XRP7725 Datasheet, PDF (21/34 Pages) Exar Corporation – Power Management System

XRP7725
Intel Node Manager Compatible Programmable
Power Management System
Multiple selections will be combined
using the OR logic function.
• External Clock-in – enables the
controller to lock to an external clock
including one from another XRP7725
applied to the GPIO0 pin. There are two
ranges of clock frequencies the controller
accepts, selectable by a user.
• HW Power Good – the Power Good
hardware monitoring function. It can only
be forwarded to GPIO1. This is an output
voltage monitoring function that is a
hardware comparison of channel output
voltage against its user defined Power
Good threshold limits (Power Good
minimum and maximum levels). It has no
hysteresis. Multiple channel selections will
be combined using the AND logic function
of all channels selected.
The Power Good minimum and maximum
levels are expressed as percentages of the
target voltage.
“PGood Max” is the upper window and
“PGood Min” is the lower window. The
minimum and maximum for each of these
values can be calculated with the following
equation:
ܤܵܮ ∗ ܰሺܸ݉ሻ ∗ 10^ହ
ܦܱܱܩܲሺ%ሻ ൌ
ݐ݁݃ݎܽݐܸሺܸሻ
Where N=1 to 63 for the PGOOD Max
value and N=1 to 62 for the PGOOD Min
value. For example, with the target
voltage of 1.5V and set point resolution of
2.5mV (LSB), the Power Good min and
max values can range from 0.17% to
10.3% and 0.17% to 10.5% respectively.
A user can effectively double the range by
changing to the next higher output
voltage range setting, but at the expense
of reduced set point resolution.
• External Clock-out – clock sent out
through GPIO1 for synchronizing with
another XRP7725 (see the clock out
section for more information).
FAULT HANDLING
There are seven different types of fault
handling:
• Under Voltage Lockout (UVLO)
monitors voltage supplied to the V_CC pin
and will cause the controller to shut down
all channels if the supply drops to critical
levels.
• Over Temperature Protection (OTP)
monitors temperature of the chip and will
cause the controller to shut down all
channels if temperature rises to critical
levels.
• Over Voltage Protection (OVP)
monitors regulated voltage of a channel
and will cause the controller to react in a
user specified way if the regulated voltage
surpasses threshold level.
• Over Current Protection (OCP)
monitors current of a channel and will
cause the controller to react in a user
specified way if the current level
surpasses threshold level.
• Start-up Time-out Fault monitors
whether a channel gets into regulation in
a user defined time period
• LDO5 Over Current Protection (LDO5
OCP) monitors current drawn from the
© 2014 Exar Corporation
21/34
Rev. 1.0.0