Showing papers on "Low-dropout regulator published in 1976"

System for synchronizing and phase shifting switching regulators

Abstract: A regulated power supply system, for a sensitive computer environment, having a plurality of switching regulators to provide highly regulated D.C. voltage to individual loads connected to each of the regulators. A centralized oscillator is used to supply the clock signal to the control circuit of each of the different switching regulators. Thus, any radio frequency interference problems will be associated with only one fundamental frequency and its related harmonics. A modified ring counter is used to stagger the turn-on point of each individual regulator so that the power demands on the source of power are not suddenly severe and instantaneous, which might generate transients disruptive of computer operations. Further, the modified ring counter is used to synchronize the frequency of each regulator to a common clock, in addition to its controlling the phase shifting of each regulator for a staggered turn-on.

High voltage transient protection circuit for voltage regulators

Abstract: A high-voltage transient protection circuit for use in combination with a voltage regulator of the type employing an error amplifier to compare a portion of the controlled output voltage against a reference voltage and adjust the output voltage accordingly. The protection circuit can be used with three terminal positive or negative voltage regulators of either the shunt transistor or series pass transistor types. Oscillation of the protection circuit around a selected transient voltage threshold is avoided by providing a hysteresis characteristic in the response of the circuit to a voltage transient. The circuit is preferably embodied as an integrated circuit in a chip of semiconductor material and is particularly well suited for protecting a voltage regulator and associated electronic systems from the detrimental voltage transients encountered in an automotive environment.

An integrated bandgap reference

Abstract: Using well-known principles a configuration has been developed for an IC reference voltage source with good performance with respect to the temperature dependency and 1/f noise. A bread-board model of this configuration has been tested. In the temperature range of 0-70/spl deg/C, the output voltage variations were less than /spl plusmn/70 ppm at an output voltage of about 2.5 V and zero load current. Low-frequency noise in a bandwidth 0.003 Hz

Switching regulator control utilizing digital comparison techniques to pulse width modulate conduction through a switching device

Abstract: A switching regulator includes a digital feedback control circuit to regulate the output voltage. The frequency output of a voltage controlled oscillator responsive to the output voltage is periodically counted. The accumulating count is continuously compared with a reference count. The elapsed time for this count to accumulate to a value equaling the reference count determines the duty cycle of periodic conduction through the switching device of the switching regulator.

Switching power supply with floating internal supply circuit

Abstract: A preregulator power supply having drive and control circuits which are isolated or floating alternately from the input and output leads to permit direct coupling to the power switching regulator device without requiring isolation devices such as transformers or optical isolators. This is achieved by an added series winding on the output choke, the common junction of which is connected to the output of the switching regulator and also forms the return lead for the floating drive and control circuits, while the added winding provides a sample output voltage for comparison by the floating drive and control circuits to control the width of pulses fed to the switching regulator device. A free-wheeling diode is also connected from the output of the switching regulator to an output terminal to maintain current in the choke during the OFF cycle of the switching regulator and provide several isolated regulated voltages in windings magnetically coupled to the choke.

Band gap voltage regulator circuit including a merged reference voltage source and error amplifier

Abstract: An improved circuit for a band gap voltage regulator is provided with a merged reference voltage source and error amplifier wherein the circuit operates simultaneously as a generator of the internal reference voltage as well as the small signal error amplifier for comparing a fraction of the output voltage to the reference voltage.

Complementary field effect transistor amplifier

Abstract: The quiescent current of a class A biased complementary field effect transistor amplifier is regulated by a bias network coupled to the gate electrodes of the output transistors which provides an offset voltage therebetween. When the amplifier supply voltage exceeds a minimum value, the bias network increases the offset voltage. Parameters of the network may be selected such that the change in offset voltage is greater than, less than or equal to the change in supply voltage. In the latter case the quiescent current is constant and the quiescent power dissipation is linearly related to the supply voltage.

Base drive regulator

Abstract: A base drive regulator for regulating the base drive voltage of the output transistor of a switching amplifier. The inputs of a comparator are separately connected to a reference voltage of either an independent source or the base of the output transistor and to a resistor network connected between the collector and emitter of the transistor. The output from the comparator is utilized to indirectly control the conductivity of the output transistor to maintain the output transistor just at saturation.

Voltage boost circuit for DC power supply

Abstract: A typical "stand alone" precision power DC to AC solid state converter reres a higher DC supply voltage than is usually available from its utility power sources. The disclosed invention is a voltage boost circuit that provides the DC-bus voltage amplitude for precision power DC to AC solid state converters by transforming only the difference between the available raw power DC voltage bus and the required precision DC voltage amplitude. This DC voltage difference obtained by the circuitry of this invention is boot-strapped to the available DC bus to obtain the required precision DC voltage.

Multi-voltage vehicular network system

Abstract: To provide a dual-voltage network for the on-board electrical system of automotive vehicles, for example to provide a higher voltage for starting of the vehicle and a normal on-board voltage for operation of vehicle appliances such as lamps, fans, motors, and the like, while using only a single voltage regulator to control the charge voltage for the vehicle battery, a voltage doubler circuit is provided which is connected to the on-board network by a diode and a coupling capacitor connected to an a-c output of a vehicle alternator, the diode being connected between the d-c output and the rectifier connected to the alternator and the capacitor so that a voltage regulator, connected to the d-c output, can accurately control the output voltage of the alternator.

Stabilized DC power supply device

Abstract: A stabilized DC power supply device providing a plurality of different stabilized DC powers with regulated voltage levels. Stabilized DC powers with rated currents of 2A. or less are taken out from transistor series regulator circuits, another stabilized power with rated current of 8-10A. or more is output from a magnetic amplifier regulator circuit and other powers with rated current of 8-10A. or less are obtained from transistor switching regulator circuits. The regulated voltage output from one of the switching regulator circuits is used as an input DC power for the series regulator circuits and is fed to them through an DC-AC inverter circuit and respective rectifier circuits. Input powers to both the switching regulator circuits and the magnetic amplifier regulator circuit are from a DC power source through a single DC-AC inverter circuit. The device is small in size and good in efficiency. Overvoltage and overcurrent prospective circuits are provided to stop the operation of the DC-AC inverter circuit when either overcurrent or overvoltage occurs.

Shunt voltage regulator

Abstract: An improvement for lowering the source impedance exhibited by a shunt voltage regulator of the type including a self-biased transistor connected between the output terminals. A sensing resistance is connected between the base and collector of the self-biased transistor for providing a voltage responsive to the collector current that controls the conduction of current by a controllable current conductive device between the output terminals.

Low loss a.c. voltage regulator

Abstract: A high speed a.c. voltage regulator comprises a transformer having a plurality of switchable primary windings across which an unregulated voltage is impressed and which control the regulated voltage, and a secondary winding across which the regulated voltage is generated. During a regulation period, which comprises one cycle of the unregulated voltage frequency, peak unregulated input voltage is compared against an upward ramping reference voltage to control a source of clock pulses, where the instantaneous level of the reference voltage is related to the number of clock pulses generated during a regulation period. The number of clock pulses generated during a regulation period controls the switchable windings.

Battery charge detector and charging system including such detector

Abstract: A detector, intended particularly for detecting end of charge of a secondary battery under constant current charge, includes a linear input stage producing an output voltage linearly related to the battery voltage. A relay contact is closed periodically by pulses from a clock to connect the output of the input stage to a capacitor and resistor in series. Any change in the output voltage between closure of the contact cause current to flow in the resistor and a comparator compares the voltage across this resistor with a reference voltage. When the battery is charged and the output voltage starts to fall, the negative voltage on the resistor cause the comparator to latch and provide an output signal.

Switching regulator power supply

Abstract: An improved switching regulator circuit is adapted for use with switch regulators in which more than one transistor is operated in parallel to provide a higher output current than normally obtained. Each transistor is operated with a separate inductor or filter on either the emitter or collector side of the transistor and each transistor possesses its own flyback diode.

Power supply with base drive control

Abstract: A power supply provides a low-level DC voltage to DC load circuits by first rectifying the standard AC voltage and thereafter reducing the rectified AC voltage to the low-level DC voltage. The reduction of the rectified AC voltage to the low-level DC voltage is accomplished by a power transformer which is switched on or off by a pair of switching transistors. The switching transistors are operated in a "push-pull" mode by a pair of control transformers operating in combination with a control circuit. The control circuit produces various pulse conditions in the control transformers which turn their respective switching transistors on and off in a prescribed manner.

Switching regulator control circuit

Abstract: A control circuit for a switching regulator comprised of silicon controlled rectifiers and inductive reactors is disclosed. The control circuit provides for fault detection and voltage regulation while using these output as control signals for a frequency variable gating mechanism to trigger the switching regulator so as to provide its maximum output capability.

Low voltage reference

Abstract: A temperature compensated low voltage reference that produces an output voltage less than the silicon band-gap voltage. The low voltage reference includes at least a first and a second transistor for providing a voltage independent of variations in the collector power supply and at least a third transistor for developing a voltage that is a fractional value of the base-to-emitter voltage drop of a transistor. The at least a third transistor for developing is coupled with the at least a first and a second transistor for providing. The low voltage reference also includes an output transistor for providing an output voltage. The output transistor is controlled by the voltage provided by the at least a first and a second transistor for providing so that the output voltage is essentially insensitive to temperature variations and is a lower value than the silicon band-gap voltage.

Fully regulated temperature compensated voltage regulator

Abstract: For coupling to a high speed logic device, a monolithic IC regulator is provided which is fully compensated for temperature and for variations in supply voltage. The temperature compensation is accomplished by the proper matching of resistances and current densities in transistor-diode circuitry and the compensation for variations in voltage supply is accomplished by coupling a feedback amplifier section to the regulator, the resistances and diodes of which are carefully matched to the resistances of the regulator so that the feedback amplifier section, being dependent only on such matching, is responsive over large fluctuations of supply current. The feedback amplifier section is also provided with a circuitry which slightly imbalances the amplifier section relative to the regulator so that current will flow through the shunt transistor of the regulator and by further matching the current density of the shunt transistor of the regulator with the current density of a component of the current mode logic device, the desirable characteristics for high speed digital logic functions are accomplished.

Voltage regulator with thermal overload protection

Abstract: There is disclosed herein a voltage regulator for a power supply for load devices such as electronic photoflash units. The voltage regulator supplies power to charge the main capacitor of the photoflash unit to an appropriate voltage, and uses a semiconductor series regulator circuit. The voltage regulator provides medium-to-long term heat integration to terminate power supplied to the electronic flash unit in the event of a thermal overload in order to protect the electronic flash unit. The circuit includes a ready indicator to indicate when the main capacitor of the flash unit has reached the appropriate charge, and also includes an overload indicator to indicate an overload condition.

Efficient bidirectional power converter for portable data gathering apparatus

Abstract: Input and output switching transistors are alternatively activated to form a charging path and a discharging path for an inductor. The inductor periodically charges through the input transistor from an unregulated rechargeable battery, and discharges through the output transistor into an output capacitor. The output voltage taken across the output capacitor is regulated by negative feedback which varies the inductor charging period through the input transistor. The converter regulation is bidirectional. The voltage from the battery is initially greater than the regulated output voltage, but decreases to a value less than the output voltage as the battery discharges. When the battery is fully charged the converter regulates the battery voltage down to the output voltage. As the battery voltage drops through discharge, the converter regulates the lower battery voltage up to the output voltage. When the output voltage is not required by the data gathering apparatus, the output transistor is deactivated terminating the output voltage and establishing a residual standby mode in the power converter.

Power supply with overcurrent protection

Abstract: A power supply provides a low-level DC voltage to DC load circuits by first rectifying the standard AC voltage and thereafter reducing the rectified AC voltage to the low-level DC voltage. The reduction of the rectified AC voltage to the low-level DC voltage is accomplished by a power transformer which is switched on or off by a pair of switching transistors. The switching transistors are operated in a "push-pull" mode by a pair of control transformers operating in combination with a control circuit. The control circuit produces various pulse conditions in the control transformers which turn their respective switching transistors on and off in a prescribed manner. An overcurrent sensing and control device prevents damage to components.

A method of surge reduction in the switching regulator

Abstract: When the switching regulator is used for the supply of the color T.V. receiver, the following two conditions are desired to be satisfied. (1) The switching operations should be completed within the retrace interval of horizontal scanning. (2) The output voltage is close to the input voltage value. To realize a regulator satisfying both of these two conditions, a reactor with two windings should be used. In this case, turn ration of windings differs far from unity. Hence a surge voltage due to leakage inductance appears across the transistor. The amount of the surge may be great enough to cause a break down in the transistor. We propose in this paper a method of cascade connection to give a solution to the problem of switching surge. The key point of the surge reduction is to make use of a cascade connection of the switching regulator with reactors of single winding. The efficiency, the voltage rating of the transistor and the regulation range are discussed on typical three kinds of circuit.

Ferroresonant regulator with supplementary regulation through waveform control

Abstract: A ferroresonant voltage regulator utilizes control of the voltage peak of a signal waveform as a voltage regulation technique. The peak of the voltage waveform is adjusted in response to a feedback control. The regulated output voltage is derived from a peak voltage detector.

Voltage and current regulator for generating systems

Abstract: A regulator for controlling the field exitation current of a generating device when the voltage developed exceeds a preset level and including a first resistor for establishing the level of a base current, a first transistor responsive to the base current for selectively developing the exitation current, a first switching device which is biased on and is connected between the first resistor and the base of the first transistor and a second switching circuit for monitoring the generator voltage and for switching the first switching device off preventing current flow in the first resistor when the voltage exceeds a preset level. The regulator also includes four terminals and a connecting strap configured to permit universal application of the regulator.

Dc series voltage regulator with gating means for output to remain off until regulation level is reached

Abstract: A series voltage regulator for producing a regulated direct output voltage from a direct input voltage that is subject to variations, such as gradually increasing with time upon application of source voltage, with first and second transistors of opposite polarity where the collector emitter path of the first transistor is in series relation between the input and output terminals and the emitter-collector path of the second transistor is in series relation between the input terminal and the base electrode of the first transistor. A voltage limiter such as a zener diode is connected between the base of the second transistor and a common input-output terminal. As source voltage increases from zero, the first transistor remains off until it is supplied base drive, which occurs only after the second transistor becomes conductive. The second transistor will conduct when the input voltage exceeds the sum of the second transistor's base emitter voltage drop and the voltage drop of the zener diode. Saturation of the second transistor will cause the regulator to produce a steady output equal to the sum of the voltage drops of the zener diode and the base collector junction of the second transistor, minus the voltage drop of the base emitter junction of the first transistor.

Pulse voltage regulator

Abstract: A pulse voltage regulator for maintaining constant output voltage pulses oss a burst of high voltage low ripple input pulses by removing exactly the same amount of ripple energy from a clamp capacitor during the interpulse period as was added to the capacitor during a pulse period.

Transistor base drive regulator

Abstract: A base drive regulator for a transistor operation in a switching mode comprising a series transistor regulator between the source of drive voltage and the base of the switching transistor and a diode with its anode element connected to the base of the series transistor regulator and its cathode connected to the collector of the switching transistor. The material used for construction of the switching transistor, series regulator transistor and the diode has similar electrical characteristics.

A frequency-stabilized free-running DC-DC converter circuit employing pulse-width control regulation

Abstract: A dc-to-dc converter circuit in the power range of 10 to 50 watts is described. While comparable to ringing choke converters or self-oscillating switching regulators in simplicity, small size, and low cost, this circuit offers many of the features usually found only in larger, more-complex driven converters.

High efficiency d.c. voltage regulator

Abstract: A high efficiency switching regulator for maintaining a constant d.c. voltage is described. An efficiency improvement of better than 20 percent is realized by use of an alternate low impedance current source for supplying base current to the control transistor of a switching regulator.