{TAIL ~ a pull up voltage supply circuit}, connected with the first power supply and the second power supply, for supplying {HEAD ~ the pull up voltage} 
{ TAIL ~ a pull up voltage supply circuit } , connected with the first power supply and the second power supply , for supplying { HEAD ~ the pull up voltage }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD