GENERAL DEscriptION

The SGM3741B is a high efficiency constant-current white LED driver with a 600kHz boost DC/DC converter. With an internal 38V/2.2A power MOSFET, the SGM3741B supports up to 10 white LEDs in series and achieves uniform brightness. The SGM3741B supports two PWM signals to control the backlight brightness. The PWM frequency is in the range from 2kHz to 60kHz, thus avoiding audible noise from inductor or ceramic capacitor. Combining the two PWM signals gets very wide brightness dimming range. The PWM pin is always used for Content Adaptive Brightness Control (CABC).

The supply voltage operates from 3V to 18V and is well suited for various applications powered by 1-cell or 2-cell batteries.

The SGM3741B includes a comprehensive set of protection features such as 38.5V over-voltage protection, cycle-by-cycle current limit and thermal shutdown. Built-in soft-start circuitry avoids excessive inrush current during startup.

The SGM3741B is available in a Green TQFN-3×3-16L package. It operates over an ambient temperature range of -40℃ to +85℃

FEATURES

• Input Voltage Range: 3V to 18V

• Integrated 38V/2.2A Switch with 0.25Ω On-Resistance

• High Efficiency Boost Bias Supply

• Support up to 10 LEDs in Series per String

• Switching Frequency: 600kHz

• 25mA Constant Current per String

• Dual PWM Dimming Scheme for Large Dimming Range

• PWM Dimming Frequency: 2kHz to 60kHz

• 1MΩ Pull-Down Resistor on CTRL Pin

• 500kΩ Pull-Up Resistor on PWM Pin

• Automatic Soft-Start for Reducing Inrush Current

• No Leakage from VIN to GND through LED String

• Protection Features

  Over-Voltage Protection

  Cycle-by-Cycle Current Limit

  Thermal Shutdown

• -40℃ to +85℃ Operating Temperature Range

• Available in a Green TQFN-3×3-16L Package

APPLICATIONS

TFT LCD Displays

Smart Phones