Sets or queries the falling current slew rate. This is 
only applicable for CC slew rate priority mode. 
0.01A/s~72.00A/s (PSW 30-36) 
0.1A/s~144.0A/s (PSW 30-72) 
0.1A/s~216.0A/s (PSW 30-108) 
0.01A/s~27.00A/s (PSW 80-13.5) 
0.01A/s~54.00A/s (PSW 80-27) 
0.01A/s~81.00A/s (PSW 80-40.5) 
0.01A/s~14.40A/s (PSW 160-7.2) 
0.01A/s~28.80A/s (PSW 160-14.4) 
0.01A/s~43.20A/s (PSW 160-21.6) 
0.001A/s ~ 9.000A/s (PSW 250-4.5) 
0.01A/s ~ 18.00A/s (PSW 250-9) 
0.01A/s ~ 27.00A/s (PSW 250-13.5) 
0.001A/s ~ 2.880A/s (PSW 800-1.44) 
0.001A/s ~ 5.760A/s (PSW 800-2.88) 
0.001A/s ~ 8.640A/s (PSW 800-4.32)