Showing papers on "Voltage regulator published in 1978"

Solid state lamp

Abstract: An integrated circuit chip containing one or more light-emitting diodes is mounted within a light-diffusing encasement having a standard incandescent light bulb lamp base. The integrated circuit chip also contains a rectifier and voltage regulator circuit. The resulting solid state lamp may then be used to replace any standard incandescent light bulb, as it can be inserted in any existing standard A.C. or D.C. lamp sockets. The encasement may be a standard hollow light bulb, or, for maximum light diffusion, a solid transparent or translucent plastic in which the chip is embedded.

Modelling, analyses and design of switching converters

Abstract: A state-space averaging method for modelling switching dc-to-dc converters for both continuous and discontinuous conduction mode is developed. In each case the starting point is the unified state-space representation, and the end result is a complete linear circuit model, for each conduction mode, which correctly represents all essential features, namely, the input, output, and transfer properties (static dc as well as dynamic ac small-signal). While the method is generally applicable to any switching converter, it is extensively illustrated for the three common power stages (buck, boost, and buck-boost). The results for these converters are then easily tabulated owing to the fixed equivalent circuit topology of their canonical circuit model. The insights that emerge from the general state-space modelling approach lead to the design of new converter topologies through the study of generic properties of the cascade connection of basic buck and boost converters.

Temperature compensated avalanche photodiode optical receiver circuit

Abstract: A photodiode receiver circuit having self-contained automatic gain control and which is temperature compensated over a wide operating range contains a resistor coupled in series between a bias power supply and one end of an avalanche photodiode. Self-generated AGC action results from the fact that the gain of an avalanche photodiode increases as the bias voltage applied across the diode increases. As the light intensity received by the diode increases, there is a corresponding increase in the current flow through the diode and the series-connected resistor. The consequential increase in IR drop across the resistor decreases the bias voltage across the diode, so that the gain of the diode is reduced. Through this action, the dynamic range of optical input of the photodiode will be increased for a fixed dynamic range of electrical output. Temperature compensation is achieved by coupling a temperature-sensitive voltage divider circuit between the bias voltage supply and the gain-controlling resistor. This voltage divider network may include a thermistor coupled in parallel with one resistor component of a resistor divider that is connected to a bias voltage source. The value of the parallel resistor is chosen to match the thermistor's characteristic to the voltage versus temperature characteristic of the APD so that a temperature-compensated bias voltage reference, to which the gain-controlling resistor is connected, is available over a wide temperature range (e.g. -40° C. to +60° C.). This temperature compensation allows the avalanche photodiode to be operated at a nearly constant available gain across this range and prevents the diode from being damaged by too high a bias voltage.

Low voltage techniques

Abstract: Techniques for the design of linear ICs, capable of operating from a single nickel-cadmium cell (> 1.1V) will be presented. Results can be achieved without compromising performance or operation at higher voltages. Emphasis will be on micropower, though not at the expense of output drive.

Fast-decoupled three-phase load flow

Abstract: Using as a reference the single-phase fast-decoupled algorithm, this paper describes the modifications required to produce an efficient three-phase fast-decoupled load flow. The compound-coil concept is used in the representation of power-system components, and the effect of automatic voltage regulators is modelled as part of the reactive-power Jacobian-matrix equation. It is shown that the three-phase modified fast-decoupled load flow displays all the characteristics of the original single-phase version.

Temperature compensated bandgap IC voltage references

Abstract: Bandgap voltage reference circuits have been developed for integrated circuit applications. Typically, a negative temperature coefficient first voltage is developed related to the base to emitter potential of a transistor. A positive temperature coefficient second voltage related to the difference in base to emitter potential between two transistors operating at different current densities is developed and combined with the first voltage so as to produce a temperature compensated reference voltage. Such first order compensation leaves second order effects uncompensated. In the invention, a third voltage having a suitable temperature coefficient is combined with the first and second voltages so that the resultant reference voltage is compensated to a second order.

Application of a Static VAR System to Regulate System Voltage in Western Nebraska

Abstract: Basin Electric Power Cooperative will commission a Static Var System (SVS) in late 1977 to provide automatic, continuous voltage control on a 115 kV network in western Nebraska. This paper describes engineering studies which were conducted to select the SVS rating and site, determine harmonic filtering requirements, synthesize the SVS voltage regulator characteristics and to simulate the steady-state and dynamic performance of the SVS. The studies have shown that the SVS will perform as intended to regulate the steady-state voltage within ±0.5% and reduce post-fault voltage swings which otherwise might cause important motor loads to trip off line.

Automatic dual mode battery charger

Abstract: This invention relates to automatic dual mode battery charging circuit which includes rectifying means and an adjustable voltage rectifier energized by the rectifying means and providing an output to a battery to be charged. The circuit includes a voltage controller connected to the voltage regulator means to set the level of voltage output from the voltage regulator and hence the charging current to the battery. The voltage regulating means provides two modes of operation, namely, a fast charge and a float mode of operation. A current detector connecting in series circuit with the voltage regulator and the battery provides a means for detecting current flow through the battery and controls the operation of the voltage controller, to change the output of the voltage regulating means between the two modes of operation.

Master-slave voltage regulator employing pulse width modulation

Abstract: A pulse width modulation (PWM) converter circuit for transforming a first DC voltage into a secondvoltage (AC or DC), wherein the magnitude of the second voltage is regulated by the converter circuit. The converter circuit comprises a clock circuit, a master pulse width modulator (PWM) circuit and n slave pulse width modulator (PWM) circuits. The clock circuit provides a symmetrical train of rectangular pulses on each of n+1 conductors, wherein only one pulse occurs on any one of the conductors at one time. The master PWM means is responsive both to the train of pulses on one of the n+1 conductors and to a feedback signal indicative of the magnitude of the second voltage; the master PWM means controls the flow of current, due to the first DC voltage, through a portion of a transformer primary winding. Each of the slave PWM circuits is responsive both to the train of pulses on n of the n+1 conductors, in a one-to-one relationship, and to an output control signal based both upon the feedback signal, indicative of the magnitude of the second voltage, and upon the difference in the magnitude of the charge passed by the master PWM circuit and the charge passed by the respective slave PWM circuits; each of the slave PWM circuits controls the flow of current, due to the first DC voltage, through a portion of the transformer primary winding.

Condition responsive battery charging circuit

Abstract: A battery charging circuit includes a ferroresonant transformer having a rectified output for providing a constant output voltage to be supplied to a battery to be charged. Battery temperature is sensed providing an input to a control circuit which operates a shunt regulator associated with the ferroresonant transformer to provide battery charge voltage as a function of battery temperature. In response to a high battery temperature the controller functions to lower the output voltage to the battery, and in response to a low battery temperature, operates to provide a higher output voltage, with suitable control for any battery temperature between minus 10° and plus 150° Fahrenheit. As the battery approaches full charge and battery acceptance current falls below a predetermined level, a charge cycle termination control allows charging to continue for a period preset by the operator, at the end of which period, line voltage is removed from the charger thereby terminating the charge cycle.

Method for reducing fuel cell output voltage to permit low power operation

Abstract: Fuel cell performance is degraded by recycling a portion of the cathode exhaust through the cells and, if necessary, also reducing the total air flow to the cells for the purpose of permitting operation below a power level which would otherwise result in excessive voltage.

Temperature compensated bandgap voltage reference circuit

Abstract: A pair of transistors, connected as a differential amplifier, is operated so that the transistors run at different current densities. A voltage divider is coupled across a pair of circuit terminals so that a portion of the terminal voltage is coupled to and used to differentially bias the transistors. An amplifier, responsive to the transistors differential output, and coupled to the divider, is used to vary the terminal voltage to force the differential output to zero. The transistor bias voltage thus generated has a positive temperature coefficient of voltage. A forward biased diode, which has a negative temperature coefficient of voltage, is also incorporated into the divider. When the terminal voltage is made equal to the semiconductor bandgap, the two temperature sensitive terms cancel to compensate the reference voltage.

Active filter circuit for regulated dc to dc power supplies

Abstract: A regulated DC to DC power supply which minimizes input bus current changes caused by low frequency cyclical load variations is disclosed. The power supply includes a regulator connected to the input bus and controlled by a pulse width modulator. The regulator converts the DC voltage on the input bus to a higher, regulated DC voltage which is supplied to a variable load. A voltage feedback circuit is connected to the output of the boost converter and generates a control voltage which is supplied to the pulse width modulator to regulate the output voltage for variations in line voltage and load. The voltage feedback circuit includes an operational amplifier having a reference voltage supplied to a positive input terminal, and the output of the regulator supplied to a negative input terminal. A frequency response shaping network is connected between the output and the negative input terminal of the operational amplifier. An input bus current-sensing servo circuit is connected to sense current variations in the input bus and generate a control signal to the pulse width modulator to regulate the input current of the regulator. The input bus current-sensing servo circuit also includes an operational amplifier and an RC frequency response shaping network. The two frequency response shaping networks are designed such that, for a variable load which exhibits a given low frequency cyclical power change, the voltage feedback circuit generates a control signal for voltage variations below the given low frequency, but the input bus current-sensing servo circuit generates a control signal for changes having a predetermined frequency range including the given low frequency.

Selectively adjustable voltage detection integrated circuit

Abstract: A voltage detection integrated circuit including a voltage regulation circuit for controlling the operation thereof is provided. The voltage detection integrated circuit includes a reference voltage circuit for producing a predetermined reference voltage, a voltage converter for converting a detected voltage for measurement and a comparator circuit for comparing the level of the reference voltage to the level of the converted voltage and for producing a comparison signal representative of the difference in voltage levels compared thereby. The voltage regulation circuit is coupled to the comparator circuit and the reference voltage circuit and/or voltage conversion circuit for selectively adjusting the level of the reference voltage produced by the reference voltage circuit and/or the converted voltage produced by the voltage converter, to thereby control the comparison signal produced by the comparator circuit.

Control circuit for use in a switching-type regulator

Abstract: A control circuit is disclosed for use in a switching-type regulator which includes a source of unregulated DC voltage, a switching circuit for interrupting the unregulated DC voltage to produce an AC voltage having a duty cycle which is a function of the operation of the switching circuit, a converter for converting the AC voltage to a regulated DC voltage, a controllable pulse generator for supplying pulses of controllable duration to the switching circuit so as to determine the duty cycle of the AC voltage, a feedback circuit responsive to variations in the regulated DC voltage for controlling the duration of the generated pulses to maintain the regulated DC voltage at a desired level, and disabling circuit for selectively limiting the operation of the pulse generator. The control circuit is used to reset the disabling circuit to an initial state and to change gradually the duration of the pulses which are generated by the pulse generator when the regulator first is turned ON. By resetting the disabling circuit, there is no limitation on the operation of the pulse generator at the outset. By gradually increasing the duration of the pulses generated by the pulse generator, the so-called "soft start" operation is performed, whereby the regulated DC voltage gradually is increased from a zero level to its desired level. The control circuit includes a voltage generator for generating a control voltage which increases rapidly during an initial interval and then increases at a significantly slower rate after it attains a first level. The disabling circuit is reset when the control voltage reaches its first level; and when the control voltage thereafter increases at a much slower rate, the slowly-increasing control voltage is used to correspondingly increase the duration of the generated pulses, whereby the level of the regulated DC voltage likewise increases.

Regulator circuit for photographic illumination

Abstract: An electrical regulator for operating a photographic illuminating lamp provides two controls on the triggering of a phase-controlled power switch. One control employs a differential switch in a feed-forward loop that adjusts the potential at which a timing capacitor triggers the power switch. The other control is a feedback loop which controls the rate at which the timing capacitor is charged. The regulator combines the feed-forward and feedback controls to regulate the mean square of the lamp voltage for a wide range of input voltage amplitudes and frequency.

Battery back-up regulator

Abstract: In an energization circuit for a memory module, the primary energization is derived from a primary power supply source fed through an isolating diode to a regulating circuit. The regulating circuit includes a series regulator device such as a darlington amplifier. A voltage detector module is provided which is characterized in very accurate operation while drawing a negligible amount of current for its own operation. The output of the voltage detector is used to control the operation of the series regulator. A stand-by, or back-up, power supply, which may be a battery is connected to the regulator circuit through a further isolating diode. The sensing circuit for the voltage detector module is so arranged that, when the primary power supply is operational, one level of output voltage for the regulator will be required to effect a controlled operation of the voltage detector; and when the back-up power supply is operational, a different voltage level output signal is required to effect a corresponding control of the voltage detector module.

Method and apparatus for saving energy

Abstract: A method and apparatus for regulating the output flux generated by a lamp with the degeneration of the voltage from a power source such as a battery. The regulating circuit maintains a constant luminous flux output from a lamp over a substantial range of voltages by switching the voltage to the lamp on and off at a preselected and controlled duty cycle. The power pulses applied to the lamp have heights that vary directly as the voltage variations of the power source and widths that vary as the inverse square of the voltage from the power source for maintaining a constant RMS voltage on the lamp and thereby constant light output flux.

Cross regulation in a two-output DC-to-DC converter with application to testing of energy-storage transformers

Abstract: Cross regulation is a technique for providing multiple regulated output voltages from an energystorage dc-to-dc converter where only one of the outputs is actually sensed by the controller and regulated to the desired value. The regulation of the remaining output voltages depends on the magnetic coupling between the multiple secondary windings of the energy-storage transformer. This paper extends the analysis of [l] by examining the cross regulation performance of a two-output voltage step-up/current step-up dc-to-dc converter operating in the continuous mmf mode under constant-frequency control. The analysis is shown to be a useful tool for generating test specifications for screening energy-storage transformers to guarantee that the leakage flux associated with the transformers does not prevent the converter from providing adequate cross regulation.

Noise Generation of a Switching Regulator

Abstract: Analytical and experimental considerations on the surge and noise generated in a typical switching regulator are discussed. There are two kinds of surges which occur in the switching instants of the transistor. These surges appear as high voltages across the semiconductor elements and decrease their reliabilities. Corresponding to the surge generation, noise voltages appear in the output terminals and may induce malfunctions of a signal processing device connected to the regulator. We analyze these surge and noise voltages by means of high-frequency equivalent circuits.

FET Voltage level detecting circuit

Abstract: There is provided a voltage level detecting circuit useful as power-up/power-down voltage indicator for a field effect transistor integrated circuit. A constant voltage reference generator is provided by a depletion type transistor in series with two enhancement type transistors coupled between power supply terminals of the integrated circuit chip. Each of the enhancement type transistors have their gate electrodes connected to their drain electrodes while the depletion type transistor has its gate electrode connected to the more negative or reference terminal of the power supply voltage. A constant voltage output is taken from between the junction of one of the enhancement mode transistors and the depletion type transistor. This constant voltage output can be compared against a voltage obtained from a voltage divider circuit which provides an output that varies in accordance with variations in the power supply. The voltage level detector circuit is particularly useful in microprocessors and microcomputer integrated circuit chips.

Voltage regulator which eliminates arcing during tap changes

Abstract: A tap changer voltage regulator permits a tap changer switch selector contact to engage an open circuited new tap without arcing and has a half-tap voltage auxiliary winding which permits halving the voltage being interrupted and doubling the number of steps and also has an auxiliary switch with a first movable contact which initially connects the selector contact on the new tap in series with a circulating current limiting inductor and the load to prevent load circuit interruption and is provided with a second movable contact in series with a pair of normally closed contacts through which flow the load current and the current which circulates while the selector contacts bridge adjacent taps during the tap change. The normally closed contacts are shunted by a pair of inverse parallel thyristors. The auxiliary switch then opens its normally closed contacts to transfer the current to the thyristors and subsequently removes gating current from the thyristors so that load and circulating current are statically interrupted by one of the thyristors at current zero, thereby permitting the second movable contact to arclessly interrupt the circuit to the selector contact on the previous tap to complete the tap change.

DC power supply circuit

Abstract: A dc power supply circuit for supplying simultaneously dc voltages to a dc load and to a standby battery employed to power the load upon a loss of dc power to the load. The load is adapted to draw varying amounts of current. The dc power supply circuit in accordance with the invention includes a capacitor which is arranged to retain a dc voltage derived from an ac voltage. A fixed voltage regulator circuit coupled to the capacitor operates to supply a fixed dc voltage to the load and to maintain this voltage as the current drawn by the load varies. An adjustable voltage regulator circuit coupled to the capacitor operates to supply a varying dc voltage to the battery as the current drawn by the load varies. The varying voltage of the adjustable voltage regulator circuit is achieved by a current sensing resistor which senses the current drawn jointly by the load and the battery and which causes control circuitry coupled to the adjustable voltage regulator circuit to vary the dc voltage thereof in accordance with variations in the current sensed by the current sensing resistor. In accordance with the invention, the current drawn jointly by the load and battery is limited to a predetermined maximum amount, for example, one ampere, with the load being supplied first and at all times with its needed current and the difference between the current drawn by the load at any given instant and one ampere being made available to the battery.

Electrical mean square voltage sensor

Abstract: A sensor for producing an electrical signal parameter responsive to the mean square of an applied alternating voltage has a rectifier element, and has a zener diode element electrically in series with a light-emitting diode element across the direct voltage which the rectifier element produces. The polarity of the direct voltage applies reverse voltage to the zener diode element and applies forward voltage to the light-emitting diode element. A photoconductor is optically coupled to receive electroluminescense which the light-emitting diode element emits.

Dual voltage regulator with low voltage shutdown

Abstract: A method and apparatus for controlling the various functions of an internal combustion engine using a program-controlled microprocessor having a memory preprogrammed with various control laws and associated control schedules receives information concerning one or more engine-operating parameters such as manifold pressure, throttle position, engine coolant temperature, air temperature, engine speed or period and the like. These parameters are sensed and then supplied to input circuits for signal conditioning and conversion into digital words usable by the microprocessor. The microprocessor system computes a digital word indicative of a computer-commanded engine control operation and output circuitry responds to predetermined computer-generated commands and to the computed digital command words for converting them to corresponding pulse-width control signals for controlling such engine operations as fuel-injection, ignition timing, proportional and/or on-off EGR control, and the like.

High voltage switch and capacitive drive

Abstract: A high voltage capacitive drive circuit for coupling a dc or pulsed dc input voltage from a control input to a relay having a high voltage output circuit is described in which the output of the high voltage relay circuit is electrically isolated from the control input thereto without the use of optical couplers. The combined capacitive drive circuit and high voltage switch circuit of the present invention may be integrated on a single silicon chip using conventional isolation fabrication techniques to provide good isolation between the control input and the output of the high voltage relay circuit. A pair of matched capacitive couplers are driven in a push-pull mode to pump electrical charge to a floating control circuit which turns on the high voltage relay contact. An exclusive OR circuit prevents high voltage signals on the contact terminals from inadvertently turning the contact ON or OFF by being responsive only to out of phase inputs. The described high voltage switch and capacitively coupled drive circuit is suitable for fabrication on a single semiconductor chip.

Signal corrected optocoupled device

Abstract: A remote gain controlled optocoupled device is disclosed utilizing a DC reference voltage in the output section to compensate for variations in the optocoupling characteristics of the circuit. The DC voltage level output of the photodetector, which is a function of the light transfer characteristics of the circuit, is compared to a remotely controlled reference DC level. The output AC signal level, which substantially tracks the DC voltage output, is gain adjusted under control of the compared DC voltage levels.

Tradeoff between threshold voltage and breakdown in high-voltage double-diffused MOS transistors

Abstract: The design of junction isolated DMOS transistors suitable for monolithic integration has been studied. The purpose of this correspondence is to describe one of the key tradeoffs when designing these devices for high breakdown voltages (200 V for our example). It is a tradeoff primarily between threshold voltage and the punchthrough voltage of the channel diffusion, however, the avalanche breakdown voltage, on-resistance, and source-to-substrate punchthrough voltage are also affected. As an example, the design of a device for 200-V operation is described. The discussion is, however, general and can be applied to other DMOS designs as well.

Power regulator for RF communications transmitter - uses directional coupler to automatically reduce transmitter power as mismatch to load increases

Abstract: The power regulator, for an RF communications transmitter, automatically reduces the transmitter's power as the degree of mismatch to the antenna increases. Overload of the individual amplifier stages is thus prevented. A directional coupler (3) is located between the load (4) and the output of the transmitter's amplifier (2). The coupler produces two output voltages: one proportional to the forward power (Uv) and the second proportional to the reflected power (Ur). The two outputs (5, 6 and 7, 8) are combined and used to regulate the output power. The combining operation may be simple addition.

Integrated circuit for detecting changes in light intensity

Abstract: An integrated circuit employing a photo-diode activates an alarm when an intruder causes a change in the ambient light patterns by more than about 5% in an area under surveillance. The circuit includes a voltage regulator for supplying a back bias voltage to the photo-diode which voltage is substantially purged of noise that may be superimposed on the main d.c. supply voltage conductors. The regulator circuit includes a modified current-mirror type current source and a V BE -multiplier circuit providing a log-log noise transfer function.