UCD90160

www.ti.com

SLVSAC8A

– NOVEMBER 2010 – REVISED APRIL 2011

Figure 8. Fusion GUI Flash-Error Log (Logged Faults)

POWER-SUPPLY SEQUENCING

The UCD90160 can control the turn-on and turn-off sequencing of up to 16 voltage rails by using a GPIO to set a

power-supply enable pin high or low. In PMBus-based designs, the system PMBus master can initiate a

serial bus. In pin-based designs, the PMBUS_CNTRL pin can also be used to sequence-on and sequence-off.

The auto-enable setting ignores the OPERATION command and the PMBUS_CNTRL pin. Sequence-on is

started at power up after any dependencies and time delays are met for each rail. A rail is considered to be on or

limit. The rail is still in regulation until the voltage drops below power-good off (POWER_GOOD_OFF). In the

case that there isn't voltage monitoring set for a given rail, that rail is considered ON if it is commanded on (either

by

OPERATION

command,

PMBUS

CNTRL

pin,

or

auto-enable)

and

(TON_DELAY

+

TON_MAX_FAULT_LIMIT) time passes. Also, a rail is considered OFF if that rail is commanded OFF and

(TOFF_DELAY + TOFF_MAX_WARN_LIMIT) time passes

(1)

In this document, configuration parameters such as Power Good On are referred to using Fusion GUI names. The UCD90xxx

Sequencer and System Health Controller PMBus Command Reference name is shown in parentheses (POWER_GOOD_ON) the first

time the parameter appears.

Copyright

© 2010–2011, Texas Instruments Incorporated

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