33 results about "Current source" patented technology

An instrument is disclosed for measuring resistivity of Earth formations from within a conductive pipe inside a wellbore drilled through the formations. The instrument includes a plurality of housings connected end to end and adapted to traverse the wellbore. At least one electrode is disposed on each housing. Each electrode is adapted to be placed in electrical contact with the inside of the pipe. The instrument includes a source of electrical current, a digital voltage measuring circuit and a switch. The switch is arranged to connect the source of electrical current between one of the electrodes and a current return at a selectable one of the top of the pipe and a location near the Earth's surface at a selected distance from the top of the pipe, and to connect selected pairs of the electrodes to the digital voltage measuring circuit. The pairs are selected to make voltage measurements corresponding to selected axial distances and selected lateral depths in the Earth formations.

A semiconductor integrated circuit having a built-in PLL circuit which has two charge pump circuits for charging and discharging capacitive elements of a loop filter in response to signals generated by a phase comparator circuit. One of the two charge pump circuits has current sources which generate current values smaller than those generated by current sources of the other charge pump circuit. The loop filter has a first capacitive element connected to a charge/discharge node, and a second capacitive element connected to the charge/discharge node through a resistive element. The first capacitive element is charged and discharged by the one charge pump circuit, while the second capacitive element is charged and discharged by the other charge pump circuit. A charging current source of the one charge pump circuit operates simultaneously with a discharging current source of the other charge pump circuit, i.e., the charge pump circuits operate in opposite phase.

The invention relates to the technical field of integrated circuits, in particular to a current mirror. The current mirror is characterized in that the current mirror is composed of a PMOS transistor MP1, a PMOS transistor MP2, an NMOS transistor MN1, a capacitor C1, a capacitor C2, a resistor R1, an input current source, an output end current source and a bias current source. The source electrode of the MP1 is connected with a power source VCC, the grid electrode of the MP1 is connected with the grid electrode of the MP2, and the drain electrode of the MP1 is connected with positive electrode of the input current source. The negative electrode of the input electrode source is grounded VSS. The drain electrode of the MN1 is connected with the power source VCC, the grid electrode of the MN1 is connected with the positive electrode of the input current source, the source electrode of the MN1 is connected with the positive electrode of the bias current source, and the substrate of the MN1 is connected with a connection point of the grid electrode of the MP1 and the grid electrode of the MP2 through the R1. A connection point of the source electrode of the MP1 and the drain electrode of the MN1 is connected with a connection point of the grid electrode of MN1 and the positive electrode of the input current source through the C1 and the C2 sequentially. The source electrode of the MP2 is connected with the power source VCC, and the drain electrode of the MP2 is connected with the positive electrode of an output current source. The current mirror has the advantages of being suitable for being used under low supply voltage, meanwhile improving the PSR of the current mirror, and being especially suitable for a current mirror circuit.

The invention relates to a high-speed serial port load automatic calibration circuit. One end of a port load resistor array of the high-speed serial port load automatic calibration circuit is connected with an analog power supply, the other end is connected with an input end of a first current source, and an output end of the first current source is connected to the ground; one end of a high-precision resistor is connected with an analog power supply, the other end is connected with an input end of a second current source, and an output end of the second current source is connected to the ground; one end of a high-speed serial port resistor array is connected with an analog power supply; a negative input end of a comparator is connected between the port load resistor array and the first current source, a positive input end is connected between the high-precision resistor and the second current source, the comparator compares voltage values of the high-precision resistor and the port load resistor array and outputs a comparison result signal to a digital state machine, the digital state machine generates a control signal to control resistance of the port load resistor array and the high-speed serial port resistor array. The high-speed serial port load automatic calibration circuit provided by the invention realizes automatic calibration of the high-speed serial port load resistor, and achieves an impedance matching effect of a high-speed serial port.

The invention relates to an automotive active engine mount capable of energy regeneration and transmitting force perception. The automotive active engine mount consists of an active engine mount actuator body and a control circuit system, wherein the active engine mount actuator body mainly consists of rubber springs, a base, a position-fixing pin, a metal framework, an electromagnetic linear module and a piezoelectric module; the upper end and the lower end of the active engine mount actuator body are respectively connected with an engine body and an automobile frame through connecting bolts;and an actuator control system mainly consists of an energy recovery module, a controller, a storage battery voltage sensor, a controllable current source, a rotating speed sensor, a force sensor, anactuator energy regeneration voltage sensor and a relay. The invention also relates to a control method of the automotive active engine mount. The automotive active engine mount is novel in structureand high in practicability and is capable of significantly reducing the impact of engine vibration on a chassis and the automobile body, improving the ride comfort of an automobile, reducing the noise in the automobile, recovering the energy of the engine vibration, reducing the energy consumption of the automobile and achieving the purpose of improving the performance of the entire automobile while reducing the energy consumption.

The invention relates to a lagging comparer, wherein it comprises current source I1, two input MOS tubes, three load MOS tubes, and lagging adjuster for adjusting the threshold value of comparer. When the input MOS tube is NMOS tube, the load MOS tube uses PMOS tube; the single threshold value of circuit is irrelative to the circuit element parameters, that one fixed input voltage of comparer can fix single threshold value; the inventive circuit has asymmetry positive feedback circuit to form the lagging circuit of lagging comparer, to generate threshold voltage and complete comparison. The invention also has positive feedback branch and output branch, MOS tube with static protection and resistance.

The invention relates to a high-gain low-noise frequency mixer which comprises a switch level module and an active load module. The common-mode voltage output end of the switch level module is connected with a common-mode feedback module which is used for stabilizing the common-mode voltage, the output end of the common-mode feedback module is connected with the active load module, the output end of the active load module is connected with the switch level module and a dual-capacitor cross coupled transconductance module, the switch level module is also connected with a tail current source module, and the switch level module uses an active Gilbert double-balance structure. According to the technical scheme, the equivalent transconductance value is effectively improved by using a gate drive and substrate drive dual-capacitor cross coupling manner on the basis of a traditional folded structure transconductance; and on the premise that the power consumption is not increase, the noise coefficient of the frequency mixer is reduced, and the gain of the frequency mixer is improved. Use of the active load module improves the conversion gain of the frequency mixer, and the common-mode feedback module is used to stabilize the common-mode voltage of the output point and improve the linearity of the frequency mixer.

The invention discloses a harmonic power flow calculation method containing a VSC (Voltage Source Converter). Firstly, the fundamental wave power flow is calculated to obtain the fundamental wave voltage of each node, and the modulation ratio of the VSC is obtained; secondly, three pieces of input data, namely, the DC voltage, the modulation ratio and the carrier frequency are substituted into theharmonic model formula of the VSC to obtain the content of each harmonic in the AC side voltage of the VSC, and the VSC is regarded as a harmonic voltage source approximately; and thirdly, in order to realize an interface between a VSC harmonic voltage source model and the harmonic power flow, the VSC and the AC side transformer thereof are equivalent to a harmonic current source with internal impedance based on the Norton's equivalence theorem to form a harmonic admittance matrix, and the harmonic power flow is calculated by harmonic current injection.

The invention provides an explodent elimination circuit. The explodent elimination circuit is used for explodent elimination during power on and power off of an output node of an audio digital-to-analog converter, and comprises four resistors, three positive channel metal oxide semiconductor (PMOS) transistors, two negative channel metal oxide semiconductor (NMOS) transistors, a comparator, a pull-up current source, a pull-down current source and a control logic module, wherein the pull-up current source and the pull-down current source slowly charge the output node or provide a discharge path and can effectively eliminate the explodent of the output node during power on and power off; and the adjustable voltage rise speed and voltage drop speed of the output node are ensured by a current source structure and feedback control. The invention has the characteristics that: the explodent elimination circuit can be widely applied to a power amplifier at the rear end of a single-bit audio digital-to-analog converter, a multi-bit audio digital-to-analog converter or the audio digital-to-analog converter, and can effectively eliminate the explodent caused by abrupt power on or power off of the output node of the audio digital-to-analog converter; the voltage rise time and the voltage drop time of the output node are controllable, complicated control logics are unnecessary, and the power consumption is low.

The invention belongs to the field of integrated circuit design, and particularly relates to a current source unit circuit of a current-steering digital analog converter. The current source unit circuit comprises a current source module, a switch module and a digital control module, wherein the current source module comprises a current source tube Mb2 and a current source tube Mb1, the digital control module comprises a first signal output end SWP and a second signal output end SWN, and the signals output by the first signal output end SWP and the second signal output end SWN are contrary. The switch module is formed by a control signal processing module and a control switch module. Via four MOS (metal oxide semiconductor) tubes including M1, M2, M3 and M4 which are particularly connected, variation amplitude of a control signal is reduced by about two threshold voltage, glitch of an output signal of the current-steering digital analog converter is reduced, dynamic performance is improved, and the current source unit circuit can be widely applied on the current-steering digital analog converter. Meanwhile, the utilization of a complementation control switch can also improve the glitch.

A method, system and program product for creating a simplified equivalent model for an IC that can be used for detailed analysis. The equivalent model takes into consideration the effects of all the I/O placement regardless of the non-uniformity of I/O placement. The equivalent model is generated, in part, by partitioning the IC into simulation windows and converting I/Os within each simulation window to a current source having the same current change rate, and then running a simulation on this intermediate model. A current change rate observed for a simulation window is then used to convert back to actual I/Os to create the equivalent model. The equivalent model can be simulated using conventional software, e.g., SPICE, for more detailed analysis such as signal integrity, timing of I/Os and noise.

The invention relates to a display control circuit and method and a flat display device. The display control circuit includes a current source, a capacitor, a discharge circuit, a subtractor, and an initial reference voltage generating module. The current source is connected to a first end of the first capacitor to generate a charging voltage that changes with time, and a second end of the first capacitor is grounded. The discharge circuit is connected to a first end of the first capacitor to clear the charging voltage at the beginning of each frame of a display panel. A negative input end ofthe subtractor is connected to a first end of the first capacitor, a positive input end of the subtractor is connected to an output end of the initial reference voltage generating module, and an output end of the subtractor outputs an adjusted reference voltage. An output end of the initial reference voltage generating module outputs a fixed initial reference voltage. The adjusted reference voltage is used for generating a gamma voltage. According to the invention, for the gamma voltage of the display panel in the same frame, different gamma voltage adjustments at far and near ends are achieved, and the improvement of the display characteristics of the entire display panel is achieved.

The invention discloses a low-power-dissipation power supply circuit. The circuit comprises a biasing sub-circuit for providing a biasing voltage, a current source sub-circuit which is connected with the biasing sub-circuit and is used in mirror current, an amplifying sub-circuit connected with the current source sub-circuit, a current mirror sub-circuit connected with the amplifying sub-circuit, and a feedback sub-circuit and compensating capacitor connected with the amplifying sub-circuit and the current mirror sub-circuit, wherein the current source sub-circuit provides work current for the low-power-dissipation power supply circuit, and the amplifying sub-circuit compares an output voltage of the feedback sub-circuit with a reference voltage of a reference voltage end and amplifies a comparison result to respond to the change of load current. In the low-power-dissipation power supply circuit, the circuit structure is stable, the change of the load current can be quickly responded to, and the nanoampere level of static power dissipation is achieved.

A nonvolatile memory comprising at least one ferromagnetic region having permeability which changes from a first state to a second state of lower permeability upon heating; at least one laser operatively associated with the at least one ferromagnetic region which selectively provides heat to the ferromagnetic region to change its p permeability; and a plurality of connectors operatively connected to the at least one laser and adapted to be connected to a current source that provides a current which causes the laser to change the at least one ferromagnetic region from a first state to a second state. Optionally, the memory is arranged as an array of memory cells. Optionally, each cell has a magnetic field sensor operatively associated therewith. Optionally, the nonvolatile memory is radiation hard. Also, a method of recording data by heating at least one ferromagnetic region to change its permeability.

An apparatus includes a current source, a current monitor circuit which monitors a current amount of the current source, and outputs a current amount signal corresponding to the current amount being monitored, a counter circuit which counts a count value based on the current amount signal, the count value corresponding to a period being taken until when the current amount reaches a predetermined value, and a control circuit which modifies an operation parameter for operating a circuit unit according to the count value.

The invention provides a testing device and method for a power frequency follow current interruption capability of a 35kV lightning protector. The testing device comprises a charging unit CHA, a powerfrequency power supply P, an impact current unit ICG, a control unit C, a protection reactor L2, a current detection unit and a voltage detection unit. According to the device provided by the invention, standard 4/10 impact current is output through the ICG and 35kV rated network voltage is generated through an LC topological circuit; the standard 4/10 impact current and the 35kV rated network voltage are applied to two ends of the 35kV lightning protector in a time sharing manner through phase control of the control unit, and the power frequency follow current interruption capability of the35kV lightning protector is verified. According to the device provided by the invention, a high-voltage impact current source is electrically connected with the power frequency power supply through aninsulating matching design; the device has the advantages of small occupied area, low testing cost, capability of ensuring the testing success rate by a one-button start function and the like.

The invention discloses a control circuit, a control method, a driving circuit and a lighting device, and relates to the field of circuit load control. The control circuit includes: a control unit, (n-1) switching units connected in series; the negative polarity end of the first controlled current source in the n controlled current sources is connected to a common ground terminal, and the positive polarity ends of the other (n-1) controlled current sources are correspondingly connected to the negative electrodes of the (n-1) switch units through one one-way switch respectively; the one-way switch is configured to block current between the corresponding switch unit and the controlled current source; the negative polarity ends of the (n-1) controlled current sources are connected to the common ground terminal; the control ends of the n controlled current sources and the control ends of the (n-1) switch units are respectively connected to the control unit; wherein n is an integer and is greater than or equal to 2. Therefore, the continuity/smoothness in the switching process between different LED array combinations is enhanced.

The invention relates to a current source converter driven asynchronous motor torque control method and system, and the method is characterized in that the method comprises the steps: adding the output filtering capacitor voltage of a current source converter into a cost function used for predicting torque control on a pre-constructed current source converter driven asynchronous motor model; and determining an optimal switching vector which minimizes the cost function so as to control the output filter capacitor voltage and the output torque of the current source type converter, and carrying out resonance suppression on an LC network formed by the output filter capacitor of the current source type converter and the stator inductance of the asynchronous motor. According to the method, energy oscillation between the filter capacitor and the stator inductor can be effectively suppressed, electromagnetic torque pulsation is reduced, meanwhile, the method has excellent steady-state performance and rapid torque dynamic response, and the method can be widely applied to the field of asynchronous motor torque control.

A power converting apparatus and a vehicle including the same according to an embodiment of the present disclosure includes a switching element; and a gate drive unit configured to apply a gate driving signal for driving the switching element to a gate terminal of the switching element, wherein the gate drive unit includes: a current source unit including a source current for sourcing current to the gate terminal in a turn-on section of the switching element, and a sink current for sinking current from the gate terminal in a turn-off section of the switching element; a control current for sinking the current from the gate terminal during a partial section of the turn-on section and the turn-off section of the switching element; and a control current controller configured to control an operation of the control current.