328 results about "Current divider" patented technology

An integrated circuit (IC) current sensor that self-calibrates to adjust its signal gain when employed in a current divider configuration is presented. The current sensor includes an integrated current conductor, a magnetic field transducer, a controllable gain stage and a calibration controller. The integrated current conductor is adapted to receive a portion of a calibration current. The calibration current corresponds to a full scale current. The magnetic field transducer, responsive to the calibration current portion, provides a magnetic field signal having a magnitude proportional to a magnetic field generated by the calibration current portion. The controllable gain stage is configured to amplify the magnetic field signal with an adjustable gain to provide an amplified magnetic field signal. The calibration controller is responsive to a calibration command signal to adjust the adjustable gain of the controllable gain stage to a calibrated gain in order to provide the amplified magnetic field signal at a predetermined voltage level that corresponds to a desired current sensor output signal voltage level if the full scale current were received by the integrated current conductor.

An electrostatic discharge (ESD) protection device includes a semiconductor layer, a source region formed in the layer, a drain region formed in the layer, a channel region in the layer between the source and drain regions, and a gate over the channel region. A plurality of current divider segments are distributed on the drain region and extend between the gate and drain contacts. The segments can be formed of polysilicon or a field oxide.

The invention provides an impact grounding impedance measuring system which comprises a high-voltage direct current source, a high-voltage pulse capacitor, a discharging loop, a high-voltage charging switch, a high-voltage discharging switch, a resistance current divider, a water resistance voltage divider, a high-voltage pulse source control table, a digital oscilloscope and an optical fiber signal transmitting system, wherein the resistance current divider is connected with the high-voltage pulse capacitor and the discharging loop in series; the water resistance voltage divider is connected with a reference grounding electrode of the discharging loop; the optical fiber signal transmitting system comprises an optical transmitter, an optical fiber and an optical receiver; the voltage divider and the current divider are respectively connected with the digital oscilloscope through the optical fiber signal transmitting system; and the high-voltage discharging switch is a motion ball gap switch. The invention has the advantages of compact structure, small volume, convenient carrying, simple operation, accurate and stable measuring value, reduction of electromagnetic interference and reduction of measuring error.

A monotonic digital-to-analog converter (DAC) for converting a digital input signal into an analog output signal comprises:

• an input node for receiving the digital input signal having at least M+L bits,
• an output node for delivering the analog output signal corresponding to the received digital input signal,
• a coarse conversion block comprising current sources and first switching means for converting M more significant bits of the digital input signal into a coarse block output current,
• a fine conversion block comprising a current divider and second switching means for converting L less significant bits of the digital input signal into a corresponding current value, the fine conversion block having means for receiving current from a first unselected current source of the coarse conversion block, and
• a first cascode means for active cascoding the coarse block output current,
• a second cascode means, for active cascoding the current from the first unselected current source.

A method for converting a digital input signal into an analog output signal is also provided.

In order to extend the measurement range of a current sensor, a current divider is formed by a first conductor formed in a current sensor that is mounted on a printed circuit board and a second conductor on the printed circuit board that electrically shorts at least one input terminal of the current sensor to at least one output terminal of the current sensor. The input terminal of the current sensor supplies the current to be measured to the first conductor and the output terminal supplies the measured current back to the printed circuit board.

The invention designs an alternating magnetic field-resistant manganin current divider, which mainly comprises a manganin resistor and sampling end points of a current divider, wherein a wire is arranged on one side of the current divider; a sampling end point is arranged on both sides of the current divider and is connected with a sampling line; the sampling line on one side is pulled to the other side; and the manganin resistor is divided into two regions of the same area; meanwhile, the sampling line is fixed with the sampling line on the side and the two sampling lines are spirally stranded to extend. In the alternating magnetic field-resistant manganin current divider, the sampling line on the side close to the manganin resistor is pulled to the other side close to the manganin resistor, and the manganin resistor is averagely divided into two regions of the same area, so that induction voltage and electromotive force are produced on the sampling line on the other side close to the manganin resistor according to faraday law of electromagnetic induction when the current divider is interfered by an external alternating magnetic field and are balanced with the induction voltage and the electromotive force produced on the manganin resistor, namely the interference of the alternating magnetic field on the current divider can be prevented.

Current through a wire is sensed with a shunt resistor and a sense resistor in a current divider circuit. The values of the shunt resistor and sense resistor are related to provide a specified gain ratio to increase a dynamic range of current measurement. The sense resistor is a trimmable resistor, the configuration of which can be discerned from a look-up table based on a level of precision needed for current measurement. The two resistors can also be related by thermal coefficients to improve linearity of current measurements.

The invention discloses a forming method of diverter used in electric energy meter, specially a forming method of diverter made by resistance metal material and conducting metal material. The purpose of the invention is providing a forming method of diverter whose operation is easy, performance is stable, and efficiency is high. The method includes three steps of selecting material, welding and punching figuration. The forming method of diverter possesses characters that course of production is unpolluted, precision is high.

The present invention provides a Claus unit tail gas hydrodesulphurization catalyst fast evaluation reaction system which consists of an air distributing device, a multicenter reaction device and a tail gas detecting and processing device, wherein, the air distributing device consists of an air source, a current divider, a drying pipe (4), a flowmeter (5), a constant flow pump (8) and a preheater (9) which are connected by a pipeline; the multicenter reaction device is a parallel reactor consisting of a plurality of fixed bed reactors (7) in parallel connection; the front end of each reactor is connected with the flowmeter by a pipeline with a valve; the tail end is connected with the tail gas detecting and processing device by the pipeline with the valve, and the reaction temperature of each reactor can be controlled independently by a program temperature controller. The present invention uses the same air source and the parallel operation of a plurality of fixed bed reactors (7) to realize the fast evaluation on the sulfur dioxide hydrogenation activity and /or the organic sulfur hydrolysis activity of the Claus unit tail gas hydrodesulphurization catalyst.

Disclosed is a protective device of an equipment power source interface circuit. The protective device of the equipment power source interface circuit comprises a voltage detection control circuit, a current limiter and a current divider. The input end of the current limiter is connected with an equipment voltage input end. The output end of the current limiter is respectively connected with the voltage detection control circuit and an equipment voltage output end. The voltage detection control circuit is respectively connected with the current divider, the equipment voltage output end and a ground terminal. The current divider is respectively connected with the equipment voltage output end and the ground terminal. The voltage detection control circuit is used for controlling the current divider to reduce an output voltage value of the equipment voltage output end to be a second preset voltage value when an input voltage value is larger than a first preset voltage value. According to the protective device of the equipment power source interface circuit, damage, caused when equipment is charged by an external DC power source or is in the working process with the external power source, to the equipment power source interface circuit is prevented, and damage, caused when main equipment supplies power to external equipment through a USB interface or a DC interface, to a main equipment power source interface circuit can also be prevented.

The invention relates to a method and apparatus for measuring voltage and current of generator rotor, which belongs to generator excitation parameter measuring technical field, including: collecting firstly voltage signal and current signal of generator rotor; converting the collected signal into optical signal; transmitting for long distance and receiving the optical signal, and outputting the electrical signal after conversion. The apparatus includes a voltage divider, a proportional amplifier, and an optical modulator of generator rotor side, an optical fiber transmission system, an optical receiving converter and an isolation power source of lower voltage side. The rotor voltage is scaled down by the voltage divider, and the voltage signal for reflecting rotor current variation information outputted by current divider is amplified by the proportional amplifier, then modulated to be optical pulse signal by the optical modulator and transmitted to the optical receiving converter by the optical fiber transmission system, demodulating the optical signal and finally outputting measurement signal of rotor voltage and current. The invention is superior in accurate measurement result, reliability, and excellent temperature stability and anti-vibration characteristics.

The invention discloses a concrete jacking and refluxing system and a construction method thereof. The concrete jacking and refluxing system comprises a concrete conveying pump and a concrete conveying pipeline, wherein the concrete conveying pipeline comprises a conveying pipe vertical pipe, a conveying pipe main pipe and conveying pipe branch pipes; the quantity of the conveying pipe branch pipes is the same as that of steel pipe columns which are required to be jacked; the conveying main pipe is communicated with a first conveying pipe branch pipe in the conveying pipe branch pipes; the first conveying pipe branch pipe is communicated with a hole on the lower pipe wall of a first steel pipe column in the steel pipe columns through a steel pipe column check valve; the conveying pipe main pipe is communicated with other conveying pipe branch pipes through main pipe current dividers; and the other conveying pipe branch pipes are communicated with holes on the lower pipe walls of the other steel pipe columns through steel pipe column check valves. According to the concrete jacking and refluxing system and the construction method thereof, concrete waste caused by pipe detachment in the conventional concrete jacking process is reduced, the construction period is saved simultaneously, the construction efficiency in unit time is increased, and the pump pipe blocking probability is lowered.

The invention provides a direct-current line single-terminal fault location method for a multiterminal flexible direct-current transmission system. The method comprises the following steps of: 1, acquiring fault transient state current magnitude from a current divider of a direct current line side of the multiterminal flexible direct-current transmission system; 2, extracting a characteristic frequency signal and calculating a characteristic frequency value according to the measured fault transient state current magnitude by spectrum analysis; and 3, calculating a fault distance according to the characteristic frequency value by combining the wave velocity under the characteristic frequency value. According to the method, only the single-terminal current data is used during fault location, the required sampling rate is low, and a calculation step is simple; a travelling wave tip is not needed to be identified, and the method is reliable and safe; and short data window accurate fault location can be realized. The fault location method is suitable for parallel, series and hybrid multiterminal flexible direct-current systems.

The invention discloses an LED driving circuit capable of realizing complete-period sampling of inductive current. The LED driving circuit is used for realizing LED constant-current driving and comprises a rectifier bridge connected with input alternating-current voltage, and an LED load, and the LED load after being connected with an inductor (L1), a power switch (M1) and a sampling resistor (R4) is parallelly connected with a filter capacitor (C1). The LED driving circuit is characterized in that the LED driving circuit switches off the power switch (M1) through a loop control circuit according to current signals flowing through the inductor (L1) when the power switch (M1) is switched on and off and switches on the power switch (M1) according to demagnetizing time of the inductor (L1).

The invention discloses a measuring device and a measuring method of a reverse small current in a direct current distribution system. The measuring system comprises a signal acquisition system, a signal conditioning system and a data processing system which are mutually connected; the direct current is tested through the combination of a current divider and a Rogowski Coil; the Rogowski Coil is output to an integrator; when an analog integrator and a digital integrator are selected respectively, the system is slightly different; the measuring method is as follows: when in a steady state, the current divider is used for measuring current; when the current is less than a set value, the current divider and the Rogowski Coil are combined to measure small current value, namely, the value measured by the current divider is used as an integral initial value, the Rogowski Coil measures a change rate of the current, the current rate is integrated by the integrator so as to obtain current variable quantity, the current variable quantity is added to the integral initial value so as to obtain a small current value, if the value is less than 0, a control signal is output, and if the value is larger than 0, the measurement is continued. A stable current and the reverse small current in the direct current circuit can be measured precisely; and the measuring device has the advantages of wide measurement range, high precision, rapid response speed, strong overload ability, high linearity, small size and convenience for installation.

The invention provides a high-power factor constant-current drive circuit and a constant-current device. The constant-current drive circuit comprises a rectifier bridge, an input capacitor, an output diode, a transformer, an output capacitor and a power switch tube, wherein the first end and the second end of the input capacitor are respectively connected with the positive and negative output ends of the rectifier bridge; the negative pole of the output diode is connected with the first end of the input capacitor; the same-polarity end of the primary winding of the transformer is connected with the first end of the input capacitor, the different-polarity end of the secondary winding of the transformer is connected with the positive pole of the output diode, and the same-polarity end of the secondary winding is connected to the ground; the first end of the output capacitor is connected with the different-polarity end of the primary winding; and the first power end of the power switch tube is connected with the second end of the output capacitor, the second power end of the power switch tube is connected to the ground through a current detection circuit, and the control end of the power switch tube receives an externally input drive signal. The high-power factor constant-current drive circuit and the constant-current device which are provided by the invention can solve the problems of complex power switch tube drive circuit and low current sampling accuracy of the conventional Buck type high-power factor constant-current drive circuit.

An intelligent charging machine for an electric forklift truck comprises a transformer, two silicon-controlled rectifier circuits arranged at two output terminals of the transformer, an accumulator anode and an accumulator cathode arranged at two output terminals of the silicon-controlled rectifier circuits respectively; a current divider is arranged between the accumulator cathode and the cathode output terminal of the silicon-controlled rectifier circuit; two terminals of the current divider are connected with a current detection amplification circuit; the intelligent charging machine also comprises a micro-processor, an A/D conversion circuit, a D/A conversion circuit and a display module; the A/D conversion circuit is connected with the current detection amplification circuit; the intelligent charging machine also comprises a trigger board which is connected with the control terminal of the silicon-controlled rectifier circuit; and a charging current control circuit is connected between the trigger board and the D/A conversion circuit. The intelligent charging circuit displays various charging parameters by a digitron, automatically judges the charging plenitude of the accumulator comprehensively by various methods, changes the over-charging and under-charging of the accumulator, avoids damaging the accumulator in advance and prolongs the service life of the accumulator.

A reduced power driver is described. This reduced power driver comprises: an input current driver for transmitting a current signal that is a fraction of a DC current signal; a first resistor coupled at one end to a first voltage supply; a first current driver coupled to the input current driver and a first switch control; a second switch coupled a first current driver output, another end of the first resistor, and the output control; a dynamic booster coupled between the first voltage supply and the output control; and wherein the reduced power driver is operative for selectively adding an overshoot current to the output control so that power consumption is reduced, while synchronizing the DC current signal with the overshoot current.

The invention relates to the technical field of iron casting cooling, in particular to an iron casting cooling device. The iron casting cooling device comprises a water storage tank. A controller is arranged on the outer surface of the water storage tank. A cooling containing plate is arranged at the upper end in the water storage tank. Drain holes are formed in the surface of the cooling containing plate. A circulating water pump machine is arranged on the bottom face in the water storage tank and electrically connected with the controller. A connecting water pipe is arranged on a water outlet of the circulating water pump machine. A spray pipe is arranged on the side face of a current divider box. Spray heads are arranged on the surface of the spray pipe. The spray pipe is located on the upper surfaces of supporting plates. The two supporting plates are symmetrically mounted on the upper surface of the water storage tank. According to the iron casting cooling device, by additionally arranging the circulating water pump machine, a cooling solution in the water storage tank can be sprayed out from the spray heads through the spray pipe, the effective heat dissipation treatment can be conducted on iron castings, the cooling consuming time of the iron castings is shortened, the used cooling solution can be recycled as well, the circulating use effect is achieved, and waste of resources is reduced.