Simplified Block Diagram
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- 2.0V to 5.5V Operation Range
- 2.5V to 5.5V with Full Functionality
- 2.0V to 2.5V with Data Retention
- Step-Up DC-DC Converter
- 1.6A Guaranteed Output Current for VIN ≥ 3.0V and VOUT ≤ 4.2V
- Adaptive Output Voltage Regulation Ensuring Highest System Efficiency Up to 90%
- Down to 3.125% Duty Cycle
- On-Chip Power MOSFET and Synchronous Rectifier
- 1MHz/2MHz/4MHz PWM Switching Frequency
- Small 1µH Inductor
- High-Side Flash/Torch/Indicator LED Current Regulator
- I2C Programmable Flash Output Current (100mA to 1600mA in 100mA Steps)
- I2C Programmable Torch Output Current (30mA to 100mA in 10mA Steps)
- I2C Programmable Indicator Output Current (1mA to 16mA in 1mA Steps)
- Adaptive Regulation Voltage (150mV typ) for Flash Mode
- Low-Dropout Voltage (100mV max) for Torch Mode
- I2C Programmable Flash Safety Timer
- Open/Short LED Detection
- Tx Mask Reducing Output Current During Tx Event
- Overvoltage Protection
- Thermal Shutdown Protection
- 1µA Shutdown Current
- 16-Bump, 0.5mm Pitch, 2.065mm x 2.065mm WLP
- Cell Phones and Smartphones
The MAX77342 provides a highly efficient solution for cell phone camera flash applications by integrating a 1.6A PWM DC-DC step-up converter and three programmable high-side, low-dropout LED current regulators. An I2C interface provides flexible control of the step-up converter, indicator, assist, torch, and flash mode selection, and flash safety timer duration settings.
The device operates down to 2.5V, making it future proof for new battery technologies. The step-up converter features an internal switching MOSFET and synchronous rectifier to improve efficiency and minimize external component count. Three high-side, high-current regulators provide support for indicator, assist, torch, and flash modes. They can source up to 1600mA in flash mode, 100mA in torch and assist light mode, and 16mA for indicator. The output voltage is adaptively controlled, stepping up voltage only as high as necessary to support the required LED forward voltage in flash mode. This approach reduces IC power dissipation by optimizing the step-up ratio and by minimizing the losses in the current regulator. In torch, assist light, and indicator, the current regulators are powered directly from IN, providing the highest system efficiency.
Additionally, the device includes a low input voltage protection function that reduces flash current during low battery conditions to prevent system undervoltage lockup. Other features include shorted LED detection, overvoltage and thermal shutdown protection, and low-power standby and shutdown modes. The MAX77342 is available in a 16-bump, 0.5mm pitch WLP package (2.065mm x 2.065mm).