ZHCSPP3 July 2022 TPS563300
PRODUCTION DATA
- 1 特性
- 2 应用
- 3 说明
- 4 Revision History
- 5 Pin Configuration and Functions
- 6 Specifications
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 Fixed Frequency Peak Current Mode
- 7.3.2 Pulse Frequency Modulation
- 7.3.3 Voltage Reference
- 7.3.4 Output Voltage Setting
- 7.3.5 Enable and Adjusting Undervoltage Lockout
- 7.3.6 Minimum On Time, Minimum Off Time, and Frequency Foldback
- 7.3.7 Frequency Spread Spectrum
- 7.3.8 Overvoltage Protection
- 7.3.9 Overcurrent and Undervoltage Protection
- 7.3.10 Thermal Shutdown
- 7.4 Device Functional Modes
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Application
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 Custom Design With WEBENCH® Tools
- 8.2.2.2 Output Voltage Resistors Selection
- 8.2.2.3 Bootstrap Capacitor Selection
- 8.2.2.4 Undervoltage Lockout Set Point
- 8.2.2.5 Output Inductor Selection
- 8.2.2.6 Output Capacitor Selection
- 8.2.2.7 Input Capacitor Selection
- 8.2.2.8 Feedforward Capacitor CFF Selection
- 8.2.2.9 Maximum Ambient Temperature
- 8.2.3 Application Curves
- 8.3 Best Design Practices
- 8.4 Power Supply Recommendations
- 8.5 Layout
- 9 Device and Documentation Support
- 10Mechanical, Packaging, and Orderable Information
7.3.7 Frequency Spread Spectrum
In order to reduce EMI, the TPS563300 introduces frequency spread spectrum. The jittering span is typically Δfc = ±6% of the switching frequency with the modulation frequency of fm = fSW / 128. The purpose of spread spectrum is to eliminate peak emissions at specific frequencies by spreading emissions across a wider range of frequencies than a part with fixed frequency operation. Figure 7-4 shows the frequency spread spectrum modulation. Figure 7-5 shows the energy is spread out at the center frequency, fc.
Figure 7-5 Energy vs Frequency