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LP8550

ACTIVE

High-Efficiency LED Backlight Driver for Notebooks

Product details

Number of channels 6 Vin (min) (V) 5.5 Vin (max) (V) 22 Vout (min) (V) 10 Vout (max) (V) 40 Type Inductive Switching frequency (max) (kHz) 1250 Duty cycle (max) (%) 100 LED current per channel (mA) 50 Peak efficiency (%) 91 Topology Boost Features Adjustable Switch Frequency, Enable/Shutdown, I2C control, PWM control Operating temperature range (°C) -30 to 85 Rating Catalog
Number of channels 6 Vin (min) (V) 5.5 Vin (max) (V) 22 Vout (min) (V) 10 Vout (max) (V) 40 Type Inductive Switching frequency (max) (kHz) 1250 Duty cycle (max) (%) 100 LED current per channel (mA) 50 Peak efficiency (%) 91 Topology Boost Features Adjustable Switch Frequency, Enable/Shutdown, I2C control, PWM control Operating temperature range (°C) -30 to 85 Rating Catalog
DSBGA (YZR) 25 7.5625 mm² 2.75 x 2.75
  • High-Voltage DC/DC Boost Converter with Integrated FET
    with Four Switching Frequency Options: 156/312/625/1250 kHz
  • 2.7-V to 22-V Input Voltage Range to Support 1x to 5x Cell Li-Ion
    Batteries
  • Programmable PWM Resolution
    • 8 to 13 True Bits (Steady State)
    • Additional 1 to 3 Bits Using Dithering During Brightness
      Changes
  • I2C and PWM Brightness Control
  • Automatic PWM & Current Dimming for Improved Efficiency
  • PWM output frequency and LED Current set through Resistors
  • Optional Synchronization to Display VSYNC Signal
  • Six LED Outputs with LED Fault (Short/Open) Detection
  • Low Input Voltage, Overtemperature, Overcurrent Detection,
    and Shutdown
  • Minimum Number of External Components
  • High-Voltage DC/DC Boost Converter with Integrated FET
    with Four Switching Frequency Options: 156/312/625/1250 kHz
  • 2.7-V to 22-V Input Voltage Range to Support 1x to 5x Cell Li-Ion
    Batteries
  • Programmable PWM Resolution
    • 8 to 13 True Bits (Steady State)
    • Additional 1 to 3 Bits Using Dithering During Brightness
      Changes
  • I2C and PWM Brightness Control
  • Automatic PWM & Current Dimming for Improved Efficiency
  • PWM output frequency and LED Current set through Resistors
  • Optional Synchronization to Display VSYNC Signal
  • Six LED Outputs with LED Fault (Short/Open) Detection
  • Low Input Voltage, Overtemperature, Overcurrent Detection,
    and Shutdown
  • Minimum Number of External Components

The LP8550 is a white-LED driver with integrated boost converter. It has six adjustable current sinks which can be controlled by PWM input or with I2C-compatible serial interface. The boost converter has adaptive output voltage control based on the LED driver voltages. This feature minimizes the power consumption by adjusting the voltage to lowest sufficient level in all conditions.

LED outputs have 8-bit current resolution and up to 13-bit PWM resolution with additional 1- to 3-bit dithering to achieve smooth and precise brightness control. Proprietary Phase Shift PWM control is used for LED outputs to reduce peak current from the boost converter, thus making the boost capacitors smaller. The Phase Shifting scheme also eliminates audible noise.

Automatic PWM dimming at lower brightness values and current dimming at higher brightness values can be used to improve the optical efficiency. Internal EEPROM is used for storing the configuration data. This makes it possible to have minimum external component count and make the solution very small.

The LP8550 has safety features which make it possible to detect LED outputs with open or short fault — low input voltage and boost overcurrent conditions are monitored, and chip is turned off in case of these events. Thermal de-rating function prevents overheating of the device by reducing backlight brightness when set temperature has been reached.

The LP8550 is a white-LED driver with integrated boost converter. It has six adjustable current sinks which can be controlled by PWM input or with I2C-compatible serial interface. The boost converter has adaptive output voltage control based on the LED driver voltages. This feature minimizes the power consumption by adjusting the voltage to lowest sufficient level in all conditions.

LED outputs have 8-bit current resolution and up to 13-bit PWM resolution with additional 1- to 3-bit dithering to achieve smooth and precise brightness control. Proprietary Phase Shift PWM control is used for LED outputs to reduce peak current from the boost converter, thus making the boost capacitors smaller. The Phase Shifting scheme also eliminates audible noise.

Automatic PWM dimming at lower brightness values and current dimming at higher brightness values can be used to improve the optical efficiency. Internal EEPROM is used for storing the configuration data. This makes it possible to have minimum external component count and make the solution very small.

The LP8550 has safety features which make it possible to detect LED outputs with open or short fault — low input voltage and boost overcurrent conditions are monitored, and chip is turned off in case of these events. Thermal de-rating function prevents overheating of the device by reducing backlight brightness when set temperature has been reached.

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Technical documentation

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Type Title Date
* Data sheet LP8550 High-Efficiency LED Backlight Driver for Notebooks datasheet (Rev. E) PDF | HTML 09 Sep 2014
Application note Some Guidelines and Tips for the LED Driver Application 14 Aug 2019
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Application note Power Budget for Backlight Drivers 27 Jun 2013
Application note Increasing Full-Load Efficiency of a Backlight Driver 05 Jun 2013

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Driver or library

LP8550SW-LINUX — Linux Driver for LP8550

The Linux driver supports the LP8550/1/2/3/5/6 and LP8557. The Linux driver supports communication through the I2C bus and interfaces with the backlight and PWM sub-system.

 

Linux Mainline Status

Available in Linux Main line: Yes
Available through git.ti.com: N/A

Supported Devices:

  • lp8550
  • lp8551
  • lp8552
  • (...)
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PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
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DSBGA (YZR) 25 Ultra Librarian

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