Abstract: A method and apparatus for providing electrical power through two terminals to a load wherein a portion of a LC filter circuit is connectable to each of the terminals. A feedback circuit having a sense capacitor is operably couplable to both portions of the LC output filter. The feedback circuit provides a feedback signal when a frequency of AC voltage across the sense capacitor substantially reaches the resonant frequency of the LC output filter so as to actively damp the voltage across the load.

Abstract: A circuit for providing a current through a load includes a first bridge circuit connectable to the load. The first bridge circuit selectively applies a voltage across the load. A second bridge circuit is connected to the first bridge circuit and is connectable to a power supply. The second bridge circuit selectively applies voltage to terminals of the first bridge circuit.

Abstract: A digital process generates a pulse-width modulated (PWM) signal for providing current to a load. In one embodiment, an input signal is repeatedly sampled at times corresponding to edges of a reference square wave. The sampled values are used to produce a PWM signal, each pulse of the PWM signal having a width corresponding to one of the sampled values. In another embodiment, the sampled values are used to produce a series of intermediate pulses, the intermediate pulses being used to construct an output PWM signal. The pulses of the output PWM signal generally have leading and trailing edges which do not coincide with the times at which sampling occurs. Therefore, in the second embodiment, sampling does not occur when the PWM signal is opening or closing a switch, and the sampling tends to occur near the average value of the input signal.

Abstract: The invention icludes a device for protecting electronic circuitry from damage, especially damage resulting from high neutron flux density produced by a nuclear explosion. The invention protects the circuitry by disabling its power supply system upon detection of the nuclear event. The power supply system is disabled both by short-circuiting the main power supply, which provides control voltages to various subsidiary powert supplies, and by short-circuiting all the output filter capacitors in the system, which may have a substantial residual charge. The invention periodically and automatically attempts to re-start the power supply system, but the system can be re-started only if the nuclear event detector is not actuated. The circuit made according to the invention is entirely analog, and therefore does not depend, for its operation, on the continued functioning of the circuitry to be protected.

Abstract: A current source is controlled by the output signal from a digital to analog converter. The output signal from the digital to analog converter is applied to an amplifier unit. The output of the amplifier unit controls current through a pass transistor element, the pass transistor element current being the current applied to the load impedance. A feedback signal is generated by a differential amplifier in response to the current applied to the load impedance. The output signal from the difference amplifier is applied to an input terminal of the digital to analog converter with a polarity resulting in a change in the output signal of the amplifier unit which compensates for any change in the current through the load impedance. A voltage level changing element is included in the pass transistor control terminal to interrupt the current to the load impedance in the event of a degradation in the power supply.