Showing papers on "Voltage droop published in 1984"

Full load to no-load control for a voltage fed resonant inverter

Abstract: 57 A control for a voltage fed series resonant inverter includes controllable switch means (83, 85) which supplies square wave voltage signals to a resonant series circuit (95; 97). The output of the inverter is coupled to a rectifier (99) to provide dc power to a load. The control comprises summer means (58) for comparing a commanded dc voltage (Eo) to an actual dc output voltage and providing an error signal. An oscillator (64) responsive to the error signal generates a frequency signal that is coupled to the controllable switch means (83, 85) to vary the frequency of the square wave voltage supplied to the resonant circuit. The duty cycle of the frequency signal is adjusted so that the frequency signal is provided in bursts during low load conditions thereby minimizing circulating currents while maintaining the output voltage with dosed loop frequency control.

Engine and transmission control system for combines and the like

Abstract: A control system is provided for a combine or other vehicle having an engine for driving both the ground wheels of the vehicle and at least one auxiliary mechanism, such as the crop-processing mechanisms of a combine. The engine is coupled to the ground wheels through a hydrostatic transmission, and the power takeoff for the auxiliary mechanism is located on the engine side of the transmission. A speed droop governor regulates the fuel input to the engine in response to changes in the engine speed. Transmission control means adjusts the setting of the hydrostatic transmission, and thus the load applied to the engine via the transmission, in response to changes in engine speed or another parameter that varies with engine load so as to control the speed changes effected by the droop governor. The combined effect of the speed droop governor and the transmission control means is to gradually reduce the operating speed of the engine as the fuel input to the engine is increased, with the total speed reduction over the full load range of the engine comprising from about 1% to about 5% of the no-load speed.

Dual voltage power supply system for vehicles

Abstract: A dual voltage power supply for a vehicle is disclosed with a DC generator, a single storage battery, a low voltage load circuit including the storage battery and a high voltage load circuit including load devices designed to be powered by voltages higher than the battery voltage. A high voltage regulator is responsive to the generator output voltage and controls the energization of the field winding of the generator for causing the generator to produce an output voltage meeting the requirements of the high voltage load circuit. A low voltage regulator receives the output voltage of the generator and produces a substantially constant regulated voltage for charging the battery and supplying the low voltage load circuit.

Liquid crystal element driving apparatus

Abstract: An apparatus for driving a liquid crystal element by an increased voltage and at a lowered frequency in conformity with temperature fall in the liquid crystal element so as to achieve complete driving of the element even in a low temperature range. In order to increase the driving voltage, the apparatus comprises a booster circuit for increasing a battery voltage, and a voltage divider circuit including an element-temperature sensor as a component thereof and serving to produce a control voltage by dividing the output voltage of the booster circuit. In such configuration, the booster circuit performs its operation in such a manner as to maintain constant the control voltage obtained from the voltage divider circuit.

Circuit for voltage multiplication

Abstract: A circuit for voltage multiplication has a capacitor which is connectible via first switching transistors to a supply voltage source and via further first switching transistors in series with the supply voltage source and with a storage capacitor which is connected in parallel to the circuit output. Clock voltages for driving the first switching transistors are switchable in amplitude from a value corresponding to the supply voltage to the value corresponding to the output voltage. In order to achieve high efficiency of the circuit, a clock voltage generator is controllable for amplitude switch over via a supply line which is connectible via a second switching transistor to the supply voltage source and is connectible via a third switching transistor to the circuit output, whereby these switching transistors are driven via the outputs of the comparator which compares the supply voltage to the output voltage. The circuit may advantageously be employed in hearing aid circuits.

Electronic circuit breaker

Abstract: A versatile output card circuit capable of switching a wide range of voltage levels for use with the central processing unit of a computer or microprocessor controller. The versatile output circuit includes an isolation switching means circuit for electrically isolating a second predetermined range of load voltage while responding to a first predetermined range of signal output voltage by switching the second predetermined range of load voltage to a desired load and an indicating means circuit coupled to and responsive to the isolation switching means circuit for indicating when the second predetermined range of load voltage has been switched to the load.

Boosting word-line clock circuit for semiconductor memory

Abstract: A voltage boosting circuit combination for semiconductor memory word-lines having a charge/discharge circuit including a first pair of MOSFET's and connected to a first clock signal. An output lead is connected from the charge/discharge circuit to a word-line of a semiconductor memory. The first clock signal ΦA thereon is connected to the charge/discharge circuit for actuating the MOSFET's to produce a voltage change on the output lead from a first voltage level to a second voltage level. The circuit combination also includes a threshold voltage circuit having a second pair of MOSFET's, which is connected to a second clock signal ΦC for controlling the voltage level in the threshold voltage circuit. A lead is provided connecting the threshold voltage circuit to the charge/discharge circuit. The circuit combination further includes an output signal boosting circuit having a third pair of MOSFET's which is connected to a third clock signal ΦD for actuating the MOSFET's to produce a voltage boosting signal. A capacitor device is provided for connecting the boosting circuit to the output lead for applying the voltage boosting signal from the voltage boosting circuit to the output lead for enhancing the voltage level change on the output lead to the first voltage level from the second voltage level.

High speed, low drift sample and hold circuit

Abstract: A sample and hold circuit which achieves both a fast acquisition time and a low droop rate is disclosed. FET or analog switches form a sample switch. When this circuit is in a hold mode the sample switch is biased so that no voltage appears across the switch. However, only one switch or a plurality of switches in parallel connect between a driving buffer and hold capacitor so that a fast acquisition time is achieved when this circuit is in a sample mode.

Electrical control apparatus and methods

Abstract: Apparatus for use in an electrical power generating system including a generator for supplying an A.C. output voltage to a load on a set of lines and a circuit responsive to the A.C. output voltage for producing a regulating voltage, the generator having a winding the D.C. energization of which controls the A.C. output voltage. The apparatus controls the energization of the winding and includes a switching circuit adapted to be connected across a resistance and which when rendered conductive bypasses the resistance to couple the voltage regulating circuit to the winding with negligible loss of energy. The switching circuit is combined with a circuit that produces a signal when an increase in the A.C. output voltage exceeding a preselected parameter occurs, and with another circuit that renders the switching circuit nonconductive in response to the signal thereby causing the resistance to consume energy from the winding. Methods of operation of the apparatus are also described.

Voltage sensing at loads remotely connected to power supplies

Abstract: A circuit for use in a power supply of the type which regulates the voltage at a load remotely connected to the output of the supply. The circuit allows the voltage at the load to be sensed so that the voltage control loop of the supply can control the load voltage in a relatively accurate manner. The circuit also provides means to detect the breakage of any one of the sense leads.

Balancing system for limiting voltage imbalance across series-connected capacitors

Abstract: When a series string of similar circuit components, such as capacitors, are connected across a source of d-c voltage and those circuit components do not divide the applied voltage equally because of having different leakage resistances, and consequently different leakage currents, the voltage imbalance may become so great that the maximum allowable voltage or voltage rating of at least one of the circuit components may be exceeded, resulting in damage to or the destruction of that component. To limit the voltage imbalance, thereby to protect the circuit components, each of those components is shunted by a separate voltage limiting device, such as a zener diode. The threshold or breakdown voltage of each limiting device is less than the maximum acceptable voltage of the device's companion circuit component so the voltage across that component will be limited to and will never be greater than that maximum acceptable level regardless of the differences that exist in the leakage resistances.

A Simple Energy-Absorbing Circuit for Current-Source Inverters

Abstract: The design and performance are described of a simple circuit using one impulse commutated thyristor which absorbs excessive energy returned to the output clamp of a current-source inverter It is well-known that the thyristor voltage stresses in a current-source inverter are roughly proportional to load current under full load conditions This Is due to the return of energy trapped in the motor leakage inductance into the commutating capacitors Most such inverters contain an output clamp circuit to provide reverse recovery suppression of the power circuit diodes, and to provide some limiting of peak capacitor voltage It is difficult to obtain short-time overload capacity due to the tendency of the voltage stresses to climb dangerously high The clamp discharge resistors cannot be made small enough to limit the voltage rise without a severe efficiency penalty under normal load The proposed circuit functions to switch in resistance only when needed to limit the voltage It is very simple in concept and requires few parts and no external control power supply Experimental results on a 20-hp current source inverter will be described, showing the ability to attain 150 percent overload with minor increases in voltage stress over nominal load

Power supply circuit having two mutually independent outputs

Abstract: A power supply circuit for converting an input d.c. voltage into a first and a second d.c. output voltage. The power supply circuit includes the series arrangement of an inductor and a controllable switch for receiving the input voltage, the first output voltage being obtained from the resulting square-wave voltage across the inductor. A series resonant circuit followed by a peak-peak rectifier is coupled to the inductor for providing the second output voltage. Arranged as such, variations in a load connected to receive one of the output voltages has substantially no effect on the other output voltage.

Battery voltage regulation system

Abstract: A battery voltage regulating system for an automotive vehicle, wherein a field current flowing through a field coil of an alternator is periodically cut off irrespectively of whether a battery voltage is higher or lower than a reference voltage, and a conduction ratio of the field current is controlled in accordance with a difference between the battery voltage and the reference voltage. The reference voltage is changed in response to an increase or decrease of the conduction ratio, so that a battery voltage is prevented from decreasing when the conduction ratio is increased.

Circuit for detecting charged voltage of electronic flash

Abstract: A voltage dividing circuit containing a switching element is connected in parallel with a main capacitor of which a highly charged voltage is applied to a flash lamp for flashing. Only when the switching element is turned on does the voltage dividing circuit produce a divided voltage. The divided voltage is compared with a reference voltage. The result of the comparison is used for detecting the charged voltage across the main capacitor.

Raster width regulation circuit

Abstract: A line deflection voltage regulator develops a regulated scan supply voltage. A line deflection circuit is coupled to the voltage regulator for generating line scanning current in a line deflection winding. The amplitude of the scanning current is dependent on the magnitude of the regulated scan supply voltage. A high voltage regulator develops a second regulated voltage. A high voltage generator is coupled to the high voltage regulator for generating an ultor output voltage at an ultor terminal. The magnitude of the ultor output voltage is dependent on the second regulated voltage. A high voltage control circuit is coupled in a feedback path between the high voltage generator and the high voltage regulator for developing a first ultor control voltage that is representative of the ultor output voltage to regulate the ultor output voltage. A second ultor control voltage that is representative of fluctuations in the ultor output voltage is developed at a point within the feedback path. The second control voltage is coupled to the line deflection voltage regulator for varying the regulated scan supply voltage to provide raster width regulation.

Gas turbine engine control

Abstract: In one form of the present invention, the thrust of a gas turbine engine is inferred. If a droop in thrust is predicted, components of the engine are modulated in response to restore thrust.

Regulating and stabilizing circuit for X-ray source

Abstract: A method and apparatus for regulating and stabilizing the radiation intensity level of an X-ray source. The apparatus includes high voltage circuitry for supplying anode and cathode voltages to an X-ray tube and filament voltage circuitry for supplying voltage to the filament of the tube. Both the high voltage and filament voltage circuitry are regulated by multiple feedback voltage level control circuits. The method of the present invention involves the forming of the high voltage and filament voltage circuitry and the supplying of appropriate feedback signals to such circuitry to maintain the high voltages and filament voltage at desired levels.

High voltage generating device for X-ray apparatus

Abstract: A high voltage generating device for an X-ray apparatus includes a DC output voltage control device for rectifying and smoothing a commercial AC power source voltage and a resonant circuit comprised of a series circuit of a capacitor and a primary winding of a transformer. The output DC voltage of the DC output voltage control device is supplied to the resonant circuit in a first direction or in a direction opposite to the first direction. The direction in which the voltage is applied to the resonant circuit is switched by a current switching means. Consequently, a high AC voltage is obtained through a secondary winding of the transformer. The AC voltage is converted by a rectifying/smoothing means to an X-ray tube voltage which is applied between an anode and a cathode filament of an X-ray tube. The DC output voltage control device permits its output voltage to be switched to an arbitrary level.

A Radar Power Supply Without A Voltage Droop

Abstract: A new principle of fine regulation applied on a high-voltage line supplying a pulsed load (radar tube) is presented. The high-voltage power-supply system is a combination of a single-series resonant converter and an efficient capacitor multiplier in the output stages. The electronic power-conversion system uses a Schwarz converter employing a series resonant circuit for the transfer and control of power. An internal frequency of 35 kHz enhances the power density of the converter model. This model provides 16 kV for the helix-cathode circuit of a klystron with an accuracy of 0.50/00 (per mille) and 11 kV for the collector-cathode circuit with an accuracy of 5 percent. The presentation is supported by experimentally acquired data. The improved high-voltage power supply should lessen the problems associated with high-voltage transformers and the high accuracy required for the voltage control for the helix-cathode circuit to avoid distortion in the returning signal of a space-borne radar system.

Control circuit for a bistable relay

Abstract: A relay driver circuit, suitable for controlling a bistable relay, includes a storage device which is charged to a first voltage level by a low current flow voltage source. A first switching circuit couples the storage device to the bistable relay when the first voltage level exceeds a predetermined value. The charge on the storage device is dumped into the relay and forces it into a first state (set). A second switching circuit is coupled to sense the voltage on the storage device and the voltage on the low voltage source. When the voltage on the low voltage source falls below the voltage on the storage device, current flows from the storage device and forces the relay into a second state (reset). The reset time is within 100 µs.

Automatic voltage line loss compensation control for an antenna receiver

Abstract: An automatic control for compensating for the voltage drop between an antenna receiver and a remotely interconnected down converter wherein an operational amplifier senses the voltage drop due to the interconnecting cables, amplifies that voltage, and adds it to the actual tuning voltage to fully compensate for the voltage drop.

An anti-droop infra-red transmitter circuit

Abstract: In a remote battery operated keyboard entry device coupled to a microcomputer (1) through an infra-red link, the drive transistor (10,17) for an infra-red LED (5) is coupled to receive serial pulses representing keystrokes through a network including a visible LED (14). The arrangement is such that for each input pulse, the visible LED is turned on to provide a visible transmission indication and also an input reference potential to determine the amplitude of the current drive of the transistor through the infra-red LED to guard against data loss caused by battery droop.

A MOSFET power amplifier with error correction

Abstract: The rapid evolution of power MOSFETs during the last few years has brought them to the point where they are now very attractive for use in audio amplifier power output stages. Important improvements include in­ creased voltage, current, and dissipation ratings, re­ duced "on" resistance, availability of complementary pairs, and greatly reduced cost. Although a 75-W MOSFET is still more expensive than a 150-W bipolar transistor, the premium is small when considered rel­ ative to total amplifier cost and improved performance. The purpose of this paper is to demonstrate the level of performance achievable with current technology and to illustrate practical circuit techniques for achieving this performance. Power MOSFETs have several fundamental advan­ tages over bipolar power transistors, most notably speed and freedom from secondary breakdown. The latter provides higher "usable" power dissipation, improved reliability, and freedom from safe-area limiter circuits, which can misbehave and cause audible degradation . MOSFETs also have some disadvantages in comparison with bipolar transistors. These include higher turn-on voltage drive requirements and smaller transconduct­ ance at low current levels . The former tends to contradict generalizations that have been made to the effect that drive circuits for power MOSFETs are less expensive, at least for the reliable source-follower configuration. The latter results in transconductance droop in the cross­ over region if bias currents are not fairly high. Such transconductance droop can result in crossover distortion.

Integrated circuit for generating a terminal voltage adjustable by a digital signal

Abstract: An integrated circuit is described which includes a digital/analog converter which together with a reference voltage generator and a current-to-voltage converter is driven by a single supply voltage. To obtain a variable output voltage from a second supply voltage, the reference voltage is dependent on this second voltage. The output voltage can be used as the tuning voltage of tuner diodes.

V-t characteristics of epoxymoldinsulationfor sustainedac voltage

Abstract: This paper describes experiments conducted to determine the cause of epoxy mold insulation breakdown under sustained applied AC voltage. It can be readily understood that epoxy mold insulation, widely used as solid insulation in gas-insulated switchgear, is subject to breakdown under sustained applied voltage when the mold insulation contains large voids. However, epoxy mold insulation which is practically void-free also deteriorates under sustained applied voltage. It has been clarified by conducting experiments using various embedded electrode materials that the deterioration of this void-free epoxy mold insulation is primarily caused by an electric field concentration due to micro-protrusions on the embedded electrode surface and a small partial discharge which occurred at minute debonded portions around the micro-protrusions.

Method and apparatus for modulating a diffraction radiation generator

Abstract: Method and apparatus for modulating coherent radiation generated by an orotron in accordance with a low voltage control signal applied to the diffraction grating to vary the grating-to-cathode voltage from the cathode-to-collector voltage over a selected voltage range determined by the maximum and minimum values of the control voltage. For amplitude modulation, the grating-to-cathode voltage is varied within a voltage range between a lower voltage at which the orotron output power starts to fall abruptly and a cutoff voltage at which coherent radiation ceases. For frequency modulation, the grating-to-cathode voltage is varied within a voltage range, including the point of maximum power output, where there is a minimum change of output power with a change in the grating-to-cathode voltage.

Breakdown phenomena in transformer oil subjected to direct voltages with ripple

Abstract: This paper reports the results of experimental investigations on the breakdown phenomenon of transformer oil under inhomogeneous field conditions (rod-plate electrode system) and subjected to DC voltage superimposed on AC voltage. The peak breakdown voltage of transformer oil is found to be decrease with the increasing of ripple content in the applied voltage and gap spacing between electrodes. It has been noticed also that the value of breakdown voltage is lower for positive DC voltage than negative voltage for any particular ripple content.