ZHCSSZ6F august 2008 – june 2020 TPS40210-Q1 , TPS40211-Q1
PRODUCTION DATA
- 1
- 1 特性
- 2 应用
- 3 说明
- 5
- 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
- 7.3.1 Minimum On-Time and Off-Time Considerations
- 7.3.2 Current Sense and Overcurrent
- 7.3.3 Current Sense and Subharmonic Instability
- 7.3.4 Current Sense Filtering
- 7.3.5 Soft Start
- 7.3.6 BP Regulator
- 7.3.7 Shutdown (DIS/ EN Pin)
- 7.3.8 Control Loop Considerations
- 7.3.9 Gate Drive Circuit
- 7.3.10 TPS40211-Q1
- 7.4 Device Functional Modes
-
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 Duty Cycle Estimation
- 8.2.2.2 Inductor Selection
- 8.2.2.3 Rectifier Diode Selection
- 8.2.2.4 Output Capacitor Selection
- 8.2.2.5 Input Capacitor Selection
- 8.2.2.6 Current Sense and Current Limit
- 8.2.2.7 Current Sense Filter
- 8.2.2.8 Switching MOSFET Selection
- 8.2.2.9 Feedback Divider Resistors
- 8.2.2.10 Error Amplifier Compensation
- 8.2.2.11 R-C Oscillator
- 8.2.2.12 Soft-Start Capacitor
- 8.2.2.13 Regulator Bypass
- 8.2.3 Application Curves
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
8.2.2.7 Current Sense Filter
To remove switching noise from the current sense, an R-C filter is placed between the current sense resistor and the ISNS pin. A resistor with a value between 1 kΩ and 5 kΩ is selected, and a capacitor value is calculated by Equation 51.
Equation 51. 
For a 1-kΩ filter resistor, 71 pF is calculated and a 100-pF capacitor is selected.