Showing papers on "Voltage regulator published in 1987"

Survey of the Secondary Voltage Control in France : Present Realization and Investigations

Abstract: The voltage control of the french power system is organized in three hierarchical levels, which concern distinct geographical areas and time constants. The rapid and random variations are compensated by local primary and automatic actions on the generators A.V.Rs, then the slow variations are regulated by the secondary (at regional level) and tertiary (at national level) actions. The paper gives a review of the present regional secondary voltage control, and the prospects for the evolution towards a co-ordinated system, based on a sensitivity matrix model, closed-loop pole assignment and adaptive techniques. Analog and digital simulations are presented.

Automatic vehicle headlamp dimming control

Abstract: An automatic vehicle headlamp dimming control is the type having an operator controlled first voltage divider across a power supply, a light sensitive resistance connected in electrical series with an electrically controlled variable resistance in a second voltage divider across the output of the first voltage divider, an energizing circuit adapted to energize the headlamp system from the power supply at high or low intensity in response to the output of the second voltage divider compared to a fixed reference voltage and first electric feedback means from the energizing circuit to the electrically controlled variable resistance for producing hysteresis feedback. The invention adds to this control a resistance between the output of the first voltage divider and the second divider to decouple the same, a capacitor in series with the second voltage divider and supply voltage, and second electric feedback means from the energizing circuit to the junction of the capacitor and second voltage divider for causing charging and discharging of the capacitor with switching between high and low headlamp intensity to produce a gradual change in the output of the second voltage divider counter to the hysteresis feedback. The circuit helps reduce the undesirable sensitivity effects of hysteresis feedback, photocell memory and misaligned sensors or headlamps.

Low Frequency Oscillations in Longitudinal Power Systems: Experience with Dynamic Stability of Taiwan Power System

Abstract: Sustained low frequency oscillations have been observed in Taiwan power system which is of longitudinal structure. It is the purpose of this paper to examine the various factors affecting the damping characteristics of these oscillations which caused dynamic instability problem in the operation of Taiwan power system. It is observed that the amount of power flow on the EHV transmission line and the characteristics of load have a significant effect on the damping of the system while the speed-governing system and the gain of automatic voltage regulator have only a minor one. Detailed investigation using both the frequency domain and time domain approaches also reveals that power system stabilizers can be employed as an effective means for improving dynamic stability of Taiwan power system.

Automatic control means providing a low-power responsive signal, particularly for initiating data preservation operation

Abstract: In a system including volatile memory, a battery backed memory may be available for preserving data in the event of a power failure. Low power condition is reliably sensed sufficiently in advance of supply voltage falling below a minimum operating voltage range so as to give an adequate time interval, e.g. 2.5 milliseconds for the saving of application operating system status. By using a voltage regulator signal which switches in a particularly sensitive manner toward a saturation or zero state well outside its normal control range to trigger a low power signal, such low power signal may provide a time interval of, e.g. from three to six milliseconds of advance warning of impending supply voltage failure. The system is particularly useful for hand-held data processing systems with rechargeable batteries since the regulator may provide its regulator signal as a common control signal for regulating multiple supply paths, and may only trigger the low power signal when all of such supply paths approach a failure condition.

Dual input low dropout voltage regulator

Abstract: A low dropout voltage regulator with a switched redundant input, which has low dropout voltage before, during, and after a switch to the redundant input. In a preferred embodiment, the inventive voltage regulator includes two transistors that are controlled by the output of an error amplifier, and redundant input voltage sources. A first one of the transistors conducts when a first input voltage is greater than a second input voltage. The other transistor conducts when the second input voltage exceeds the first input voltage. When both input voltages are have substantially equal magnitude, both transistors conduct. In a preferred embodiment, one input voltage is supplied by a battery, and the other is supplied by a storage capacitor charged by the battery. When the battery fails, the storage capacitor will discharge, thus serving as a time-varying redundant voltage source in the event of battery failure.

A 580 kHz switching regulator using on-off control

Abstract: The analysis and design of a 580 kHz switching regulator incorporating a series-resonant converter is described. On-off control is used in the feedback loop of the regulator to achieve regulation of the output voltage. An easy-to-use graphical method of analysis of transient currents is introduced as a tool for the analysis and design of the regulator. The 40W regulator circuit which has been built shows exceptionally good transient load regulation and high efficiency.

A new on-chip converter for submicrometer high-density DRAMs

Abstract: The converter described is a feedback-type voltage regulator which supplies a reduced voltage to an entire RAM circuit. A novel timing activation method was introduced to save power. The converter has been implemented on an experimental 4-Mb dynamic RAM. It was found that an even faster access time and higher reliability compared to a conventional design could be achieved by using an on-chip voltage converter and shorter channel transistors. This voltage converter is suitable for high-density, high-speed, and high-reliability DRAMs with submicrometer transistors.

A Josephson array voltage standard at 10 V

Abstract: The technology of Josephson voltage standards has been extended to an array of 14 184 junctions which is capable of generating over 150 000 quantized voltage levels spanning the range from -12 to +12 V. This makes possible the direct calibration of 10-V Zener reference standards without the use of a voltage divider.

Power regulator for a contactless credit card system

Abstract: 1 A power transfer arrangement provides regulated power transfer from a station to a contactless portable data card without the need for regulation circuitry on the card itself. The station includes a primary coil for magnetically coupling power to a secondary coil, located on the card, when the data card is brought into close association with the station. The arrangement includes a microprocessor, a power amplifier including the primary coil, a variable voltage source and apparatus for measuring current flow in the primary coil. When the portable data card is not in close association with the station, the microprocessor causes the variable voltage source to provide a sequence of stepped voltages. Quiescent current flow is measured at each step and stored in memory. When the portable data card is brought into close association with the station, the microprocessor causes the variable voltage source to provide a sequence of stepped voltages. Active current flow is measured at each step and stored in memory. Power delivered to the data card is calculated as the difference between active and quiescent currents multiplied by the magnitude of the variable voltage source. The sequence of active current measurements continues until the calculated value of power delivered to the data card exceeds a predetermined threshold power, at which time the data card is receiving a precise, predetermined amount of power.

Power supply voltage level sensing circuit

Abstract: A power supply voltage level sensing circuit on an integrated circuit generates a reset signal that holds the components of the integrated circuit in a defined state when the power supply voltage level drops below a predetermined voltage. The reset signal is released when the power supply voltage level returns to above the predetermined voltage. The voltage level sensing circuit is comprised of two inverters and a filter circuit. The inverters start to conduct at different power supply voltage levels and have different trigger point characteristics. The power supply voltage level sensing circuit may be coupled with a power-on reset circuit to create a voltage sensing power-on reset circuit which generates a reset signal not only when the power supply voltage is first supplied to the circuit, but also when the power supply voltage level temporarily falls below a selected value.

Inrush-current limiter for switching regulator power supply

Abstract: A DC voltage power supply circuit for suppressing turn-on transients applied to a switching voltage regulator circuit includes a relatively high impedance current suppression element connected in series between a rectifier circuit and a capacitive load, means for sensing a voltage drop developed across the suppression element, a diode network for developing a reference potential, and a silicon-controlled rectifier having a gate electrode responsive to the voltage drop developed across the current suppression element and the reference potential developed across the diode, for energizing a relay having contacts for disabling the switching regulator from supplying the load during the initial turn-on phase, and for shunting the current suppression element and activating the switching regulator after the capacitive load is substantially charged.

Vehicular power supply system having a plurality of power supply voltages

Abstract: A vehicular power supply system having a plurality of power supply voltages comprises a generator including first and second armature windings electrically isolated from each other and a field winding, a first rectifier unit converting a first a.c. output of the first armature windings into a first d.c. voltage, a second rectifier unit converting a second a.c. output of the second armature windings into a second d.c. voltage, a first battery connected to an output terminal of the first rectifier unit, a second battery connected in series with the first battery and connected also to an output terminal of the second rectifier unit, a first voltage regulator detecting the terminal voltage of the first battery thereby controlling current supplied to the field winding of the generator, a second voltage regulator detecting a mean voltage of the second battery thereby controlling on-off of a power switching element connected between the second battery and the second rectifier unit, the second voltage regulator acting to decrease the conduction ratio of the power switching element when the mean voltage of the second battery is high but to increase the conduction ratio when the mean voltage is low.

Output impedance considerations for switching regulators with current-injected control

Abstract: The output Impedance of current-Injected controlled (CIC) buck regulators can be significantly reduced by deriving the current control signal from the output capacitor Instead of the Inductor. This technique Is shown to be mathematically equivalent to CIC with load-current feedforward. Performance comparisons with normally Implemented CIC and voltage control are given.

Automatic gain control circuit for controlling gain of video signal in television receiver

Abstract: An intermediate-frequency automatic gain control circuit generates an IFAGC voltage for controlling the gain of an IF amplifier, in accordance with the level of the output signal of the IF amplifier. An RFAGC voltage provides a voltage for controlling the gain of an RF amplifier of a tuner, in accordance with the IFAGC voltage level. The output voltage of the RFAGC circuit is supplied to a time-constant circuit made up of a series circuit including first and second resistors and a first capacitor, and a second capacitor connected in parallel with the series circuit. The time-constant circuit is connected to a time-constant control circuit made up of first and second diodes connected in parallel with the second resistor. When the output voltage level of the RFAGC circuit increases or decreases above or below the diode voltage, the first or second diode is conductive, to decrease the time constant of the time constant circuit. An RFAGC voltage for controlling the gain of the RF amplifier of the tuner is derived from the node between the second resistor and the first capacitor.

Power regulator utilizing only battery current monitoring

Abstract: For a power system having a single maximum power point and varying loads, the present invention provides a power regulator which adjusts the operating point of one source as a function of only the sensed current conditions of the secondary source. In the preferred embodiment, a solar array is controlled by a regulator which determines whether the battery is properly charging. Upon the occurrence of an undercharging condition, the array operating point is adjusted so as to minimize undercharge current. Upon the occurrence of a charging condition, the operating point is adjusted so as to continue battery charging according to predetermined limits.

A light-activated light valve with a silicon control element

Abstract: In contrast to existing light addressed light valves for projection displays which use a homogeneous CdS or Se photoconductive layer as the control element for a liquid crystal cell, a silicon photo-diode array is disclosed which makes an effective control element capable of applying a spatially varying AC voltage across a liquid crystal light valve. Writing may be done with a miniature CRT in an optical or electron excitation mode. It is shown that for a video mode the ratio of diode capacitance to liquid crystal cell capacitance associated with the diode, and the frequency of the applied square wave voltage, define the buildup or decay time of the liquid crystal cell voltage. Thus, the frequency of the applied AC voltage can be used to control sensitivity and transient response and there is no lag. The dynamic range of the cell voltage is shown to depend on the ratio of diode capacitance to liquid crystal cell capacitance. The display can be used in a storage mode by erasing with an AC voltage and writing with a constant voltage. The silicon photodiode array is compatible with a CCD frame store using direct minority carrer injection for writing. This light addressed version thus represents a desirable milestone in achieving an all solid-state projection display.

Variable speed constant frequency power system with boost converter auxiliary output

Abstract: A DC link variable speed constant frequency power system is provided with a voltage boost circuit connected to receive voltage from a pair of DC link conductors and to supply voltage to an auxiliary supply bus. During normal system operation, the voltage boost circuit transfers the DC link voltage to the auxiliary supply bus. When a system fault occurs, such that the DC link voltage is reduced, the voltage boost circuit is activated to boost the reduced DC link voltage level and supply that boosted voltage level to the auxiliary supply bus.

On-chip high voltage generator and regulator in an integrated circuit

Abstract: An EEPROM constructed in accordance with our invention includes a voltage multiplier for generating an erase voltage and a voltage regulator circuit for controlling the magnitude of the erase voltage. The voltage regulator circuit includes a capacitive voltage divider for providing a first voltage proportional to the erase voltage, a reference voltage lead for providing a reference voltage and a control circuit for controlling the voltage multipler circuit so that if the first voltage is less than the reference voltage, the voltage multiplier circuit will increase the erase voltage, but if the first voltage is greater than the reference voltage, the voltage multiplier will not continue to increase the erase voltage. The voltage multiplier includes novel capacitors and transistors constructed using standard EEPROM processing to withstand high voltages without breaking down.

Output hold-up circuit for a step-up voltage regulator

Abstract: An arrangement for enhancing the available energy storage capability of a hold-up energy storage element for use with the step-up or boost regulator stage of a power supply enables use of smaller hold-up storage elements, such as capacitors. The circuit stores energy at the boost regulator output and returns the energy either to the regulator input in the event of a transient line failure, or to the regulator output during a load transient. The invention provides improved transient fault tolerance by increasing the hold-up time of the storage element.

Apparatus for improving the efficiency of a lighting element

Abstract: A voltage reduction unit for reducing the voltage supplied to a lighting element to a prescribed value and for maintaining the prescribed voltage across the lighting element independently of the current flowing through it A lighting element is connected in series with a current switch, and the current switch is controlled by a voltage/current control unit which monitors the lighting element for changes and voltage and current characteristics The voltage/current control unit comprises a differentiator circuit for detecting a slope of an AC voltage waveform and a comparator circuit for detecting a prescribed voltage on the waveform The voltage/current control unit allows current to flow through the lighting element when both a first prescribed voltage and a prescribed voltage slope of the voltage waveform is detected, and it inhibits current flow through the lighting element when a second prescribed voltage is detected A signaling circuit receives signals from the comparator circuit and the differentiator circuit, and it communicates switching signals to the current switch for rendering the current switch conductive when signals representing the prescribed voltage and slope of the voltage waveform occur When the comparator detects the second prescribed voltage, it emits a second signal, and the signaling unit, in turn, communicates a signal for turning off the current switch

Ac generator for vehicle

Abstract: PURPOSE:To increase an output from a generator by boosting and rectifying one part of an output from an armature coil and supplying an exciting coil with one part of the output. CONSTITUTION:A boosting and rectifying circuit 5 is connected in parallel with a main rectifier circuit 2 to a three-phase armature coil 1. The circuit 5 consists of auxiliary diodes 6a-6c and capacitors 7a, 7b, 8a, 8b, 9a, 9b, and constitutes a voltage doulbing rectifier circuit. An output from the boosting and rectifying circuit 5 is connected to an exciting coil 10. Another side of the exciting coil 10 is connected to a voltage regulator 11 for controlling exciting currents and adjusting output voltage from a generator at fixed voltage. Accordingly, exciting currents can be increased, thus elevating an output.

Universal regulator for maximising the power of photovoltaic electrical power supplies and for high-efficiency DC/DC voltage converters

Abstract: This regulator increases the output power of photovoltaic modules exactly to that output voltage (battery charging voltage) which is just required even when the solar radiation is weak, and at the same time keeps the solar module very close to the characteristic point of maximum energy yield (Maximum Power Tracking, MPT). Inflating of the number of solar cells is superfluous, that is to say 20-30% of the investment costs are saved. Use of a single, very simple circuit results in: MPT plus charging regulator with overload protection and deep-discharge protection - without any reductions in efficiency, which can be 100% in the case of full solar radiation and approximately 98% in the case of weak solar radiation. The trick is to reverse the principle of the voltage-reducing in-phase regulator: a voltage source (negative impedance) which is controlled by the output voltage and is supplied from the solar module is used instead of a regulating resistor, which consumes energy. The voltage from said solar module, which is controlled automatically, is added to the module voltage. The circuit is generally suitable for any variable DC voltage source, for achieving constant (or controlled) output voltages at high efficiency and at low cost.

Program clock for an electronic demand register with automatic calibration based on sensed line frequency

Abstract: An electronic demand register includes a microprocessor including a program clock for performing timekeeping functions for the register. A power supply connected across the AC voltage source provides power to the microprocessor through a voltage regulator. The program clock is maintained by the line frequency of the AC source. Electronic circuits are provided for calibrating the program clock to be compatible with either a 50 Hz or a 60 Hz line frequency. A detection signal corresponding to the line frequency is generated by a line frequency detector circuit in the power supply. A reference signal is generated by a quartz crystal clock. A frequency comparator circuit includes a microprocessor program that measures the time period between detection signal pulses. This time period is compared to the known period of a 50 Hz or a 60 Hz signal and respective counters are incremented accordingly. The microprocessor and program clock operating parameters are established for either 50 Hz of 60 Hz operation when one of the counters has reached a value of five, indicating that five zero crossings have been detected at the particular frequency. The electronic demand register also comprises a display including an array of LCD segments for continuous simultaneous display of the time and date. The display also includes an array of LCD segments, arranged in a pattern, that are sequentially illuminated corresponding to the rate of rotation of the shutter disk of the pulse initiator.

Circuit arrangement for producing high voltages

Abstract: In a circuit arrangement for producing high voltages by means of a voltage multiplier with rectifiers and capacitors and fed from an alternating current source in which circuit arrangement, a low amplitude voltage lying at the high voltage level is produced by the ripple voltage across one or more of the component parts of the voltage multiplier, the average potential of which component part (s) does not differ substantially from the high voltage. In the case of an X-ray tube high voltage supply the total filament circuit may be approximately on the high cathode voltage and no severe requirements for insulation need to be fulfilled. The ripple voltage may be used to produce other small amplitude voltages lying at a high voltage level.

Digital-to-time converter

Abstract: A monolithic integrated circuit generates a programmable time delay under control of a digital word. The delay is generated by comparing a ramp signal to a threshold determined by the value of the digital word and appears as a time difference between a trigger pulse and a pulse generated when the value of the ramp voltage equals the value of the threshold voltage. The ramp voltage is generated by a simple resistance/capacitance charging circuit whose time constant can be adjusted by the user. The threshold voltage is set by a digital-to-analog converter (DAC) and resistor circuit which converts the digital control word into a variable voltage. In order to stabilize the device against changes in temperature and power supply variations, a voltage coupling circuit forces the threshold voltage to track changes in the ramp voltage caused by temperature and power supply variations. The coupling circuit obviates the need for precision voltage sources or current mirrors conventionally used to compensate for temperature and power supply changes. Without the need for the latter devices, the integrated circuit can be easily and inexpensively fabricated of transistors of a single bipolar type.

High DC voltage power supply for motor vehicle electrical system

Abstract: A high DC voltage power supply includes a three-phase autotransformer and a three-phase full-wave rectifier applied to the usual motor vehicle electrical system of the low DC voltage type. The low three-phase AC voltage of the usual system is transformed by the autotransformer to obtain a high three-phase AC voltage which is then rectified by the rectifier to provide a high DC voltage. The load energized by the high DC voltage is ungrounded to reduce the voltage available for inadvertent discharge from either load terminal to ground. Switching apparatus is provided for selectively applying the low three-phase AC voltage to the autotransformer only when it is desired to energize the load thereby avoiding at all other times the energy losses that would otherwise be associated with energization of the autotransformer. In one embodiment, the load is a windshield heater element and the autotransformer has multiple sets of input taps to provide deice and defog modes of operation, respectively. The tapping of the autotransformer on the input or primary side yields efficiencies in the construction and operation of the autotransformer. The engine driven generator of the vehicle electrical system is excited from a voltage source independent of the low three-phase AC voltage put out by the generator, at least during any period that the generator is overloaded, thereby to prevent a degenerative collapse in the generator output voltage.

Apparatus for processing vegetable raw material

Abstract: An apparatus for processing a vegetable raw material comprises a casing mounted on shock absorbers and accommodating a drum having pins, electrodes and a control electrode connected to a relay. The apparatus also comprises a power regulator connected to the relay output and an input of a voltage regulator. The relay and voltage regulator are connected to the three-phase power supply. Each output of the voltage regulator is connected to a respective electrode.

Power voltage regulator circuit.

Abstract: A power voltage regulator circuit has a power terminal (VDD) to which an external power voltage is supplied, an output line (Ll), and a voltage-drop circuit (48) connected between the power terminal (VDD) and the output line (Ll). The voltage drop circuit (48) includes an N-channel MOS transistor (Tl) having a drain connected to the power terminal (VDD) and a source connected to the output line (Ll), a constant voltage generator (52) for supplying a voltage, lower than the external power voltage, to a gate of the MOS transistor, and a semiconductor well (72-l) whose surface area serves as a channel region of the MOS transistor (Tl).

CMOS substrate charge pump voltage regulator

Abstract: A substrate bias voltage regulator (10) is disclosed having a voltage divider (22) for generating a reference voltage, a low gain stage (24) for developing a drive voltage independent of the supply voltage (V cc ) and for driving a current source/mirror circuit (26). The current source/mirror circuit (26) operates in conjunction with a current sink circuit (30) for providing a logic output of the regulator (10) for controlling a substrate charge pump circuit (18). Connected to the current sink circuit (30) is a compensation circuit (32) for adjusting the drive to the current sink circuit (30) in response to transistor threshold voltage and temperature considerations.