LP8557 High-Efficiency LED Backlight Driver for Tablets | TI.com

LP8557 (ACTIVE) High-Efficiency LED Backlight Driver for Tablets

 

Recommended alternative parts

  • LP8556  - The device has the SAME FUNCTIONALITY as the compared device, but is not pin-for-pin equivalent and may not be parametrically equivalent.   Recommended for designs which require 2 or 3 cells versus the LP8557 is recommended for 1 cell designs.
  • TPS61176  - The device has the SAME FUNCTIONALITY as the compared device, but is not pin-for-pin equivalent and may not be parametrically equivalent.   TPS61176 offers similar basic functionality on QFN Package

Description

The LP8557 and LP8557I are high-efficiency LED drivers each featuring an integrated DC-DC inductive boost converter and six high-precision current sinks. LP8557 is intended for applications that exclusively use a pulse width modulated (PWM) signal for controlling the brightness while LP8557I is intended for applications that can utilize an I2C master as well.

The boost converter has adaptive output voltage control. This feature minimizes the power consumption by adjusting the voltage to the lowest sufficient level under all conditions.

The adaptive current sink headroom voltage control scales the headroom voltage with the LED current for optimal system efficiency.

The LED string auto-detect function enables use of the same device in systems with 1 to 6 LED strings for the maximum design flexibility.

Proprietary hybrid PWM plus current mode dimming enables additional system power savings. Phase-shift PWM allows reduced audible noise and smaller boost output capacitors.

Flexible CABC support combines brightness level selections based on the PWM input and I2C commands.

For all available packages, see the orderable addendum at the end of the data sheet.

Features

  • High-Efficiency DC-DC Boost Converter With 28-V Integrated Power MOSFET
  • 2.7-V to 5.5-V VDD Range for Supporting Single-Cell Li-Ion Battery Applications
  • Six 25-mA High-Precision LED Current Sinks
  • Adaptive Boost Voltage and LED Current Sink Headroom Controls for Maximum System Efficiency
  • LED String Count Auto-Detect for Maximum Design Flexibility
  • Smart Phase Shift PWM Mode for Reduced Audible Noise
  • PWM Input Duty Cycle Brightness Control, PWM Output Frequency Selectable Independent of Input Frequency
  • Hybrid PWM Plus Current Dimming for Higher LED Drive Optical Efficiency
  • Switching Frequency, PWM Output Frequency, and LED Current can be set Through Resistors or I2C Interface
  • Programmable Boost SW Slew Rate Control and Spread Spectrum Scheme for Reduced Switching Noise and Improved EMI Performance
  • UVLO, TSD, BST_OVP, BST_OCP, BST_UV, LED OPEN* and LED Short Fault Coverage
  • Minimum Number of External Components

Parametrics

Compare all products in Backlight LED drivers Email Download to Excel
Part number Order Channels (#) Vin (Min) (V) Vin (Max) (V) Vout (Min) (V) Vout (Max) (V) Switching frequency (Max) (kHz) Type LED current per channel (mA) LED (#) Topology Shutdown current (Typ) (uA) Peak efficiency (%) LED configuration Function Features Operating temperature range (C) Package Group Package size: mm2:W x L (PKG)
LP8557 Order now 6     2.7     5.5     7     28     1000     Inductive     25     48     Boost     0.001     93     6 LED channels
Parallel    
  CABC
Edge Rate Control    
-30 to 85     DSBGA | 16     See datasheet (DSBGA)    
LM36274 Order now 4     2.7     5     27     30     1050     Inductive     30     32     Boost
Current Sink    
1.2     92     Parallel
Series    
  Adjustable Switch Frequency
CABC
I2C Control
OVP
Thermal Shutdown    
-40 to 85     DSBGA | 24     See datasheet (DSBGA)    
LM36923H Order now 3     2.5     5.5     0     37     1050     Inductive     30     30     Boost
Current Sink
Multi-Channel    
1.2     92     Parallel
Series    
  Adjustable Switch Frequency
CABC
Direct PWM Dimming
Enable/Shutdown
I2C Control
OVP
Thermal Shutdown    
-40 to 85     DSBGA | 12     12DSBGA: 2 mm2: 1.16 x 2 (DSBGA | 12)    
LP8553 Order now 4     2.7     22     10     40     1250     Inductive     50     40     Boost     1     93         PWM Control     -30 to 85     DSBGA | 25     25DSBGA: 8 mm2: 2.8 x 3 (DSBGA | 25)    
LP8555 Order now 12     2.7     20     7     28     1000     Inductive     50     96     Boost     3     93