Load control device having a controllable filter circuit

A method for controlling a filter circuit in a load control device, the load control device comprising a first terminal adapted to be coupled to an alternating-current (AC) power source and a second terminal adapted to be coupled to an electrical load, the method comprising:

• receiving an input to turn on the electrical load;
• controlling a bidirectional semiconductor switch of the load control device to provide a phase-control voltage to the electrical load, the bidirectional semiconductor switch coupled in series between the first terminal and the second terminal;
• configuring the filter circuit for a first impedance level;
• waiting a predetermined amount of time;
• and
• after the predetermined amount of time, configuring the filter circuit for a second impedance level by rendering a controllable switch of the filter circuit conductive to connect a first capacitor of the filter circuit in series connection between the first terminal and the second terminal.

A method for controlling a controllable filter circuit in a load control device, the load control device comprising a first terminal adapted to be coupled to an alternating-current (AC) power source and a second terminal adapted to be coupled to an electrical load, the method comprising:

• determining a target intensity level of the electrical load;
• determining whether the target intensity level is in a first range or a second range;
• and
• configuring an impedance level of the filter circuit between the first and second terminals based on the determination of whether the target intensity level is in the first range or the second range.

A method for controlling a controllable filter circuit in a load control device, the load control device comprising a first terminal adapted to be coupled to an alternating-current (AC) power source and a second terminal adapted to be coupled to an electrical load, the method comprising:

• rendering a bidirectional semiconductor switch of the load control device conductive, the bidirectional semiconductor switch coupled between the first and second terminals;
• receiving a feedback signal indicating a magnitude of a voltage developed across the load control device;
• measuring a slope of the feedback signal when the bidirectional semiconductor switch is transitioning from a non-conductive state to a conductive state;
• and
• configuring an impedance level of the filter circuit between the first and second terminals in response to the slope of the feedback signal.