■ DESCRIPTION

The AIC1574 combines a synchronous voltage mode controller with three linear controller as well as the monitoring and protection functions in this chip. The PWM controller regulates the microprocessor core voltage with a synchronous rectified buck converter. The three linear controllers regulate power for the 1.5V or 3.3V AGP bus power, the 1.5V GTL bus and the 1.8V power for the chip set core voltage and/or cache memory circuits.

■ FEATURES

• Compatible with HIP6021.

• Provides 4 Regulated Voltages for Microprocessor Core, AGP Bus, Memory and GTL Bus Power.

• TTL Compatible 5-bit Digital-to-Analog Core Output Voltage Selection. Range from 1.3V to 3.5V.

0.1V Steps from 2.1V to 3.5V.

0.05V Steps from 1.3V to 2.05V.

• ±1.0 Output Voltage for VCORE, ±3.0 Accuracy for Linear Controller Outputs.

• Simple Voltage-Mode PWM Control and Built in Internal Compensation Networks.

• N-Channel MOSFET Driver for PWM Buck Converter.

• Linear Controller Drives Compatible with both N – Chanel MOSFET and NPN Bipolar Series Pass Transistor.

• Operates from +3.3V, +5V and +12V Inputs.

• Fast Transient Response.

• Full 0 to 100 Duty Ratios.

• Adjustable Current Limit without External Sense Resistor.

• Microprocessor Core Voltage Protection against Upper MOSFET shorted to +5V.

• Power Good Output Voltage Monitor.

• Over-Voltage and Over-Current Fault Monitors.

• 200KHz Free-Running Oscillator Programmable up to 700KHz.

■ APPLICATIONS

• Full Motherboard Power Regulation for Computers.