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MAX77387：Dual-Phase Adaptive DC-DC Step-Up Converter with 2x 1000mA High-Side Current Regulators

Industry's Smallest 2A Flash Driver Solution

The MAX77387 provides a high-efficiency solution for smartphone camera flash applications by integrating a dual-phase 2A PWM DC-DC step-up converter and two programmable 1A high side, low-dropout LED current regulators for flash and torch functions. An I²C interface provides flexible control of the step-up converter, torch, flash mode selection, and torch/flash safety timer duration settings. The IC operates down to 2.5V, making it futureproof for new battery technologies. The step-up converter features an internal switching MOSFET and synchronous rectifier to improve efficiency and minimize external component count. Dual-phase operation ensures low output ripple and provides smallest possible solution size. The IC also includes dual high-side high-current regulators for supporting torch and flash modes. The high current regulators can source up to 1A each in flash mode and up to 250mA each in torch mode. The high-current regulators can be combined to drive a single LED up to 2A in flash mode and up to 500mA in torch mode. The output voltage can be adaptively controlled, boosting only as high as necessary to support the required LED forward voltage. Adaptive mode can be used in either flash or torch mode and works with both DAC and/or PWM dimming control schemes. This approach reduces IC power dissipation by optimizing the boost ratio and by minimizing the losses in the current regulators. The IC includes control for external NTC, dual Tx mask, flash strobe, and torch enable functions. This allows for flexible control of the IC. Additionally, the IC includes MAXFLASH 2.0 function that adaptively reduces flash current during low battery conditions to help prevent system undervoltage lockup. Other features include shorted LED detection, overvoltage and thermal shutdown protection, and low-power standby and shutdown modes. The IC is available in a 20-bump, 0.4mm pitch WLP package (2.1mm x 1.73mm).

Key Features Input Supply of 2.5V to 5.5V with Full Functionality Dual-Phase Interleave Step-Up DC-DC Converter True Shutdown Output 2A Guaranteed Output Current for VIN > 2.7V and VOUT ≤ 4.0V Adaptive Output Voltage Regulation to Ensure Industry's Highest System Efficiency Over 90% Peak Efficiency 3.125% Minimum Duty Cycle Skip Mode Capable On-Chip Power MOSFET and Synchronous Rectifier Up to 4MHz PWM Switching Frequency per Phase Small 0.47µH Inductor per Phase High-Side Torch/Flash LED Current Regulator I²C Programmable Flash Output Current (15.625mA to 1000mA in 15.625mA Steps) I²C Programmable Torch Output Current (3.91mA to 250mA in 3.91mA Steps for Non-PWM Dimming) (125mA to 1000mA in 125mA Steps for PWM Dimming with Programmable Duty Cycle from 3.125% to 25% in 3.125% Steps) Low-Dropout Voltage (80mV typ) at 1000mA I²C-Programmable Flash Safety Timer I²C-Programmable Torch Safety Timer and Optional Disabled Torch Timer Dual Independent TX_MASK Inputs for Limiting Flash Current During Tx Events Open/Shorted LED Detection NTC Monitoring for LED Protection Overvoltage Protection MAXFLASH 2.0 Preventing System Undervoltage Lockup Thermal Shutdown Protection < 1µA Shutdown Current 20-Bump, 0.4mm Pitch 2.1mm x 1.73mm WLP

MAX77387: Simplified Block Diagram Applications/Uses Cell Phones and Smartphones Tablets

DataSheet

Parametrics

Design kits & evaluation modules

• MAX77387EVSYS

Quality and Environmental Data

• MAX77387.pdf

Ordering Information