858results about "Open-loop automatic control systems" patented technology

Envelope tracking (ET) methods and systems for controlling the delivery of power to radio frequency power amplifiers (RFPAs). An exemplary ET system includes an RFPA and a wide bandwidth capable and power efficient envelope modulator that includes a first power supplying apparatus and a second power supplying apparatus. The first power supplying apparatus includes a switch-mode converter and a regulator. The first mode converter is operable to dynamically step down a fixed power supply voltage according to amplitude variations in an envelope signal received by the regulator, and use the resulting dynamic power supply signal to power the regulator. The second power supplying apparatus is connected in parallel with the first power supplying apparatus. Depending on a power of an output signal to be generated at an output of the power amplifier, power is supplied to the power amplifier from either or both of the first and second power supplying apparatuses.

A distributed power system including multiple DC power sources and multiple power modules. The power modules include inputs coupled respectively to the DC power sources and outputs coupled in series to form a serial string. An inverter is coupled to the serial string. The inverter converts power input from the serial string to output power. A signaling mechanism between the inverter and the power module is adapted for controlling operation of the power modules.

High-efficiency envelope tracking (ET) methods and apparatus for dynamically controlling power supplied to radio frequency power amplifiers (RFPAs). An exemplary ET circuit includes a switch-mode converter coupled in parallel with a split-path linear regulator. The switch-mode converter is configured to generally track an input envelope signal Venv and supply the current needs of a load (e.g., an RFPA). The split-path linear regulator compensates for inaccurate envelope tracking by sourcing or sinking current to the load via a main current path. A current sense path connected in parallel with the main current path includes a current sense resistor used by a hysteresis comparator to control the switching of the switch-mode converter. The split-path linear regulator is configured so that current flowing in the current sense path is a lower, scaled version of the current flowing in the main current path.

This interface is an apparatus for controlling a power supply delivering power to a DC powered tool. The interface is connected between the DC power supply and the DC tool wherein the interface is configured to read signals from the tool and control the power supplied by allowing the power supply to run, brake, reverse or jog the tool. A microprocessor is connected to the interface programmed to provide a specific power in response to the signals from the tool read by the interface. The interface includes a number of field effect transistors. They are PFET1, PFET2, NFET1, and NFET2.

A supply voltage controlled power amplifier that comprises a power amplifier, a closed power control feedback loop configured to generate a power control signal, and a dual voltage regulator coupled to the power control feedback loop, the dual voltage regulator comprising a first regulator stage and a second regulator stage, wherein the closed power control loop minimizes noise generated by the first regulator stage.

A voltage comparator of a power supply apparatus detects overshoot by comparing an output voltage with a threshold voltage. The power supply apparatus is provided with three switches. Upon detection of overshoot, the boosting operation of a booster circuit is suspended and the first through third switches are turned on. While the boosting operation is being suspended, the second switch operates to lower the output voltage. Concurrently, the first and third switches operate to forcibly lower an input voltage to allow the output voltage, occurring after the boosting operation is resumed, to approach a preset voltage.

A dimmable, light-emitting diode (LED) power supply adapted to provide a direct current (DC), constant current (“constant current source”) from a conventional, phase-controlled 120 VAC, 60 Hz power source is disclosed. The constant current source of the present invention utilizes two processes to control dimming. In a first process, the phase angle of the input voltage is used to control the duty cycle of a line frequency pulse width modulation (PWM). In a second process, a proportional-current limit adjustment is used to control the average current to the LED during the ON time of the line frequency by PWM. As a result, at relatively low phase angles, peak currents can be lowered, reducing flicker and improving the audible noise levels generated by the circuit.

The present invention is a power supply (10) that starts a load (20) with a heavy start-up power draw from a power grid (12) and then switches the load to a generator (22) for lower power draw operation thereby avoiding the need for a large capacity generator capable of initial start-up of the load (20). The power supply comprises a conductor (15) for connecting to a power grid, an electrical power generation device (30), an electrical power using device or load (20) and a switching mechanism (40) for 1) isolating the power grid (12) from the power generation device (30), 2) connecting the power grid conductor (15) to the electrical power using device (20) for the initial start-up of the power using device (20), and 3) connecting the power generation device (30) to the power using device (20) after initial start-up. In addition the power supply (10) can also serve as a backup source of power for multiple circuits whose total startup load exceeds the total output of the generator (30) during periods of grid power failure by selectively turning off interruptible circuit load (20) during the startup of other circuits (16) or allowing intermittent circuit loads (20) to complete their cycle and return to an off state prior to the start-up of other circuits (16).

A reference voltage register stores a reference value Vref indicating the output voltage Vout of a power supply circuit. A digital filter amplifies the difference between the output voltage Vout from the power supply circuit and the reference value Vref stored in the reference voltage register. A pulse width computation unit computes the duty such that the output voltage Vout matches the reference value Vref, and generates the on-time of a pulse signal corresponding to the duty. A reference value operation unit updates the reference voltage register depending on the output current from the power supply circuit or the temperature around the power supply circuit.

The present invention provides a low-cost current detection device having a magnetic sensor easily placed on a choke coil, wherein assembly and manufacturing costs are reduced and a product is miniaturized. A current detection device including a choke coil for smoothing an input current or an output current and a magnetic sensor 1a built into the choke coil to detect the input current or output current, wherein the choke coil is composed of: a pair of cores 5 provided with an outer magnetic leg 5a constituting a closed magnetic circuit and a center magnetic leg 5b for providing a gap; and an air core coil 6 mounted on the center magnetic leg 5b, and space 6b is provided to a part of winding of the air core coil 6 with the magnetic sensor 1a placed in the gap between the space 6b and the center magnetic leg 5b.

A power conversion circuit operates in a discontinuous switching mode over a wide range of loading conditions and varies a coil peak current to maintain efficiency over the wide range of loading conditions. The coil peak current is adjustable based at least in part on a feedback signal generated in response to a load condition.

A method and corresponding apparatus provide a determination of available power capacity of a phase of a power supply in a data center rack. The method includes metering the power of a power supply and calculating an average peak power draw per phase of the power supply. Using average peak power draw per phase of the power supply and the expected power draw data corresponding to data center equipment coupled to the power supply, the available power capacity can be calculated on a per phase of the power supply. A method and corresponding apparatus for managing data center equipment may use the phase based available power capacity calculations to determine the optimal placement of new data center equipment within a data center configuration.

Aspects of the invention are directed to power distribution systems and methods for distributing power from a primary power source and a backup power source to a load. In one particular aspect, a power distribution system includes a first input to receive input power from the primary power source, a second input to receive input power from the backup power source, an output that provides output power from at least one of the primary power source and the backup power source, a first switch operatively coupled to the first input and the output and operative to selectively couple the first input to the output, a second switch operatively coupled to the second input and the output and operative to selectively couple the second input to the output, and a controller operatively coupled to the first switch and to the second switch and configured to control the first switch and the second switch to provide an electrical interlock.

Methods, systems, and devices are described for sensing a phase-cut dimming signal and outputting a control signal compatible with a switching power circuit. Embodiments of the invention generate at least one of a low-frequency pulse-wave-modulated control signal, an analog output control signal, or a digital (e.g., higher-frequency pulse-wave-modulated) output control signal. Some embodiments further provide preloading and / or startup control functionality to allow proper functioning of the circuitry under small-conduction-angle (i.e., highly dimmed) conditions.

An active load management system (ALMS) controllably restarts electrical service to service points in a utility service area after a power outage. The ALMS includes client devices installed at the service points and a central controller. In one embodiment, the controller associates numbers with the service points and stores the associations. Each service point may be associated with a unique number or a group of service points may share a number. After receiving notification that power is available, the controller determines a number and communicates the number to one or more of the client devices. Where the number was determined randomly, the client devices associated with the number may restart electrical service upon receipt of the number. Where the number was determined sequentially, a client device may determine its own random number and compare it to the received number. If a match occurs, electrical service can be restarted.

Handshaking circuits are provided in a communications cable and in a device operable to be mated with the communications cable. Before a device can utilize the power supply signal of such a communications channel, the two handshaking circuits must sufficiently identify one another over a power supply signal with a decreased voltage. The decreased voltage allows for a cable plug to be provided with a safe, protected power that cannot cause harm to a human. The decreased voltage also reduces the chance that a device can receive a primary power supply signal from the cable before the device sufficiently identifies itself. Accordingly, a laptop may be connected to a portable music player, but the voltage of the power supply signal provided by the laptop to the cable may be decreased on-cable until the handshaking circuit of the portable music player sufficiently performs a handshaking operation with a on-cable handshaking circuit.

The invention relates to a control method and a controller for a DC-DC converter, such as a synchronous Buck converter, which exploits the principle of capacitor charge balance to allow the converter to recover from a positive and / or negative load current step in the shortest achievable time, with the lowest possible voltage undershoot / overshoot. The control method may be implemented by either an analog or a digital circuit. The controller may be integrated with existing controller schemes (such as voltage-mode controllers) to provide superior dynamic performance during large-signal transient conditions while providing stable operation during steady state conditions. The invention also relates to a method and a modification of a DC-DC converter topology that comprises connecting a controlled current source between an input terminal and an output terminal of the DC-DC converter; detecting a load current step to a new load current; modifying a duty cycle of the DC-DC converter; and modifying current through a parallel output capacitor of the DC-DC converter by controlling current of the current source. The methods and circuits provided herein are applicable to Buck converters and Buck-derived converters such as forward, push-pull, half-bridge, and full-bridge converters.

An LED driver circuit operating from the AC power line providing high efficiency, good line and load regulation, high power factor, low line current harmonics, low conducted EMI, high LED utilization, and lamp dimming compatibility, while consisting of a minimal number of components. No inductors, nor capacitors (including electrolytics), nor high current switching transistors are employed. The top of a string of series connected LED segments is connected to the output of a rectifier, which in turn is connected to an AC sine wave power source. The string is tapped at various locations, including the bottom of the string. Each segment can consists of any number of serial or parallel connected LEDs. Current control elements or regulators sink current at each tap and are sequentially turned on and off one at a time, tracking the rectified sine wave voltage. Voltage across each regulator and current when conducting is individually controllable. Power loss in the regulators is minimized by keeping regulator voltage to a minimum. The regulators may control current in a multitude of ways, including a constant current, or a current dependent on voltage across the regulators including a resistor, or a combination. The driver is self-commutating, with the sequencing of the current control elements an inherent feature closely integrated with the current control elements and providing optimal performance over variable operating conditions. Given the large number of design variables, the driver circuit can be optimized for various performance criteria including input voltage range, line / load regulation, output power / current, efficiency, power factor, line current harmonics, dimmer compatibility, and LED utilization.

A sample-and-hold (SAH) current estimating circuit and a first switching power supply are disclosed. The first switching power supply provides a first switching power supply output signal based on a series switching element and a setpoint. The SAH current estimating circuit samples a voltage across the series switching element of the first switching power supply during an ON state of the series switching element and during a ramping signal peak to provide an SAH output signal based on an estimate of an output current of the first switching power supply output signal. The first switching power supply selects the ON state of the series switching element, such that during the ramping signal peak, the series switching element has a series current having a magnitude, which is about equal to a magnitude of the output current of the first switching power supply output signal.

A digital current-mode controller for a DC-DC converter is disclosed. The controller comprises a digital current reference; and a current loop compensator adapted to receive a digital current error signal derived from a digital current sample sensed from the DC-DC converter and the digital current reference and to generate a duty-cycle command, wherein the current loop compensator comprises a low-pass filter that is used in generating the duty-cycle command. A DC-DC regulator comprising a digital current-mode controller and a method of controlling a DC-DC converter are also disclosed.

A transformer module includes a main primary winding coupled to a first input power source to receive a medium voltage signal, multiple main secondary windings each to couple to a power cell of a drive system, and an auxiliary primary winding coupled to a second input power source to receive a low voltage signal. The auxiliary primary winding can be spatially separated from the main windings to increase leakage inductance. The auxiliary primary winding can be active during a pre-charge operation to pre-charge the power cells.

Circuitry, which includes a direct current (DC)-DC converter having a first switching power supply is disclosed. The first switching power supply includes a first switching converter, an energy storage element, a first inductive element, which is coupled between the first switching converter and the energy storage element, and a first snubber circuit, which is coupled across the first inductive element. The first switching power supply receives and converts a DC power supply signal to provide a first switching power supply output signal based on a setpoint.

The aim of this invention focuses on the development of a high-efficiency bidirectional converter for power sources with great voltage diversity. In traditional bidirectional converters, the circuit topology with transformer form is the common usual. Moreover, the soft-switching techniques including zero-voltage-switching (ZVS) or zero-current-switching (ZCS) are usually used for alleviating the corresponding switching losses. However, there are four and upward power semiconductor switches in these circuit schemes. By this way, it will result in the increase of production cost, and the degeneration of conversion efficiency. The coupled-inductor bidirectional scheme in the proposed converter only adopts three power semiconductor switches to accomplish the objective of bidirectional current control. Under the situation of non-isolation circuit topology, it still possesses the protection of electric safety for operators. Due to the characteristics of high step-up and step-down ratio, the battery module with low voltage could be injected into a high-voltage dc bus for the later utilization, e.g., high-voltage load, front-end of inverter. Since the techniques of voltage clamping, synchronous rectification and soft switching are manipulated in this circuit topology, and the corresponding device specifications are adequately performed, it can achieve the goal of high-efficiency bidirectional power conversion for power sources with great voltage diversity.

An electronic endoscope is detachably connected to a processor via a first control connector and a second control connector. Contacts provided at side ends of the flat-shaped second control connector are connected to a CPU. The CPU detects start of removal of the first control connector in response to a change in voltage of one of ports, to which the contacts are connected, from low to high. When the CPU detects the start of the removal, drive signals from a CCD driver to a CCD is stopped. Then, power supply from a power supply section to the CCD is stopped.

In accordance with some embodiments, a buck-boost circuit is contemplated which is bi-directional. That is, the buck-boost circuit be configured to produce a load voltage for a load responsive to a source voltage from a voltage source, and the buck-boost circuit may also be configured to produce a charging voltage for the voltage source responsive to a second voltage source connected to the load. In an embodiment, the buck-boost circuit may be operating in boost mode when providing the load voltage and may be operating in buck mode when providing the charging voltage.

Methods and apparatus operative in a portable electronic device having a processor and a switching mode power supply detect entry of the processor into a power saving mode during active operations and signal the switching mode power supply that the processor has entered a power saving mode. In response to the signaling the switching mode power supply optimizes its operating state in order to increase power supply efficiency.