4-ch, 80V Boost WLED Controller with I2C



The MP3385A is a step-up controller with four regulated current channels designed to drive WLED arrays for mid- and large-sized LCD panel backlighting applications. The MP3385A uses peak-current mode and PWM control architecture for system loop regulation. The MP3385A drives an external MOSFET to boost up the output voltage from a 4.5V-to-33V input supply. The MP3385A employs an I2C digital interface that can flexibly set operation and protection modes, including dimming mode, dimming current and dimming ratio, OCP, OVP, LED short protection threshold, and switching frequency. For easy application use and board debugging, the MP3385A detects and disables the unused LED strings automatically during start-up to avoid charging the output to the OVP threshold. The MP3385A achieves 1.8% current matching between each string. The low regulation voltage on the LED current sources improves efficiency and reduces power loss to achieve a higher current output. The MP3385A supports analog, PWM, and combined analog and PWM dimming modes to meet different application requirements. Full protection features include over-current protection (OCP), over-temperature protection (OTP), under-voltage protection (UVP), over-voltage protection (OVP), LED short/open protection, and inductor/diode short protection. The MP3385A is available in a QFN-20 (4mmx4mm) package.


  • 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 I2C Interface
  • o Direct PWM Dimming Mode
  • o Internal Fixed 23kHz PWM Dimming Mode by I2C
  • o Analog Dimming Mode by Input Pulse
  • o Internal Analog Dimming Mode by I2C
  • o Mixed Dimming Mode by Input Pulse
  • o Internal Mixed Dimming Mode by I2C
  • 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 (OVP), 2V/Step
  • 0.15V to 0.5V Latch-Off/Recoverable Over-Current Protection (OCP) Threshold, 50mV/Step
  • Recoverable Thermal Shutdown Protection


  • Ishutdown (µA)1
  • Vin (min) (V)4.5
  • Vin (max) (V)33
  • Channels4
  • fsw (min) (kHz)100
  • Ichannel (max) (A)0.3
  • LEDx ABS Voltage (V)80
  • fsw (max) (kHz)900
  • Vfb (V)0.6
  • GradeCatalog
  • PackageQFN-20 (4x4)
  • Power MOSFETExternal
  • TopologyBoost
  • Dimming (Output)P-Dim, A-Dim
  • Iq (mA)3
  • Typical LCD Screen SizesMedium (10"-29"), Large (30"-45")
  • Other FeaturesCascade, I2C, Inductor Short Protection