XRP7725 Datasheet, PDF (13/34 Pages) Exar Corporation – Power Management System

XRP7725
Intel Node Manager Compatible Programmable
Power Management System
FUNCTIONAL OVERVIEW
The XRP7725 is a quad-output digital pulse
width modulation (DPWM) controller with
integrated gate drivers for use with
synchronous buck switching regulators. Each
output voltage can be programmed from 0.6V
to 5.5V without the need for an external
voltage divider. The wide range of
programmable DPWM switching frequency
(from 105 kHz to 1.2 MHz) enables the user to
optimize for efficiency or component sizes.
Since the digital regulation loop requires no
external passive components, loop
performance is not compromised due to
external component variation or operating
condition.
The XRP7725 provides a number of critical
safety features, such as Over-Current
Protection (OCP), Over-Voltage Protection
(OVP), Over Temperature Protection (OTP)
plus input Under Voltage Lockout (UVLO). In
addition, a number of key health monitoring
features such as warning level flags for the
safety functions, Power Goods (PGOOD), etc.,
plus full monitoring of system voltages and
currents. The above are all programmable
and/or readable from the SMBus and many
are steerable to the GPIOs for hardware
monitoring.
For hardware communication, the XRP7725
has two logic level General Purpose Input-
Output (GPIO) pins and three, 15V, open
drain, Power System Input-Output (PSIO)
pins. Two pins are dedicated to the SMBus
data (SDA) and clock (SCL). Additional pins
include Chip Enable (Enable), Aux Boost
Feedback (BFB) and External PLL Capacitor
(CPLL).
In addition to providing four switching outputs,
the XRP7725 also provides control for an Aux
boost supply, and two stand-by linear
regulators that produce 5V and 3.3V for a total
of seven customer usable supplies in a single
device.
The 5V LDO is used for internal power and is
also available for customer use to power
external circuitry. The 3.3V LDO is solely for
customer use and is not used by the chip.
There is also a 1.8V linear regulator which is
for internal use only and should not be used
externally.
A key feature of the XRP7725 is its advinced
power management capabilities. All four
outputs are independently programmable and
provide the user full control of the delay,
ramp, and sequence during power up and
power down. The user may also control how
the outputs interact and power down in the
event of a fault. This includes active ramp
down of the output voltages to remove an
output voltage as quickly as possible. Another
useful feature is that the outputs can be
defined and controlled as groups.
The XRP7725 has two main types of
programmable memory. The first type is
runtime registers that contain configuration,
control and monitoring information for the
chip. The second type is rewritable Non-
Volatile Flash Memory (NVFM) that is used for
permanent storage of the configuration data
along with various chip internal functions.
During power up, the run time registers are
loaded from the NVFM allowing for standalone
operation.
The XRP7725 brings an extremely high level of
functionality and performance to a
programmable power system.
Ever
decreasing product budgets require the
designer to quickly make good
cost/performance tradeoffs to be truly
successful. By incorporating four switching
channels, two user LDOs, a charge pump
boost controller, along with internal gate
drivers, all in a single package, the XRP7725
allows for extremely cost effective power
system designs. Another key cost factor that
is often overlooked is the unanticipated
Engineering Change Order (ECO). The
programmable versatility of the XRP7725,
along with the lack of hard wired configuration
components, allows for minor and major
changes to be made in circuit by simple
reprogramming.
© 2014 Exar Corporation
13/34
Rev. 1.0.0