SNVS871M
July 2012 – June 2020
LP8556
PRODUCTION DATA.
1
Features
2
Applications
Simplified Schematic
3
Description
4
Revision History
5
Device Options
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
Electrical Characteristics — Boost Converter
7.7
Electrical Characteristics — LED Driver
7.8
Electrical Characteristics — PWM Interface
7.9
Electrical Characteristics — Logic Interface
7.10
I2C Serial Bus Timing Parameters (SDA, SCL)
7.11
Typical Characteristics
8
Detailed Description
8.1
Overview
8.2
Functional Block Diagram
8.3
Feature Description
8.3.1
Boost Converter
8.3.1.1
Boost Converter Operation
8.3.1.2
Setting Boost Switching Frequency
8.3.1.3
Output Voltage Control
8.3.1.3.1
Adaptive Control
8.3.1.3.2
Manual Control
8.3.1.4
EMI Reduction
8.3.2
Brightness Control
8.3.2.1
BRT_MODE = 00
8.3.2.2
BRT_MODE = 01
8.3.2.3
BRT_MODE = 10
8.3.2.4
BRT_MODE = 11
8.3.2.5
Output Dimming Schemes
8.3.2.5.1
PWM Control
8.3.2.5.2
Pure Current Control
8.3.2.5.3
Adaptive Control
8.3.2.6
Setting Full-Scale LED Current
8.3.2.7
Setting PWM Dimming Frequency
8.3.2.8
Phase Shift PWM Scheme
8.3.2.9
Slope and Advanced Slope
8.3.2.10
Dithering
8.3.3
Fault Detection
8.3.3.1
LED Fault Detection
8.3.3.1.1
Open Detect
8.3.3.1.2
Short Detect
8.3.3.2
Undervoltage Detection
8.3.3.3
Overcurrent Protection
8.3.3.4
Thermal Shutdown
8.4
Device Functional Modes
8.4.1
Shutdown Mode
8.4.2
Active Mode
8.5
Programming
8.5.1
I2C-Compatible Serial Bus Interface
8.5.1.1
Interface Bus Overview
8.5.1.2
Data Transactions
8.5.1.3
Acknowledge Cycle
8.5.1.4
Acknowledge After Every Byte Rule
8.5.1.5
Addressing Transfer Formats
8.5.1.6
Control Register Write Cycle
8.5.1.7
Control Register Read Cycle
8.5.1.8
Register Read and Write Detail
8.6
Register Maps
8.6.1
Register Bit Explanations
8.6.1.1
Brightness Control
8.6.1.2
Device Control
8.6.1.3
Status
8.6.1.4
Direct Control
8.6.1.5
LED String Enable
8.6.2
EPROM Bit Explanations
8.6.2.1
LP8556TM (DSBGA) Configurations and Pre-Configured EPROM Settings
8.6.2.2
LP8556TM (DSBGA) Configurations and Pre-configured EPROM Settings Continued
8.6.2.3
LP8556SQ (WQFN) Configurations and Pre-configured EPROM Settings
8.6.2.4
CFG98
8.6.2.5
CFG9E
8.6.2.6
CFG0
8.6.2.7
CFG1
8.6.2.8
CFG2
8.6.2.9
CFG3
8.6.2.10
CFG4
8.6.2.11
CFG5
8.6.2.12
CFG6
8.6.2.13
CFG7
8.6.2.14
CFG9
8.6.2.15
CFGA
8.6.2.16
CFGE
8.6.2.17
CFGF
9
Application and Implementation
9.1
Application Information
9.1.1
Using LP8556 With I2C Host
9.1.1.1
Setting Boost Switching and PWM Dimming Frequencies
9.1.1.2
Setting Full-Scale LED Current
9.1.2
Using LP8556 With Configuration Resistors and IO Pins
9.1.2.1
Setting Boost Switching and PWM Dimming Frequencies
9.1.2.2
Setting Full-Scale LED Current
9.2
Typical Application
9.2.1
Design Requirements
9.2.2
Detailed Design Procedure
9.2.2.1
Recommended Inductance for the Boost Power Stage
9.2.2.2
Recommended Capacitances for the Boost and LDO Power Stages
9.2.3
Application Curves
10
Power Supply Recommendations
11
Layout
11.1
Layout Guidelines
11.2
Layout Examples
12
Device and Documentation Support
12.1
Receiving Notification of Documentation Updates
12.2
Community Resources
12.3
Trademarks
12.4
Electrostatic Discharge Caution
12.5
Glossary
13
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
YFQ|20
MXBG174
RTW|24
MPQF167C
Thermal pad, mechanical data (Package|Pins)
RTW|24
QFND450A
Orderable Information
snvs871m_oa
snvs871m_pm
7
Specifications