초록 ▼

A load control device may include a semiconductor switch, a control circuit, and first and second terminals adapted to be coupled to a remote device. The load control device may include a first switching circuit coupled to the second terminal, and a second switching circuit coupled between the first

A load control device may include a semiconductor switch, a control circuit, and first and second terminals adapted to be coupled to a remote device. The load control device may include a first switching circuit coupled to the second terminal, and a second switching circuit coupled between the first terminal and the second terminal. The control circuit may be configured to render the first switching circuit conductive to conduct a charging current from an AC power source to a power supply of the remote device during a first time period of a half-cycle of the AC power source, and further configured to render the first and second switching circuits conductive and non-conductive to communicate with the remote device via the second terminal during a second time period of the half-cycle of the AC power source.

대표청구항 ▼

1. A load control system for controlling an amount of power delivered to an electrical load from an AC power source, the system comprising: a load control device adapted to be coupled between the AC power source and the electrical load to control the amount of power delivered to the electrical load,

1. A load control system for controlling an amount of power delivered to an electrical load from an AC power source, the system comprising: a load control device adapted to be coupled between the AC power source and the electrical load to control the amount of power delivered to the electrical load, the load control device comprising a first terminal and a second terminal, the load control device comprising a first switching circuit coupled to the second terminal, and a second switching circuit coupled between the first and second terminals; anda remote device adapted to be coupled to the first terminal and the second terminal of the load control device, the remote device comprising a power supply configured to conduct a charging current from the AC power source through the first switching circuit of the load control device;wherein the load control device is configured to control the second terminal in an active pull-up state by rendering the first switching circuit conductive and the second switching circuit non-conductive, the load control device further configured to control the second terminal into an active pull-down state by rendering the second switching circuit conductive and the first switching circuit non-conductive, the load control device configured to render the first switching circuit conductive to allow the power supply of the remote device to charge through the second terminal during a first time period of a half-cycle of the AC power source, the load control device and the remote device operable to communicate with each other by controlling the second terminal into the active pull-up state and the active pull-down state during a second time period of the half-cycle of the AC power source. 2. The load control system of claim 1, wherein the load control device is further configured to control the second terminal in a high impedance state by rendering the first and second switching circuits non-conductive. 3. The load control system of claim 1, wherein the load control device further comprises a control circuit coupled to the first and second switching circuits for rendering the first and second switching circuits conductive and non-conductive. 4. The load control system of claim 3, wherein the control circuit is operable to render the first and second switching circuits conductive and non-conductive on a complementary basis to transmit a digital message via the second terminal during the second time period. 5. The load control system of claim 4, wherein the control circuit is operable to render the first switching circuit conductive and the second switching circuit non-conductive in an active pull-up state to transmit a first bit during the second time period, and to render the first switching circuit non-conductive and the second switching circuit conductive in an active pull-down state to transmit a first second during the second time period. 6. The load control system of claim 5, wherein the control circuit is operable to render the first and second switching circuits non-conductive to generate a high impedance state on the second terminal. 7. The load control system of claim 6, wherein the control circuit is operable to render the first and second switching circuits non-conductive in the high impedance state outside of the first and second time periods of the half-cycle of the AC power source. 8. The load control system of claim 4, wherein the control circuit is operable to render the first switching circuit conductive and the second switching circuit non-conductive to enable a charging path to allow the power supply of the remote device to charge through the second terminal during the first time period. 9. The load control system of claim 8, wherein the control circuit is operable to render the first switching circuit conductive and the second switching circuit non-conductive such that the first time period starts immediately following a zero-crossing at the beginning of the half-cycle of the AC power source. 10. The load control system of claim 9, wherein the remote device is operable to detect the start of the first time period for determining when the second time period will occur to receive a digital message transmitted by the load control device. 11. The load control system of claim 1, wherein the load control device further comprises an energy storage device operable to charge from the AC power source, the first switching circuit coupled between the energy storage device. 12. The load control system of claim 11, wherein the energy storage device comprises a capacitor. 13. The load control system of claim 1, wherein the load control device and the remote device are operable to transmit and receive digital messages via the second terminal during the second time period of the half-cycle. 14. The load control system of claim 13, wherein the digital messages comprise a command to control the amount of power delivered to the electrical load. 15. The load control system of claim 1, wherein the first time period is approximately 2 msec and the second time period is approximately 3.75 msec. 16. The load control system of claim 1, wherein the first time period occurs before the second time period during each half-cycle. 17. The load control system of claim 1, wherein the load control device is adapted to communicate by actively pulling up the second terminal and actively pulling down the second terminal. 18. A load control device for controlling an amount of power delivered to an electrical load from an AC power source, the load control device adapted to be coupled to a remote device, the load control device comprising: a semiconductor switch configured to conduct a load current from the AC power source to the electrical load;first and second terminals adapted to be coupled to the remote device;a first switching circuit coupled to the second terminal, the first switching circuit configured to conduct a charging current from the AC power source to a power supply of the remote device;a second switching circuit coupled between the first terminal and the second terminal; anda control circuit configured to control the semiconductor switch to control the power delivered to the electrical load, the control circuit configured to render the first switching circuit conductive to conduct the charging current from the AC power source to the power supply of the remote device during a first time period of a half-cycle of the AC power source, the control circuit further configured to render the first and second switching circuits conductive and non-conductive to communicate with the remote device via the second terminal during a second time period of the half-cycle of the AC power source. 19. The load control device of claim 18, wherein the first terminal is configured to be connected to the AC power source and the second terminal comprises an accessory terminal, the accessory terminal configured to be coupled to the remote device via accessory wiring. 20. The load control device of claim 18, wherein the first terminal is configured to be connected to the electrical load and the second terminal comprises an accessory terminal, the accessory terminal configured to be coupled to the remote device via accessory wiring.