Showing papers on "Voltage droop published in 1977"

Integrated circuit with threshold regulation

Abstract: Threshold voltage regulation of field-effect transistors on a common substrate of an integrated circuit is achieved by adjusting the back bias on the substrate using a charge pump that is selectively operated whenever the threshold voltage of a designated enhancement mode FET falls below a reference voltage. A voltage divider provides the reference voltage that is applied to the gate of the enhancement mode FET, which when turned-on enables the charge pump.

Steady state growth of phytoplankton in continuous culture: comparison of internal and external nutrient equations1,2

Abstract: Previously, there have been conflicts over whether external or internal nutrient concentrations control phytoplankton growth rates at steady state in continuous culture. To experimentally demonstrate that both equations equally describe steady state growth, continuous culture studies with phosphorus-limited growth of the chrysophyte Monochrysis lutheri Droop were carried out over the entire growth rate region up to biomass washout. Data were examined using both the Monod and Droop equations, and, even though there were significant variations in the yield coefficient with growth rate, the data fit both equations reasonably well. Because of their relative simplicity, the Droop equation and an equation combining both the Monod and Droop equations are better suited for expressing kinetic data than the Monod equation. It is crucial, though, that the criteria necessary to achieve steady state be fulfilled.

CMOS voltage comparator with internal hysteresis

Abstract: A CMOS voltage comparator with internal positive current feedback to achieve a predetermined hysteresis. The voltage level at which the switching occurs is precisely settable. Hysteresis is introduced such that when the set voltage level is exceeded, the output switches quickly and will remain in that state until the input voltage drops by a predetermined hysteresis voltage.

Voltage regulator and current regulator

Abstract: A voltage regulator including a current regulator for maintaining predetermined currents in the voltage regulator is disclosed. The voltage regulator includes an output terminal for providing an output voltage; an adjustment terminal; and a control circuit connected to the output terminal at a level that differs from the voltage at the adjustment terminal by a predetermined voltage difference. The control circuit of the voltage regulator includes a resistive divider coupled between the output terminal and the adjustment terminal; a pair of transistors having their collectors connected in common and their bases respectively coupled to the resistive divider to provide a portion of the voltage difference between the output terminal and the adjustment terminal across their bases. The two transistors are adapted for operating at different current densities for providing a predetermined ratio in current flow through the pair of transistors when the voltage difference between the output terminal and the adjustment terminal is the predetermined voltage difference. The control circuit further includes a high-gain amplifier circuit connected to the emitters of the pair of transistors and to the output terminal for driving the output terminal to a maintained voltage level at which the current flow through the pair of transistors is at the predetermined current ratio and the voltage difference between the output terminal and the adjustment terminal is the predetermined voltage difference. The disclosed voltage regulator is useful as a negative voltage regulator.

Abnormal voltage detection circuit

Abstract: An abnormal voltage detection circuit includes a series circuit of a resistor and a capacitor coupled across a power source by means of a switch, an inverter with the input terminal coupled to the junction of the resistor and capacitor, and an R-S flip-flop circuit with the set and reset input terminals coupled to the output terminal of the inverter and a manual switch respectively. The R-S flip-flop circuit is set by a first threshold voltage lower than the threshold voltage of the inverter, and reset by a second threshold voltage higher than the threshold voltage of the inverter.

Static voltage balancer

Abstract: An in-line voltage balancing circuit sums a trim voltage with each phase voltage of a polyphase generating system to assure that the voltage between each phase and neutral is equal to the average voltage of all the phases. An individual error signal representative of the difference between each phase voltage and the average voltage is provided to individual phase modulator circuits. The phase modulator circuits develop pulse width modulated signals wherein the pulse width is proportional to the amplitude of the error signal. The outputs of the phase modulator circuits are connected to switching amplifiers which provide trim voltages proportional to the phase modulated signals. Summing transformers are employed to sum the individual trim voltage with appropriate phase voltage so that the voltage for each phase equals the average voltage.

Instrument amplifier and load driver having offset elimination and common mode rejection

Abstract: The disclosure describes improved apparatus for driving a load, such as a meter, in proportion to a source voltage produced by a signal generator. The apparatus includes a non-differential gain stage for generating an amplified voltage between a gain stage output and one of the generator outputs. The non-differential gain stage is followed by a differential stage which generates a rereferenced voltage between the differential stage output and one of the load terminals. The rereferenced voltage is proportional to the amplified voltage and is substantially independent of any offset voltage between the one generator output and the one load terminal. By coupling the rereferenced voltage to the load, the load voltage is made proportional to the source voltage irrespective of changes in the offset voltage between the one generator output and the one load terminal. The load may include a meter and an amplifying stage for ranging and zeroing the meter.

Voltage limited ignition system, particularly for an internal combustion engine

Abstract: To prevent application of excessive spark energy in an ignition system designed for proper firing voltages even under low-battery voltage conditions, upon rise of the battery voltage to normal or excessive values, a voltage sensing circuit, including a threshold stage, is connected to the secondary of the ignition coil to sense the secondary voltage, the threshold stage providing an output when the voltage is exceeded and blocking continued supply of power to the ignition coil of the system to thereby limit the ignition voltage.

Generation of low frequency, high voltages

Abstract: A circuit arrangement for applying low frequency high voltage waveforms across a load and which includes low and high voltage circuits. The low voltage circuit includes a sinusoidal signal generator for producing a low voltage electrical waveform, and a transmitter circuit having first and second light emitting diode circuits by which first and second light signals are generated which are transmitted to the high voltage circuit by respective fibre optic light guides. The high voltage circuit includes first and second high voltage d.c. supplies and first and second triode valves. Grid modulation devices are associated with the first and second triode valves and are respectively responsive to the first and second light signals transmitted via the fibre optic light guides for varying the current through said first and second triode valves and the load in direct proportion to the positive and negative variations of said low voltage electrical waveform to thereby reproduce the positive and negative variations of the low voltage waveform at high voltage across the load.

Stepped Voltage Dc/Ac Inverter --Part I: Analysis

Abstract: A DC/AC inverter whose voltage is constructed from discrete low level DC sources to form a stepped sine-wave-like output is introduced. The criterion of optimal approximation of the stepped waveform to a sinewave was the minimum mean square error. The internal resistance of the generated source voltage is time varying since the total series resistance changes with the wave shape. When a constant resistive load is connected to such a load, the load voltage shape does not follow the source voltage and the optimal approximation to a sinewave of the two voltages will depend on two different switching policies: one adaptive to the source voltage and the other adaptive to the load voltage'. The inverter operation for both cases is analysed, and the main harmonic voltage and power, harmonic spectrum and distortion are obtained. The proposed inverter has superior properties characterized by its low distortion and high efficiency.

High voltage protection circuit having predictable firing point

Abstract: A rectifying device, a switching device and a reference voltage device are coupled in parallel relationship between a winding of a transformer associated with the deflection circuitry of a television receiver and a filter capacitor of a power supply circuit for providing operating voltage to other portions of the receiver. The reference voltage device is also coupled to a control terminal of the switching device to control its conduction. Under normal conditions, the rectifying device is conductive in only one direction so that the filter capacitor is charged to a sufficient operating voltage to permit the normal operation of the receiver. The reference voltage device is selected so that if, under abnormal conditions, the difference between the voltage developed across the filter capacitor and the voltage developed across the transformer winding exceeds a level corresponding to an excessively high and therefore possibly harmful deflection voltage, the reference voltage device conducts a conduction control current to the control terminal of the switching device sufficient to render it conductive. Under these conditions, the development of sufficient voltage across the capacitor to support the normal operation of the receiver is inhibited and a viewer is effectively warned of the abnormal and potentially harmful condition.

Power supply network for resonant loads - incorporates voltage controlled oscillator controlled by phase difference between voltage supplied to load and that across capacitor in load

Abstract: The power supply, for resonant loads, has a voltage controlled oscillator and a device supplying the load with the oscillator output. A phase detector monitors the phase of the voltage supplied to the load and the voltage developed across a capacitor in the load. It produces an output depending on the relative phase of these two voltages. The phase detector's output is averaged and compared with a reference and the result used to control the oscillator.

Non-linear operational circuit

Abstract: A non-linear operational circuit with reference voltage sources and switching means, wherein the output voltage of the operational circuit is compared with the reference voltages to open and close the switching means in accordance with their magnitudes relative to one another and thereby to non-linearly vary the output voltage of the operational circuit in response to changes in the input voltage. The reference voltage sources and the switching means are connected in series between the output terminal and the ground terminal of the operational circuit, whereby at the inflection point at which the ratio of the change in the output voltage of the operational circuit to the change in the input voltage changes, the output voltage is caused to change continuously.

Semiconductor device circuit

Abstract: PURPOSE: To make easy for circuit integration, by making variable the output voltage and increasing the amplification factor of inverters, through controlling the resistance value with the MOSFET parallely connected to obtain output bias voltage, in an analog voltage comparison circuit. COPYRIGHT: (C)1979,JPO&Japio

Bias voltage generator

Abstract: PURPOSE:To make stable the circuit operation, by changing the bias voltage depending on the rate of change of the output amplitude or frequency of the oscillating circuit due to change in the power supply voltage and temperature.

X-ray diagnostics generator comprising a directly heated x-ray tube

Abstract: In the illustrated embodiments the primary voltage of the high voltage transformer is supplied via a voltage divider so that the secondary voltage does not exceed a desired value during heating of the X-ray tube filament. As the secondary load increases with a consequent tendency to reduce secondary voltage, an element or elements of the voltage divider are switched so as to increase the voltage supplied to the primary winding of the high voltage transformer. In a monopulse circuit, diode means are associated with the voltage divider which are poled such that the voltage divider controls the positive polarity secondary half wave voltage. In one embodiment, a single switch may simultaneously bypass the series resistance of the voltage divider and remove a parallel resistance with respect to one polarity of primary current. In another embodiment, the parallel voltage divider resistance is progressively increased during heating of the X-ray tube filament and then the series resistance of the voltage divider is bypassed with respect to one polarity of primary current, for example, so as to tend to maintain a desired secondary voltage with respect to the corresponding secondary monopulse polarity. Similar circuits are applicable to multipulse generators.

Controller of dc ac converting circuit

Abstract: PURPOSE: To enable performing a motor stable smooth operation by suppressing and controlling an inverter output voltage lower than a proportional value for a frequency at a regenerative braking time. CONSTITUTION: A voltage compensating circuit 14 receives a DC voltage VDC output from a rectifier 2 through a varibale resistor and an output of a slant signal generating circuit 7, discriminates a polarity of the DC voltage VDC and in case of negative i.e. when a motor 5 is under a regenerative braking start, the above mentioned megative voltage is applied to a voltage controlling circuit 8 according to an output value of the slant signal generating circuit 7 and performs a compensating action so as an inverter output voltage V and a frequency f to be a curve C shown in the drawing. COPYRIGHT: (C)1979,JPO&Japio

Fermilab Capacitor Tree

Abstract: The Fermilab Capacitor Tree is a capacitor bank used in series with the feeders carrying 3-phase, 13.8 kV power to the main ring power supply system. Its function is to reduce the voltage droop of the power supplies at high currents, by acting in series resonance with the leakage inductances of the system. This paper describes the electrical system and our operational experience since May, 1976.

Regulator for DC voltage supply - using single control loop for regulating and low frequency load voltage modulation

Abstract: A regulator for a direct voltage supply receiving a primary voltage and contg. a switch as the central element has a switching frequency filter connected after the switch which is controlled by a variable pulse width signal from a control device. The latter is activated by a comparator with a demand signal input. It achieves regulation of the primary voltage and modulation of the direct load voltage using a single control loop. One of the comparator inputs has a superimposed alternating component to enable generation of a low frequency modulated direct voltage.