4913 results about "Converter circuit" patented technology

The LED brightness control system for a wide range of luminance control includes a brightness control module that provides a pulse width modulation (PWM) control signal and a peak current control signal. A pulse width modulation (PWM) converter circuit receives the PWM control signal and converts it to a PWM signal. A multiplier receives the PWM signal and the peak current control signal from the brightness control module and multiplies the same to provide a light emitting diode (LED) current control signal with a variable “on” time as well as variable “on” level. A voltage-controlled current source utilizes the LED current control signal and an LED current feedback signal for providing an LED current. An LED illuminator array receives the LED current. A current sensing element connected to the LED illuminator array for providing an LED current feedback signal representing LED peak current. The voltage-controlled current source controls a drive voltage to the LED illuminator array at a commanded level.

The present invention provides an efficiency booster circuit and accompanying switch mode power conversion technique to efficiently capture the power generated from a solar cell array that would normally have been lost, for example, under reduced incident solar radiation. In an embodiment of the invention, the efficiency booster circuit generates an output current from the solar cell power source using a switch mode power converter. A control loop is closed around the input voltage to the converter circuit and not around the output voltage. The output voltage is allowed to float, being clamped by the loading conditions. If the outputs from multiple units are tied together, the currents will sum. If the output(s) are connected to a battery, the battery's potential will clamp the voltage during charge. This technique allows all solar cells in an array that are producing power and connected in parallel to work at their peak efficiency.

The present invention provides a converter circuit and accompanying switch mode power conversion technique to efficiently capture the power generated from a solar cell array that would normally have been lost, for example, under reduced incident solar radiation. In an embodiment of the invention, the converter circuit generates an output current from the solar cell power source using a switch mode power converter. A control loop is closed around the input voltage to the converter circuit and not around the output voltage. The output voltage is allowed to float, being clamped by the loading conditions. If the outputs from multiple units are tied together, the currents will sum. If the output(s) are connected to a battery, the battery's potential will clamp the voltage during charge. This technique allows all solar cells in an array that are producing power and connected in parallel to work at their peak efficiency.

A light-emitting diode (LED) driver is adapted to control either the magnitude of the current conducted through a LED light source or the magnitude of a voltage generated across the LED light source. The LED driver comprises a power converter circuit for generating a DC bus voltage, and an LED drive circuit for receiving the bus voltage and adjusting the magnitude of the current conducted through the LED light source. The LED driver is operable to dim the LED light source using either a pulse-width modulation technique or a constant current reduction technique. The LED drive circuit may comprise a controllable-impedance circuit, such as a linear regulator. The LED driver may be operable to control the magnitude of the bus voltage to optimize the efficiency and reduce the power dissipation in the LED drive circuit, as well ensuring that the load voltage and current do not have any ripple.

To provide an induced power transmission circuit that transmits, from a transmission antenna (1) connected to a power supply circuit, an AC power having an angular frequency ω to a spaced reception antenna (2) with an excellent efficiency, thereby transmitting it to a load circuit. The induced power transmission circuit comprises a circuit the two ends of which are coupled by a capacitor (C1) and in which the power supply circuit is connected in series to a midway port (1) (P1) of the transmission antenna (1) having an effective self-inductance L1; and a circuit the two ends of which are coupled by a capacitor (C2) and in which the load circuit is connected in series to a midway port (2) (P2) of the reception antenna (2) having an effective self-inductance L2; wherein for a coupling coefficient k of the electromagnetic induction between the antennas and for a phase angle β having an arbitrary value, the angular frequency ω is set to the square root of the reciprocal of a value of L2×C2×(1+k*cos (β)), the output impedance of the power supply circuit is set to approximately kωL1*sin (β), and the input impedance of the load circuit is set to approximately kωL2*sin (β). There is also provided an impedance converting circuit that converts the circuit impedances.

The object is to reliably detect a ground fault of a solar battery. To detect a ground fault position to take an efficient measure against the ground fault, DC power input from a solar battery is converted into AC power and supplied to a system. In a system interconnection inverter (utility connected inverter) having non-insulated input and output, the input voltage of a converter circuit and/or the intermediate voltage between the converter circuit and an inverter circuit are varied to control the potential to ground at each portion of the solar battery to a value other than a value close to zero.

A converter circuit and related technique for providing high power density power conversion includes a reconfigurable switched capacitor transformation stage coupled to a magnetic converter (or regulation) stage. The circuits and techniques achieve high performance over a wide input voltage range or a wide output voltage range. The converter can be used, for example, to power logic devices in portable battery operated devices.

A non-volatile semiconductor memory device comprises a memory cell array including a plurality of memory cells arrayed capable of storing information of N bits (N≧2) in accordance with variations in threshold voltage. A parity data adder circuit adds parity data for error correction to every certain data bits to be stored in the memory cell array. A frame converter circuit uniformly divides frame data containing the data bits and the parity data into N pieces of subframe data. A programming circuit stores the subframe data divided into N pieces in respective N sub-pages formed corresponding to the information of N bits.

An LED driver for controlling the intensity of an LED light source includes a power converter circuit for generating a DC bus voltage, an LED drive circuit for receiving the bus voltage and controlling a load current through, and thus the intensity of, the LED light source, and a controller operatively coupled to the power converter circuit and the LED drive circuit. The LED drive circuit comprises a controllable-impedance circuit adapted to be coupled in series with the LED light source. The controller adjusts the magnitude of the bus voltage to a target bus voltage and generates a drive signal for controlling the controllable-impedance circuit. To adjust the intensity of the LED light source, the controller controls both the magnitude of the load current and the magnitude of the regulator voltage. The controller controls the magnitude of the regulator voltage by simultaneously maintaining the magnitude of the drive signal constant and adjusting the target bus voltage.

According to some embodiments of the present invention, an impedance transformation circuit is provided for use with a transmitter, a receiver, and an antenna. The transmitter may provide transmission signals for transmission by the antenna. The antenna may provide received signals having an associated signal parameter to the receiver. The impedance transformation circuit includes an impedance adjusting circuit and a controller. The impedance adjusting circuit is connected between the antenna, the receiver, and the transmitter. The impedance adjusting circuit is configured to change an impedance difference presented between at least one of: 1) the transmitter and the antenna, and 2) the antenna and the receiver, in response to a control signal. The controller generates the control signal to change the presented impedance difference in response to a signal parameter.

In an inverter and a method for operating an inverter, the inverter includes a step-up converter circuit, a dynamic intermediate circuit, and a step-down converter circuit for converting a direct voltage of a direct voltage generator or string into an alternating voltage for supplying a network. The step-up converter circuit increases the direct voltage if the latter is lower than a peak-to-peak maximum of the network voltage, and the step-down converter circuit lowers a dynamic intermediate circuit voltage, as needed, to a lower voltage currently required in the network. The step-up converter circuit dynamically increases the direct voltage to the value currently required in the network and in the process temporarily supplies an approximately sinusoidal voltage curve for the intermediate circuit voltage.

A power conversion circuit system comprises a primary conversion circuit, a secondary conversion circuit, and a control circuit for controlling the primary and secondary conversion circuits. The primary conversion circuit comprises a primary full bridge circuit, which includes a bridge section composed of both a primary coil in a transformer and a primary magnetic coupling reactor in which two reactors are magnetically coupled, a first input/output port disposed between a positive bus bar and a negative bus bar of the primary full bridge circuit, and a second input/output port disposed between the negative bus bar of the primary full bridge circuit and a center tap of the primary coil in the transformer. The secondary conversion circuit has a configuration similar to that of the primary conversion circuit.

According to a display device of the present invention, a frame memory is integrally formed on a substrate (pixel substrate) on which a pixel portion is formed. With this construction, one row of data can be simultaneously read from the frame memory and can be input to a drive circuit for pixels in parallel. As a result, a need for transferring image data in serial is eliminated. Then, a parallel/serial converting circuit and a serial output circuit, and a serial/parallel converting circuit and a parallel input circuit are not necessary. Therefore, a display device having a frame memory and a pixel portion can be constructed in a simpler construction and with an easier circuit. As a result, the noise can be reduced, and the low power consumption can be achieved.

A configurable light-emitting diode (LED) driver is adapted to control a plurality of different LED light sources, which may be rated to operate using different load control techniques, different dimming techniques, and different magnitudes of load current and voltage. The LED driver comprises a power converter circuit for generating a DC bus voltage, and an LED drive circuit for receiving the bus voltage and adjusting either the magnitude of the current conducted through the LED light source or the magnitude of the voltage across the LED light source. The LED driver is operable to dim the LED light source using either a pulse-width modulation technique or a constant current reduction technique, and may be configured using a programming device and a personal computer.

A modular power converter including a first housing enclosing a converter circuit, and a selectively detachable second housing enclosing a retractable power cable. In a first orientation the detachable second housing is secured to the first housing to form a unitary housing. In a second orientation, the second housing is detached from the first housing such that a first end of the extended power cable may tether to the first housing output a selectable distance therefrom. The cable also has a second end extendable from the second housing a predetermined distance. This modular power converter forms a single compact device when the power cable is not extended from the second housing.

A regulated power factor corrected power supply apparatus is provided. The apparatus includes an input rectifier circuit for receiving an input AC voltage and outputting a full-wave rectified DC voltage. A single-stage isolated buck-type converter is coupled with the input circuit. The converter circuit comprises an isolated buck-type converter circuit including an isolation transformer. An output rectifier and semiconductor tap switch are coupled to a secondary winding of the isolation transformer. The tap switch couples a larger portion of the secondary winding to an output bulk capacitor during the portions of the input sinewave half-cycle, which are low in amplitude. The tap switch enables the single-stage isolation buck-type converter to operate over a much larger portion of the input sinewave, but also allows the converter to operate at high-efficiency over the majority of the input sinewave.

A traction inverter circuit includes a first energy storage device configured to output a DC voltage, a first bi-directional DC-to-AC voltage inverter coupled to the first energy storage device, and a first electromechanical device. The first electromechanical device includes a first plurality of conductors coupled to the first bi-directional DC-to-AC voltage inverter, a second plurality of conductors coupled together, and a plurality of windings coupled between the first plurality of conductors and the second plurality of conductors. The traction converter circuit also includes a charge bus comprising a first conductor coupled to the second plurality of conductors of the first electromechanical device, the charge bus configured to transmit a charging current to or receive a charging current from the first electromechanical device to charge the first energy storage device via the first electromechanical device and the first bi-directional DC-to-AC voltage inverter.

An arc fault detector for detecting electric power lines includes a sensor for sensing the derivative of the current on the electric power line, a converter circuit for converting the derivative of the line current into first and second signals, the first signal responsive to positive step transitions of arc fault current, and the second signal responsive to negative step transitions of arc current, and a temporal detector for signaling the presence of an arc fault when one of the first and second signals follows the other within a predetermined time, or window, and in which a sequence of one of the signals following the other signal occurs in a second predetermined interval of time.

Circuits and methods for bidirectional power conversion are provided that allow mobile and other devices to generate power suitable to support multiple modes of operation. The bidirectional power converters of the present invention may operate in both step up and step down configurations rather than having a single dedicated conversion function and use many of the same components thereby reducing converter size and complexity.

A DC-DC converter has converter circuit portions 11 and 12, transformers Tr.sub.1 and T r.sub.2, and rectifier circuit portions 21 and 22. Two sets of converter circuit portions 11 and 12 respectively include two pairs of switching elements Q.sub.1 to Q.sub.4, and two pairs of switching elements Q.sub.5 to Q.sub.8 connected in full bridge configuration, series capacitors C.sub.1 and C.sub.2 are inserted and connected between the converter circuit portions 11 and 12 and the transformers Tr.sub.1 and Tr.sub.2 respectively. The switching phase of one switching element Q.sub.4 or Q.sub.8 is shifted by a 1/3n period from the switching phase of the other switching element Q.sub.1 or Q.sub.5 in the pair of switching elements. The switching phases of corresponding switching elements Q.sub.1 and Q.sub.5 in the converter circuit portions 11 and 12 are shifted by a 1/2n period from each other.