LM3633 Datasheet, PDF (10/59 Pages) Texas Instruments – Complete Lighting Power Solution for Smartphone Handsets

LM3633
SNVS867 – JUNE 2014
7 Detailed Description
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7.1 Overview
The LM3633 provides the power for three high-voltage LED strings and six low-voltage LEDs. The three high-
voltage LED strings are powered from an integrated boost converter. The six low-voltage LEDs are powered from
an integrated 2X charge pump. The device is programmable over an I²C-compatible interface. Additional features
include a Pulse Width Modulation (PWM) input for content adjustable brightness control and 6 programmable
pattern generators for RGB and indicator blinking functions on the low-voltage LEDs.
7.2 Functional Block Diagram
IN
HWEN
Hardware Enable,
Reference and
Thermal Shutdown
PWM
Internal Low Pass
Filter
SDA
SCL
I²C Compatible
Interface
Programmable
Overvoltage
Protection (16V, 24V,
32V, 40V)
1A Current Limit
Programmable
500kHz/1MHz
Switching
Frequency
LED String
Open/Short
Detection
Backlight LED Control
1. 5-bit Full-Scale
Current Select
2. 11-bit brightness
adjustment
3. Linear/Exponential
Mapping
4. LED Current
Ramping
Gain Control
(Automatic, 1X,
2X)
6 x Programmable
Pattern
Generators
Indicator LED Control
1. 5-bit Full-Scale
Current Select
2. 8-bit Brightness
Adjustment
3. Linear/Exponential
Mapping
4, LED Current
Ramping
SW
Boost
Converter
OVP
High-Voltage
Current Sinks
HVLED1
HVLED2
HVLED3
GND
2X
Charge Pump
C+
C-
CPOUT
Low Voltage
Current Sinks
LVLED1
LVLED2
LVLED3
LVLED4
LVLED5
LVLED6
7.3 Feature Description
7.3.1 Control Bank Mapping
Control of the LM3633’s current sinks is not done directly, but through the programming of Control Banks. The
current sinks are then assigned to the programmed Control Bank. This allows a wide variety of current control
possibilities where LEDs can be grouped and controlled via specific Control Banks (see Figure 12 and
Figure 17).
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