{HEAD ~ a processing circuit} that controls {TAIL ~ the current control signal} according to the comparison output signal to calibrate the driving current, 
controls
{ HEAD ~ a processing circuit } that controls { TAIL ~ the current control signal } according to the comparison output signal to calibrate the driving current ,
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH