{HEAD ~ an adjustable current generator} that converts {TAIL ~ a reference} current into a driving current according to a current control signal 
converts
{ HEAD ~ an adjustable current generator } that converts { TAIL ~ a reference } current into a driving current according to a current control signal
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH