ZHCSJU9E January 2007 – June 2019 TPS40077
PRODUCTION DATA.
- 1 特性
- 2 应用
- 3 说明
- 4 修订历史记录
- 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 Minimum Pulse Duration
- 7.3.2 Slew Rate Limit On VDD
- 7.3.3 Setting The Switching Frequency (Programming The Clock Oscillator)
- 7.3.4 Loop Compensation
- 7.3.5 Shutdown and Sequencing
- 7.3.6 Boost and LVBP Bypass Capacitance
- 7.3.7 Internal Regulators
- 7.3.8 Power Dissipation
- 7.3.9 Boost Diode
- 7.3.10 Synchronous Rectifier Control
- 7.4 Programming
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Applications
- 8.2.1
Buck Regulator 8-V to 16-V Input, 1.8-V Output at 10 A
- 8.2.1.1 Design Requirements
- 8.2.1.2
Detailed Design Procedure
- 8.2.1.2.1
Power Train Components
- 8.2.1.2.1.1 Output Inductor, LOUT
- 8.2.1.2.1.2 Output Capacitor, COUT, ELCO and MLCC
- 8.2.1.2.1.3 Input Capacitor, CIN ELCO and MLCC
- 8.2.1.2.1.4 Switching MOSFET, QSW
- 8.2.1.2.1.5 Rectifier MOSFET, QSR
- 8.2.1.2.1.6 Timing Resistor, RT
- 8.2.1.2.1.7 Feed-Forward and UVLO Resistor, RKFF
- 8.2.1.2.1.8 Soft-Start Capacitor, CSS
- 8.2.1.2.1.9 Short-Circuit Protection, RILIM and CILIM
- 8.2.1.2.1.10 Boost Voltage, CBOOST and DBOOST (Optional)
- 8.2.1.2.1.11 Closing the Feedback Loop, RZ1, RP1, RPZ2, RSET1, RSET2, CZ2, CP2, and CPZ1
- 8.2.1.2.1
Power Train Components
- 8.2.1.3 Application Curves
- 8.2.1
Buck Regulator 8-V to 16-V Input, 1.8-V Output at 10 A
- 8.3 Additional System Examples
- 9 Layout
- 10器件和文档支持
- 11机械、封装和可订购信息
8.2.1.2.1.2 Output Capacitor, COUT, ELCO and MLCC
Several parameters must be considered when selecting the output capacitor. The capacitance value should be selected based on the output overshoot, VOVER, and undershoot, VUNDER, during a transient load, ISTEP, on the converter. The equivalent series resistance (ESR) is chosen to allow the converter to meet the output ripple specification, VRIPPLE. The voltage rating must be greater than the maximum output voltage. Another parameter to consider is equivalent series inductance, which is important in fast-transient load situations. Also, size and technology can be factors when choosing the output capacitor. In this design, a large-capacitance electrolytic type capacitor, COUT ELCO, is used to meet the overshoot and undershoot specifications. Its ESR is chosen to meet the output ripple specification. Smaller multiple-layer ceramic capacitors, COUT MLCC, are used to filter high-frequency noise.
The minimum required capacitance and maximum ESR can be calculated using Equation 21, Equation 22, and Equation 23.
The capacitance for COUT should be greater than 444 μF, and its ESR should be less than 12 mΩ. The 470-μF/6.3-V capacitor from Panasonic's FC series was chosen. Its ESR is 160 mΩ. MLCCs of 47 μF and 22 μF/16 V are also added in parallel to achieve the required ESR and to reduce high-frequency noise.