MP3385B

MP3385B

4-String, 80V Output WLED Controller with I²C Interface

Datasheet

Description

The MP3385B is a step-up controller with four regulated LED current (I_LED) channels, designed to drive white LED (WLED) arrays for mid-sized and large-sized LCD panel backlighting applications. The MP3385B employs peak current control mode and pulse-width modulation (PWM) control architecture for system loop regulation. It drives an external MOSFET to boost the output voltage (V_OUT) from a 4.5V to 33V input voltage (V_IN) supply.

The MP3385B provides an I²C digital interface to flexibly set the operation and protection modes, including dimming mode, the dimming current, the dimming ratio, over-current protection (OCP), over-voltage protection (OVP), the LED short protection threshold, and the switching frequency (f_SW).

For ease of use and board debugging, the MP3385B automatically detects and disables the unused LED strings during start-up to avoid charging the output to the OVP threshold. The device achieves 1.8% current matching between each string. The low regulation voltage on the LED current source improves efficiency and reduces power loss, which can result in a higher current output.

The MP3385B supports analog, PWM, and combined analog and PWM dimming modes to meet different application requirements. Full protection features include OCP, over-temperature protection (OTP), under-voltage protection (UVP), OVP, LED short and open protection, and inductor and diode short protection.

The MP3385B is available in a QFN-20 (4mmx4mm) package.

Features & Benefits

4-String, Max 300mA/String White LED (WLED) Driver
4.5V to 33V Input Voltage (V_IN) Range
80V Absolute Maximum Rating for Each String
1.8% Current Matching Accuracy between Each String
Unused Channel Auto-Detection during Start-Up
100kHz to 900kHz Configurable Switching Frequency (f_SW)
Multiple Dimming Modes Selectable via the I²C Interface:
- Direct Pulse-Width Modulation (PWM) Dimming Mode
- Internal, Fixed 23kHz PWM Dimming Mode via the I²C
- Analog Dimming Mode via an Input Pulse
- Internal Analog Dimming Mode via the I²C
- Mixed Dimming Mode via an Input Pulse
- Internal Mixed Dimming Mode via the I²C
2% to 100% Configurable Full-Scale Current with 8-Bit Resolution
0% to 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 and Recoverable Over-Current Protection (OCP) Threshold, 50mV/Step
Recoverable Thermal Shutdown Protection
Available in a QFN-20 (4mmx4mm) Package