KTZ8850中文資料芯凱電子數(shù)據(jù)手冊(cè)PDF規(guī)格書

Features

? Wide input range: 3.0V~5.5V

? Low quiescent current

? Drive up to 10 series LEDs or 2 parallel strings

of 8 series LEDs

? Backlight efficiency: up to 86

? Integrated 40V Power MOSFET

? Flexible dimming control

■ 256-step I2C Controlled or

■ High resolution PWM 5~100kHz

? High accuracy across full load range

? Programmable LED open-circuit (OVP)/Short

protection

? Low 200mV feedback voltage

? Internal over voltage protection (default 36V)

? Programmable dual Bias output regulator based

on single inductor solution

? Charge pump PFM mode at light load

? LCD Bias efficiency: up to 90

? Wide dual output voltage range

■ +/-4.0V to +/-6.3V (100mV/step)

? +/-1.5 VPOS/VNEG output voltage accuracy

? Maximum peak output current up to 80mA

? Active output discharge function

? Cycle-by-cycle inductor current limit

? 1 μA shutdown current

? Pb-free Package: WLCSP-18

? -40°C to +85°C Temperature Range

Applications

? Smartphone/Tablet Backlight

? Netbook/Notebook Backlight

? PDA/GPS Backlight

? Portable Media Player

Brief Description

The KTZ8850 is a multifunction power management IC

combining a high efficiency step-up LED driver with dual

output LCD bias power regulator. It features a versatile

constant current LED driver with a high efficiency DC-DC

step up “boost” converter architecture. The low-side 40V

power MOSFET is integrated in the device, minimizing the

total number of external components. Unique technology

and high 1.3A current limit allow KTZ8850 to drive up to

36V output (single string of 10 LEDs in series or 2 parallel

strings of 8 LEDs in series).

The optimized 1.1MHz switching frequency results in small

external component size. The driver is equipped with an

internal decoder that allows digital FB control dimming for

256-step (8-bit) current programming and can be used for

dimming via I2C interface.

High resolution PWM dimming control is also included for

extended dimming range. For power savings, the PWM pin

can be used for Content Adaptive Brightness Control

(CABC) schemes.

Various protection features are built into the KTZ8850,

including cycle-by-cycle input current limit protection, LED

open-circuit (output over voltage) protection and thermal

shutdown protection. The leakage current in shutdown

mode is less than 1μA.

An LDO and a charge pump generate dual outputs at +5V

(default) and -5V (default), whose voltages can be

programmed via an I2C interface. By integrating

synchronous rectification MOSFETs for the step-up

converter and charge pump, the KTZ8850 maximizes

conversion efficiency up to 90.

The device integrates compensation and soft-start

circuitry, which results in a simpler and smaller solution

with much fewer external components. High switching

frequency (2.2MHz) allows the use of a smaller inductor

and capacitor to further reduce the solution size.

The I2C-compatible interface controls the dual output

voltages and accesses the programmable functions and

registers on the device.

KTZ8850 is available in a RoHS compliant 18-ball 2.47 x

1.27mm WLCSP package.