LED Color and Brightness Control Apparatus and Method

A method for controlling brightness and color of a group of red, green and blue light emitting diode channels, comprising:

• in a lighting module comprising a red light emitting diode channel, a green light emitting diode channel and a blue light emitting diode channel, based on a predetermined color, determining three color digital values and saving the three color digital values in three corresponding color registers;
• based on a predetermined brightness level, determining a brightness digital value and saving the brightness digital value in a brightness register;
• and
• multiplying the three color digital values with the brightness digital value to achieve three PWM signals to control currents flowing through the red light emitting diode channel, the green light emitting diode channel and the blue light emitting diode channel, respectively.

A system comprising:

• a plurality of lighting modules, each of which comprises a red light emitting diode channel, a green light emitting diode channel and a blue light emitting diode channel;
• and
• a light emitting diode control apparatus comprising:
• a bandgap voltage reference configured to generate a current reference for controlling the plurality of lighting modules;
• a plurality of MOSFET devices connected in parallel and coupled between a cathode of one light emitting diode channel and ground, wherein the plurality of MOSFET devices is configured to control a current flowing through the light emitting diode channel;
• and
• a control circuit configured to generate gate drive signals for the plurality of MOSFET devices, wherein the gate drive signals are configured to adjust the current flowing through the light emitting diode channel based on a predetermined color and a predetermined brightness level of the light emitting diode channel.