General Description

The MAX25069 is a highly integrated TFT power supply

and LED backlight driver IC for automotive TFT-LCD applications.

This IC integrates one boost converter, one

inverting buck-boost converter, two gate-driver supplies,

and a boost/SEPIC controller that can power 1 to 6 strings

of LEDs in the display backlight.

The source-driver power supplies consist of a boost converter

which can provide up to +18V in unipolar mode

and an inverting buck-boost converter that can generate

a voltage down to -10.5V. The AVDD output can deliver

up to 300mA at 13.5V, while NAVDD can provide up to

200mA. The positive source-driver supply-regulation voltage

(VAVDD) is set using internal NV memory or through

I2C. The negative source-driver supply voltage (VNAVDD)

is always tightly regulated to -VAVDD. The source-driver

supplies operate from an input voltage between 2.65V and

5.5V.

The gate-driver power supplies consist of regulated

charge pumps that generate up to +31.5V and down to

-18V and can deliver up to 15mA each.

The IC features a 6-string LED driver with input switch

control (NGATE) that can power up to 6 strings of LEDs

with 150mA (max) of current per string.

Logic-controlled and I2C-controlled pulse-width modulation

(PWM) dimming are included, with minimum pulse

widths as low as 300ns and the option of phase shifting

the LED strings with respect to one another. When phase

shifting is enabled, each string is turned on at a different

time, reducing the input and output ripple, as well as audible

noise. With phase shifting disabled, the current sinks

turn on simultaneously and parallel connection of current

sinks is possible.

The startup and shutdown sequences for all power domains

are controlled using one of the eight preset modes,

which are selectable using internal nonvolatile memory or

through the I2C interface.

The MAX25069 is available in a 7mm x 7mm, 48-pin

TQFN package with an exposed pad, and operates over

the -40°C to +125°C ambient temperature range.

Benefits and Features

● 4-Output TFT-LCD Bias Power

• 2.65V to 5.5V Input for the TFT-LCD Section

• Integrated 420kHz or 2.1MHz Boost and Buck-

Boost Converters

• Positive and Negative 15mA Gate Voltage

Regulators with Adjustable Output Voltage (Tripler/

Inverting Doubler)

• Flexible Sequencing

• Undervoltage Detection on All Outputs

• Low-Quiescent-Current Standby Mode

● 6-Channel, 36V LED Backlight Driver

• NGATE Control for External nMOSFET Series

Switch

• Programmable nMOSFET Current Limit

• Up to 150mA Current per Channel

• 4.5V to 36V Input Voltage Range, 3V Operation

after Startup

• Integrated Boost/SEPIC Controller (400kHz to

2.2MHz with Synchronization)

• Dimming Ratio 16,667:1 at 200Hz

• Adaptive Voltage Optimization to Reduce Power

Dissipation in the LED Current Sinks

• Open-String, Shorted-LED, and Short-to-GND

Diagnostics

● Low EMI

• Phase-Shift Dimming of LED Strings

• Spread Spectrum on LED Driver and TFT

• Selectable Switching Frequency

● I2C Interface for Control and Diagnostics

• Fault Indication through the FLTB Pin and I2C

• Nonvolatile Configuration Memory

● Overload and Thermal Protection

● -40°C to +125°C Ambient Temperature Operation

● 48-Pin, 7mm x 7mm TQFN Package with Exposed Pad

● AEC-Q100 Grade 1

Applications

● Automotive Dashboards

● Automotive Central Information Displays

● Automotive Head-Up Displays

● Automotive Navigation Systems