Showing papers on "Voltage regulator published in 1991"

Switching regulator circuit using magnetic flux-sensing

Abstract: Control circuits for a switching voltage regulator circuit which uses magnetic flux sensing are provided. These circuits can be used to improve output voltage regulation by reducing parasitic effects inherently present in magnetic flux-sensed feedback switching voltage regulator designs.

Integrated charge pump circuit with back bias voltage reduction

Abstract: An integrated charge pump circuit with back bias voltage reduction includes one or more diode type voltage multiplier stages, with each stage having a diode-connected NMOS transistor in place of the conventionally-used p-n junction diode. The transistors are formed within a P-type well, which forms the back gate of each transistor within the well, and the transistor threshold voltages are dependent on the potential of the P-type well. Performance of the charge pump circuit using NMOS transistors is enhanced by the use of a bias circuit which generates a bias voltage as a function of the output voltage generated by the charge pump circuit, and applies this bias voltage to the P-type well to minimize the back-body effects of the NMOS transistors. The bias circuit thus permits the construction of an integrated charge pump circuit with significantly lower MOS diode voltage drops than would otherwise be possible.

A new approach to low ripple-noise switching converters on the basis of switched-capacitor converters

Abstract: A new approach to a low ripple-noise switching converter is presented. The starting circuit is a basic switched-capacitor (SC) converter cell from which several types of low ripple-noise switching converters are generated. Two generated converters are employed for switching regulators hybridized by copper thick films on alumina substrates to realize low ripple noise. As a result, the ripple noise in the output voltages is reduced to less than 5 mVpp. Finally, this approach enables design of an ideal switching converter with zero input and output current ripple. >

A study on voltage collapse mechanism in electric power systems

Abstract: A mechanism of the dynamic phenomenon of voltage collapse is presented from the physical point of view. It is shown that an iterative reaction of voltage drop between a dynamic load and the system network can cause voltage collapse. The dynamic phenomenon of voltage collapse is analyzed on a simple power system model which includes a synchronous motor. Dynamic equations describing the mechanism of voltage collapse caused by a very small disturbance are derived, and the physical explanation of the voltage collapse mechanism is presented in detail for the case when the system is operating near the bifurcation point and its linearized system matrix has a very small negative eigenvalue. It is shown that an iterative reaction of voltage drop between a dynamic load and the system network can cause voltage collapse. >

Simple topologies for single phase AC line conditioning

Abstract: This paper presents a variety of single phase AC line conditioning approaches. The topologies use a minimal number of devices and feature buck-boost voltage regulation capability without a transformer, while preserving a neutral connection which is common with the input AC line. The simplest form of the converter is seen to be an AC voltage regulator with output voltage range of 0-2 p.u. with reasonable line current waveform. Modifications allow the circuit to operate with fully controlled input current. The circuit can be further extended to provide significant ride-through capability without using a battery. Finally, a full function single phase UPS can also be realized if required. The paper contains analytical, simulation and experimental results. >

Recent results in secondary voltage control of power systems

Abstract: Recent results are reported on a pilot-point-based secondary voltage control in power systems. Similarities and differences compared to the optimal power flow methodology are described, and theoretical background for secondary voltage controller design is reviewed. Two complementary design problem formulations are reported, together with simulations on the New England 39 bus and Bonneville Power Administration 338 bus power system models. The results show the feasibility of the pilot-point approach and reveal the nature of the tradeoffs involved in secondary voltage controller designs. >

Method and apparatus for voltage regulation depending on battery charge

Abstract: The method of regulating a voltage produced by a generator with a voltage regulator according to a battery charge state includes providing a controller containing a clock and a memory able to store battery and power supply reference data, battery voltage and generator rotation speed; maintaining a regulated voltage produced by the generator at a normal value (UR) during a first time interval (t1); measuring a battery voltage (UB) and decreasing the regulated voltage (UR) during a second time interval (t2); determining the battery charge state from the measured battery voltage (UB) according to the stored battery- and power supply-reference data; and, when the battery charge state is determined to be unsatisfactory, determining an additional time interval (t4) with the controller and an amount of increase of the regulated voltage (UR) sufficient to obtain a satisfactory battery charge state during the additional time interval (t4) without damaging the voltage sensitive components of the voltage regulator; and increasing the regulated voltage above the normal value (UR) by the thus determined amount and turning on no voltage-critical consuming device during the additional time interval (t4). A voltage regulator including the controller is also described.

Class E low dv/dt synchronous rectifier with controlled duty ratio and output voltage

Abstract: A class-E high-frequency low-dv/dt synchronous rectifier/DC regulator is analyzed. The circuit is derived from a class-E rectifier by replacing a diode with a controllable switch. It can then both rectify and regulate the rectified output against variations in DC load and amplitude of the AC input voltage. The switch consists of a transistor and an antiparallel diode or a series diode. The DC output voltage of the rectifier is regulated by varying the ON duty ratio of the switch. The AC input voltage can be at a constant or varying frequency. The controllable switch turns on and off at zero voltage with low dv/dt, reducing switching losses, stresses, and noise. Equations governing the circuit operation are derived. Experimental results at 0.5 MHz were in good agreement with the theoretical predictions. The rectifier can be used in high-frequency-power-density multiple-output power supplies, all of whose outputs are regulated. The frequency need not be varied to regulate the DC output. >

High bandwidth low dropout linear regulator

Abstract: A linear voltage regulator for regulating the voltage and current in a DC supply is described. The invention includes current and voltage sense elements. The outputs from the sensed elements are summed together as the gate input to an FET pass transistor which regulates the power supplied. The two feedback loops provide high bandwidth and improve dynamic response.

Apparatus protecting a synchronous machine from under excitation

Abstract: Apparatus for protecting a synchronous generator from under-excitation, includes a limiter implemented as part of a microprocessor based voltage regulator The limiter selectively characterizes one or more limiting parameters, such as, system stability, machine capability and loss of field protection, as straight line segments in the real/reactive power plane to provide versatile, easily modified limits on excitation

Class D current-driven rectifiers for resonant DC/DC converter applications

Abstract: Analyses and experimental results are given for a family of three Class D current-driven rectifiers. The diode current is half-sine wave and the diode voltage is a square wave. The diode forward voltage and forward resistance are taken into account in the analyses. The basic performance parameters of the rectifiers are determined, such as input resistance, voltage transfer function, efficiency, and power factor. The ripple voltage is estimated, and some effects of the equivalent series resistance and equivalent series inductance of filter capacitors on the ripples are discussed. The experimental results were obtained using IR31DQ06 Schottky diodes at 1 MHz and 16 W output power. >

Voltage supply circuit for use in an integrated circuit

Abstract: The invention relates to a voltage supply circuit used in a semiconductor integrated circuit wherein switching between voltages generated is carried out in dependency upon whether the circuit is in an ordinary operating state or in a standby state. This voltage supply circuit includes a first reference voltage generator for supplying a reference voltage through an amplifier circuit to an internal circuit in the operating state, and a power supply voltage converter for supplying a voltage to the internal circuit at least in the standby state, wherein a second reference voltage generator provided independently of the first reference voltage generator becomes operative for a transient time period during which the second reference voltage generator shifts from the standby state to the operating state. By the action of the second reference voltage generator, a setup time at the time of start of the operation is shortened. Further, by allowing the first reference voltage generator to be inactive in the standby state, low power consumption is realized.

Power supply tracking regulator for a memory array

Abstract: A voltage regulator is provided for controlling an on-chip voltage generator which produces a boost voltage across a charge reservoir for supply to one input of a plurality of word line drivers in a memory array. The regulator is configured such that the charge reservoir voltage will track the power supply voltage and the difference between the power supply voltage and the charge reservoir voltage will be maintained substantially constant over a predefined power supply range. The voltage regulator includes a bandgap reference generator, a first differential circuit for producing a transition voltage from the reference voltage and the power supply voltage, a first transistor for comparing the power supply voltage with the boost voltage, a second transistor for comparing the transition voltage with the reference voltage and a latching comparator for equating the signal outputs from the first and second transistors so as to define a control signal for the on-chip voltage generator. Along with further specific details of the voltage regulator, a preferred bandgap reference generator is described.

Programming voltage generator circuit for programmable memory

Abstract: Electrically programmable memories often include an internal circuit for establishing a programming voltage Vpp higher than the supply voltage. This circuit is formed by a charge pump followed by a voltage regulator. Previously, an analog circuit was usually provided behind the regulator to convert the level of voltage Vpp, set up by the charge pump, into a signal with a slow-rising edge (to reduce the constraints on the programmed cells and increase their lifetime). Instead of such analog circuit, the present invention provides a digital control circuit to control the regulator to set up a regulation voltage that rises gradually from a low value up to the desired value Vpp. The digital control circuit comprises counter with k outputs which enables the gradual short-circuiting and unshort-circuiting of the various series-mounted transistors constituting the regulator, thus making the regulation voltage increase slowly.

Implantable medical devices employing capacitive control of high voltage switches

Abstract: An implantable device for treating a malfunctioning heart is disclosed. The device includes a high voltage circuit having a tank capacitor for storing therein during a charging mode of operation thereof high voltage DC electrical energy and for delivering such energy to a malfunctioning heart in the form of an electrical shock during a discharging mode of operation thereof. The device further includes a high voltage switch coupled to the high voltage circuit for switching, in the order of microseconds, the high voltage circuit between its charging and discharging modes of operation; a power supply for providing low voltage electrical energy for use in controlling the high voltage switch; a control circuit coupled between the power supply and the high voltage switch and capable of driving the high voltage switch to switch its output in the order of microseconds, for controlling the operation of the high voltage switch; and capacitors for capacitively coupling the power supply to the control circuit and electrically isolating the high voltage DC electrical energy from the power supply. The control circuit includes a common mode switch for rejecting common mode noise, and an additional switch for rapidly changing the output state of the high voltage switch.

An expert system for reactive power control of a distribution system. I. System configuration

Abstract: An expert system configuration is developed which can be used as a money saving online controller in cooperation with the input/output interface unit. It also can be used in the distribution system planning stage. The proposed optimum reactive power compensation (ORPC) expert system utilizes the human expert's (HE's) heuristic rules as well as the technical literature expertise (TLE) such as algorithms and formulas to build the knowledge base of the system. The distribution system component data and network topography are stored in the database. The distribution system voltage profile is kept within the desired limits by proper choice of both shunt capacitors and voltage regulators. The most economical mode of operation for the distribution system is ensured all the time, without violating any of the system voltage constraints. >

AC line current controller utilizing line connected inductance and DC voltage component

Abstract: A controller for controlling currents in an AC line connected to the controller is capable of causing the controlled current to assume any pre-determined magnitude and wave form. The pre-determined AC magnitude and wave form need not be of the same frequency or wave form existing at AC power lines connected to the controller. The controller uses the voltage at the AC power lines and an additional DC voltage as two sources of power to control the current in an inductor connected in series with the AC lines. A plurality of electronic switches are arranged so that at any instant in time, closing of appropriate switches will apply either the line voltage, or the sum of the line voltage and the DC voltage, or the difference between the line voltage and the DC voltage to the inductor. This causes the current of the inductor to increase or decrease at a rate determined by the net applied voltage. Because of the two sources of power, either a positive or negative voltage is available at any time for connection to the inductor. Modulation of the switches provides a time varying average voltage across the inductor that results in the desired time varying inductor current which, due to its series connection is also the AC line current. Applications of the controller include control of power factor, at unity or any desired lagging or leading level, neutralizing of harmonic line currents, and recovery of power generating externally of the controller by feeding regenerative current back to the AC power lines.

Optical voltage and current sensors used in a revenue metering system

Abstract: The authors discuss the development of an optical voltage sensor as part of an all optical sensor based revenue metering system. The magnetooptic or Faraday effect was used to implement a magnetooptic voltage transducer (MOVT) to measure voltage by sensing the current flow through a capacitor connected from a 161 kV transmission line to ground. The current sensor was a magnetooptic current transducer (MOCT) developed previously. The design of the voltage sensors using the magnetooptic effect allows the implementation of a revenue metering system using all optical sensors. This method of measuring voltage was previously unproven. The components of the all optical sensor revenue metering system, the site installation, and the data acquisition system used to monitor the system are described. Decisions leading to the design of the MOVT are discussed. >

Class-D BICMOS hearing aid output amplifier

Abstract: An invention, which is fabricated using a Bipolar and Complementary Metal Oxide Semiconductor (BICMOS) technology which offers both bipolar and CMOS devices on the same silicon substrate is disclosed. The major part of the internal circuitry uses bipolar devices while the output circuit driving the transducer at the output uses CMOS inverters. A voltage regulator which is fed from the battery lines is used to power the majority of the internal circuitry leaving only the CMOS output driver and part of a level converter to be powered directly from the battery lines. This architecture guarantees that no signal is fed back to the previous stages of the hearing aid system through the battery lines, ensuring stable operation for an extended range of the battery internal impedance value. The bipolar front-end blocks of the circuit are designed using low-voltage bipolar design techniques to operate at the 1 volt level produced by the internal voltage regulator. The voltage regulator employs a bipolar base-emitter voltage reference, which ensures the tracking of its output voltage with the headroom requirements of the bipolar circuitry over the temperature and process variations.

Integrated semiconductor memory with internal voltage booster of lesser dependency on power supply voltage

Abstract: A word-line drive voltage generation circuit for use in a dynamic random-access memory is disclosed which is connected to a word line via a row decoder including MOS transistors The circuit includes a charge-bootstrap capacitor having insulated electrodes, one of which is connected to a first reference voltage generator via a switching MOS transistor, and the other of which is connected via a MOS transistor to a second reference voltage generator These voltage generators provide the capacitor with the constant dc voltage that are essentially insensitive to variation in the power supply voltage for the memory The resultant word-line drive voltage may thus be free from variation in the power supply voltage during the operation modes of the memory This enables the word-line voltage to be high enough to allow successful "H" level writing at a selected memory cell without creation of any unwantedly increased dielectric breakdown therein, in the entire allowable range of the power supply voltage

X-ray power supply utilizing A.C. frequency conversion to generate a high D.C. voltage

Abstract: An output voltage of an A.C. power source is input to an frequency converter and the frequency thereof is increased. A plurality of high voltage transformers of small capacity each of which has a secondary winding of a small number of turns and which are connected in parallel with one another are connected to an output terminal of the frequency converter. Outputs of the high voltage transformers are respectively connected to high voltage rectifier circuits. Outputs of the high voltage rectifier circuits are serially coupled, the output voltages thereof are added together, and the addition result is applied to an X-ray tube. Combinations of the high voltage transformers and the high voltage rectifier circuits are molded into units one or a preset number at a time with solid insulating material including gel insulating material.

Multiple device control system

Abstract: A train communication and control system is described having the cars (A, B) of the train connected by a two-wire train line (14) running continuously from car to car. Any car may be selected to be a master unit. The selection of one car as a master unit disconnects the power sources (64) of all other cars from the train line, leaving the master unit power source as the sole power source for the line. The master unit (A) communicates with each other car by causing a high voltage ('mark' state or logic one) or a low voltage ('space' state or logic zero) to be on the train line (14). Each non-master car (B) can receive (46) a communication from the master unit, or can transmit (44) to another car by applying a low impedance across the train line to change from a 'mark' state to a 'space' state. The power source consists of a voltage regulator (40) with precision constant current limit. Output voltage is maintained substantially constant until a load greater than the rated current limit causes the power source to change to a substantially constant current regulator, whereby its regulated voltage falls rapidly to the 'space' state voltage.

Constant voltage generation of semiconductor device

Abstract: A constant voltage generator of a semiconductor device includes an oscillator for generating an AC signal, a charge pump for pumping charge from a power voltage supply line by a predetermined pumping ratio in accordance with the AC signal of the oscillator, a charge storage capacitor for storing the pumped charge, and a voltage limiter for limiting the voltage across the charge storage capacitor at a predetermined voltage level, then outputting a constant voltage. According to the present invention, the charge of the storage capacitor is quickly stored, a constant voltage is obtained independent of a power source voltage, and the reference voltage output can be greater than the power source voltage.

Control of three phase power supplies for ultra low THD

Abstract: Current regulators are proposed and investigated for high-power three-phase power supplies with ultra-low total harmonic distortion (THD) (less than 0.5%). Two valid approaches to realize three-phase power supplies can be proposed. In the first approach, current regulated pulse-width-modulated (PWM) inverters along with high bandwidth voltage control loops are proposed. In the second approach, an internal voltage synthesizer under closed loop current control is used. Both approaches have mechanisms to decouple the LC filter interactions and to lower the THD. The tradeoffs of these two basic approaches are investigated. The influence of different current regulators in case of the current-regulated PWM (CRPWM) converter is investigated as well as different approaches to control the voltage synthesizer under current control. The study compares the effectiveness of these current regulator in soft-switching PWM inverters and describes a method to measure accurately ultra-low THDs. >

Voltage regulator for variable speed permanent magnet alternators

Abstract: A voltage regulating system for a permanent magnet alternating current generator that has a rotor and a three phase Y-connected output winding. The system has first and second three phase full wave bridge rectifiers each comprised of a plurality of controlled rectifiers. The ends of the phase windings of the output winding are connected to the AC input terminals of the first bridge rectifier. The phase windings are connected to taps and these taps are located between the neutral and the ends of the phase windings. The taps are connected to the AC input terminals of the second bridge rectifier. The first bridge rectifier is enabled and the second bridge rectifier is disabled at speeds of rotation of the rotor below a predetermined speed. At rotor speeds above the predetermined speed, the first bridge rectifier is disabled and the second bridge rectifier is enabled.

AC stabilization using a low frequency zero created by a small internal capacitor, such as in a low drop-out voltage regulator

Abstract: AC stabilization and temperature compensation improves phase margin and permits high temperature (significantly above 125° C.) operation for an exemplary low drop-out voltage regulator with a PNP output transistor. The low drop-out voltage regulator (FIG. 1) includes a PNP output transistor (Q OUT ) together with a voltage reference circuit (12), a gain circuit (14), and a current limit circuit (16). To provide AC stabilization, a small internal capacitor (C INT ) of about 10 pF is coupled between the input of the gain circuit and the base of the output PNP, using Miller multiplication to substantially increase the effective capacitance of the stabilization capacitor, and introducing a zero into the gain-phase plot for the voltage regulator, substantially cancelling the pole, with a concomitant increase in phase margin. To provide temperature compensation, a dual-collector temperature compensation PNP (Q TC ) is configured as a current mirror current source that, at high temperatures with collector currents less than uncompensated or resistively compensated junction leakage currents, the temperature compensation PNP provides the required negative base drive to supply sufficient hole current into the base of the output PNP to offset junction leakage.

Cascaded switching and series regulators

Abstract: The voltage regulator of the boosting/lowering type is comprised of a switching regulator block and a series regulator block, which are cascade-connected to each other. One input terminal of an error amplifier of the switching regulator block is connected to a dividing node of bleeder resistors in the series regulator block to constitute a regulative feedback loop effective to improve an efficiency of the voltage regulator.

Device for supplying power to an electronic computer in a motor vehicle

Abstract: A device for supplying power to an electronic computer in a motor vehicle has first and second voltage regulators, operable independently of one another and having parallel inputs and outputs, and in which a desired output voltage is regulated downwards from an input voltage provided by a vehicle network. The first and second regulators each include at least one capacitive storage element at their inputs. A protective device is coupled to the inputs of the first and second regulators for connecting and disconnecting the first and second regulators from the input voltage. A voltage monitoring circuit is coupled to the first and second regulators and the protective device for detecting and evaluating the input voltage and includes at least one output each for individually controlling activation of the first and second regulators and the protective device. The voltage monitoring circuit includes circuit for controlling, as a function of an evaluation result of the input voltage: no activation of the first and second regulators in an input voltage range from zero up to a first limit; activation of the first regulator in the input voltage range exclusively between the first and a second limit; activation of the second regulator in the input voltage range exclusively between a third and a fourth limit, the third limit being below and the fourth limit above the second limit; and activation of the protective device above the fourth limit for disconnecting the first and second regulators from the input voltage to be regulated downwards.