ZHCSMX7A August 2021 – December 2021 TPS92519-Q1
PRODUCTION DATA
- 1 特性
- 2 应用
- 3 说明
- 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
- 7.3.1 Buck Converter Switching Operation
- 7.3.2 Switching Frequency and Adaptive On-Time Control
- 7.3.3 Minimum On-Time, Off-Time, and Inductor Ripple
- 7.3.4 Enable
- 7.3.5 LED Current Regulation and Error Amplifier
- 7.3.6 Start-up Sequence
- 7.3.7 Analog Dimming and Forced Continuous Conduction Mode
- 7.3.8 External PWM Dimming and Input Undervoltage Lockout (UVLO)
- 7.3.9 Shunt FET Dimming or Matrix Beam Application
- 7.3.10 Bias Supply
- 7.3.11 Bootstrap Supply
- 7.3.12 Faults and Diagnostics
- 7.3.13 Output Short Circuit Fault
- 7.3.14 Output Open Circuit Fault
- 7.3.15 Parallel Operation
- 7.4 Device Functional Modes
-
8 Application and Implementation
- 8.1
Application Information
- 8.1.1 Duty Cycle Consideration
- 8.1.2 Switching Frequency Selection
- 8.1.3 LED Current Set Point
- 8.1.4 Inductor Selection
- 8.1.5 Output Capacitor Selection
- 8.1.6 Input Capacitor Selection
- 8.1.7 Bootstrap Capacitor Selection
- 8.1.8 Compensation Capacitor Selection
- 8.1.9 Input Undervoltage Protection
- 8.1.10 CSN Protection Diode
- 8.2
Typical Application
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 Calculating Duty Cycle
- 8.2.2.2 Calculating Minimum On-Time and Off-Time
- 8.2.2.3 Minimum Switching Frequency
- 8.2.2.4 LED Current Set Point
- 8.2.2.5 Inductor Selection
- 8.2.2.6 Output Capacitor Selection
- 8.2.2.7 Bootstrap Capacitor Selection
- 8.2.2.8 Compensation Capacitor Selection
- 8.2.2.9 PWM Dimming and Input Voltage Protection
- 8.2.3 Application Curves
- 8.1
Application Information
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
8.2.2.9 PWM Dimming and Input Voltage Protection
The device channel enable function and external PWM signal is achieved by controlling UDIM input. The device modulates the LED current based on the PWM duty cycle of the external signal.
Input undervoltage lockout function is implemented by selecting RUV1 and RUV2 resistor along with internal hysteresis.
Equation 30. 
A standard 191-kΩ resistor is selected for RUV2.
Equation 31. 
A standard 8.45-kΩ resistor is selected for RUV1.