Method for driving a light-emitting unit and circuit therefor

A method for driving a light emitting unit, comprising:

• providing the light emitting unit and a switching element, the light emitting unit having an input and an output and the switching element coupled to the output of the light emitting unit;
• providing a first voltage at the input of light emitting unit;
• continuously monitoring the first voltage to generate a monitor signal;
• generating an output signal from the light emitting unit in response to a state of the switching element;
• and
• using the monitor signal to control the switching element in response to the first voltage.

A method for driving a light emitting unit, comprising:

• providing the light emitting unit having first and second terminals;
• providing a switching element having a control terminal and first and second conducting terminals, the first conducting terminal coupled to the second terminal of the light emitting element;
• providing a control element having a supply input coupled for receiving an inductor signal;
• providing a first voltage at the input of light emitting unit;
• and
• using the first voltage to provide power to the control element in response to operating in a first operating mode.

A driver circuit, comprising:

• a series-connected unit having a light-emitting element having an input and an output and an inductor having first and second terminals, the first terminal coupled to the output of the light-emitting element;
• a switching element having a control terminal and first and second current conducting terminals;
• a first controller having a first input and an output, the output coupled to the control terminal of the switching element;
• and
• a second controller coupled to the first input of the first controller.