Dimming control for led-based luminaires

A pulse width modulated (PWM) dimmer comprising:

• a source terminal;
• a load terminal;
• a power stage coupled between the source terminal and the load terminal and configured to receive from the source terminal an AC supply signal having an envelope with a positive half-cycle and a negative half-cycle for each cycle and provide to the load terminal a pulsed AC load signal that tracks the envelope and comprises a plurality of pulses in each of the positive half-cycle and the negative half-cycle for each cycle based on a control signal;
• an interface configured to receive dimming control information bearing on a dimming level;
• and
• control circuitry configured to receive the dimming control information from the interface and generate the control signal based on the dimming control information, wherein an RMS value of the pulsed AC load signal varies as the dimming level varies and corresponds to the dimming level;
• a duty cycle of the pulsed AC load signal varies as the dimming level varies;
• and the control signal is a PWM signal that corresponds with the pulsed AC load signal.

A pulse width modulated (PWM) dimmer comprising:

• a source terminal;
• a load terminal;
• a power stage coupled between the source terminal and the load terminal and configured to receive from the source terminal an AC supply signal and provide to the load terminal an AC load signal;
• a user input interface configured to, in a first mode, directly receive human input indicative of a dimming level and provide dimming control information bearing on the dimming level;
• a communication interface configured to, in a second mode, transmit fixture control information indicative of the dimming level and intended for at least one remote lighting fixture;
• and
• control circuitry configured to:
• receive the dimming control information;
• in a first mode, cause the power stage to provide the AC load signal to the load terminal, such that an RMS value of the AC load signal varies as the dimming level varies and corresponds to the dimming level;
• and
• in a second mode, cause the power stage to pass the AC supply signal substantially unaltered to the load terminal and cause the communication interface to transmit the fixture control information indicative of the dimming level to the at least one remote lighting fixture, wherein the at least one remote lighting fixture outputs light at the dimming level.