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).
Applications
- Cell Phones and Smartphones
- Tablets
