ZHCSGG8F July 2011 – March 2018 LM25118
PRODUCTION DATA.
- 1 特性
- 2 應用
- 3 說明
- 4 修訂歷史記錄
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Detailed Description
-
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 R7 = RT
- 8.2.2.3 Inductor Selection – L1
- 8.2.2.4 R13 = RSENSE
- 8.2.2.5 C15 = CRAMP
- 8.2.2.6 Inductor Current Limit Calculation
- 8.2.2.7 C9 - C12 = Output Capacitors
- 8.2.2.8 D1
- 8.2.2.9 D4
- 8.2.2.10 C1 – C5 = Input Capacitors
- 8.2.2.11 C20
- 8.2.2.12 C8
- 8.2.2.13 C16 = CSS
- 8.2.2.14 R8, R9
- 8.2.2.15 R1, R3, C21
- 8.2.2.16 R2
- 8.2.2.17 Snubber
- 8.2.2.18 Error Amplifier Configuration
- 8.2.3 Application Curves
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文檔支持
- 12機械、封裝和可訂購信息
8.2.2.4 R13 = RSENSE
To select the current sense resistor, begin by calculating the minimum K values for each mode using Equation 20 and Equation 21. K represents the slope compensation of the controller and is different for each mode, KBUCK and KBUCK-BOOST. KBUCK and KBUCK-BOOST were selected to be 1.33 and 3, respectively.
Use Equation 24 and Equation 25 to calculate RSENSE for each mode of operation. A design margin, M, should be selected between 10%-30% to allow for component tolerances. For this design M was selected to be 10%.
An RSENSE value of no more than 15.5 mΩ must be used to ensure the required maximum output current in the buck-boost mode. A standard value of 15 mΩ was selected for this design.