XRP7724 Datasheet, PDF (20/29 Pages) Exar Corporation – Quad Channel Digital PWM/PFM Programmable Power Management System

XRP7724
Quad Channel Digital PWM/PFM
Programmable Power Management System
HW Flags – these are hardware monitoring
functions forwarded to GPIO0 only. The
functions include Under-Voltage Warning,
Over- Temperature Warning, Over-Voltage
Fault, Over-Current Fault and Over -Current
Warning for every channel. Multiple selection
is available in which case the resulting signal
is the OR logic function
 “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 by the following
equation:
 External Clock-in – enables the
controller to lock to an external clock
including one from another XRP7724
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. It 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 selection is
available in which case the resulting signal
is the AND logic function of all channels
selected.
 The Power Good minimum and maximum
levels are expressed as percentages of the
target voltage.
 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 values
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 XRP7724 (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 Vcc pin
and will cause the controller to shutdown
all channels if the supply drops to critical
levels.
 Over Temperature Protection (OTP)
monitors temperature of the chip and will
cause the controller to shutdown 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
© 2012 Exar Corporation
20/29
Rev. 1.0.1