Datasheet LTC1921 (Analog Devices) - 9

LTC1921
U U W U APPLICATIO S I FOR ATIO
47k –48V 5V RETURN FUSE STATUS R1 R2 100k 100k 3
V V SUPPLY STATUS A B
MOCD207 OK OK 0 RTN 47k 1 4 5V OK UV OR OV 1 V OUT F A UV OR OV OK 1 SUPPLY STATUS UV OR OV UV OR OV 1 8 VB OK: WITHIN SPECIFICATION OV: OVERVOLTAGE LTC1921 2 UV: UNDERVOLTAGE FUSE A
V V FUSE A FUSE B FUSE STATUS
7 5 = V = V 0 A B FUSE B OUT A = VA ≠ V 1 B ≠ V = V 1 A B R3 ≠ VA ≠ V 1* B 47k 0: LED/PHOTODIODE ON 6 1/4W OUT B 1: LED/PHOTODIODE OFF *IF BOTH FUSES (F1 AND F2) ARE OPEN, F1 SUPPLY A ALL STATUS OUTPUTS WILL BE HIGH –48V OUT –48V SINCE R3 WILL NOT BE POWERED F2 SUPPLY B 1921 F03a = LOGIC COMMON –48V
Figure 3a. Combined Supply Status
47k –48V 5V RETURN STATUS R1 R2 100k 100k MOC207 3 RTN 1 4 LOGIC V OUT F A COMMON 8 VB LTC1921
V V FUSE A FUSE B V V STATUS
2
A B
FUSE A = V = V A B OK OK 0 ALL OTHER CONDITIONS 1 7 5 OK: WITHIN SPECIFICATION FUSE B OUT A 0: LED/PHOTODIODE ON 1: LED/PHOTODIODE OFF 6 OUT B R3 47k SUPPLY A 1/4W –48V OUT –48V SUPPLY B 1921 F03b –48V
Figure 3b. All Outputs Combined
1921f 9