Patent ID: 7570235

Claim:
A communication diode driver circuit (CDDC) for selectively illuminating at least one communication diode (CD) in response to incoming digital data pulses, the communication diode driver circuit comprising: at least one Communication Light Emitting Circuit (CLEC) having a Communication Light Emitting Branch (CLEB) with at least one CD, and designed to drive said CLEB at a nominal LED drive current I N for selectively illuminating said at least one CD, each CLEC of said at least one CLEC including a driver unit for comparing a pulsed analog data voltage ADV(t) corresponding to the incoming digital data pulses, and a variable shift voltage SV(t) for issuing a pulsed drive voltage DV(t) for driving said CLEB with a pulsed LED drive current I LED (t) for selectively illuminating said at least one CD in accordance with the incoming digital data pulses, and each CLEC of said at least one said CLEC including a closed loop feedback unit for tapping said CLEB for continuously monitoring a pulsed monitor voltage MV(t) directly proportional to said LED drive current I LED (t) for increasing said shift voltage SV(t) up to a maximum shift voltage SV max less than a threshold drive voltage for continuously illuminating said at least one CD after a long absence of incoming digital data pulses, except for intermittently stepwise decreasing said shift voltage SV(t) in response to each single incoming digital data pulse contributing to a LED drive current satisfying the condition I LED (t)>I N .