The operational amplifiers are a pre drive to {HEAD ~ the pass transistors} to allow {TAIL ~ smaller sense resistors} to be used 
to allow
The operational amplifiers are a pre drive to { HEAD ~ the pass transistors } to allow { TAIL ~ smaller sense resistors } to be used
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH