Dimmer decoder with low duty cycle handling for use with LED drivers

A system operable to control illumination from multiple light emitting diodes (LEDs) operated with a phase cut dimmer, comprising:

• an LED driver configured to generate a drive signal for controlling the supply of LED current to control illumination from the LEDs;
• and
• a dimmer decoder configured to:
• receive a dimmer sense signal with a dimmer duty cycle based on a dimmer phase angle;
• generate an LED drive signal with an LED duty cycle for driving the LED current to the LEDs, the LED duty cycle based on the dimmer duty cycle;
• and
• generate a holding current for the dimmer when the dimmer duty cycle is less than a specified threshold, including:
• generating a current sense signal corresponding to the LED current;
• generating a reference current corresponding to a minimum current through the dimmer;
• generating the holding current based on a difference between the LED current and the reference current;
• such that a current through the dimmer corresponds to the reference current.

An apparatus operable to control illumination from multiple light emitting diodes (LEDs) operated with a phase cut dimmer, comprising:

• a digital block configured to:
• receive a dimmer sense signal with a dimmer duty cycle based on a dimmer phase angle;
• generate an LED drive signal with an LED duty cycle for driving an LED current to the LEDs, the LED duty cycle based on the dimmer duty cycle;
• and
• a dynamic hold current generation circuit configured to generate a holding current for the dimmer when the pulse duty cycle is less than a specified threshold, including:
• generating a current sense signal corresponding to the LED current;
• generating a reference current corresponding to a minimum current through the dimmer;
• generating the holding current based on a difference between the LED current and the reference current;
• such that a current through the dimmer corresponds to the reference current.