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ADP8870:  Charge Pump Parallel Backlight Driver with Image Content PWM Input

Product Details

Product Status:Recommended for New Designs

The ADP8870 combines a programmable backlight LED charge pump driver with automatic phototransistor control of the brightness (LED Current) and a PWM input to control the scale of the output current. This combination allows for significant power savings because it automatically changes the current intensity based on the sensed ambient lighting levels and the display image content. It performs this function automatically and so removes the need for a processor to be monitoring the phototransistor. The light intensity thresholds are fully programmable via the I2C interface.

The ADP8870 allows up to six LEDs to be independently driven up to 30 mA (maximum). An additional seventh LED can be driven to 60 mA (maximum). All LEDs are individually programmable for minimum/maximum current and fade in/out times through an I2C interface. These LEDs can also be combined into groups to reduce the processor instructions during fade in/out.

Driving all of this is a two capacitor charge pump with gains of 1×, 1.5×, and 2×. This setup is capable of driving a maximum IOUT of 240 mA from a supply of 2.5 V to 5.5 V. A full suite of safety features including short-circuit, overvoltage, and overtemperature protection allow easy implementation of a safe and robust design. Additionally, input inrush currents are limited via an integrated soft start combined with controlled input to output isolation.

FEATURES and BENEFITS

  • Charge pump with automatic gain selection of 1x, 1.5x, and 2x for maximum efficiency.
  • Two high accuracy (±5%) phototransistor inputs for automated ambient light sensing (ALS)
  • 5 programmable ambient light-sensing zones for optimal backlight power savings
  • PWM input can be used for Content Adaptive Brightness Control (CABC) of any, or all, of the LEDs
  • Independent ALS control of D7, for automated response of keypad lighting to ambient light levels
  • PWM input can be used for content adaptive brightness control (CABC) of any, or all, of the LEDs; PWM input scales the LED output current
  • Seven independent and programmable LED drivers: Six drivers capable of 30 mA (max); One additional driver capable of 60 mA (max)
  • Programmable maximum current limit (128 levels)
  • Standby mode for <1 μA current consumption
  • 16 programmable fade in and fade out times (0.1 s to 5.5 s) with choice of square or cubic rates.
  • Fading override
  • I2C compatible interface for all programming
  • Dedicated reset pin and built-in power on reset (POR).
  • Short circuit, over voltage, and over temperature protection.
  • Internal soft start to limit inrush currents
  • Input to output isolation during faults or shutdown
  • Operates down to Vin = 2.5 V, with undervoltage lockout (UVLO) at 2.0 V.
  • Small wafer level chip scale package (WLCSP) or lead frame chip scale package (LFCSP)

Documentation

Title Content Type File Type
ADP8870: Charge-Pump, Parallel Backlight Driver with Image Content PWM Input Data Sheet (Rev B, 01/2014) (pdf, 975 kB) Data Sheets PDF
Low-Voltage Current Sink Controls High-Voltage LED String  (pdf)
Discusses how a single programmable LED driver can be combined with a low-cost boost converter to achieve a flexible, high-efficiency, easy-to-program solution.
Analog Dialogue PDF
RAQs index Rarely Asked Questions HTML
Glossary of EE Terms Glossary HTML

Design Tools,Models,Drivers & Software

Title Content Type File Type
ADP8870 Back-light LED Linux Driver (Wiki Site) Device Drivers HTML

Evaluation Kits & Symbols & Footprints

Evaluation Boards & KitsView the Evaluation Boards and Kits page for documentation and purchasing

Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

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Price, packaging, availability

ADP8870 Model Options
Model Package Pins Temp.
Range
Packing,
Qty
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
Purchase/Sample
ADP8870ACBZ-R7 Status: Production CHIPS W/SOLDER BUMPS/WLCSP 20 Ind Reel, 3000 - $1.48 Y  Material Info PCN Purchase Sample
ADP8870ACPZ-R7 Status: Production LFCSP:LEADFRM CHIP SCALE 20 Ind Reel, 1500 - $1.82 Y  Material Info PCN Purchase Sample
Price Table Help

The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

ADP8870 Evaluation Board
Model Description Price RoHS View PCN/ PDN Check Inventory/
Purchase/Sample
ADP8870DBCB-EVALZ Status: Production Evaluation Board $100.00 Yes -

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.

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