主权项 |
1. A controller for inserting signaling transitions onto a line voltage to be received by an electrical device connected to the line voltage, comprising:
an auto-transformer having first and second end terminals, and configured to include a first winding portion connected between the first end terminal and a transformer tap, and a second winding portion connected between the transformer tap and the second end terminal, the first and second end terminals connected to the line voltage; a first switch having a first switch terminal connected to the first end terminal of the auto-transformer, and a second switch terminal connected to an output node of the controller; a second switch having a first switch terminal connected to the transformer tap of the auto-transformer, and a second switch terminal connected to the output node; and a switch controller configured to output first and second switch signals responsive to a control signal, to control the first and second switches to insert the signaling transitions onto the line voltage by selectively connecting a nominal line voltage at the first end terminal and a signaling voltage at the transformer tap to the output node, the difference between the nominal line voltage and the signaling voltage being distinguishable over nominal line voltage fluctuations, and the signaling voltage being greater than a drop-out voltage of the electrical device, wherein the switch controller is further configured to output the first and second switch signals to control the first and second switches to insert a second signaling transition after a plurality of first signaling transitions, a time interval between the second signaling transition and a last of the first signaling transitions (i) being set responsive to a value of the control signal and (ii) corresponding to an action for the electrical device, the electrical device being configured to detect the signaling transitions and perform the action in response to the signaling transitions. |