APW6021
Advanced PWM and Triple Linear Power Controllers
Functional
•
4 Regulated Voltages are provided
•
Microprocessor Core (1.3V to 3.5V)
•
AGP Bus (1.5V or 3.3V)
•
Memory (1.8V)
•
GTL Bus (1.5V)
Applications
•
Motherboard Power Regulation for Computers
General Description
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
DC
to 2.05 V
DC
in 0.05V steps and from 2.1 V
DC
to
3.5 V
DC
in 0.1V increments. The precision reference
and voltage-mode control provide
±1%
static
regulation. The AGP bus power linear controller’s
output (V
OUT2
) is user-selectable, through a TTL-com-
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
OUT3
)
and 1.8V±3% (V
OUT4
), or user-adjustable by means
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
DS(ON)
.
•
•
•
•
Linear Controllers Drives with both MOSFET
and Bipolar Series Pass Transistors
Fixed or Externally Resistor-Adjustable Linear
Outputs (FIX Pin)
Simple Single-Loop Control Design
•
Voltage-Mode PWM Control
Fast PWM Converter Transient Response
•
High-Bandwidth Error Amplifier
•
Full 0% to 100% Duty Ratio
•
Excellent Output Voltage Regulation
•
Core PWM Output:
±
1% Over Temperature
•
Other Outputs:
±
3% Over Temperature
•
TTL-Compatible 5- Bit DAC Microprocessor
Core Output Voltage Selection
•
Wide Range - 1.3V
DC
to 3.5 V
DC
•
•
Power-Good Output Voltage Monitor
Over-Voltage and Over-Current Fault Monitors
•
Switching Regulator Does Not Require
Extra Current Sensing Element, Uses
MOSFET’s r
DS(ON)
•
Small Converter Size
•
Constant Frequency Operation
•
200kHz Free-Running Oscillator; Program-
mable From 50kHz to Over 1MHz
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.
Copyright
ANPEC Electronics Corp.
Rev. P.4 - Mar., 2001
1
www.anpec.com.tw
ANPEC [ ANPEC ELECTRONICS COROPRATION ]
