{HEAD ~ a fourth switching element} disposed between a control terminal of the first switching element and a control terminal of {TAIL ~ the third switching element} 
{ HEAD ~ a fourth switching element } disposed between a control terminal of the first switching element and a control terminal of { TAIL ~ the third switching element }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL