the second power supply supplies a second power supply voltage obtained by adding {HEAD ~ a voltage} corresponding to {TAIL ~ a forward voltage drop} of the second and fourth diodes to the second predetermined voltage 
corresponding to
the second power supply supplies a second power supply voltage obtained by adding { HEAD ~ a voltage } corresponding to { TAIL ~ a forward voltage drop } of the second and fourth diodes to the second predetermined voltage
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH