Electronic switch having an in-line power supply

A two-wire electronic switch for controlling the power delivered from an AC power source to an electrical load, the electronic switch comprising:

• a latching relay adapted to be coupled in series electrical connection between the source and the load for turning the load on and off;
• a first bidirectional semiconductor switch coupled in parallel electrical connection with the relay, the first bidirectional semiconductor switch comprising a control input;
• a controller configured to turn on the load by first rendering the first bidirectional semiconductor switch conductive and then rendering the relay conductive, the controller configured to turn off the load by first rendering the relay non-conductive and then rendering the first bidirectional semiconductor switch non-conductive;
• an output capacitor arranged to develop a DC supply voltage for powering the controller;
• and
• an in-line power supply coupled in series electrical connection with the relay, the first bidirectional semiconductor switch being electrically connected in parallel with the series combination of the relay and the power supply, the in-line power supply being coupled to the output capacitor for generating the DC supply voltage across the output capacitor when the relay is conductive, the power supply being configured to conduct the load current through the output capacitor for at least a portion of a line cycle of the AC power source when the relay is conductive;
• wherein the first bidirectional semiconductor switch is rendered conductive in response to an over-current condition in the output capacitor of the power supply.

A two-wire electronic switch for controlling the power delivered from an AC power source to an electrical load, the electronic switch comprising:

• a latching relay adapted to be coupled in series electrical connection between the source and the load for turning the load on and off;
• a first bidirectional semiconductor switch coupled in parallel electrical connection with the relay, the first bidirectional semiconductor switch comprising a control input;
• a controller configured to turn on the load by first rendering the first bidirectional semiconductor switch conductive and then rendering the relay conductive, the controller configured to turn off the load by first rendering the relay non-conductive and then rendering the first bidirectional semiconductor switch non-conductive;
• an output capacitor arranged to develop a DC supply voltage for powering the controller;
• and
• an in-line power supply coupled in series electrical connection with the relay, the first bidirectional semiconductor switch being electrically connected in parallel with the series combination of the relay and the power supply, the in-line power supply being coupled to the output capacitor for generating the DC supply voltage across the output capacitor when the relay is conductive, the power supply comprising a second bidirectional semiconductor switch electrically connected in series with the relay and in parallel with the output capacitor, the power supply being configured to render the second bidirectional semiconductor switch non-conductive to charge the output capacitor when the relay is conductive;
• wherein the first bidirectional semiconductor switch is rendered conductive in response to an over-current condition in the output capacitor of the power supply, and the relay is rendered non-conductive in response to an over-temperature condition in the power supply.

A load control device for controlling power delivered from an AC power source to an electrical load, the load control device comprising:

• a controllably conductive device adapted to be coupled in electrical connection between the AC power source and the electrical load, the controllably conductive device arranged to conduct a load current through the electrical load when the controllably conductive device is conductive;
• a controller configured to control the controllably conductive device to be conductive and non-conductive to conduct and not conduct, respectively, the load current through the electrical load;
• a capacitor arranged to develop a DC supply voltage for powering the controller;
• and
• a power supply coupled in electrical connection with the controllably conductive device, the power supply further coupled to the capacitor for generating the DC supply voltage across the capacitor when the controllably conductive device is conductive, the power supply configured to conduct the load current through the capacitor for at least a portion of a line cycle of the AC power source when the controllably conductive device is conductive;
• wherein the controllably conductive device is rendered non-conductive in response to an over-temperature condition in the load control device.