ZHCSCK0C June 2014 – September 2021 TPS55340-Q1
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
- 7.4 Device Functional Modes
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Applications
- 8.2.1
TPS55340-Q1 Boost Converter
- 8.2.1.1 Design Requirements
- 8.2.1.2
Detailed Design Procedure
- 8.2.1.2.1 Custom Design With WEBENCH® Tools
- 8.2.1.2.2 Selecting the Switching Frequency (R4)
- 8.2.1.2.3 Determining the Duty Cycle
- 8.2.1.2.4 Selecting the Inductor (L1)
- 8.2.1.2.5 Computing the Maximum Output Current
- 8.2.1.2.6 Selecting the Output Capacitor (C8 through C10)
- 8.2.1.2.7 Selecting the Input Capacitors (C2 and C7)
- 8.2.1.2.8 Setting the Output Voltage (R1 and R2)
- 8.2.1.2.9 Setting the Soft-Start Time (C7)
- 8.2.1.2.10 Selecting the Schottky Diode (D1)
- 8.2.1.2.11 Compensating the Control Loop (R3, C4, and C5)
- 8.2.1.3 Application Curves
- 8.2.2
TPS55340-Q1 SEPIC Converter
- 8.2.2.1 Design Requirements
- 8.2.2.2
Detailed Design Procedure
- 8.2.2.2.1 Selecting the Switching Frequency (R4)
- 8.2.2.2.2 Duty Cycle
- 8.2.2.2.3 Selecting the Inductor (L1)
- 8.2.2.2.4 Calculating the Maximum Output Current
- 8.2.2.2.5 Selecting the Output Capacitor (C8 Through C10)
- 8.2.2.2.6 Selecting the Series Capacitor (C6)
- 8.2.2.2.7 Selecting the Input Capacitor (C2 and C7)
- 8.2.2.2.8 Selecting the Schottky Diode (D1)
- 8.2.2.2.9 Setting the Output Voltage (R1 and R2)
- 8.2.2.2.10 Setting the Soft-Start Time (C3)
- 8.2.2.2.11 Mosfet Rating Considerations
- 8.2.2.2.12 Compensating the Control Loop (R3 and C4)
- 8.2.2.3 Application Curves
- 8.2.1
TPS55340-Q1 Boost Converter
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
8.2.1.2.7 Selecting the Input Capacitors (C2 and C7)
At least 4.7-µF of ceramic input capacitance is recommended. Additional input capacitance can be required to meet ripple requirements, transient requirements, or both. High-quality ceramic-type X5R or X7R capacitors are recommended to minimize capacitance variations over temperature. The capacitor must also have an RMS current rating greater than the maximum RMS input current of the TPS55340-Q1 device as calculated with Equation 24. The input capacitor must also be rated greater than the maximum input voltage. Use Equation 25 to calculate the input voltage ripple.
In the design example, the input RMS current is calculated to be 191 mA. The selected input capacitor is a 10-µF, 35-V 1210 X7R with 3-mΩ ESR. Although a capacitor with a lower voltage rating can be used, a 35-V rated capacitor was selected to limit the effects of DC bias and to allow the circuit to be rated for the entire input range of the TPS55340-Q1 device. The input ripple is calculated to be 30 mV. An additional 0.1-µF, 50-V 0603 X5R is located close to the VIN pin and the GND pin for additional decoupling.