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POWER MANAGEMENT

SC1471

Power Supply Controller for Portable

Description

.eatures

Applications

Revision 2, March 2001

The SC1471 PowerStep™ II controller is a high speed,

high performance hysteretic mode PWM controller.

Teamed with the SC1405 Smart Driver™ , it powers ad-

tures extended Intel Mobile Voltage Positioning (IMVP) to

increase battery life by reducing the voltage at the pro-

SpeedStep™ processors for even longer battery life, in-

cluding IMVP extensions. The SC1471 incorporates di-

rect “deeper sleep” mode support, which eliminates an

external multiplexer in many applications.

A 5-bit DAC, accurate to 0.85%, sets the output voltage

reference and implements the 0.600V to 1.750V range

required by the processor. The hysteretic converter uses

a comparator without an error amplifier, and therefore

provides the fastest possible transient response, while

avoiding the stability issues inherent to classical PWM

controllers.

The SC1471 operates from either 3.3Vdc or 5Vdc Vcc

and also features soft-start, an open-drain power-good

indication with power-good blanking, and an enable in-

put. Programmable current limiting uses a separate com-

parator to protect against overloads and short-circuits.

In addition, it comes in a space-saving TSSOP-24 pack-

age.

efficiency over a wide operating load range

sors

blanking

Sleep” mode

K Laptop and notebook computers

K High performance microprocessor-based systems

K High efficiency distributed power supplies

Typical Application Circuit

SC1471

Extended IMVP

CONTROLLER

VID [4:0]

SC1405C

Smart

MOSFET

Driver

Lo

+VCC_CPU_CORE

Co

+V_IN

+V_5

0.600V-1.75V

Up to 25A

Extended

IMVP

Logic

PWM

Controller

Power

Control

Signals

Control

Signals

SC1471

Extended IMVP

CONTROLLER

VID [4:0]

SC1405C

Smart

MOSFET

Driver

Lo

+VCC_CPU_CORE

Co

+V_IN

+V_5

0.600V-1.75V

Up to 25A

Extended

IMVP

Logic

PWM

Controller

Power

Control

Signals

Control

Signals