Abstract: Apparatus and methods for selective protection of an electrical load from disturbances on an input power line. A power protection circuit includes a selectively variable inrush current limiting circuit and a switch for disconnecting the input power line from the load. A control circuit determines that the electrical load is in a first operational state, such as a standby mode or normal operation, or a second operational state, such as full operation at rated current. The power protection circuit provides variable inrush current limiting to the electrical load in response to a first category of disturbances when the electrical load is in the first operational state. The power protection circuit inhibits disconnecting the electrical load in response to a second category of disturbances when the electrical load is in the second operational state. Species of selectively variable current limiting circuits are also described.

Abstract: Novel circuits for providing ride-through during unpredictable power line disturbances are disclosed in connection with low-power electronic devices. Such low-power electronics devices are typically subjected to undesirable lock-ups and reboots under momentary power line disturbances such as voltage sags, voltage swells, and other momentary line power disturbances. Diagnostics and visual indication are also integrated in the circuits to allow consumers to correlate equipment lock-up and malfunction with power disturbances, and to provide service providers with various analytics and historical data on the recorded disturbances. To reduce cost, the disclosed circuits utilize a simple DC capacitor without any additional power conditioning switches or converters. In one exemplary embodiment, the disclosed circuits are embedded inside a power line cord to provide a ride-through during the brief interval of time such power line disturbances occur.

Abstract: A sag corrector apparatus for providing voltages temporarily (ride-through) to a load during momentary electrical disturbances in the power supply line. In one embodiment, the disclosed apparatus compensates for voltage sags by using a variable duty cycle boost converter to boost the sagged line voltage to resemble desired voltage levels during occurrence of voltage sags. The boosted voltage available to a connected load during a sag depends on a sequence of operation of various control pulses. Duty cycle of the boost converter is controlled by changing the width (duration) of the control pulses. To prevent voltage shoot-throughs from over-boosting, an energy clamp circuit is provided to dissipate excess energy. Embodiments of the sag corrector circuit can be additionally integrated with power protection functions.

Abstract: Apparatus and methods for selective protection of an electrical load from disturbances on an input power line. A power protection circuit includes a selectively variable inrush current limiting circuit and a switch for disconnecting the input power line from the load. A control circuit determines that the electrical load is in a first operational state, such as a standby mode or normal operation, or a second operational state, such as full operation at rated current. The power protection circuit provides variable inrush current limiting to the electrical load in response to a first category of disturbances when the electrical load is in the first operational state. The power protection circuit inhibits disconnecting the electrical load in response to a second category of disturbances when the electrical load is in the second operational state. Species of selectively variable current limiting circuits are also described.

Abstract: A sag corrector apparatus for providing voltages temporarily (ride-through) to a load during momentary electrical disturbances in the power supply line. In one embodiment, the disclosed apparatus compensates for voltage sags by using a variable duty cycle boost converter to boost the sagged line voltage to resemble desired voltage levels during occurrence of voltage sags. The boosted voltage available to a connected load during a sag depends on a sequence of operation of various control pulses. Duty cycle of the boost converter is controlled by changing the width (duration) of the control pulses. To prevent voltage shoot-throughs from over-boosting, an energy clamp circuit is provided to dissipate excess energy. Embodiments of the sag corrector circuit can be additionally integrated with power protection functions.

Abstract: Novel circuits for providing ride-through during unpredictable power line disturbances are disclosed in connection with low-power electronic devices. Such low-power electronics devices are typically subjected to undesirable lock-ups and reboots under momentary power line disturbances such as voltage sags, voltage swells, and other momentary line power disturbances. Diagnostics and visual indication are also integrated in the circuits to allow consumers to correlate equipment lock-up and malfunction with power disturbances, and to provide service providers with various analytics and historical data on the recorded disturbances. To reduce cost, the disclosed circuits utilize a simple DC capacitor without any additional power conditioning switches or converters. In one exemplary embodiment, the disclosed circuits are embedded inside a power line cord to provide a ride-through during the brief interval of time such power line disturbances occur.