Abstract: Techniques for controlling motor winding current by employing ON/OFF duty cycle control switching between an upper and a lower current threshold to establish an average motor winding current approximately midway between the two thresholds. Rising current during ON time intervals is directly measured, and an upper threshold detector is employed to turn OFF a switching transistor when the upper current threshold is reached. Rather than directly measuring decay or flyback current which circulates in the motor windings through free-wheeling diodes for comparison against the lower current threshold, the decay time is simulated. A lower current threshold detector and an upper current threshold detector are employed. Following winding energization, the lower threshold current detector starts a timing device. The upper threshold current detector subsequently stops the timing device, and turns OFF the switching transistor.

Abstract: A voltage controlled semiconductor power switch including a bipolar transistor efficiently driven by a field effect transistor coupled between collector and base electrodes for providing a non-saturated conduction of the transistor and rapid switching speeds. The switch is employed in voltage converter circuits which require minimum dead time in the application of drive pulses, and have an efficient circuit operation and reduced circuit complexity.

Abstract: A free-running switching regulator of the type including a transistor switch serially-connected between a voltage source and a load is disclosed. The duty cycle of the switch is varied in response to changes in the load voltage to maintain it at a predetermined regulated magnitude. Feedback means is provided for controlling the switching frequency and the duty cycle of the switch substantially independently of the load impedance such that feedback loop stability is maintained irrespective of the load reactance and an essentially constant switching period of duration T is maintained despite changes in the load resistance.

Abstract: A battery monitor circuit for rechargeable multicell batteries that provides a reliable indication of battery failure independent of temperature, load and age, by continuously comparing the impedance of the cells of the battery against each other. Comparison means are provided responsive to a first voltage at a tapped terminal of the battery that divides the battery cells into two groups, and to a second voltage that represents a fraction of the battery voltage corresponding to the ratio of the number of cells in each group, said comparison means generating an error signal when said first and second voltages change so as to experience a reversal in relative magnitude, which is indicative of cell deterioration.

Abstract: A switching regulator having a solid state switch which turns on and off as needed to maintain output regulation, a choke which tries to maintain constant current flow, a voltage and current comparator which controls the solid state switch, and a flyback diode in series with an offset voltage which provides a current flow path for the choke when the solid state switch becomes non-conducting. The offset voltage results in a lower voltage across the diode and solid state switch when they are non-conducting. The offset control provides higher efficiencies with the most improvement at ultrasonic frequencies and higher voltages. Radio frequency interference is also significantly reduced.

Abstract: A speed control system for an electrically commutated motor which is readily adaptable to digital velocity control input and which provides highly efficient and accurate control in a relatively inexpensive manner. Desired motor rotational velocity is commanded by an input clock rate, which may be variable, rather than by a voltage or current signal. A sensor is provided for determining actual rotor position, and actual rotor position is periodically compared with instantaneous desired motor position as indicated by the time of occurance of one of the input clock signals or pulses. Depending upon the results of this periodic comparison, a dynamically established active current limit is modified. Specifically, if motor rotor actual position leads desired position, the current limit is reduced. If, on the other hand, actual motor position is lagging, the current limit is increased. If the rotor is at the correct position, or within a predetermined deadband, the current limit is unchanged.

Abstract: An electronic sensor is disclosed, having circuits for identifying electromagnetic radiation signals caused by nuclear detonations. Circuits also are provided for discriminating against false indications due to electromagnetic radiation caused by lightning.

Abstract: Circuitry is described for detecting a waveshape having a change of slope, such as the optical signal wave from a nuclear explosion. The wave is amplitude-sampled at a rate determined by a variable frequency clock pulse generator. Signal pulses indicative of the slope of the wave are generated from the amplitude samples, and a certain number of the most recently generated slope signals are stored in a shift register. Majority logic circuitry, connected to the shift register, generates an output signal when the majority of the slope signals in the shift register changes from a first slope majority to a second slope majority.

Abstract: A dc power supply system comprising two or more voltage regulator units connected in parallel to a common load, there being at least one more regulator unit provided than is required to meet the rated load current requirement. The spare or redundant regulator assumes the load automatically if another regulator fails, and does so in a manner such that it does not interfere with operation of other regulators when they are operating normally and such that its own operation is not affected by the others in the event of their failure.