SLUU161 – April, 2003

4

TPS40051-Based Design Converts 12-V Bus to 1.8 V at 15 A (SLUP195)

TPS40051-Based Design Converts 12-V Bus to

1.8 V at 15 A (SLUP195)

Mark Dennis

System Power

Contents

1

Introduction

4

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2

Features

4

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3

Schematic

5

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4

Component Selection

6

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5

Test Setup

10

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6

Test Results and Performance Data

11

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7

EVM Assembly Drawing and PCB Layout

12

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8

List of Materials

15

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9

References

16

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1

Introduction

In many modern electronic applications there is a growing demand for circuits to convert a12-V bus to digital

voltages as low as, but not limited to 1.8 V. The current requirements can range from below 1 A to over 15 A.

For high-efficiency and small circuit size the TPS40051 wide-input synchronous buck controller can be used

to provide the necessary control and drive functions to implement these converters. The TPS40051EVM–001

operates at 300 kHz and delivers 1.8 V at 15 A with efficiency over 90% for much of the load range, and a full

load efficiency of 88%.

The TPS40051 synchronous buck controller offers a variety of user programmable functions such as operating

frequency, soft-start time, voltage feed-forward, high-side current limit, and external loop compensation. This

controller also provides a regulated 10-V bias voltage which supplies onboard drivers for the N-channel switch

and synchronous rectifier MOSFETs, utilizing adaptive gate drive logic to prevent cross conduction of the power

2

Features

The specification of this design is as follows: