Datasheet TPS62902 (Texas Instruments) - 8

TPS62902
SLVSFM1 – MARCH 2021
www.ti.com 7 Detailed Description 7.1 Overview
The TPS62902 synchronous switched mode power converters are based on DCS-Control (Direct Control with Seamless Transition into power save mode). DCS-Control is an advanced regulation topology that combines the advantages of hysteretic, voltage mode, and current mode control. This control loop takes information about output voltage changes and feeds it directly to a fast comparator stage. It sets the switching frequency, which is constant for steady-state operating conditions, and provides immediate response to dynamic load changes. To get accurate DC load regulation, a voltage feedback loop is used. The internally-compensated regulation network achieves fast and stable operation with small external components and low-ESR capacitors.
7.2 Functional Block Diagram
PG VIN Ref VI ± 1.0V HS Limit + EN VO Internal/External Device Control Power Control FB Divider & Logic SW /VSET Power Save Mode Resistor-to-Digital Gate Forced PWM Smart-Enable Driver 100% Mode Ref-System VFB UVLO SS/TR Start-up Handling Smart-CONFIGTM PG-Control Thermal Shutdown Resistor-to-Digital MODE /S-CONF MODE Detection LS Limit VO Direct VOS V Control I TON timer VFB ± V + O Device VREF DCS-ControlTM Control GND 8 Submit Document Feedback Copyright © 2021 Texas Instruments Incorporated Product Folder Links: TPS62902 Document Outline 1 Features 2 Applications 3 Description Table of Contents 4 Revision History 5 Pin Configuration and Functions 6 Specifications 6.1 Absolute Maximum Ratings 6.2 ESD Ratings 6.3 Recommended Operating Conditions 6.4 Thermal Information 6.5 Electrical Characteristics 6.6 Typical Characteristics 7 Detailed Description 7.1 Overview 7.2 Functional Block Diagram 7.3 Feature Description 7.3.1 Mode Selection and Device Configuration MODE/S-CONF 7.3.2 Adjustable VO Operation (External Voltage Divider) 7.3.3 Setable VO Operation (VSET and Internal Voltage Divider) 7.3.4 Soft Start / Tracking (SS/TR) 7.3.5 Smart Enable with Precise Threshold 7.3.6 Power Good (PG) 7.3.7 Undervoltage Lockout (UVLO) 7.3.8 Current Limit And Short Circuit Protection 7.3.9 Thermal Shutdown 7.4 Device Functional Modes 7.4.1 Pulse Width Modulation (PWM) Operation 7.4.2 AEE (Automatic Efficiency Enhancement) 7.4.3 Power Save Mode Operation (Auto PFM/PWM) 7.4.4 100% Duty-Cycle Operation 7.4.5 Output Discharge Function 7.4.6 Starting into a Pre-Biased Load 8 Application and Implementation 8.1 Application Information 8.2 Typical Application with Adjustable Output Voltage 8.2.1 Design Requirements 8.2.2 Detailed Design Procedure 8.2.2.1 Custom Design With WEBENCH® Tools 8.2.2.2 Programming the Output Voltage 8.2.2.3 External Component Selection 8.2.2.4 Inductor Selection 8.2.2.5 Capacitor Selection 8.2.2.5.1 Output Capacitor 8.2.2.5.2 Input Capacitor 8.2.2.5.3 Soft-Start Capacitor 8.2.2.6 Tracking Function 8.2.2.7 Output Filter and Loop Stability 8.2.3 Application Curves 8.2.4 Typical Application with Setable VO using VSET 8.2.4.1 Design Requirements 8.2.4.2 Detailed Design Procedure 8.2.4.3 Application Curves 8.3 System Examples 8.3.1 LED Power Supply 8.3.2 Powering Multiple Loads 8.3.3 Voltage Tracking 8.3.4 Precise Soft-Start Timing 9 Power Supply Recommendations 10 Layout 10.1 Layout Guidelines 10.2 Layout Example 10.2.1 Thermal Considerations 11 Device and Documentation Support 11.1 Device Support 11.1.1 Development Support 11.1.1.1 Custom Design With WEBENCH® Tools 11.2 Receiving Notification of Documentation Updates 11.3 Support Resources 11.4 Trademarks 11.5 Electrostatic Discharge Caution 11.6 Glossary 12 Mechanical, Packaging, and Orderable Information