Rainbow Electronics MAX5965B - Manual (Page 41)

MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
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The three ICUT_ bits (Tables 34a and 34b) allow pro-
gramming of the current-limit and overcurrent thresholds
in excess of the IEEE 802.3af standard limit. The
MAX5965A/MAX5965B can automatically set the ICUT
register or can be manually written to by the software
(see Table 3). Class 1 and 2 limits can also be programmed by soft-
ware independently from the classification status. See
Table 3. A reset or power-up sets R2Ah = R2Bh = 00h.
Table 32. Miscellaneous Configurations 2
ADDRESS = 29h
SYMBOL BIT R/W
DESCRIPTION
7 — Reserved
6 — Reserved
5 — Reserved
4 — Reserved
3 — Reserved
Reserved
2 — Reserved
1 R/W IVEE[1]
IVEE
0 R/W IVEE[0]
Table 34a. ICUT Registers 1 and 2
ADDRESS = 2Ah
SYMBOL BIT R/W
DESCRIPTION
Reserved 7 — Reserved
6 R/W ICUT2[2]
5 R/W ICUT2[1] ICUT2
4 R/W ICUT2[0]
Reserved 3 — Reserved
2 R/W ICUT1[2]
1 R/W ICUT1[1] ICUT1
0 R/W ICUT1[0]
Table 34b. ICUT Registers 3 and 4
ADDRESS = 2Bh
SYMBOL BIT R/W
DESCRIPTION
Reserved 7 — Reserved
6 R/W ICUT4[2]
5 R/W ICUT4[1] ICUT4
4 R/W ICUT4[0]
Reserved 3 — Reserved
2 R/W ICUT3[2]
1 R/W ICUT3[1] ICUT3
0 R/W ICUT3[0]
Table 33. Current-Limit Scaling Register
IVEE[1:0]
(ADDRESS = 29h)
CURRENT LIMIT
(%)
00 Default
01 -5
10 -10
11 -15
The IVEE bits enable the current-limit scaling (Table
32). This feature is used to reduce the current limit for
systems running at higher voltage to maintain the desired output power. Table 33 sets the current-limit
scaling register. A reset or power-up sets R29h = 00h.