a voltage regulator, selectively enabled and disabled in response to {TAIL ~ a control input}, {HEAD ~ a pair} of voltage monitors, 
a voltage regulator , selectively enabled and disabled in response to { TAIL ~ a control input } , { HEAD ~ a pair } of voltage monitors ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH