Copyright  ANPEC Electronics Corp.

Rev. P.4 - Mar., 2001

APW6021

www.anpec.com.tw

1

ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and advise

customers to obtain the latest version of relevant information to verify before placing orders.

Advanced PWM and Triple Linear Power Controllers

General Description

Applications

Functional

The APW6021 provides the power control and pro-

tection for four output voltages in high-performance,

graphics intensive microprocessor and computer

applications. The IC integrates voltage-mode PWM

controller and three linear controllers, as well as the

monitoring and protection functions into a 28-pin SOIC

package. The PWM controller regulates the micro-

processor core voltage with a synchronous-rectified

buck converter. The linear controllers regulate the

computer system’s AGP 1.5V or 3.3V bus power, the

1.5V GTL bus power, and the 1.8V power for the

North/South Bridge core voltage and/or cache

memory circuits. The APW6021 includes an Intel-

compatible, TTL 5-input digital-to-analog converter

(DAC) that adjusts the core PWM output voltage from

1.3 V

3.5 V

and voltage-mode control provide

±1% static

regulation. The AGP bus power linear controller’s

output (V

patible signal applied at the SELECT pin, for levels of

1.5V or 3.3V with

±3% accuracy. Based on the sta-

tus of the FIX pin, the other two linear regulators pro-

vide either fixed output voltages of 1.5V

± 3% (V

and 1.8V

±3% (V

of an external resistor divider. All linear controllers

can employ either N-channel MOSFETs or bipolar

NPNs for the pass transistor.

The APW6021 monitors all the output voltages. A

single Power Good signal is issued when the core is

within

±10% of the DAC setting and all other outputs

are above their under-voltage levels. Additional built-

in over-voltage protection for the core output uses

the lower MOSFET to prevent output voltages above

115

% of the DAC setting. The PWM controller’s over-

current function monitors the output current by using

the voltage drop across the upper MOSFET’s r

••••• Microprocessor Core (1.3V to 3.5V)

••••• AGP Bus (1.5V or 3.3V)

••••• Memory (1.8V)

••••• GTL Bus (1.5V)

and Bipolar Series Pass Transistors

Outputs (FIX Pin)

••••• Voltage-Mode PWM Control

••••• High-Bandwidth Error Amplifier

••••• Full 0% to 100% Duty Ratio

••••• Core PWM Output: ± 1% Over Temperature

••••• Other Outputs: ± 3% Over Temperature

Core Output Voltage Selection

••••• Wide Range - 1.3V

••••• Switching Regulator Does Not Require

Extra Current Sensing Element, Uses

MOSFET’s r

DS(ON)

••••• Constant Frequency Operation

••••• 200kHz Free-Running Oscillator; Program-

mable From 50kHz to Over 1MHz