07/19/02

IRDCiP2001-A, 500kHz, 40A, 2-phase Synchronous Buck

Converter using iP2001

Overview

In this document, table 1 and figure 1 are provided to enable engineers to

easily evaluate the iP2001 in a 2-phase configuration that is capable of

providing up to 40A in a lab environment without airflow. Figures 3, 4, 5 and

6 and the complete bill of materials in table 2 are provided as a reference

design to enable engineers to very quickly and easily design a 2-phase

converter. In order to optimize this design to your specific requirements

refer to the data sheet for the controller listed in the bill of materials. A variety

of other controllers may also be used, but the design will require layout and

control circuit modifications.

Demoboard Quick Start Guide

Initial Settings:

The output is set to 1.7V, but can be adjusted from 1.1 to 1.85V by setting

S1 according to the VID codes provided in Table 1. Droop control is set to 50mV at 40A, but can be adjusted by

following the instructions in the data sheet for the PWM controller.

The switching frequency per phase is set to 500kHz with the frequency set resistor R4. This creates an effective

output frequency of 1MHz. The graph in figure 1 shows the relationship between R4 and the switching frequency

per phase. This frequency may be adjusted by changing R4 according to this graph; however, extreme changes

from the 500kHz set point may require redesigning the control loop and adjusting the values of input and output

capacitors. Also, refer to the SOA graph in the iP2001 datasheet for maximum operating current at different

frequencies.

Procedure for Connecting and Powering Up Demoboard:

1. Apply input voltage (5-12V) across V

the power-up sequence.

2. Apply +5V logic power across +5V (TP19) and PGND (TP20).

3. Apply load across VOUT pads (TP11 & TP12) and PGND pads (TP15 & TP16)

4. Set ENABLE high.

5. Monitor switch node signals (optional) via TP7 & TP8.

6. Adjust load accordingly.

iP2001 Recommended Operating Conditions

(refer to the iP2001 datasheet for maximum operating conditions)

Input voltage:

5 - 12V

Output voltage:

1.1 - 1.85V

Output current:

20A per phase, 40A total for 2-phase demo board.

Switching Freq:

500kHz per phase, 1MHz effective output frequency.

IRDCiP2001-A

International Rectifier