ZHCSGO2H September 2003 – November 2018 LM5007
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
-
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 Custom Design With Excel Quickstart Tool
- 8.2.2.3 Feedback Resistors, RFB1 and RFB2
- 8.2.2.4 Switching Frequency Selection, RON
- 8.2.2.5 Buck Inductor, L1
- 8.2.2.6 Output Capacitor, COUT
- 8.2.2.7 Type I Ripple Circuit, RC
- 8.2.2.8 Input Capacitor, CIN
- 8.2.2.9 Current Limit, RCL
- 8.2.3 Application Curves
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文档支持
- 12机械、封装和可订购信息
8.2.2.5 Buck Inductor, L1
The inductor is selected to provide a current ripple of 40% to 50% of the full-load current. In addition, the peak inductor current at maximum load must be smaller than the minimum current limit threshold provided in Electrical Characteristics. The inductor current ripple is given by Equation 10.
The maximum ripple is observed at the maximum input voltage. Using VIN = 75 V and ΔIL= 50% x IOUT(max) results in L1= 114 µH. Select a standard inductor value of 100 µH. The inductor current ripple ranges from 88 mA to 228 mA depending on input voltage. The peak inductor and switch current at full load are given by Equation 11.
At maximum VIN, the peak inductor current is 514 mA, which is lower than the minimum current limit threshold of 535 mA. The selected inductor should be able to operate at the maximum current limit of 900 mA without saturation during startup and overload conditions.