245 results about "Linear circuit" patented technology

Circuits and methods that improve linearity with use of cancellation of at least a portion, and preferably, substantially all of, at least one significant harmonic from the output of a primary circuit, e.g., the 3.sup.rd harmonic, using the output of a substantially functionally identical auxiliary circuit.

A feed-forward correction circuit in a PWM controller adjusts an error signal inversely with respect to a supply voltage for a switching voltage regulator to quickly compensate for changes or transients in the supply voltage. The adjusted error signal is provided to a PWM comparator to control a duty cycle of an output signal. The switching voltage regulator can be a DC-to-DC converter or a DC-to-AC converter, and the output signal is used to generate one or more driving signals to control semiconductor switches in the switching voltage regulator. The feed-forward correction circuit uses an offset compensation technique or a translinear circuit to maintain a substantially inverse product relationship between the supply voltage and the duty cycle of the output signal, thereby reducing overshoots and undershoots in a regulated output voltage of the switching voltage regulator.

A motor driving circuit includes an inverter circuit including switching devices connected in a bridge manner, electric-current detection resistances connected between the lower switching devices in the inverter circuit and the ground, so as to enable detection of the phase currents with the electric-current detection resistances, a PWM circuit which controls ON / OFF of the switching devices and repeatedly causes powering and regenerative time intervals, by alternately turning on and off the upper switching devices and the lower switching devices. During a time interval during which the lower switching devices, the electric-current detection resistances and the motor constitute a closed circuit and a regenerated electric current flows through the circuit, when the electric current values detected are equal to or greater than a predetermined electric current value, it is determined that a ground fault has occurred in the connection lines between the inverter circuit and the motor.

A voltage regulator includes an input terminal, an output terminal, a control circuitry, a buck mode switching converter, and a low dropout regulator circuit. The buck mode switching converter is arranged to convert a voltage signal received at the input terminal to a first voltage signal at the output terminal responsive to a first predetermined signal output from the control circuitry. The buck mode switching converter includes an electronically controlled switch in communication with an energy storage element. The low dropout regulator circuit is coupled between the input terminal and the output terminal and includes a linear circuit and is arranged to control a voltage drop across the linear circuit so as to provide a second voltage signal at the output terminal responsive to a second predetermined signal output from the control circuitry.

A system and method are disclosed for waveform based variational static timing analysis. A circuit is divided into its linear circuit parts and non-linear circuit parts and modeled together, by a combination of linear modeling techniques, into linear equations that may be represented by matrices. The linear equations in matrix form may be readily solved by a computer such that an input waveform to an input pin of the circuit can be sequentially “pushed” through the various interconnects and logic networks of the circuit to an output pin. Output voltage waveforms are obtained at each stage of the waveform pushing and may be used to perform static timing analysis.

The invention discloses an LED linear constant current control circuit. The LED linear constant current control circuit comprises: an input voltage sampling network, which is used for carrying out sampling on an input voltage; a comparison and logic control circuit, which is used for outputting a comparison result according to a sampling voltage of the input voltage sampling network and a threshold voltage; and a multipath selection switch, which is used for controlling a portion of or whole LED conduction according to the comparison result. In addition, the LED linear constant current control circuit also includes a current control loop, which is used for controlling currents flowing through the LED. Meanwhile, the invention discloses an LED linear circuit.

A multiple temperature resistance characteristic sensing cable comprised of 1˜6 metal conductors with restorable insulation layer. Each cable contains different temperature resistance characteristic, and is wrapped by 1-2 layers of outer sheath. The metal conductors are wrapped by 1-2 insulation layers and twisted together. These twisted wires are inside the 1-2 layers of outer sheath. The temperature sensor comprises an interface unit, a sensing cable corresponding to temperature resistance characteristics, and a cable terminal unit. The interface unit comprises a signal amplifier and linear circuit, an A / D converter, a microprocessor, a display and operation circuit, a pulse output circuit, and a timer circuit. The temperature sensor realizes the differential temperature, fixed temperature or differential fixed temperature alarm among low, mid and high temperature sections.

A method is provided for analyzing stability and passivity of physical systems. A physical system having time delays is represented as a linear circuit model. The linear circuit model is transformed into a corresponding transform domain circuit model. Sensitivity analysis is applied to the transform domain circuit model for generating information indicative of the stability or the passivity of the physical system having the time delays. A graphical representation may be created of the information indicative of the stability or passivity of the physical system having the time delays.

The invention relates to a switchable chaotic analog circuit based on a Chua chaotic circuit system. The switchable chaotic signal source by a memristor circuit and a nonlinear circuit comprises a Chua chaotic circuit post-stage switchable-mode main circuit which is composed of an integrating circuit, a control switch circuit (S) arranged at the post stage of the integrating circuit, an absolute value function circuit (H(.)) disposed at the post stage of the control switch circuit (S), a first multiplying circuit (M1) mounted at the post stage of the absolute value function circuit (H(.)) and a negative resistance circuit arranged at the post stage of the first multiplying circuit (M1). The chaotic analog circuit has characteristics of simple circuit structure and strong implementability. In addition, switching of chaotic signals can be realized by the memristor circuit and the nonlinear circuit. Meanwhile, chaotic systems capable of generating two types of different charotic attractors and complex chaotic scrolls both show complex dynamic characteristics and become a novel chaotic signal source.

A method, transceiver integrated circuit (IC), and communications device that employs a PIN Diode switch in connection with a transceiver integrated circuit in order to provide a highly linear path for simultaneously transmitted signals in a multi-band wireless communications device. A high linearity switch (HLS) utility / controller configures the PIN diode switch for switching between dual and single transmission modes. In the dual transmission mode, both a series PIN diode and a shunt PIN diode of the switch are biased to an on-state. A first transceiver generates and simultaneously transmits different transmission signals occupying different frequency bands to at least one antenna by utilizing a highly linear circuit path that includes the series PIN diode. In single transmission mode, both diodes are biased to an off-state which allows a second transceiver to transmit a single transmission signal to at least one antenna via a switch path with a low insertion loss impact.

A system and a method are disclosed for performing a timing or signal propagation delay analysis on a circuit. The disclosure includes representing a drive logic stage as a representative linear circuit driven by a current source. The current source is represented as a function of a current at a constant value, a start time, a tail-start time, and a time constant of an equivalent capacitive circuit. Once the current source model is constructed, a logic stage can be analyzed for timing or signal propagation delay using conventional linear circuit analysis techniques. The disclosure also is applicable to resistance capacitance (“RC”) interconnect circuits using a current source model in which an RC load is represented as an effective capacitance and the current source for use in a linear analysis is constructed using an iterative approach.

To provide a highly reliable semiconductor device (an RF tag) which operates normally even when a communication distance is extremely short, a protection circuit (a limiter circuit) for protecting an element which forms a semiconductor device (an RF tag) capable of wirelessly communicating data is provided. When the DC power supply potential which is generated in a rectifier circuit is equal to or greater than a predetermined value (a reference value), the protection circuit is made to operate, and the value of the generated DC power supply potential is reduced. On the other hand, when the DC power supply potential which is generated in the rectifier circuit is equal to or less than the predetermined value (reference value), the protection circuit is made not to operate, and the value of the generated DC power supply potential is used without change.

The invention discloses a transformer-free type low-leakage-current photovoltaic grid-connected inverter circuit with an active clamp and a modulation method thereof. The transformer-free type low-leakage-current photovoltaic grid-connected inverter circuit with the active clamp comprises two filter capacitors Cdc1, Cdc2, eight switch tubes S1, S2, S3, S4, S5, S6, S7, S8 and two filter inductors L1, L2, and is characterized in that an active switch tube is additionally arranged in the circuit so as to form a clamping unit, common-mode voltage in a grid-connected inductance follow current stage is clamped to the midpoint of a bus capacitor by being matched with an appropriate switching sequence, common-mode voltage disturbance of the system is removed, and thus a suspension problem of common-mode voltage of a decoupling inverter in zero level output is solved; and parasitic oscillation of a common-mode circuit is removed at the same time, and a phenomenon of common-mode resonance is suppressed. The photovoltaic grid-connected inverter circuit disclosed by the invention has the advantages of simple circuit structure, high efficiency, simple modulation method and the like. The photovoltaic grid-connected inverter circuit can ensure an inverter not to be affected by a current zero crossing point in unit power factor running, and can avoid current waveform distortion caused by influences of grid power fluctuations or operations at a non unit power factor.

The invention discloses a direct-current frequency conversion electric fan. A motor (5) of the electric fan is a three-phase motor; a rectification circuit (1) for converting alternating current into direct current, a filter circuit (3) for realizing the effects of filter smoothing and energy storage of the direct current and an inverter circuit (4) for converting the direct current into the alternating current to realize frequency modulation and voltage regulation are arranged between a commercial power access end and the motor (5), wherein an inverter (4) is also connected with the driving signal end of a microprocessor circuit (6). The direct-current frequency conversion electric fan can save energy substantially and improve the comfort level.

A distortion circuit is provided for correcting the distortion from a nonlinear circuit element by generating a frequency dependent signal having a sign opposite to the distortion signal produced by the nonlinear circuit and substantially the same magnitude. The distortion circuit includes an input signal and a first nonlinear device coupled to the input signal for generating a first signal and where the first nonlinear device has a first bias level. Also included is a second nonlinear device different from same first nonlinear device and coupled to the first nonlinear device for modifying the first signal to produce an output second signal, the second nonlinear device having a second bias level. A bias control means is provided for adjusting the first and said second bias levels so that the magnitude, phase and frequency of the output second signal can be adjusted.

The invention provides a voltage dip source positioning method based on the disturbance power direction and belongs to automatic monitoring methods for power grid voltage dip source positioning. The method is characterized in that under the effect that a disturbance voltage in a power grid fault process is obtained according to the superposition principle of linear circuits, the direction of an active disturbance power flow is used for accurately positioning a voltage dip source; when active disturbance power is positive, a disturbance source is located at the upstream portion of a monitoring point; when the active disturbance power is negative, the disturbance source is located at the downstream portion of the monitoring point; an algorithm of the corresponding disturbance power is given. The voltage dip source positioning method can be used for certainly positioning voltage dips caused by various power grid faults, is suitable for radiation type or ring type or single-circuit type or two-circuit type or single-power-supply type or multi-power-supply type grid structure power grids, and is also suitable for voltage dip source positioning caused by capacitor switching, transformer switching and large motor starting disturbance; according to the voltage dip source positioning method, the voltage and current of the monitoring point need to be sampled synchronously.

A device for driving a light emitting diode (LED) module is disclosed, wherein alternating current (AC) power is rectified and applied to an LED module and brightness of the LED module is adjusted by adjusting the maximum value of an LED current passing through the LED module, thereby achieving natural brightness adjustment. The device for driving an LED module may include a driver, a control signal receiver, a control signal converter, and a linear circuit.

The torque control circuit of a hand tool contains a motor driving circuit, a current detection circuit, a reference voltage generation circuit, a current limiting circuit, and a torque configuration circuit. In the last stage of operation of the hand tool and when the average current has reached a predetermined level, the average current is maintained for a period of time to provide a constant average power and therefore to achieve an appropriate tightness of the bolt or nut being operated. The detection and control of current is achieved by a linear circuit which is robust to the heavy noises produced by the motor. A microprocessor is adopted to consider factors such as temperature in determining a suitable current level.

A motor driving circuit includes an inverter circuit including switching devices connected in a bridge manner, electric-current detection resistances connected between the lower switching devices in the inverter circuit and the ground, so as to enable detection of the phase currents with the electric-current detection resistances, a PWM circuit which controls ON / OFF of the switching devices and repeatedly causes powering and regenerative time intervals, by alternately turning on and off the upper switching devices and the lower switching devices. During a time interval during which the lower switching devices, the electric-current detection resistances and the motor constitute a closed circuit and a regenerated electric current flows through the circuit, when the electric current values detected are equal to or greater than a predetermined electric current value, it is determined that a ground fault has occurred in the connection lines between the inverter circuit and the motor.

The invention discloses a light-emitting diode (LED) linear current control circuit. The LED linear current control circuit comprises an LED lamp string, an input voltage sampling network, a comparison and control circuit and a multi-path selection switch, wherein the LED lamp string is formed by connecting at least one LED in series; the input voltage sampling network is used for sampling the input voltage of the LEDs; the comparison and control circuit compares the input voltage of each LED with a reference voltage to obtain a comparison result; and the multi-path selection switch is respectively connected to the LEDs and changes conduction impedance according to the comparison result so as to control the conduction of a part of the LEDs or all the LEDs. The invention also discloses an LED linear circuit.

The invention discloses an air plasma cutting machine, comprising a main circuit and a control circuit. The main circuit is composed of a superior main circuit and an inferior circuit which are connected in series. The superior main circuit is composed of an alternating current (AC) power source, an input rectifying wave filter circuit and a full bridge inverter circuit which are connected in series. The inferior main circuit is composed of an output rectifying wave filter circuit, a high power switch circuit and an output resistor. The control circuit is composed of a superior control circuit and an inferior control circuit, wherein the superior control circuit is connected with the full bridge inverter circuit through a superior frequency determining and pulse-width determining circuit and a superior drive circuit which are in series connection. The inferior control circuit is composed of a current detecting circuit, a given circuit, a comparison amplifying circuit, a PWM circuit and an inferior drive circuit, which connects the current detecting circuit with the comparison amplifying circuit. Under the mutual function of the superior inverter and the inferior chopper, the invention can obtain an external feature of constant current and a good dynamic feature; thereby obtaining a high-quality welding seam with small volume, light weight, convenient movement, material saving, and high efficiency and energy reserving.

The invention discloses a low stray linear circuit structure applied to a fraction frequency division phase-locked loop, which includes a first phase frequency detector, a first charge pump, a loop filter, a voltage controlled oscillator, a frequency divider, a second phase frequency detector, and a second charge pump. An output end of the second phase frequency detector is connected to an input end of the second charge pump. The second phase frequency detector generates a UP3 signal and a DN2 signal having phase differences according to obtained two paths of reference signals to control the second charge pump to generate a second bias current. An input end of the loop filter is connected to an output end of the first charge pump and an output end of the second charge pump. A first bias current and the second bias current are combined to form an input current of the loop filter. An output end of the loop filter is connected to an input end of the voltage controlled oscillator so as to input voltage signals to the voltage controlled oscillator according to the input current. The noise aliasing effect caused by the nonlinearity of PFD / CP can be eliminated, the in-band noise is reduced, and reference stray is not deteriorated.

A system and method are disclosed for waveform based variational static timing analysis. A circuit is divided into its linear circuit parts and non-linear circuit parts and modeled together, by a combination of linear modeling techniques, into linear equations that may be represented by matrices. The linear equations in matrix form may be readily solved by a computer such that an input waveform to an input pin of the circuit can be sequentially “pushed” through the various interconnects and logic networks of the circuit to an output pin. Output voltage waveforms are obtained at each stage of the waveform pushing and may be used to perform static timing analysis.

A system or methods are provided for the overall improvement in efficiency in photovoltaic solar cells. In various embodiments, a variety of the sun wavelength are utilize in a multifunction arrangement to create an amplification process. The wavelength that are normally pass through a typical solar is utilize as bias to create a electro magnetic field or voltage source to accelerate the electron or increase the electron flow out of the solar circuit. A portion of the sun energy is utilized in a secondary circuit to create a power source that is further used to generate an additional power source. This invention relates to a solar amplification process and a device configured with photovoltaic semiconductors.

The present invention discloses a novel improvement applied to egg grader machines used in poultry farms and the like. Said continuous egg grader machine differs from other egg grader machines because it does not comprise the above-mentioned 90-degree curve existing in the egg circuit, i.e., the continuous egg grader machine of the present invention comprises a completely continuous linear circuit, wherein the great advantage of using the continuous egg grader machine disclosed herein is related to the gain obtained by the egg reduced speed when multiple rows of eggs are provided.

A wireless communication base station includes: a high frequency power amplifier for amplifying and sending transmission signals via receiving and transmitting antennas; an A / D converter; a linear circuit mounted at an input side of the high frequency power amplifier, a mirror frequency interference restraining transducer mounted between the linear circuit and the high frequency power amplifier, and comprising a first phase shift circuit, a first D / A converter and a second D / A converter used for directly converting an output of the linear circuit into a corresponding analog signal, and a first and a second mixing circuit for using output of the first and the second D / A converter as orthogonal signals of an I channel and a Q channel, and mixing the orthogonal signals of the I channel the a Q channel with an oscillation signal having a higher frequency than the output of the first and the second D / A converter, the phases of the orthogonal signals are shifted with 90 DEG respectively.

The invention belongs to the technical field of chaos systems, and discloses a high-order novel three-dimensional chaos model and a circuit thereof. The circuit of the high-order novel three-dimensional chaos model comprises three channel circuits. The circuit of the high-order novel three-dimensional chaos model consists of thirty-nine elements, including nine 3554BM operational amplifiers, six multiplying units, three capacitors and twenty-one resistors. The high-order novel three-dimensional chaos circuit disclosed by the invention has a plurality of balance points and a high-order non-linear term, is more complex and abundant in dynamic behaviors, and can be applied to non-linear circuit course experiments. Moreover, the defect that encrypted information of an existing Chaos system isliable to decryption can be overcome, and a basis is laid for the application of a Chaos system.

The invention relates to a circuit for measuring a voltage transformer voltage coefficient, and further relates to a method for measuring the voltage transformer voltage coefficient through the circuit. The circuit for measuring the voltage transformer voltage coefficient comprises a first single-stage voltage transformer (T1), a second single-stage voltage transformer (T2) and a passive linear circuit composed of an isolation transformer (T3). Both the rated transformation ratio of the first single-stage voltage transformer (T1) and the rated transformation ratio of the second single-stage voltage transformer (T2) are equal to K; the rated transformation ratio of the isolation transformer (T3) is equal to 1; a primary low-voltage terminal (X1) of the first single-stage voltage transformer (T1) is connected with a primary high-voltage terminal A2 of the second single-stage voltage transformer (T2); a secondary high-voltage terminal a1 of the first single-stage voltage transformer (T1) is connected with a primary high-voltage terminal A3 of the isolation transformer (T3); a secondary low-voltage terminal x1 of the first single-stage voltage transformer (T1) is connected with a primary low-voltage terminal X3 of the isolation transformer (T3); a secondary low-voltage terminal x3 of the isolation transformer (T3) is connected with a secondary high-voltage terminal a2 of the second single-stage voltage transformer (T2). According to the circuit and method for measuring the voltage transformer voltage coefficient, the effect of shielding errors of a voltage transformer on a series addition line can be overcome, and power frequency voltage addition can be effectively used in a 220 kV high-voltage interval and can even be used in a 330kV-1000kV extra-high-voltage interval.

A distortion circuit is provided for correcting the distortion from a nonlinear circuit element by generating a frequency dependent signal having a sign opposite to the distortion signal produced by the nonlinear circuit and substantially the same magnitude. The distortion circuit includes an input signal and a first nonlinear device coupled to the input signal for generating a first signal and where the first nonlinear device has a first bias level. Also included is a second nonlinear device different from same first nonlinear device and coupled to the first nonlinear device for modifying the first signal to produce an output second signal, the second nonlinear device having a second bias level. A bias control means is provided for adjusting the first and said second bias levels so that the magnitude, phase and frequency of the output second signal can be adjusted.