C1+

C1-

C2+

C2-

1.25 V

Ref.

Soft

Start

1.3 MHz.

Switch

Frequency

VIN

LM3535

2.7V to 5.5V

3/2X and 1X

Regulated Charge Pump

GroupA Current Sinks

GroupB

Current

Sinks

D1C Current

Sink

GAIN

CONTROL

Brightness

Control

Brightness

Control

I

2C Interface

Block

General Purpose Register

Brightness Control Registers

Group A and Group B

Brightness

Control

Brightness Control Register

D1C

RSET

SDIO

SCL

D1A

D2A

D3A

D4A

D62

D1B/INT

D1C/ALS

D53

CIN

HWEN

VOUT

PWM

COUT

1 PF

ALS

VIO

INT

OR

1 PF

1 PF

GND

1 PF

10

LM3535

SNVS598B – AUGUST 2010 – REVISED MARCH 2018

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7 Detailed Description

7.1 Overview

The LM3535 is a white LED driver system based upon an adaptive 3/2× – 1× CMOS charge pump capable of

supplying up to 200 mA of total output current. With three separately controlled groups of constant current sinks,

the LM3535 is an ideal solution for platforms requiring a single white LED driver IC for main display, sub display,

and indicator lighting. The tightly matched current sinks ensure uniform brightness from the LEDs across the

entire small-format display.

Each LED is configured in a common anode configuration, with the peak drive current set to 25 mA. An I2C

compatible interface is used to enable the device and vary the brightness within the individual current sink

Groups. For GroupA, 128 exponentially-spaced analog brightness control levels are available. GroupB and

GroupC have 8 linearly-spaced analog brightness levels.

Additionally, the LM3535 provides 1 inputfor an ambient light sensor to adaptively adjust the diode current based

on ambient conditions, and a PWM pin to allow the diode current to be pulse width modulated to work with a

display driver utilizing dynamic or content adjusted backlight control (DBC or CABC).

7.2 Functional Block Diagram