Showing papers on "Voltage regulator published in 2005"

Area-efficient linear regulator with ultra-fast load regulation

Abstract: We demonstrate a fully integrated linear regulator for multisupply voltage microprocessors implemented in a 90 nm CMOS technology. Ultra-fast single-stage load regulation achieves a 0.54-ns response time at 94% current efficiency. For a 1.2-V input voltage and 0.9-V output voltage the regulator enables a 90 mV/sub P-P/ output droop for a 100-mA load step with only a small on-chip decoupling capacitor of 0.6 nF. By using a PMOS pull-up transistor in the output stage we achieved a small regulator area of 0.008 mm/sup 2/ and a minimum dropout voltage of 0.2 V for 100 mA of output current. The area for the 0.6-nF MOS capacitor is 0.090 mm/sup 2/.

Switched constant current driving and control circuit

Abstract: The driving and control device according to the present invention provides a desired switched current to a load including a string of one or more electronic devices, and comprises one or more voltage conversion means, one or more dimming control means, one or more feedback means and one or more sensing means. The voltage conversion means may be a DC-to-DC converter for example and based on an input control signal converts the magnitude of the voltage from the power supply to another magnitude that is desired at the high side of the load. The dimming control means may comprise a switch such as a FET, BJT, relay, or any other type of switching device, for example, and provides control for activation and deactivation of the load. The feedback means is coupled to the voltage conversion means and a current sensing means and provides a feedback signal to the voltage conversion means that is indicative of the voltage drop across the current sensing means which thus represents the current flowing through the load. The current sensing means may comprise a fixed resistor, variable resistor, inductor, or some other element which has a predictable voltage-current relationship and thus will provide a measurement of the current flowing through the load based on a collected voltage signal. Based on the feedback signal received, the voltage conversion means can subsequently adjust its output voltage such that a constant switched current is provided to the load.

High boost converter using voltage multiplier

Abstract: With the increasing demand for renewable energy, distributed power included in fuel cells have been studied and developed as a future energy source. For this system, a power conversion circuit is necessary to interface the generated power to the utility. In many cases, a high step-up DC/DC converter is needed to boost low input voltage to high voltage output. Conventional methods using cascade DC/DC converters cause extra complexity and higher cost. The conventional topologies to get high output voltage use flyback DC/DC converters. They have the leakage components that cause stress and loss of energy that results in low efficiency. This paper presents a high boost converter with a voltage multiplier and a coupled inductor. The secondary voltage of the coupled inductor is rectified using a voltage multiplier. High boost voltage is obtained with low duty cycle. Theoretical analysis and experimental results verify the proposed solutions using a 300 W prototype.

A fixed-frequency pulsewidth modulation based quasi-sliding-mode controller for buck converters

Abstract: This paper presents the design and analysis of a fixed-frequency pulsewidth modulation (PWM)-based quasi-sliding-mode voltage controller for buck converters from a circuit design perspective. A practical design approach that aims at systematizing the procedure for the selection of the control parameters is presented. In addition, a simple analog form of the controller for practical realization is provided. The resulting controller exhibits the same structure as a PWM proportional derivative (PD) linear controller, but with an additional component consisting of the instantaneous input voltage and the instantaneous output voltage. Simulation and experimental results show that the performance of the converter agrees with the theoretical design.

LED light source for backlighting with integrated electronics

Abstract: An LED backlight structure and technique for setting the voltages and currents for the LEDs are described. In one embodiment, red LEDs are connected in series between a first voltage regulator and a first controllable current source, green LEDs are connected in series between a second voltage regulator and a second controllable current source, and blue LEDs are connected in series between a third voltage regulator and a third controllable current source. The current sources may linear current regulators. After all the LEDs are mounted on a printed circuit board, each voltage regulator is controlled so that there is a minimum voltage drop across the current source to minimize energy dissipation by the current source. Also, after all the LEDs are mounted on the printed circuit board, the current sources are controlled to balance the three colors to achieve a target light output of the board using a light detection chamber. In another embodiment, a constant current source is connected to the series string of LEDs. PWM controllers control transistor switches connected in parallel across groups of LEDs, where the duty cycles set the average current through each group of LEDs. The control values used to achieve the target light characteristics are then stored in a memory on the board. With such a technique, LEDs do not need to be binned to match their efficiencies, since the controllable voltage and current sources compensate for the variety of LED efficiencies. Accordingly, all boards will have the same target light output using the particular values stored on each board. In other embodiments, not all the LEDs of a particular color are connected in series. The brightness levels of the LEDs may be further controlled by a PWM controller. The backlight may be for an LCD television or other color display.

A novel winding-coupled buck converter for high-frequency, high-step-down DC-DC conversion

Abstract: This paper analyzes the fundamental limitations of the buck converter for high-frequency, high-step-down dc-dc conversion. Further modification with additional coupled windings in the buck converter yields a novel topology, which significantly improves the efficiency without compromising the transient response. An integrated magnetic structure is proposed for these windings so that the same magnetic cores used in the buck converter can be used here as well. Furthermore, it is easy to implement a lossless clamp circuit to limit the device voltage stress and to recover inductor leakage energy. This new topology is applied for a 12V-to-1.5V/25A voltage regulator module (VRM) design. At a switching frequency of 2MHz, over 80% full-load efficiency is achieved, which is 8% higher than that of the conventional buck converter.

Power factor improving circuit

Abstract: A power factor improving circuit including: a boost reactor that inputs a rectified voltage obtained by rectifying an AC power supply voltage of an AC power supply by a rectifier circuit; a main switch that inputs the rectified voltage through the boost reactor and is turned on/off; a converting section that converts a voltage obtained when the main switch is turned on/off into a DC output voltage; and a control section that controls turn-on/off of the main switch to shape an AC power supply current to a sine wave form, controls an output voltage of the converting section to a predetermined voltage, and controls a switching frequency of the main switch according to a value of current flowing into the AC power supply, or that of current flowing into the rectifier, or that of current flowing into the main switch.

Electric control and supply system

Abstract: In at least some embodiments, an electrically controlled subsea production system includes a subsea electrical distributor that receives a high direct current (DC) voltage. The electrical distributor converts the high DC voltage to a lower DC voltage. The electrically controlled subsea production system also includes a plurality of subsea trees coupled to the subsea electrical distributor, wherein valves of the subsea trees selectively operate based on the lower DC voltage.

Novel anti-windup of a current regulator of a surface-mounted permanent-magnet motor for flux-weakening control

Abstract: This paper proposes a novel antiwindup method of current regulator for the drive system of a surface-mounted permanent-magnet synchronous motor at flux-weakening region. It is designed in conjunction with the synchronous-frame proportional and integral current regulator and the space vector pulse width modulation. The difference between the regulator output voltage and the saturated voltage on the q-axis of the regulator is used for flux-weakening control, which modifies the d-axis current reference. With this method, the antiwindup and the flux-weakening control can be achieved simultaneously. Since the proposed method utilizes the dc-link voltage more efficiently, it makes the motor generate higher output torque than the conventional antiwindup and/or flux-weakening control methods under the same voltage and current limitation. The effectiveness of this method is confirmed by computer simulations and experiments

Electrical starting, generation, conversion and distribution system architecture for a more electric vehicle

Abstract: A system (200) for distributing electrical power, includes: a first high voltage AC power distributing unit (210a) including a first high voltage AC bus (214a-1, 214a-2), which is selectively connected to a first high voltage AC generator (224a), and a first start bus (212a); a second high voltage AC power distributing unit (210b) including a second high voltage AC bus (214b-1, 214b-2), which is selectively connected to a second high voltage AC generator (224b), and a second start bus (212b); a first high voltage DC power distributing unit (240a) including, a first high voltage DC bus (246a), and a second high voltage DC power distributing unit (240b) including a second high voltage DC bus (246b). The first high voltage AC bus (214a-1, 214a-2) is selectively connectable to the second high voltage AC bus (214b-1, 214b-2), such that the system (200) provides redundancy for high voltage power distribution.

Compensation voltage control in dynamic voltage restorers by use of feed forward and state feedback scheme

Abstract: This paper discusses the control of the compensation voltages in dynamic voltage restorers (DVR). It first analyzes the power circuit of a DVR system in order to come up with appropriate control limitations and control targets for the compensation voltage control. Based on this power stage analysis, a combined feed forward and state feedback control structure for the compensation voltages of DVRs is developed. This paper also discusses the time delay problems inherent in the digital control system of a DVR. Digital control systems normally have control delay from the sampling period, the switching frequency of the inverter, the sensor transmission time, etc. The control delay increases the dimension of the system transfer function. This makes the control system more unstable. This paper analyzes the control performance related with the control delay, closed loop damping factor, and the output filter parameters in DVR systems. Based on the control system analysis, design guidelines are proposed for the control gains and the inverter switching frequency of DVRs. The proposed theory is verified by an experimental DVR system with a full digital controller.

Impacts of AC Generators and DSTATCOM devices on the dynamic performance of distribution systems

Abstract: This paper presents a dynamic study about the influences of ac generators (induction and synchronous machines) and distribution static synchronous compensator (DSTATCOM) devices on the dynamic behavior of distribution networks. The performance of a DSTATCOM as a voltage controller or a power factor controller is analyzed. The impacts of these controllers on the stability and protection system of distribution networks with distributed generators are determined. Computer simulation results show that a DSTATCOM voltage controller can improve the stability performance of induction generators significantly. On the other hand, a DSTATCOM power factor controller may adversely affect the stability performance of synchronous generators. It has also been observed that a DSTATCOM has no influence on short-circuit currents provided by ac generators during faults.

Integrated tire pressure sensor system

Abstract: The present invention provides a tire pressure sensor system that has multiple functions and is integrated into a small package. The system includes one or more Micro Electro Mechanical System (MEMS)-based sensors, including a MEMS-based pressure sensor; a MEMS-oscillator-based wireless signal transmitter; and a microcontroller, where the microcontroller processes the data generated by at least one of the MEMS-based sensors, controls at least one of the MEMS-based sensors, and controls the encoding and timing of transmission of data from the wireless signal transmitter. Preferably, the MEMS-based sensors, MEMS-oscillator-based wireless signal transmitter, and microcontroller are integrated onto one or more chips in one or more packages. The system also preferably includes a MEMS-based motion sensor, a low frequency (LF) receiver, an IC-based voltage sensor, a voltage regulator, a temperature sensor and a polarization voltage generator. Thus, the disclosed tire pressure sensor system is high in functionality, yet small in size.

Algorithms for controlling both the DC boost and AC output voltage of the Z-source inverter

Abstract: This paper aims to achieve the good performances of both the DC boost control and AC output voltage control of the Z-source inverter. The algorithm to control linearly the capacitor voltage is suggested in order to improve the transient response for DC boost control of the Z-source inverter. The peak AC output voltage is used to control exactly the AC output voltage to its desired level. The proposed algorithms are verified with simulation and experiment with 32-bit DSP

Design of low-power analog drivers based on slew-rate enhancement circuits for CMOS low-dropout regulators

Abstract: Low-power analog driver based on a single-stage amplifier with an embedded current-detection slew-rate enhancement (SRE) circuit is presented. By developing a systematic way to design both the response time and optimal sizing of driving transistors in the SRE circuit, the SRE circuit can be controlled to turn on or turn off properly. In addition, the analog driver only dissipates low static power and its transient responses are significantly improved without transient overshoot when driving large capacitive loads. Implemented in a 0.6-/spl mu/m CMOS process, a current-mirror amplifier with the current-detection SRE circuit has achieved over 43 times improvement in both slew rate and 1% settling time when driving a 470-pF load capacitor. When the proposed analog driver is employed in a 50-mA CMOS low-dropout regulator (LDO), the resultant load transient response of the LDO has 2-fold improvement for the maximum load-current change, while the total quiescent current is only increased by less than 3%.

PWM buck regulator with LDO standby mode

Abstract: A voltage regulator is disclosed having a PWM portion and an LDO portion on a single chip. The PWM portion switches a large MOS transistor (or synchronous MOS transistors) at a high frequency to supply medium and high currents (e.g., 600 mA) to a load. During a standby mode, the regulator switches to an LDO mode and disables the PWM portion. The LDO mode controls a very small MOS series transistor to supply the standby mode current. Since the gate of the series MOS transistor is small, only a small variation in gate charge is needed to adequately control the conductance of the series transistor during the standby mode. Therefore, much less control current is used by the LDO than if the LDO used a series transistor of the same size as the switching transistor.

Omni voltage direct current power supply

Abstract: A battery operated LED lighting apparatus including: a battery outputting a battery voltage; a light emitting diode or array of light emitting diodes; and a power supply including a boost regulating circuit. The power supply being in communication with the battery and the light emitting diodes such that a constant voltage or constant current is supplied to the light emitting diodes as the battery discharges and the battery voltage falls below the output voltage. In a preferred embodiment the power supply further includes a buck regulator to maintain the proper output voltage when the battery voltage is greater than the output voltage.

Post-placement voltage island generation under performance requirement

Abstract: High power consumption not only leads to short battery life for handheld devices, but also causes on-chip thermal and reliability problems in general. As power consumption is proportional to the square of supply voltage, reducing supply voltage can significantly reduce power consumption. Multi-supply voltage (MSV) has previously been introduced to provide finer-grain power and performance trade-off. In this work we propose a methodology on top of a set of algorithms to exploit non-trivial voltage island boundaries for optimal power versus design cost trade-off under performance requirement. Our algorithms are efficient, robust and error-bounded, and can be flexibly tuned to optimize for various design objectives (e.g., minimal power within a given number of voltage islands, or minimal fragmentation in voltage islands within a given power bound) depending on the design requirement. Our experiment on real industry designs shows a ten-fold improvement of our method over current logical-boundary based industry approach.

Power conditioning system for energy sources

Abstract: Apparatus for conditioning power generated by an energy source includes an inverter for converting a DC input voltage from the energy source to a square wave AC output voltage, and a converter for converting the AC output voltage from the inverter to a sine wave AC output voltage.

A novel stand-alone dual stator-winding induction generator with static excitation regulation

Abstract: On the basis of the new idea of electric power integration, a novel stand-alone dual stator-winding induction generator (DWIG) system is built. In this generator, there are two sets of windings to be embedded in the stator slots. One, referred to as the 12-phase power winding, supplies power to the dc load via a 12-phase bridge rectifier, and the other, called the 3-phase excitation winding, is connected to a pulsewidth modulation (PWM) voltage source static excitation regulator (SER). A solid iron squirrel cage rotor is suitable for high speed generation. Experiments and simulations show the ac capacitors can reduce the inductance of rectifier loads and help to reduce the capacitance of the SER. A simple control methodology based on stator voltage orientation (SVO) is presented to regulate the output voltage of the 12-phase bridge rectifier in this paper. Moreover, the electric energy quality and the relative influence factors are studied by detailed experiments and analyses. The proposed system is especially suitable for self contained electrical systems, such as those found on electric vehicles, ships, and aircraft, where high performance and compact size are essential.

The fast response double buck DC-DC converter (FRDB): operation and output filter influence

Abstract: The fast response double buck (FRDB) dc-dc converter was presented like a low output voltage dc-dc converter with fast transient response, in order to feed devices such as microprocessors and digital signal processors (DSPs). The topology of the FRDB is composed of two buck converters connected in parallel, each one of them with different features and aims, and controlled by means of the novel linear-non-linear (LnL) control. In this paper, the topology, the control strategy and the operation principle are shown. Finally, experimental results in different prototypes are presented to show both, the transient response and the recovery time when these prototypes are subjected to load current steps, and the influence of the output filter on these parameters.

Novel concept for mains voltage proportional input current shaping of a VIENNA rectifier eliminating controller multipliers

Abstract: This paper proposes a novel mains voltage proportional input current control concept eliminating the multiplication of the output voltage controller output and the mains ac phase voltages for the derivation of mains phase current reference values of a three-phase/level/switch pulsewidth-modulated (VIENNA) rectifier system. Furthermore, the concept features low input current ripple amplitude as, e.g., achieved for space-vector modulation, a low amplitude of the third harmonic of the current flowing into the output voltage center point, and a wide range of modulation. The practical realization of the analog control concept as well as experimental results for application with a 5-kW prototype of the pulsewidth-modulated rectifier are presented. Furthermore, a control scheme which relies only on the absolute values of the input phase currents and a modified control scheme which does not require information about the mains phase voltages are presented.

Influence of excitation system control modes on the allowable penetration level of distributed synchronous generators

Abstract: This paper investigates the impacts of different excitation system control modes on potential factors that can limit the maximum allowable number of synchronous generators connected to power distribution systems. Excitation systems acting as either a voltage regulator or a power factor regulator are examined. The impacts on steady-state voltage, angle stability, short-circuit currents and voltage stability are determined. Simulation results show that the usage of the excitation system as a voltage regulator can increase the maximum penetration level of synchronous generators in distribution systems.

Voltage Regulation Performance of a Shunt Active Filter Intended for Installation on a Power Distribution System

Abstract: This paper discusses a shunt active filter intended for installation on a power distribution system, with focus on voltage regulation capability. The active filter has capability of regulate the distribution-line voltage by means of adjusting its reactive power. Theoretical analysis investigates the dynamic performance of harmonic damping and voltage regulation as well as computer simulation does. As a result, it is clarified that a harmonic detection error may increase the voltage fluctuations in transient states. A new compensation method is proposed to reduce the voltage fluctuations in transient states. Experimental results show that the proposed method makes it possible to reduce the voltage fluctuation in transient states

SRAM employing virtual rail scheme stable against various process-voltage-temperature variations

Abstract: An SRAM employs a virtual rail configuration that is stable against process-voltage-temperature (PVT) variation. The SRAM provides a virtual power supply voltage to an SRAM cell that is obtained by lowering a power supply voltage by a threshold voltage of a transistor and a virtual ground voltage obtained by raising a ground voltage by a threshold voltage of a transistor. Due to the use of PMOS and NMOS transistors of diode types connected between the power supply voltage and the virtual power supply voltage and the use of NMOS and PMOS transistors of diode types connected between the ground voltage and the virtual ground voltage, a virtual power supply voltage level and a virtual ground voltage level that are stable even against various PVT variations are provided, so that low-leakage current characteristics are stable.

A self-driven soft-switching voltage regulator for future microprocessors

Abstract: In conventional high frequency 12-V input voltage regulators (VR), large gate driver loss and body diode conduction loss raise crucial challenges to its gate driver implementation. The proposed self-driven topologies are basically buck-derived multiphase interleaving soft switching topologies, which eliminate the synchronous rectifier MOSFET drivers and save driving loss and body diode loss, so that it is a high efficiency, high power density solution for future microprocessors. A 1U four-phase 1.3-V/100-A VRM running at 1MHz demonstrates its advantages (cost, size and efficiency) over the conventional multiphase buck converter.

New technique for frequency and amplitude estimation of power system signals

Abstract: This paper describes the design, analysis and computational aspects of a technique for the measurement of power system voltage, current and frequency. This technique can be used in a digital AVR for the state estimation of turbine-generator terminal quantities or in a digital relay for protection of a power system. This technique provides fast and accurate estimation of power system frequency, and is used in a Kalman-filtering algorithm to estimate power system voltage and current signals. Practical considerations such as the effect of power system harmonics, noise, frequency changes, mechanical and electrical load changes are taken into account during implementation of this technique. Several computer simulation tests are presented to highlight the usefulness of the technique. Simulation results show that the technique can simultaneously estimate the amplitude and frequency of a sinusoidal signal, even in the case that the signal is distorted by harmonics or noise or encounters frequency changes.

Active transient response circuits, system and method for digital multiphase pulse width modulated regulators

Abstract: Disclosed is a multi-phase pulse width modulated voltage regulator and method in which transient voltage excursions or deviations that exceed the load line voltage by more than a pre-determined amount are detected by an ATR circuit and a correction signal is applied. The correction signal is in the form of asynchronous pulses and the number of such pulses is a function of the magnitude of the voltage excursion as determined by the number of thresholds that are exceeded. Also disclosed is an adaptive voltage positioning (AVP) circuit and method for early detection of a transient event by sensing voltage changes at the load and adjusting the target voltage with pre-determined current values prior to the time that ATR event changes in the current at the load are detected. The AVP load line is pre-positioned for more precise current control. Also disclosed is an adaptive filter with adjustable frequency characteristics in response to an ATR event. Also disclosed is a pulse limiting circuit. Also disclosed is a tri-state implementation. Response to transient events is further improved with an external ATR circuit coupled to the load.

Three-level inverter configuration with common-mode voltage elimination for induction motor drive

Abstract: A scheme for a three-level voltage space phasor generation with common-mode voltage elimination is proposed An open-end-winding induction motor, fed from both ends by two three-level inverters, which are realised by a cascading two two-level inverter, is used in this configuration The voltage space vectors of individual three-level inverters, which generate the same common-mode voltage in the inverter pole voltage, are variously grouped When these voltage space vectors are used to switch individual three-level inverters, it results in zero common-mode voltage across the motor windings In the proposed scheme, voltage space phasors from individual inverters with zero common-mode voltage in the inverter pole voltage are used for PWM control For the proposed drive configuration, the DC link voltage requirement is only half when compared to the DC link voltage of a conventional neutral-point-clamped (NPC) three-level inverter The proposed inverter configuration offers reduced circuit and control complexity when compared to similar schemes with NPC or H-bridge inverter configurations

System and method for driving light-emitting diodes (LEDs)

Abstract: System and method for improving efficiency in driving LEDs. A preferred embodiment comprises a switch current regulator coupled to a current control signal input, the switch current regulator to control an amount of current provided to the LED based upon a magnitude of a voltage on the current control signal input, a switching voltage regulator coupled to the switch current regulator and the LED, the switching voltage regulator to provide current to the LED, and a sensor coupled to the switch current regulator, the LED, and a signal feedback circuit, the sensor to measure status information regarding the switch current regulator and the LED and provides the information to a controller, wherein the status information can be used to adjust the current on the current control signal input.