Abstract: This invention relates to a power supply circuit wherein first transistors, resistors, ann sscood rajsitoos itt a polarity opposite to that of said first transistors are series-connected between the power supply side and the output side. In one embodiment, the circuit is provided as a semiconductor integrated circuit wherein first transistor elements, diffusion resistor elements, and second transistor elements with a polarity opposite to that of said first transistor elements are respectively formed on a common semiconductor substrate together with interconnects.

Abstract: An electrical power conversion circuit having a readily varied conversion ratio and accommodating bidirectional energy flows is disclosed. The converter employs a series connected and a shunt connected semiconductor switch which may be either unidirectional or bidirectional (depending upon whether AC/DC or DC only operation is sought) and an inductor. The switches are insulated gate voltage controlled devices with charge storing capacity present at the gate. The switches are operated from a variable duty cycle rectangular pulse which is differentiated at the leading and trailing edges to form two pairs of oppositely sensed short duration pulses. The two pairs of short duration pulses are then coupled by a transformer having two matched but oppositely sensed secondaries to the gate circuits of the two semiconductor switches.

Abstract: A High Voltage Regulation apparatus which uses an amplifier having an arbitrarily large number of stacked MOSFETs to provide low impedance shunt regulation with a "domino effect". Voltages of many kilovolts can be conveniently regulated. voltage sharing among the devices is assured by the domino arrangement. External capacitances are added to optimize low impedance voltage regulation, including an external capacitor connected between the drain and gate of each stage to equalize the drain to gate and gate to source capacitances. There may also be an external capacitor connected between the drain and source of each stage to provide low amplifier impedance at high frequency, or a lumped external capacitor connected across the entire amplifier string, to provide low amplifier impedance at high frequency. The amplifier uses a unity-gain inverting amplifier as its basic building block. N-number of these building blocks are stacked to accommodate whatever voltage stand-off level is desired.

Abstract: A method of controlling the supply of power to electrical loads with a minimum of switching surges in which the loads are each electrically subdivided into at least two equal subloads. The subloads of each load can be connected each time arbitrarily in at least three main power stages to an A.C. mains. In order to obtain a minimum switching surge effect on the A.C. mains while providing finer power control six additional intermediate power stages are provided, in which starting from one of the three main power stages, the subloads are switched in a continuously repeated cycle of six A.C. half waves in the first intermediate power stages during the third and sixth half waves in each cycle and in the second intermediate power stages additionally during the second and fifth half waves each time to the next lower main power stage, which in the case of a series arrangement is that in which the power consumption is switched off.

Abstract: A circuit is provided for distributing load current among multiple power transistors in an output stage, each power transistor being adapted to conduct current over a different range of collector-emitter voltages. The circuit includes a first power transistor having a large ballast resistance for conducting current between the input and output of the circuit when the input/output voltage differential is high, and a second power transistor having a small ballast resistance for conducting current between the input and output of the circuit when the input/output voltage differential is low. Both transistors respond to a single control signal, and buffering is provided to prevent either transistor from overloading the common control point. Individual current limit protection circuitry is provided for each transistor, including a foldback network which reduces the current limit value of the current limit circuitry when the input/output voltage differential reaches a threshold value.

Abstract: A DC-to-DC power converter is constructed by coupling two parallel-connected inductors in series with a DC input power source. A communication switch is connected in series of each of the inductors. One terminal of each of these switches is connected to one terminal of the input power supply, and the other terminal of both of the switches is connected to the common side of the power supply. The commutation switches are controlled so that they have a switching duty cycle that is greater than 50%. Thus, whenever one of the switches turns off or on, the other switch will remain engaged during this switching time. As a result of this construction, the sum of the currents that flow through the inductors provides an output current to the load which has a greatly reduced ripple and a more constant output current. Also, harmonics of lesser amplitude and higher frequency content are drawn from lines, reducing the size of filter components required to reduce these input-current harmonics.

Abstract: A voltage regulator circuit which provides a regulated output voltage by regulating output current at an output terminal is provided. The voltage regulator circuit operates in response to a clocked control signal. The regulated output voltage and a delayed signal of the regulated output voltage are both used to bias a selected one of series-connected transistors which sink current from the output terminal in response to the value of the output voltage and the frequency of the clocked control signal. A second control signal is provided for enabling or disabling the voltage regulator circuit.

Abstract: A voltage converting circuit has an output MIS transistor which gives a low output impedance and outputs an intermediate level of power source voltage. The output level is set with a high accuracy through a voltage dividing ratio determined by an impedance element. This impedance element is connected with a compensating MIS transistor to compensate for variations of the gate threshold voltage caused by the manufacturing process.

Abstract: The invention relates to a controlled source of current (1) having an inductive load (3), particularly a gradient coil adaptable to a nuclear spin imaging assembly. In order to cut down the reversal time of a current flowing in the load, the circuit is provided, according to the invention, with controlled energy storage instruments (2) connected in series with source of current (1) and inductive load (3) for increasing the rate of conversion of energy stored in said inductive load (3). Said instruments (2) preferably comprise capacitor means (C1, C2) and switch means (F1 . . . F4) for controlling the capacitors, facilitating a quick transfer of energy into or out of load (3). Said switch means (F1 . . . F4) are controlled by means of instruments (6) sensing a current flowing in inductive load (3), the conversion of energy being thus accurately controlled.

Abstract: A monolithically integratable control circuit for switching inductive loads, comprising a Darlington-type final stage, is described. The base of the Darlington control transistor is coupled to the collector of a transistor for extracting charge, the transistor conducting in phase opposition to the Darlington control transistor. The emitter of the transistor for extracting charge is coupled to the negative supply terminal and to the output terminal of the final stage, via a first and a second diode respectively.

Abstract: An automatic linear compression circuit for a telephone "handsfree" loudspeaker is provided. The circuit consists of a variable attenuator the level of attenuation of which is controlled by the input signal level. The input signal is passed through a positive peak detector to obtain a time averaged signal corresponding to the average positive peak values of the input signal and this time averaged signal is compared against a time increasing reference voltage. As long as the reference voltage is below the value of the time averaged signal a positive attenuator control signal is derived. This positive control signal keeps the attenuator portion of the circuit operative. In the attenuator the input voltage is sampled to a first capacitor. The first capacitor is subsequently connected to and disconnected from a second capacitor a number of times as long as the positive attenuator control signal is present.

Abstract: CMOS reference voltage generation circuit comprising p- and n-channel MOS transistors in series from Vcc to ground having their gates and drains interconnected. The circuit includes transmission gates for isolating the reference voltage node, and a device for enhancing the slew rate of said node.

Abstract: A voltage comparator with both analog and digital outputs. The analog output being useful to control a analog processer such as a voltage regulator while the digital output gives an indication of the controlled state. The present circuitry may be adapted as a lowcost means of adding microprocessor control to an ongoing process whose behavior is dependent upon the state of another parameter such as the voltage exhibited by a non-rechargeable battery supply.

Abstract: In a buck-boost, switching regulator, separate signals are developed to control duty cycles of regulator switches. Control exercised by a pair of feedback-determined reference signal voltages through which a ramp signal is swept at inputs of separate comparators, comparator outputs control respective switches. A predetermined maximum voltage difference is permitted between the reference signal voltages. The reference used to control switching of one end of the regulator inductance is limited to a minimum voltage corresponding to a minimum duty cycle greater than 0% while the other reference is used to control the other end of that inductance and is limited to a maximum voltage corresponding to a minimum duty cycle less than 100%. A current limiting feedback from one of the switches is operated in response to current in excess of a predetermined level to force the ramp signal to a level corresponding to 0% duty cycle for both switches at the same time.

Abstract: A programmable attenuator includes MOS FET switches to electronically select a plurality of attenuation factors in a 1-2-5 step sequence. Such an attenuator is particularly suited for use in the input circuit of an oscilloscope.

Abstract: A testable load driving circuit apparatus includes a solid-state load driver for controlling AC current loads coupled in series with a winding of a saturable core reactor used for sensing the presence or absence of load current through a load current monitor which is coupled to another winding in the reactor. The load driving circuitry may be tested during circuit operation by injecting a signal of insufficient duration to substantially affect the load circuit.

Abstract: Methods for operating a control circuit, having a programmable signal characteristic, in a manner so as to gradually vary a D.C. analog output level from an initial value to a final value, as well as for abrupt changes therein, when an isolation-and-rectification network is used to recover a D.C. voltage of programmably controlled amplitude. The methods also provide for a pulsed output condition in a circuit for providing a periodic signal of programmably controlled amplitude. In such a circuit, the output signal amplitude may be controlled by external data signals to values less than, equal to and greater than, the substantially constant amplitude of an oscillator waveform. Both programmable (computer-controlled) and hard-wired circuitry are disclosed for controlling the output signal by the methods of this invention.

Abstract: A device including a main circuit comprising a switching main transistor unit, a smoothing reactor, a smoothing condenser and a commutation diode. To control the conduction and nonconduction of said main transistor unit by means of the output obtained by detecting and amplifying the output voltage of said main circuit, the main transistor unit comprises at least two main transistors connected in parallel with each other. A secondary winding of a current transformer is connected between the bases of the main transistors. A parallel circuit comprising a diode and a condenser is connected between the neutral point of the secondary winding and the emitters of the main transistors.

Abstract: A circuit for providing the gate of a bubble memory with a precision current pulse at a high voltage is manufactured using a low voltage process; i.e. BV.sub.ceo is approximately 18 volts. In order to accomplish this, first and second voltage level shifting stages are cascoded and the output transistors thereof are used as Zener level shifters each level shifting downward by a BV.sub.ceo when only a small voltage is dropped across the load. If the voltage drop across the load increases, the cascoded output transistors may enter their active region and are prevented from going into saturation by saturation clamps so as to not introduce unwanted delays in the rise or fall times of the current pulse.

Abstract: Band gap voltage regulator employing a self-balancing bridge circuit for controlling current flow through two parallel branches. Voltage points in each branch are alternately sampled and applied to one input of a comparator in a delta modulator circuit. The output of the delta modulator circuit is applied to the other input of the comparator. The output of the comparator is applied to a control circuit which controls a current source in each of the two branches. The voltages at each voltage point are alternately compared with the voltage at the other input of the comparator, and the result is employed to control the current sources so that the voltages at both points are equalized despite any offset voltage in the comparator.

Abstract: A power supply particularly suited for driving coils in a magnetic nuclear resonance device, or scanner, is described. Bipolar switches driven by field-effect devices are used to couple the coil to a high potential when a rapid current change is required, control devices also comprises bipolar transistors driven by field-effect transistors are used to control the current through the coil in steady state conditions.

Abstract: A circuit, for providing a periodic signal of programmably controllable amplitude, includes an oscillator having a substantially constant amplitude signal of desired frequency and waveform at an output thereof connected to the input of a first programmable voltage divider having its output connected to one input of an operational amplifier. The remaining operational amplifier input is connected to the output thereof via a second programmable voltage divider used as a programmably controllable feedback network. The operational amplifier output signal amplitude may be controlled by external data signals to values less than, equal to, and greater than, the substantially constant oscillator waveform amplitude. Both computer and hard-wired circuitry for controlling the output signal are disclosed. An isolation-and-rectification network may be used to recover a D.C. voltage of programmably controlled amplitude.

Abstract: A step-controlled attenuator circuit which, in order to avoid audible switching clicks in audio equipment, employs current-controlled switches. A switch is switched on by means of a gradually increasing control current and a switch to be switched off is turned off by means of a gradually decreasing control current.

Abstract: An improved induction heating apparatus comprises a full bridge inverter with each inverter leg fabricated of first and second serially coupled field effect transistors. A control apparatus coupled to the gate of each field effect transistor of each leg alternately renders the first and second field effect transistors of each inverter leg conductive. By varying the phase delay between initiation of alternate conduction of the field effect transistors of one inverter leg and subsequent initiation of alternate conduction of the field effect transistors of the other inverter legs in response to operator commands, smooth induction heating apparatus power control is achieved.

Abstract: An electronic control system for a high power load is provided with a plurality of parallel current paths divided into two groups (11-12), with control devices (Q.sub.1 -Q.sub.n) in the current paths of one group each having a current limiting resistor (13), and control devices (Q.sub.21, Q.sub.22) in the current paths of the other group each having no current limiting resistor, so that when the control devices of the second group are turned fully on, a short circuit is achieved by the arrangement of parallel current paths. Separate but coordinated control signals (1, 2) are provided by suitable means (P.sub.1 -P.sub.3) to first turn on the control devices of the first group and increase their conduction toward saturation as a function of control input, and when fully on, or shortly before, to turn on the control devices of the second group and increase their conduction toward saturation as a function of the control input as that input continues to increase.

Abstract: A circuit, for controlling the output level of a load circuit connected thereto, has a single input for receiving a control signal to provide both a selectable level on/off output signal at a first output connected to an on/off terminal of the load circuit, and a pair of essentially equal control currents drawn in shunt from a pair of output terminals connected to load output-level-setting input terminals. The shunt control currents are provided by a current-mirror circuit having a pair of substantially identical current sinks, each responsive to an input signal applied thereto in parallel from the single control circuit input.

Abstract: A method and circuit as disclosed herein for varying the current to N electrical loads by the use of SCR's, the arrangement being such that the total current is sinusoidal and of uniform amplitude at a particular setting. The technique involves the steps of generating a load sequence waveform, the period of which is nN full cycles of the ac source where n is any positive integer, and, during each period of the waveform, generating a load firing pattern for initiating the flow of a current I in each load, the load pattern being such that (a) the currents in each of the loads are initiated at instants which are n full cycles of the ac source apart, and (b) maintaining the current in each load for d full cycles of the ac source, where d is a duty factor and is any positive integer equal to or greater than n, but less than or equal to nN, whereby the total current drawn from the ac source is uniform and equal to dI/n.

Abstract: A temperature-compensated IC voltage reference comprising a Zener diode serving as the principal voltage source, in combination with a compensating voltage source including a transistor providing a forward-biased junction, and control circuitry. The compensating voltage is summed with the Zener voltage to produce a reference voltage. The compensating voltage source includes an adjustment element for trimming the reference output to a specified voltage, and the control circuitry operates with that adjustment element to automatically produce optimum temperature compensation when the output has been adjusted to the specified value.

Abstract: Two high voltage power supplies having negative outputs with respect to common are combined to provide positive as well as negative output with respect to common. An operational preamplifier is used as an inverter. The combination includes provision for programming by means of a voltage returned to common making the system compatible with Conventional remote control systems.

Abstract: Two high voltage power supplies programmable by external voltage and each having their positive output terminals as common are combined so that the output has the negative terminal grounded. Also the input programming voltage is applied referenced to ground.