Abstract: A current control circuit for high voltage applications includes series-connected high and low voltage sources through which the current to be regulated flows. The low voltage source is a capacitor which is periodically recharged through a flyback transformer by a series of constant energy pulses having a very low duty cycle. The peak value of the flyback pulses are detected to provide a "condition signal" which is representative of the state-of-charge on the capacitor and can be used to protectively inhibit operation of the control circuit and can, in a variant of the circuit be used as an error control signal to maintain the current at a constant level. In the preferred embodiment a sensing capacitor is placed in parallel to the pulsed capacitor to detect the fluctuations in potential and form a sense current which is representative of the regulated current and which is used in a feedback loop to form a control signal for maintaining the regulated current constant.

Abstract: A power on-off reset generator for monitoring a power supply for a logic system powered from the monitored power supply. A precision-voltage sensor produces a control signal for a time delay circuit when the power supply rises above a preselected value. A delay signal is generated which maintains an active-LOW control signal to the logic system and causes a Schmitt trigger circuit to produce a HIGH control signal to the logic system at the end of the delay signal.

Abstract: A power distribution system intended for use in a highly modular desk top computer system is disclosed. The invention provides a programmable modular DC power supply including a power module that produces a first fixed regulated DC voltage which is coupled from the power module to a power bus. Thereafter the first voltage is distributed to a plurality of DC-to-DC convertors, each of which is operable to change the first DC voltage to a second regulated DC voltage selected from a plurality of programmed voltage values.

Abstract: An apparatus especially adapted for use in AC power systems of the type having a device for reducing power consumption by reducing load voltage, the apparatus having a sensor for detecting an increase in load current and for controlling a responsive increase in load voltage to compensate for the added load causing the increase in current. The apparatus can be used in three-phase AC systems for controlling each phase independently and can be made sufficiently sensitive to operate in a 28,000 Watt fluorescent light load while responding to as little as 400 Watt load additions to assure quick and efficient ignition of newly turned-on lights. A digital memory device, in the form of a state machine in the preferred embodiment, is used to control operation and timing for one to three phases while permitting low line voltage override and periodic timing override operation.

Abstract: A power supply system for operating fluorescent lamps in a hazardous atmosphere comprises a 1 kHz to 500 kHz constant current power supply which feeds primary windings of transformers which are connected together in series. Fluorescent lamps are connected across the transformer secondary windings. A voltage control circuit is connected to the supply supply output to ensure that the amount of electrical energy supplied to the transformers cannot ignite the atmosphere under any normal or fault condition. Capacitors are connected in series with the transformer primary windings to reduce the circuit reactance so that, for a given level of supply voltage, an increased number of lamps can be fed with starting voltage. Due to the substantially constant current which is fed through the transformer primary windings, the situation cannot occur that the firing of one lamp prevents the others from firing. The transformers preferably include windings to feed heaters of the lamps.

Abstract: A stabilized DC power outputs supply devices for providing a plurality of DC power outputs which are selectively consumed, is provided by use of a single power control circuit. A plurality of DC power outputs are taken out from the single power control circuit through rectifier circuits and low-pass filter circuits. A voltage of each of the DC power outputs is sensed by a corresponding voltage sensing circuit and is compared with a corresponding reference voltage at a corresponding voltage comparing circuit. Detecting circuits for detecting one of the DC power outputs which is being consumed are provided to apply to a control signal generator the output of one of the comparing circuits which is corresponding to the DC power output detected by the detecting circuits. The control signal generator provides a control signal to the single power control circuit to stabilize the voltage of the DC output which is being consumed.

Abstract: A constant current driving circuit for driving light emitting diodes, wherein a variation detecting circuit comprising a resistor and a field effect transistor is provided and the output voltage of the detecting circuit is effectively used to control the variation of electric current which flows through the driving transistor.

Abstract: The unregulated AC electrical power provided by an engine driven alternator to an airborne electronic engine control system which controls the performance of a gas turbine engine, is rectified to provide unregulated DC voltage signals for system electrical power. The system provides position control of a plurality of controlled surfaces within the engine through a plurality of digital effector servo actuators, each of which includes a mechanical assembly for providing displacement of the surface in each of two directions in response to a magnetic field provided by a respective one of two oppositely polarized solenoids disposed within the actuator.

Abstract: A wide range power conversion system which produces a highly regulated output over a wide range of variations in input AC source frequency and magnitude. A square full duty cycle voltage waveform is provided to current limiting means comprising a saturable-core reactor. The waveform has substantially constant volt-second characteristics, and the current produced by the waveform is controlled by the current limiter to provide a constant magnitude current to a load.

Abstract: A circuit for use with an oximeter system which provides constant current pulses to light-emitting diodes in a sequential and cyclical manner. The circuit maintains magnitudes of pulses in the pulse train equal to certain other pulses in the pulse train over extremes of temperature variation, voltage variation, and time duration. Each diode is energized by a series of pulses having the same magnitude, although pulse magnitudes will vary from diode to diode. Therefore, light output from one light-emitting diode remains proportional to light output from the others.

Abstract: A power supply circuit using a silicon controlled rectifier to rectify alternating voltage and apply the rectified voltage across a capacitor. To obtain one polarity of rectified voltage, the cathode of the SCR is connected to the AC source and the output circuit of a switching transistor is connected in series with the gate of the SCR. The input circuit of the transistor is connected in series with a constant voltage element across the capacitor. The switching semiconductor only conducts when the capacitor discharges to a predetermined level. To obtain the opposite polarity rectified voltage the cathode of the SCR is connected to one terminal of the capacitor and, instead of the semiconductor switch, a constant voltage device is connected between the gate of the SCR and the other terminal of the capacitor so that the SCR conducts only when the voltage across the capacitor drops below the voltage of the constant voltage device.