Abstract:
A load control device for controlling power delivered from an AC power source to an electrical device may be configured to conduct current through earth ground and may disconnect a switching circuit to reduce an amount of current conducted through the earth ground. The load control device may comprise a controllably conductive device configured to control the power delivered from the AC power source to the electrical device so as to generate a switched-hot voltage, a switching circuit electrically coupled with a detect circuit, and a control circuit configured to render the switching circuit conductive and nonconductive. The detect circuit may generate a detect signal indicating a magnitude of the switched-hot voltage. The control circuit may be configured to monitor the detect signal and to render the switching circuit non-conductive after detecting an edge on the detect signal to reduce the total current through the earth ground.
Abstract:
A load control device may control power delivered from a power source, such as an alternating-current (AC) power source, to at least two electrical loads, such as a lighting load and a motor load. The load control device may include multiple load control circuit, such as a dimmer circuit and a motor drive circuit, for controlling the power delivered to the lighting load and the motor load, respectively. The load control device may adjust the rotational speed of the motor load in a manner so as to minimize acoustic noise generated by the load control device and reduce the amount of time required to adjust the rotational speed of the motor load. The load control device may remain powered when one of the electrical loads (e.g., the lighting load) has been removed (e.g., electrically disconnected or uninstalled) and/or has failed in an open state (has “burnt out” or “blown out”).
Abstract:
A load control device for controlling power delivered from an alternating-current power source to an electrical load may comprise a controllably conductive device, a control circuit, and an overcurrent protection circuit that is configured to be disabled when the controllably conductive device is non-conductive. The control circuit may be configured to control the controllably conductive device to be non-conductive at the beginning of each half-cycle of the AC power source and to render the controllably conductive device conductive at a firing time during each half-cycle (e.g., using a forward phase-control dimming technique). The overcurrent protection circuit may be configured to render the controllably conductive device non-conductive in the event of an overcurrent condition in the controllably conductive device. The overcurrent protection circuit may be disabled when the controllably conductive device is non-conductive and enabled after the firing time when the controllably conductive device is rendered conductive during each half-cycle.