Patent ID: 8120277

Claim:
An illumination control circuit comprising: a controlling module comprising: one or more analog output signals producing output control voltages each individually variable within a range of values, and one or more digital output signals and producing digital pulses between logic “1” and logic “0” each with relative duty cycles individually variable within a range of values; one or more intensity modules receiving said one or more analog output signals and said one or more digital output signals of said controlling module to control one or more illumination sources; wherein said one or more intensity modules are controlled according to said one or more analog output signals and said one or more digital output signals of said controlling module to vary the intensity of said illumination sources in proportion to a voltage level of said analog output signals, and additionally in proportion to the relative duty cycles of said digital pulses of said one or more digital output signals, and wherein said intensity modules each comprise a switching regulator circuit containing a switching device wherein said switching device includes an input pin capable of disabling its output and receiving in its feedback loop one of said one or more analog output signals from said controlling module; a pair of transistors configured to form an open-drain, non-inverting buffer; wherein said non-inverting buffer receives as its input one of said one or more digital output signals from said controlling module, and produces a buffered digital output signal; and wherein said buffered digital output signal from said non-inverting buffer is received by said switching device in said switching regulator circuit through said input pin.