SNVS871M July   2012  – June 2020 LP8556

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Simplified Schematic
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Options
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics
    6. 7.6  Electrical Characteristics — Boost Converter
    7. 7.7  Electrical Characteristics — LED Driver
    8. 7.8  Electrical Characteristics — PWM Interface
    9. 7.9  Electrical Characteristics — Logic Interface
    10. 7.10 I2C Serial Bus Timing Parameters (SDA, SCL)
    11. 7.11 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Boost Converter
        1. 8.3.1.1 Boost Converter Operation
        2. 8.3.1.2 Setting Boost Switching Frequency
        3. 8.3.1.3 Output Voltage Control
          1. 8.3.1.3.1 Adaptive Control
          2. 8.3.1.3.2 Manual Control
        4. 8.3.1.4 EMI Reduction
      2. 8.3.2 Brightness Control
        1. 8.3.2.1  BRT_MODE = 00
        2. 8.3.2.2  BRT_MODE = 01
        3. 8.3.2.3  BRT_MODE = 10
        4. 8.3.2.4  BRT_MODE = 11
        5. 8.3.2.5  Output Dimming Schemes
          1. 8.3.2.5.1 PWM Control
          2. 8.3.2.5.2 Pure Current Control
          3. 8.3.2.5.3 Adaptive Control
        6. 8.3.2.6  Setting Full-Scale LED Current
        7. 8.3.2.7  Setting PWM Dimming Frequency
        8. 8.3.2.8  Phase Shift PWM Scheme
        9. 8.3.2.9  Slope and Advanced Slope
        10. 8.3.2.10 Dithering
      3. 8.3.3 Fault Detection
        1. 8.3.3.1 LED Fault Detection
          1. 8.3.3.1.1 Open Detect
          2. 8.3.3.1.2 Short Detect
        2. 8.3.3.2 Undervoltage Detection
        3. 8.3.3.3 Overcurrent Protection
        4. 8.3.3.4 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Active Mode
    5. 8.5 Programming
      1. 8.5.1 I2C-Compatible Serial Bus Interface
        1. 8.5.1.1 Interface Bus Overview
        2. 8.5.1.2 Data Transactions
        3. 8.5.1.3 Acknowledge Cycle
        4. 8.5.1.4 Acknowledge After Every Byte Rule
        5. 8.5.1.5 Addressing Transfer Formats
        6. 8.5.1.6 Control Register Write Cycle
        7. 8.5.1.7 Control Register Read Cycle
        8. 8.5.1.8 Register Read and Write Detail
    6. 8.6 Register Maps
      1. 8.6.1 Register Bit Explanations
        1. 8.6.1.1 Brightness Control
        2. 8.6.1.2 Device Control
        3. 8.6.1.3 Status
        4. 8.6.1.4 Direct Control
        5. 8.6.1.5 LED String Enable
      2. 8.6.2 EPROM Bit Explanations
        1. 8.6.2.1  LP8556TM (DSBGA) Configurations and Pre-Configured EPROM Settings
        2. 8.6.2.2  LP8556TM (DSBGA) Configurations and Pre-configured EPROM Settings Continued
        3. 8.6.2.3  LP8556SQ (WQFN) Configurations and Pre-configured EPROM Settings
        4. 8.6.2.4  CFG98
        5. 8.6.2.5  CFG9E
        6. 8.6.2.6  CFG0
        7. 8.6.2.7  CFG1
        8. 8.6.2.8  CFG2
        9. 8.6.2.9  CFG3
        10. 8.6.2.10 CFG4
        11. 8.6.2.11 CFG5
        12. 8.6.2.12 CFG6
        13. 8.6.2.13 CFG7
        14. 8.6.2.14 CFG9
        15. 8.6.2.15 CFGA
        16. 8.6.2.16 CFGE
        17. 8.6.2.17 CFGF
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Using LP8556 With I2C Host
        1. 9.1.1.1 Setting Boost Switching and PWM Dimming Frequencies
        2. 9.1.1.2 Setting Full-Scale LED Current
      2. 9.1.2 Using LP8556 With Configuration Resistors and IO Pins
        1. 9.1.2.1 Setting Boost Switching and PWM Dimming Frequencies
        2. 9.1.2.2 Setting Full-Scale LED Current
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Recommended Inductance for the Boost Power Stage
        2. 9.2.2.2 Recommended Capacitances for the Boost and LDO Power Stages
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.6 Electrical Characteristics — Boost Converter

over operating free-air temperature range (unless otherwise noted)(1)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
RDS_ON Switch ON resistance ISW = 0.5A 0.19 Ω
VBOOST_MIN Boost minimum output voltage VBOOST_RANGE = 0
VBOOST_RANGE = 1		 7
16		 V
VBOOST_MAX Boost maximum output voltage VBOOST_MAX = 100, VBOOST_RANGE = 0
VBOOST_MAX = 101, VBOOST_RANGE = 0
VBOOST_MAX = 110, VBOOST_RANGE = 0
VBOOST_MAX = 111, VBOOST_RANGE = 0 		19
24.0
28.0
32		 21
25
30
34		 22
27
32
37		 V
VBOOST_MAX = 010, VBOOST_RANGE = 1
VBOOST_MAX = 011, VBOOST_RANGE = 1
VBOOST_MAX = 100, VBOOST_RANGE = 1
VBOOST_MAX = 101, VBOOST_RANGE = 1
VBOOST_MAX = 110, VBOOST_RANGE = 1
VBOOST_MAX = 111, VBOOST_RANGE = 1		 17.9
22.8
27.8
32.7
37.2
41.8		 21
25
30
34.5
39
43		 23.1
27.2
31.5
36.6
40.8
44.2		 V
ILOAD_MAX Maximum continuous output load current VIN = 3 V, VOUT = 18 V 220 mA
VIN = 3 V, VOUT = 24 V 160
VIN = 3 V, VOUT = 30 V 120
VOUT/VIN Conversion ratio(2) fSW = 625 kHz 15
fSW = 1250 kHz 12
fSW Switching frequency BOOST_FREQ = 00
BOOST_FREQ = 01
BOOST_FREQ = 10 		312
625
1250		 kHz
VOVP Overvoltage protection voltage VBOOST_RANGE = 1 VBOOST + 1.6 V
VUVLO VIN undervoltage lockout threshold UVLO_EN = 1 V
UVLO_TH = 0, falling
UVLO_TH = 1, falling		 2.5
5.2
VUVLO_hyst VUVLO hysteresis VUVLO[rising]
VUVLO[falling]		 UVLO_TH = 0 50 mV
UVLO_TH = 1 100
tPULSE Switch minimum pulse width No load 50 ns
tSTARTUP Start-up time See(3) 8 ms
ISW_LIM SW pin current limit(4) IBOOST_LIM_2X = 0 IBOOST_LIM = 00
IBOOST_LIM = 01
IBOOST_LIM = 10
IBOOST_LIM = 11		 0.66
0.88
1.12
1.35		 0.9
1.2
1.5
1.8		 1.16
1.40
1.73
2.07		 A
IBOOST_LIM_2X = 1 IBOOST_LIM = 00
IBOOST_LIM = 01
IBOOST_LIM = 10		 1.6
2.1
2.6		 A
ΔVSW / toff_on SW pin slew rate during OFF to ON transition EN_DRV3 = 0 AND EN_DRV2 = 0
EN_DRV3 = 0 AND EN_DRV2 = 1
EN_DRV3 = 1 AND EN_DRV2 = 1		 3.7
5.3
7.5		 V/ns
ΔVSW / ton_off SW pin slew rate during ON to OFF transition EN_DRV3 = 0 AND EN_DRV2 = 0
EN_DRV3 = 0 AND EN_DRV2 = 1
EN_DRV3 = 1 AND EN_DRV2 = 1		 1.9
4.4
4.8		 V/ns
ΔtON / tSW Peak-to-peak switch ON time deviation to SW period ratio (spread spectrum feature) SSCLK_EN = 1 1%
(1) Minimum (MIN) and Maximum (MAX) limits are verified by design, test, or statistical analysis. Typical numbers are for information only.
(2) Verified by design and not tested in production.
(3) Start-up time is measured from the moment boost is activated until the VBOOST crosses 90% of its target value.
(4) 1.8 A is the maximum ISW_LIM supported with the DSBGA package. For applications requiring the ISW_LIM to be greater than 1.8 A and up to 2.6 A, WQFN package should be considered.