Shunt device in lighting control system without neutral wire

A method of supplying power to a load having first and second load terminals, via an electronic controller connected to an external power source which is external to the electronic controller and which external power source outputs an AC voltage between a first power terminal thereof and a second power terminal thereof, wherein the load is configured to receive a load voltage between the first and second load terminals and is further configured to allow a load current to flow between the first and second load terminals, and wherein the electronic controller is configured to control at least one of the load voltage and the load current so as to selectively power the load and disable the load, the method comprising:

• providing a series combination of a bleeding circuit in series with a switch, the series combination having a first terminal directly connected to an output terminal of the electronic controller and having a second terminal directly connected to the second power terminal of the external power source,
• operating the switch to connect the bleeding circuit between the output terminal of the electronic controller and the second power terminal of the external power source when the electronic controller is in an OFF state and the load is powered OFF, the bleeding circuit providing a current path for leakage current between the output terminal of the electronic controller and the second power terminal of the external power source,
• operating the switch to disconnect the bleeding circuit between the output terminal of the electronic controller and the second power terminal of the external power source when the electronic controller is in an ON state and the load is powered ON, and
• before disconnecting the bleeding circuit between the output terminal of the electronic controller and the second power terminal of the external power source, delaying the disconnection of least 100 msec after transition of the electronic controller from the OFF state to the ON state to enable the electronic controller to remain operable during an initial ON state, wherein the leakage current continues to have a current path between the output terminal of the electronic controller and the second power terminal of the external power source for the duration of the delay.

A device configured to be connected to an output terminal of an electronic controller, which in turn has a single input terminal connected to a first power terminal of an external power source which is external to the electronic controller and which external power source outputs an AC voltage between the first power terminal and a second power terminal thereof, the device comprising:

• a series combination of a bleeding circuit in series with a switch, the series combination having a first terminal configured to be directly connected to an output terminal of the electronic controller and having a second terminal configured to be directly connected to the second power terminal of the external power source;
• and
• a switch control device configured to detect whether the electronic controller powers a load or disables the load, the switch control device further configured to:
• connect the bleeding circuit between the output terminal of the electronic controller and the second power terminal of the external power source when the electronic controller is in an OFF and the load is powered OFF state such that the bleeding circuit provides a current path for leakage current between the output terminal of the electronic controller and the second power terminal of the external power source,
• disconnect the bleeding circuit between the output terminal of the electronic controller and the second power terminal of the external power source when the electronic controller is in an ON state and the load is powered ON, and
• before disconnecting the bleeding circuit between the output terminal of the electronic controller and the second power terminal of the external power source, delay the disconnection by least 100 msec after transition of the electronic controller from the OFF state to the ON state to enable the electronic controller to remain operable during an initial ON state, wherein the leakage current continues to have a current path between the output terminal of the electronic controller and the second power terminal of the external power source for the duration of the delay.