SS7529 Datasheet, PDF (1/8 Pages) Silicon Standard Corp. – Synchronous Buck PWM and Linear Power Controller

SS7529
Synchronous Buck PWM and Linear Power Controller
FEATURE
Controller operates from 5V and 12V
Drives two N-channel MOSFETs for switching buck
converter
Drives an N-channel MOSFET on the linear output
Fixed 600kHz constant switching frequency
Full range 0~100% duty cycle
Internal soft start
Fast transient response
UVP monitoring on both outputs
Internal 0.8V reference voltage.
APPLICATIONS
Graphics-GPU and memory supplies
ASIC power supplies
Embedded processor and I/O supplies
Cable Modem, Set Top Box, and DSL Modems
DSP and Core Communications Processor
supplies
GENERAL DESCRIPTION
The SS7529 consists of a dual-output power controller
and the protection circuits in a single SO-14 package
for graphic cards and other applications.
The dual-output power controller provides regulation by
driving two N-MOSFETs in a synchronous rectified buck
converter, and one N-MOSFET in a linear configuration.
The synchronous rectified buck converter provides
simple, single feedback loop, voltage mode control with
fast transient response, from an internal 0.8V temperature-
compensated reference voltage. A fixed 600kHz
frequency oscillator reduces design complexity, while
balancing typical application cost and efficiency.
The internal soft-start function and the 12V direct drive
on the switching output help to save the bootstrap circuit.
Furthermore, the internal POR (power on reset) helps to
prevent the system from sequencing issues during the
startup and turn-off. Reacting to fault conditions,
the SS7529 will shutdown both outputs when the
voltage on either FB or FB2 pins drops below 51% of
their nominal value.
TYPICAL APPLICATIONS
Vin (3.3V or 5V)
Q3
Vout
5V
12V
5VCC
12VCC
DRIVE2
FB2
Linear
Controller
Vref
Control
Logic
Shutdown
FB
Comp
Error Amp
OSC
GND
UGATE
Q1
LGATE
Q2
PGND
Vout
Rev.1.01 4/26/2004
www.SiliconStandard.com
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