Controllable-load circuit for use with a load control device

1. A method for controlling an amount of power delivered from an AC power source to an electrical load, the method comprising:

receiving a phase-control voltage from a dimmer switch, the phase-control voltage characterized by a conduction period;

controlling the amount of power delivered to the electrical load in response to the conduction period of the phase-control voltage;

conducting a pulse of controllable-load current from the AC power source through the dimmer switch for a first portion of each half-cycle of the AC power source;

maintaining a magnitude of the controllable-load current at an initial constant magnitude for a second portion of each half-cycle of the AC power source, wherein the second portion follows the first portion;

decreasing the magnitude of the controllable-load current from the initial constant magnitude to a decreased constant magnitude;

maintaining the magnitude of the controllable-load current at the decreased constant magnitude for the second portion of each half-cycle of the AC power source;

based at least in part on decreasing the magnitude of the controllable-load current from the initial constant magnitude to the decreased constant magnitude, monitoring the conduction period of the phase-control voltage;

determining whether the conduction period of the phase-control voltage remains substantially constant;

further adjusting the magnitude of the controllable-load current from the decreased constant magnitude to an adjusted constant magnitude based at least in part on determining whether the conduction period of the phase-control voltage remains substantially constant; and

maintaining the magnitude of the controllable-load current at the adjusted constant magnitude for the second portion of each half-cycle of the AC power source.

2. The method of claim 1 , wherein the decreased constant magnitude is less than the initial constant magnitude and greater than approximately zero amps.

3. The method of claim 2 , wherein decreasing the magnitude of the controllable-load current further comprises decreasing the magnitude of the controllable-load current by a predetermined amount from the initial constant magnitude to the decreased constant magnitude.

4. The method of claim 3 , wherein further adjusting the magnitude of the controllable-load current further comprises decreasing the magnitude of the controllable-load current by the predetermined amount when the conduction period of the phase-control voltage remains substantially constant.

5. The method of claim 4 , wherein further adjusting the magnitude of the controllable-load current further comprises:

incrementally decreasing the magnitude of the controllable-load current by the predetermined amount until the magnitude of the controllable-load current is equal to a minimum magnitude; and

ceasing subsequent adjustment of the magnitude of the controllable-load current after the magnitude of the controllable-load current is equal to the minimum magnitude.

6. The method of claim 3 , wherein further adjusting the magnitude of the controllable-load current further comprises increasing the magnitude of the controllable-load current by the predetermined amount when the conduction period of the phase-control voltage does not remain substantially constant.

7. The method of claim 1 , wherein adjusting the magnitude of the controllable-load current further comprises decreasing the magnitude of the controllable-load current to a minimum magnitude, the method further comprising:

ceasing subsequent adjustment of the magnitude of the controllable-load current is maintained constant after the magnitude of the controllable-load current is equal to the minimum magnitude.

8. The method of claim 7 , wherein the minimum magnitude is approximately zero amps.

9. The method of claim 1 , further comprising:

transmitting a start-adjustment message before decreasing the magnitude of the controllable-load current; and

transmitting a stop-adjustment message after adjusting the magnitude of the controllable-load current.

10. The method of claim 1 , further comprising:

receiving a start-adjustment message;

maintaining the magnitude of the controllable-load current at the initial constant magnitude in response to receiving the start-adjustment message;

receiving a stop-adjustment message; and

decreasing the magnitude of the controllable-load current from the initial constant magnitude to the decreased constant magnitude in response to receiving the stop-adjustment message.

11. A method for controlling an amount of power delivered from an AC power source to an electrical load, the method comprising:

receiving a phase-control voltage from a dimmer switch, the phase-control voltage characterized by a conduction period;

conducting a controllable-load current from the AC power source through the dimmer switch;

maintaining a magnitude of the controllable-load current constant for at least a portion of each half-cycle of the AC power source;

determining a total number of load control devices that are coupled to the dimmer switch and are receiving the phase-control voltage; and

decreasing the magnitude at which the controllable-load current is maintained constant from an initial magnitude to a decreased magnitude;

wherein decreasing the magnitude at which the controllable-load current is maintained constant further comprises controlling the magnitude at which the controllable-load current is maintained constant in response to the total number of load control devices that are coupled to the dimmer switch.

12. The method of claim 11 , wherein determining the total number of load control devices that are coupled to the dimmer switch further comprises transmitting a query message and receiving at least one query response message via a communication circuit; and

wherein the decreased magnitude at which the controllable-load current is maintained constant is equal to a maximum magnitude divided by the total number of load control devices coupled to the dimmer switch.

13. A method of controlling current drawn from an AC power source through a dimmer switch, the method comprising:

receiving a phase-control voltage from the dimmer switch, the phase-control voltage characterized by a conduction period;

conducting a pulse of controllable-load current from the AC power source through the dimmer switch for a first portion of each half-cycle of the AC power source;

maintaining a magnitude of the controllable-load circuit at an initial constant magnitude for a second portion of each half-cycle of the AC power source, wherein the second portion follows the first portion;

decreasing the magnitude at which of the controllable-load current during the second portion of each half-cycle of the AC power source, such that the magnitude is decreased from the initial constant magnitude to a decreased constant magnitude;

based at least in part on decreasing the magnitude of the controllable-load current from the initial constant magnitude to the decreased constant magnitude, monitoring the conduction period of the phase-control voltage;

determining whether the conduction period of the phase-control voltage remains substantially constant; and

further adjusting the magnitude of the controllable-load current during the second portion of each half-cycle of the AC power source from the decreased constant magnitude to an adjusted constant magnitude based at least in part on determining whether the conduction period of the phase-control voltage remains substantially constant.

14. The method of claim 13 , wherein the decreased constant magnitude is less than the initial constant magnitude and greater than approximately zero amps.

15. The method of claim 14 , wherein decreasing the magnitude of the controllable-load current during the second portion of each half-cycle of the AC power source further comprises decreasing the magnitude of the controllable-load current by a predetermined amount from the initial constant magnitude to the decreased constant magnitude; and

wherein further adjusting the magnitude of the controllable-load current further comprises decreasing the magnitude of the controllable-load current by the predetermined amount when the conduction period of the phase-control voltage remains substantially constant.

16. The method of claim 14 , wherein decreasing the magnitude of the controllable-load current during the second portion of each half-cycle of the AC power source further comprises decreasing the magnitude of the controllable-load current by a predetermined amount from the initial constant magnitude to the decreased constant magnitude; and

wherein further adjusting the magnitude of the controllable-load current further comprises increasing the magnitude of the controllable-load current by the predetermined amount when the conduction period of the phase-control voltage does not remain substantially constant.

17. The method of claim 13 , wherein the adjusted constant magnitude is approximately zero amps.

18. The method of claim 13 , wherein further adjusting the magnitude of the controllable-load current further comprises increasing the magnitude of the controllable-load current back to the initial constant magnitude when the conduction period of the phase-control voltage does not remain substantially constant.

19. The method of claim 13 , wherein further adjusting the magnitude of the controllable-load current further comprises decreasing the magnitude of the controllable-load current to a minimum magnitude, the method further comprising:

ceasing subsequent adjustment of the magnitude of the controllable-load current after the magnitude of the controllable-load current is equal to the minimum magnitude.

20. The method of claim 13 , further comprising:

transmitting a start-adjustment message before decreasing the magnitude of the controllable-load current; and

transmitting a stop-adjustment message after adjusting the magnitude of the controllable-load current.

21. The method of claim 13 , further comprising:

receiving a start-adjustment message;

maintaining the magnitude of the controllable-load current at the initial constant magnitude in response to receiving the start-adjustment message;

receiving a stop-adjustment message; and

decreasing the magnitude of the controllable-load current from the initial constant magnitude to the decreased constant magnitude in response to receiving the stop-adjustment message.

22. The method of claim 13 , further comprising:

controlling an amount of power delivered to the electrical load in response to the phase-control voltage received from the dimmer switch.