UCD9080_16 Datasheet, PDF (26/38 Pages) Texas Instruments – 8-CHANNEL POWER-SUPPLY SEQUENCER AND MONITOR

UCD9080
SLVS692E – SEPTEMBER 2006 – REVISED MAY 2008................................................................................................................................................... www.ti.com
With external rail voltage divider:
Vraw = ^{1024 ´ VRAILUV} ´
R_PULLDOWN
V_REF
R_PULLDOWN + R_PULLUP
(4)
OverVoltageThresholds
The OverVoltageThreholds field in the configuration parameters specifies each rail overvoltage threshold that is
used when monitoring this rail. The address map for these registers is as follows:
ADDRESS
0xE120
0xE122
0xE124
0xE126
0xE128
0xE12A
0xE12C
0xE12E
SIZE
2
2
2
2
2
2
2
2
DEFAULT VALUE
0x0400
Overvoltage threshold for rail 8
0x0400
Overvoltage threshold for rail 7
0x0400
Overvoltage threshold for rail 6
0x0400
Overvoltage threshold for rail 5
0x0400
Overvoltage threshold for rail 4
0x0400
Overvoltage threshold for rail 3
0x0400
Overvoltage threshold for rail 2
0x0400
Overvoltage threshold for rail 1
DESCRIPTION
The format for each register is as follows:
15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
Vraw
The voltage conversion is dependent upon the configured voltage reference, and the pullup/pulldown resistors
used on the board for each rail. The voltage reference is selected as either 2.5 V (internal) or V_CC (external). The
formula to convert the desired rail OverVoltageThreshold to Vraw follows:
Without external rail voltage divider:
Vraw = ^{1024 ´ VRAILOV}
V_REF
(5)
With external voltage divider:
Vraw = ^{1024 ´ VRAILOV} ´
R_PULLDOWN
V_REF
R_PULLDOWN + R_PULLUP
(6)
RampTime
The RampTime field in the configuration parameters specifies the maximum amount of time for each rail to
achieve regulation. The address map for these registers is as follows:
ADDRESS
0xE130
0xE132
0xE134
0xE136
0xE138
0xE13A
0xE13C
0xE13E
SIZE
2
2
2
2
2
2
2
2
DEFAULT VALUE
DESCRIPTION
0x0FA0
Maximum voltage ramp time for rail 1
0x0FA0
Maximum voltage ramp time for rail 2
0x0FA0
Maximum voltage ramp time for rail 3
0x0FA0
Maximum voltage ramp time for rail 4
0x0FA0
Maximum voltage ramp time for rail 5
0x0FA0
Maximum voltage ramp time for rail 6
0x0FA0
Maximum voltage ramp time for rail 7
0x0FA0
Maximum voltage ramp time for rail 8
15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
0
0
0
0
RAMPTIME
RAMPTIME = RAILn RailTime (in units of ms).
26
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