ZHCSNC8A February 2021 – March 2021 TPS541620
PRODUCTION DATA
- 1 特性
- 2 應用
- 3 說明
- 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, Internally Compensated Advanced-Current-Mode Control
- 7.3.2 Enable and UVLO
- 7.3.3 Internal LDO
- 7.3.4 Pre-biased Output Start-up
- 7.3.5 Current Sharing
- 7.3.6 Frequency Selection and Minimum On-Time and Off-Time
- 7.3.7 Ramp Compensation Selection
- 7.3.8 Soft Start
- 7.3.9 Remote Sense Function
- 7.3.10 Adjustable Output Voltage
- 7.3.11 Power Good
- 7.3.12 Overcurrent Protection
- 7.3.13 Overvoltage and Undervoltage Protection
- 7.3.14 Overtemperature Protection
- 7.3.15 Frequency Synchronization
- 7.4 Device Functional Modes
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Application - Dual Independent Outputs
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 Switching Frequency
- 8.2.2.2 Output Inductor Selection
- 8.2.2.3 Output Capacitor
- 8.2.2.4 Input Capacitor
- 8.2.2.5 Output Voltage Resistors Selection
- 8.2.2.6 Adjustable Undervoltage Lockout
- 8.2.2.7 Bootstrap Capacitor Selection
- 8.2.2.8 BP5 Capacitor Selection
- 8.2.2.9 PGOOD Pullup Resistor
- 8.2.2.10 Current Limit
- 8.2.2.11 Soft-Start Time Selection
- 8.2.2.12 MODE1 and MODE2 Pins
- 8.2.3 Application Curves
- 8.2.4
Typical Application - 2-Phase Operation
- 8.2.4.1 Design Requirements
- 8.2.4.2
Detailed Design Procedure
- 8.2.4.2.1 Switching Frequency
- 8.2.4.2.2 Output Inductor Selection
- 8.2.4.2.3 Output Capacitor
- 8.2.4.2.4 Input Capacitor
- 8.2.4.2.5 Output Voltage Resistors Selection
- 8.2.4.2.6 Adjustable Undervoltage Lockout
- 8.2.4.2.7 Bootstrap Capacitor Selection
- 8.2.4.2.8 BP5 Capacitor Selection
- 8.2.4.2.9 PGOOD Pullup Resistor
- 8.2.4.2.10 Current Limit
- 8.2.4.2.11 Soft-Start Time Selection
- 8.2.4.2.12 MODE1 Pin
- 8.2.4.3 Application Curves
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
8.2.2.5 Output Voltage Resistors Selection
The output voltage is set with a resistor divider created by RFB_T1 and RFB_B1 from the output node to the FB1 pin. It is recommended to use 1% tolerance or better resistors. For this example design, 10.0 kΩ is selected for RFB_B1. Using Equation 38, RFB_T1 is calculated as 10.0 kΩ for VOUT1 = 1 V. For this example design, 10.0 kΩ is selected for RFB_B2. Using Equation 38, RFB_T2 is calculated as 56.0 kΩ for VOUT2 = 3.3 V.
where
- VFB = 0.5 V