EV3385-R-00A
4 String WLED Controller With I
2
C Interface
Evaluation Board
EV3385-R-00A Rev.1.1 www.MonolithicPower.com 1
5/21/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
The Future of Analog IC Technology
DESCRIPTION
The MP3385 is a step-up controller with 4
regulated current channels designed to drive
WLED arrays for middle and large-size LCD
panel backlighting applications.
The MP3385 uses peak current mode, PWM
control architecture for system loop regulation.
It drives an external MOSFET to boost up the
output voltage from a 4.5V to 33V input supply.
It employs an I
2
C digital interface and can
flexibly set the operation and protection modes,
including dimming mode, dimming current and
dimming ratio, OCP, OVP, LED short protection
threshold, and the switching frequency. For
easy application use and board debugging, the
MP3385 detects and automatically disables the
unused LED strings during start-up to avoid
charging the output to the OVP threshold.
The MP3385 achieves 1.8% current matching
between each string. The low regulation voltage
on the LED current sources improves efficiency
and reduces power loss in order to achieve a
higher current output.
The MP3385 supports analog, PWM, and
combined analog and PWM dimming modes to
meet different application requirements. Full
protection features include OCP, OTP, UVP,
OVP, LED short/open protection, and
inductor/diode short protection.
The MP3385 is available in a QFN-20
4mm x 4mm and a TSSOP20-EP package.
ELECTRICAL SPECIFICATIONS
Paramete
Symbol
alue Units
Input Voltage V
IN
4.5 – 33 V
Output Voltage VLED <80 V
LEDs # 4 string
LED Current I
LED
120/string mA
FEATURES
• 4-String, Max 300mA/String WLED Driver
• 4.5V to 33V Input Voltage Range
• 80V Abs. Rating for Each String
• 1.8% Current Matching Accuracy for Each
String
• Unused Channel Auto-Detection Function
during Start-Up
• 100kHz-900kHz Programmable Switching
Frequency
• Multiple Dimming Modes Selected by I
2
C
Interface:
1. Direct PWM Dimming Mode
2. Internal Fixed 23kHz PWM Dimming
Mode
3. Analog Dimming Mode by Input Pulse
4. Internal Analog Dimming Mode
5. Mixed Dimming Mode by Input Pulse
6. Internal Mixed Dimming Mode
• 2%-100% Programmable Full Scale Current
with 8-Bit Resolution
• 0%-100% LED Dimming Range with 10-Bit
Resolution for Internal Dimming Mode
• Cascading Capability with a Single Power
Source
• 18V to 80V Over-Voltage Protection,
2V/Step
• 0.15V to 0.5V Latch-Off/Recoverable OCP
Protection Threshold, 50mV/Step
• Recoverable Thermal Shutdown Protection
APPLICATIONS
• Desktop LCD Flat Panel Displays
• All In One
• 2D/3D LCD TVs
All MPS parts are lead-free and adhere to the RoHS directive. For MPS green
status, please visit MPS website under Products, Quality Assurance page.
“MPS” and “The Future of Analog IC Technology” are registered trademarks of
Monolithic Power Systems, Inc.
