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