Table 12. supply event register – Rainbow Electronics MAX5965B User Manual
Page 30
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
30
______________________________________________________________________________________
The MAX5965A/MAX5965B continuously monitor the
power supplies and set the appropriate bits in the sup-
ply event register (Table 12). V
DD_OV
/V
EE_OV
is set to 1
whenever V
DD
/V
EE
exceeds its overvoltage threshold.
V
DD_UV
/V
EE_UV
is set to 1 whenever V
DD
/V
EE
falls
below its undervoltage threshold.
OSC_FAIL is set to 1 whenever the amplitude of the
oscillator signal at the OSC_ input falls below a level
that might compromise the AC disconnect detection
function. OSC_FAIL generates an interrupt only if at
least one of the ACD_EN (R13h[7:4]) bits is set high.
A thermal shutdown circuit monitors the temperature of
the die and resets the MAX5965A/MAX5965B if the
temperature exceeds +150°C. TSD is set to 1 after the
MAX5965A/MAX5965B return to normal operation. TSD
is also set to 1 after every UVLO reset.
When V
DD
and/or |V
EE
| is below its UVLO threshold, the
MAX5965A/MAX5965B are in reset mode and securely
holds all ports off. When V
DD
and |V
EE
| rise to above
their respective UVLO thresholds, the device comes out
of reset as soon as the last supply crosses the UVLO
threshold. The last supply corresponding UV and UVLO
bits in the supply event register is set to 1.
A 1 in any supply event register’s bits forces R00h[7] to
1. As with any of the other events register, the supply
event register has two addresses. When read through
the R0Ah address, the content of the register is left
unchanged. When read through the CoR R0Bh
address, the register content is cleared. A reset sets
R0Ah/R0Bh to 00100001b if V
DD
comes up after V
EE
or
to 00010100b if V
EE
comes up after V
DD
.
Table 12. Supply Event Register
ADDRESS
0Ah
0Bh
SYMBOL
BIT
R/W
R/W
DESCRIPTION
TSD
7
R
CoR
Overtemperature shutdown
V
DD_OV
6
R
CoR
V
DD
overvoltage condition
V
DD_UV
5
R
CoR
V
DD
undervoltage condition
V
EE_UVLO
4
R
CoR
V
EE
undervoltage lockout condition
V
EE_OV
3
R
CoR
V
EE
overvoltage condition
V
EE_UV
2
R
CoR
V
EE
undervoltage condition
OSC_FAIL
1
R
CoR
Oscillator amplitude is below limit
V
DD_UVLO
0
R
CoR
V
DD
undervoltage lockout condition