ZHCSLC6B May 2020 – January 2022 TPS92200
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
- 7.4 Device Functional Modes
- 8 Application and Implementation
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
8.2.3.2.1 Inductor Selection
For this application, input voltage is 5-V rail with 10% variation, output is a single IR LED, and the inductor current ripple requirement is less than 60% of maximum LED current.
Use Equation 12 to calculate the minimum value of the output inductor (LMIN).
where
- KIND is a coefficient that represents the amount of inductor ripple current relative to the maximum LED current.
- ILED is the maximum LED current.
- VOUT is the sum of the voltage across LED load and the voltage across sense resistor.
With the chosen inductor value, the user can calculate the actual inductor current ripple using Equation 13.
In this design, VIN(max) = 5.5 V, VOUT = 1.85 V, ILED = 1 A, choose KIND = 0.6. The calculated inductance is 2.046 μH. A 2.2-μH inductor is chosen. With this inductor, the ripple, peak, and RMS currents of the inductor are 0.56 A, 1.28 A, and 1.01 A, respectively.