herunterladen
User’s Guide
SLUU181 - January 2004
1
5-V Input, Variable Output, 20-A High-Efficiency
Synchronous Buck Converter Using the UCC27223
with Predictive Gate Drive Technology
System Pow
er
Contents
1 Introduction 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Description 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Electrical Performance Specifications 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Schematic 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Variable Output Voltage 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 Test Set up 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7 Power Up/Power Down Test Procedure 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 Predictive Gate Drive Technology 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9 Performance Data 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 Evaluation Module Layout 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11 List of Materials 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 References 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Introduction
The UCC27223EVM evaluation module (EVM) is a high efficiency, synchronous buck converter
providing a variable output between 0.9 V and 1.8 V at up to 20 A from a 5-V input. The EVM is
designed to start up from a single 5-V supply, and no additional bias voltage is required for
start-up. The module uses the UCC27223 high-efficiency predictive synchronous buck driver
with enable, along with the UCC3803 low-power BiCMOS current-mode PWM controller for
demonstrating the Predictive Gate Drive (PGD) technique. Several advanced TI design and
packaging technologies are used, providing the highest possible efficiency from step-down
converters. Configured for voltage-mode control, UCC27223EVM operates at 500 kHz with a
peak efficiency of 92% and a full load efficiency over 86% for V
OUT
= 1.8 V.
The addition of the UCC27223’s start-up and ENABLE features allow the EVM to start up the
pre-biased supply or run in a low-power disabled mode by grounding a single pin. In this
disabled mode, the EVM draws only 7 mA of current at 5 V and produces a floating output,
allowing the pre-bias to return to the output and wait for the release of the ENABLE pin.
Verzeichnis
- ・ Blockdiagramm on Seite 5 Seite 6
- ・ Technische Daten on Seite 4
- ・ Anwendungsbereich on Seite 2 Seite 19
- ・ Elektrische Spezifikation on Seite 11
