Circuit and methodology for supplying pulsed current to a load, such as a light emitting diode

A circuit for controlling light intensity of a light emitting diode (LED), comprising:

• first and second reference nodes for receiving a supply voltage;
• an input node for receiving a timing signal;
• a controlled switch coupled between the first reference voltage node and the LED for supplying current to the LED, the controlled switch having a control electrode for controlling on and off states of the controlled switch;
• pull-up circuitry coupled between the control electrode and first reference voltage node;
• a pull-down switch coupled between the control electrode and second reference voltage node;
• and
• a source of reference voltage that is independent of supply voltage;
• and
• a control circuit coupled between the input node and control electrode of the controlled switch for controlling the control electrode to vary in voltage between a voltage of the first electrode of the switch and a prescribed fixed voltage, related to the reference voltage, below that of the first electrode voltage.

A circuit for supplying pulsed current to a load, comprising:

• first and second reference nodes for receiving a supply voltage;
• an input node for receiving a timing signal;
• a controlled switch coupled between the first reference voltage node and the load, the controlled switch having first and second electrodes and a control electrode for controlling on and off states of the controlled switch;
• pull-up circuitry coupled between the control electrode and first reference voltage node;
• a pull-down switch coupled between the control electrode and second reference voltage node;
• a source of reference voltage having a magnitude independent of supply voltage magnitude;
• and
• a feedback circuit configured to drive the control electrode of the controlled switch in response to the timing signal and reference voltage source.