SNVSB83B
June 2019 – January 2020
LP8867-Q1
,
LP8869-Q1
PRODUCTION DATA.
1
Features
2
Applications
3
Description
Simplified Schematic
LED Backlight Efficiency
4
Revision History
5
Device Comparison Table
6
Pin Configuration and Functions
Pin Functions
7
Specifications
7.1
Absolute Maximum Ratings
7.2
ESD Ratings
7.3
Recommended Operating Conditions
7.4
Thermal Information
7.5
Electrical Characteristics
7.6
Internal LDO Electrical Characteristics
7.7
Protection Electrical Characteristics
7.8
Current Sinks Electrical Characteristics
7.9
PWM Brightness Control Electrical Characteristics
7.10
Boost and SEPIC Converter Characteristics
7.11
Logic Interface Characteristics
7.12
Typical Characteristics
8
Detailed Description
8.1
Overview
8.2
Functional Block Diagram
8.3
Feature Description
8.3.1
Integrated DC-DC Converter
8.3.1.1
DC-DC Converter Parameter Configuration
8.3.1.1.1
Switching Frequency
8.3.1.1.2
Spread Spectrum and External SYNC
8.3.1.1.3
Recommended Component Value and Internal Parameters
8.3.1.1.4
DC-DC Converter Switching Current Limit
8.3.1.1.5
DC-DC Converter Light Load Mode
8.3.1.2
Adaptive Voltage Control
8.3.1.2.1
Using Two-Divider
8.3.1.2.2
Using T-Divider
8.3.1.2.3
Feedback Capacitor
8.3.2
Internal LDO
8.3.3
LED Current Sinks
8.3.3.1
LED Output Configuration
8.3.3.2
LED Current Setting
8.3.3.3
Brightness Control
8.3.4
Power-Line FET Control
8.3.5
LED Current Dimming With External Temperature Sensor
8.3.6
Fault Detections and Protection
8.3.6.1
Supply Fault and Protection
8.3.6.1.1
VIN Undervoltage Fault (VIN_UVLO)
8.3.6.1.2
VIN Overvoltage Fault (VIN_OVP)
8.3.6.1.3
VIN Overcurrent Fault (VIN_OCP)
8.3.6.2
Boost Fault and Protection
8.3.6.2.1
Boost Overvoltage Fault (BST_OVP)
8.3.6.2.2
SW Overvoltage Fault (SW_OVP)
8.3.6.3
LED Fault and Protection (LED_OPEN and LED_SHORT)
8.3.6.4
Thermal Fault and Protection (TSD)
8.3.6.5
Overview of the Fault and Protection Schemes
8.4
Device Functional Modes
8.4.1
STANDBY State
8.4.2
SOFT START State
8.4.3
BOOST START State
8.4.4
NORMAL State
8.4.5
FAULT RECOVERY State
8.4.6
State Diagram and Timing Diagram for Start-up and Shutdown
9
Application and Implementation
9.1
Application Information
9.2
Typical Applications
9.2.1
Typical Application for 4 LED Strings
9.2.2
Design Requirements
9.2.3
Detailed Design Procedure
9.2.3.1
Inductor Selection
9.2.3.2
Output Capacitor Selection
9.2.3.3
Input Capacitor Selection
9.2.3.4
LDO Output Capacitor
9.2.3.5
Diode
9.2.4
Application Curves
9.2.5
SEPIC Mode Application
9.2.5.1
Design Requirements
9.2.5.2
Detailed Design Procedure
9.2.5.2.1
Inductor
9.2.5.2.2
Diode
9.2.5.2.3
Capacitor C1
9.2.5.3
Application Curves
10
Power Supply Recommendations
11
Layout
11.1
Layout Guidelines
11.2
Layout Example
12
Device and Documentation Support
12.1
Device Support
12.1.1
Development Support
12.2
Documentation Support
12.2.1
Related Documentation
12.3
Receiving Notification of Documentation Updates
12.4
Community Resources
12.5
Trademarks
12.6
Electrostatic Discharge Caution
12.7
Glossary
13
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
PWP|20
MHTS001G
Thermal pad, mechanical data (Package|Pins)
PWP|20
PPTD027Z
Orderable Information
snvsb83b_oa
snvsb83b_pm
9.2.5.3
Application Curves
4 strings, 4 LEDs per string
f
sw
= 2.2 MHz
IHCL-4040DZ-5A 4.7 μH
Figure 26.
SEPIC Efficiency
4 strings, 4LEDs per string
f
sw
= 2.2 MHz
IHCL-4040DZ-5A 4.7 μH
Figure 27.
LED Backlight Efficiency