A summing resistor is connected across {HEAD ~ the two sense inputs}, and coupling circuitry is operable to couple voltages appearing across {TAIL ~ the current sensing resistors} to the summing resistor 
A summing resistor is connected across { HEAD ~ the two sense inputs } , and coupling circuitry is operable to couple voltages appearing across { TAIL ~ the current sensing resistors } to the summing resistor
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH