, programmable logic controller, keyboard, and LCD display.

The invention belongs to the field of pressurized water reactor nuclear power stations, in particular to a principal current controller of a rod position measuring system in a nuclear power station in the manner of pulse-width modulation closed loop feedback regulation, aiming at realizing stable output, reducing heat generation and simplifying rod dropping measuring processes. In the invention, a principal current controller adopts a pulse-width modulation closed loop feedback regulation control mode, a primary winding current amplitude value is adjusted and controlled through a digital potentiometer by taking a signal generated by a sine wave generator as an original signal and a detector auxiliary coil induced voltage as a main regulating variable. A control scheme of direct current pulse-width modulation is utilized for a drive circuit, a pulse width modulation amplifier is used as a power amplifying element, thereby the heat productivity of a rod position measurement device is reduced. A novel and convenient test mode of rod dropping time is adopted, rod dropping time holes and key selector switches of the rod dropping time test state / normal operating state are arranged on a panel of the principal current controller, the operation is very simple, rod dropping signal waveforms are directly obtained, and the processing is very convenient.

The invention relates to an ultrasonic generator, which aims at solving the problem that a traditional ultrasonic generator can only achieve manual tracking instead of automatical frequency tracking. The invention provides a digital ultrasonic generator, including a rectification filter circuit, an inverter unit, a matching circuit, a transducer, an oscillation and drive circuit. The digital ultrasonic generator also includes a control unit, a current detection circuit used for detecting the current input to the rectification filter circuit and for outputting current detection signals to the control unit, a first digital potentiometer which is connected with the control unit and outputs power regulating signals to the oscillation and drive circuit, a second digital potentiometer which is connected with the control unit and outputs the power regulating signals to the oscillation and drive circuit, and input keystrokes connected with the control unit. The ultrasonic generator provided by the invention has the advantages of full digitalization, reliability and strong anti-interference ability, more important, the ultrasonic generator is able to automatically find a frequency point which ensures the input current of a half-bridge inverter circuit to reach the maximum.

A method and a circuit for controlling light power output and extinction ratio of a light emitting machine applies an APC circuit and back-lighted phototube monitor to alter Ibias and regulate Pav. The method includes setting an initial working point of a light source under the ordinary temperature, designing the allowed variation sphere for Pav, Ibias, Ith, OMA, ER and Imo to utilize APC to make Pav unchanged and monitor other variable quantities, when variables of temperature and time surpass the variation sphere, then other variables are regulated to restore the controlled variables to original spheres, computing Pav, I bias, Ith and SE ordinary temperature set value and regulating Imod to enable OMA and ER at the initial set value. The circuit includes a driver, a digital potentiometer, a microprocessor and a laser etc.

The invention discloses a multichannel high-precision thermal resistance breadboard based on extensions for instrumentation (PXI) bus. The multichannel high-precision thermal resistance breadboard based on extensions for instrumentation (PXI) bus comprises an analog part and a digital part; the analog part comprises a calibration unit and a plurality of output resistance modules; the output resistance modules are used for being connected with external instruments, and are formed by connecting m digital potentiometers in parallel and then connecting the m digital potentiometers with a resistor R in parallel; the calibration unit is provided with an internal resistance module which has the same structure as the output resistance modules, and is used for realizing the measurement and calibration of the resistances of the internal resistance module or an external resistor; and consequently, the calibration parameters are obtained through utilizing a calibration circuit to calibrate the internal resistance module and are used for revising the output resistance of the output resistance modules. The digital part is used for controlling all the parts and realizing the data interaction with a PXI bus controller. The thermal resistance breadboard can provide multichannel thermal resistance output, the output resistance modules have high precision, are low in price, and have a small size and small temperature drift, through changing the resistor R, the output range of the output resistance can be adjusted, and the output resistance precision is not influenced.

A dimming circuit of an LED (Light Emitting Diode) lighting lamp is formed by a switch and brightness control signal given unit, a brightness control signal conversion unit and a brightness adjustment driving unit. According to a dimming method of the LED lighting lamp, a method that positive and negative half waves of an alternating current power supply are controlled to be passed through or not is utilized and a single fire-wire mode is utilized to give a brightness control signal of the LED lighting lamp; the brightness control signal controls a digital potentiometer to output PWM (Pulse Width Modulation) duty ratio modulation voltage; a PWM brightness control signal is generated after the PWM duty ratio modulation voltage is in comparison with a triangular wave signal; and the duty ratio adjustable PWM brightness control signal controls the brightness change of the LED lighting lamp through the brightness adjustment driving unit. The dimming circuit of the LED lighting lamp can achieve replacement and upgrade of the ordinary lighting lamp without remote control, control line or power line re-laying.

A method of charging a battery at multiple charges rates includes determining a type of power source connected to a charging circuit and determining a voltage of a battery to be charged by the power source. A desired charging voltage is determined in response to the power source type and the battery voltage. A difference between the desired charging voltage and the battery voltage is determined. A digital potentiometer is selectively commanded to adjust the desired charging voltage to vary the difference and alter a charging rate of the battery, such that the difference is increased to increase the charging rate or is decreased to decrease the charging rate.

The invention relates to the CCD driving technology, more particularly to a system for realizing drive of an EMCCD signal by a transformer. According to the invention, problems that a current driving method has high power and is difficult to be realized can be solved. An amplitude adjustment of an output signal of the system is carried out by changing a resistance value of a digital potentiometerin a first adjustable voltage transformer, so that an output voltage of the first adjustable voltage transformer is changed and thus a primary coil voltage of a high frequency transformer; therefore,a digital control on the output signal amplitude is realized; according to a digital parameter value received by the second adjustable transformer, a resistance value of a digital potentiometer in the second adjustable transformer is changed, thereby changing an output voltage value in a DC-DC boosted circuit; and a direct current polarization is provided for an RLC resonant circuit through a direct current level clamped circuit, so that the high and low levels of the output signal are still in a normal working range after the change of the amplitude value of the output signal each time. According to the invention, circuit power consumption and dependence on a high speed and high power device are substantially reduced.

The invention relates to a device and a method for a plurality of sound sources to share an audio power amplifier on the same terminal, which solves the technical problems of great software complexity, high hardware cost and power consumption in the plan that a plurality of sound sources share one audio power amplifier. The core idea of the invention is that a feedback circuit of the audio power amplifier can adopt an adjustable digital potentiometer, and a baseband processor adjusts the digital potentiometer according to the different sound sources characteristics to achieve the purpose of adjusting the gain value of the audio power amplifier. The invention provides a thorough solution to the volume differences between different sound sources caused by the hardware and signal characteristics, thus improving the acoustic effects.

The invention discloses a power amplifier circuit comprising a digital potentiometer which comprises a temperature sensor, a memory, and a variable resistance, wherein the corresponding information of temperature data and variable resistance value is kept in the memory; the variable resistance is connected with the bias circuit, controlling the linear, the efficiency, and the gain of the power amplifier circuit. The invention also discloses an initializing method for the power amplifier circuit, comprising variable resistance value in digital potentiometer when different temperature record makes the linear, the efficiency, and the gain of the circuit reach a good index. The invention also discloses a power amplifying method for power amplifier circuit, changing variable resistance value according to the temperature information collected by temperature sensor and regulating the power control circuit to keep good linear, efficiency, and gain under different temperature.

The invention, which relates to the fiber optical communication technology field, discloses a small from-factor pluggable (SFP) module with low costs and a high precision digit diagnosis function. The invention aims at providing a SFP module which is with low costs and possesses a digital diagnosis function provided in a SFF-8472. The invention is characterized in that: using a single chip, which is integrated by a laser driver and a limiting amplifier, and cooperating with a controller unit so as to realize a high precision digit diagnosis function; accessing a filter between a light receiving interface component, the laser driver and the limiting amplifier of a limiting amplifier unit so as to improve sensitivity of the module and signal quality; adopting a applied resistor mode to a pin of a digital potentiometer of the controller unit so as to avoid a fault problem of nonluminescence when power is on. The SFP module can be used for a LC bi-directional single fiber SFP module, a SC bi-directional single fiber SFP module and a LC two fiber SFP module.

The invention discloses a measurement instrument for dynamic parameters of a piezoelectric transducer, and measurement methods for the measurement instrument. The measurement instrument comprises a micro controller, a sine signal generation circuit, and the piezoelectric transducer which are sequentially connected, an analog-to-digital conversion circuit which is connected with the output ends of the sine signal generation circuit and the piezoelectric transducer respectively, and a measurement resistance unit which is connected between the output end of the piezoelectric transducer and the input end of the sine signal generation circuit; and the output of the analog-to-digital conversion circuit is connected with the micro controller which is connected with a personal computer (PC) through a universal serial bus (USB) interface. The measurement methods comprise a measurement method for the PC, and a measurement method for the micro controller in a lower computer. According to the measurement instrument, double functions of power supply of the USB interface and signal transmission are fully utilized, and the circuit design is simplified. A measurement resistor connected with a five-gear digital switch is arranged in the circuit, so if a digital potentiometer cannot work normally, the measurement resistor can be used through the arrangement of a wire jumper, and the resistances are switched through the digital switch.

A digital potentiometer includes a string of impedance units in series. The string includes identical first and second sets of impedance units whose individual impedance values increment by a power of two. One of a plurality of switches is coupled in parallel with each respective impedance unit. The switches that are coupled to the first set of impedance units receive logical control signals complementary to logical control signals received by the respective switches coupled to the second set of impedance units, so that for every impedance unit of the first set that is bypassed (not bypassed), the identical impedance unit of the second set is not bypassed (bypassed). The string may include only the first and second sets of impedance units, or may include at least one third impedance unit in series with the first and second sets in a multi-stage design.

The invention relates to a method for simulating NTC sensor parameters, which comprises the following steps: setting the current temperature value; acquiring the resistance value corresponding to thecurrent temperature value; and controlling a digital potentionmeter to output the resistance value according to the resistance value. The invention also relates to a device for simulating the NTC sensor parameters. The implementation of the method and the device for simulating the NTC sensor parameters have the following beneficial effects: as a resistance regulating unit, a key input unit and a display unit are adopted, and the resistance regulating unit corresponds to the value displayed by the display unit under the control of a control unit, the simulation is more accurate, and the use isconvenient.

The invention discloses a quick-response constant current source parallel system and an implementation method thereof. The system comprises a constant current source parallel unit, a system output current detection unit, an MCU data processing unit and a digital potentiometer, wherein the constant current source parallel unit consists of a plurality of constant current source modules which are connected in parallel; each module outputs a corresponding current according to a given current signal; the system output current detection unit detects the output current of the constant current source parallel unit in real time to output a detected current signal; the MCU data processing unit receives and detects the current signal detected by the system output current detection unit and a given system current signal to output a voltage division ratio signal; and the digital potentiometer receives the voltage division ratio signal transmitted by the MCU data processing unit to determine and output the given current signal of each constant current source module. Quick adjustment for variation in output current can be realized by a simple implementation method without complex control software when single or more modules are failed; and the cost can be saved and constant output current of the system can be ensured.

The invention discloses a rotary transformer decoding circuit. A rotary transformer decoding chip outputs a preset excitation signal, and inputs the preset excitation signal to the input end of an excitation signal push-pull amplifier circuit connected with the rotary transformer decoding chip. The excitation signal push-pull amplifier circuit receives the preset excitation signal and amplifies the preset excitation signal. The excitation signal push-pull amplifier circuit outputs an excitation signal needed for a rotary transformer according to the resistance of a digital potentiometer. A digital signal processor control circuit is connected with the rotary transformer decoding chip, receives a feedback signal of the rotary transformer decoding chip, and adjusts the resistance of the digital potentiometer connected with the digital signal processor control circuit, thus realizing adaptive matching for different rotary transformers. The invention further discloses a control method of the rotary transformer decoding circuit.