SGM3740.pdf
No.10869
? High-Efficiency Boost DC/DC WLED Bias Supply
? Internal 38V, 0.25Ω Power MOSFET
? 3V to 18V Input Voltage Range
? 600kHz Constant Switching Frequency
? Up to 10 Serial White LEDs per Channel
? 25mA Constant Current per Channel
? Switch Current Limit: 2.2A
? Dual Dimming Scheme for Large Dimming Range
? One-Wire Enable and 32-Step Dimming
? PWM Dimming
? 2kHz to 60kHz PWM Dimming Frequency
? Internal 1MΩ Pull-Down Resistor at CTRL Pin
? Internal 500kΩ Pull-Up Resistor at PWM Pin
? Internal 38.5V Over-Voltage Protection
? Cycle-by-Cycle Over-Current Protection
? Soft-Start Function
? No Leakage from VIN to GND through LED String
? Thermal Shutdown
? -40℃ to +85℃ Operating Temperature Range
? Available in Green TQFN-3×3-16L Package
The SGM3740 is a 3-channel step-up DC/DC converter designed for driving the white LEDs with an internal 25mA constant current per channel. This device features integrated, 38V power MOSFETs that is capable of driving up to 10 white LEDs per channel, providing inherent current matching for uniform brightness. The SGM3740 supports PWM and one-wire digital interface to control the backlight brightness. The PWM frequency is in the range from 2kHz to 60kHz to avoid audible noise from inductor or ceramic capacitor, combining PWM and one-wire to get very wide brightness dimming range. PWM pin is always used for Content Adaptive Brightness Control (CABC) schemes. Constant 600kHz switching frequency is used in SGM3740.
The SGM3740 features a variety of protection circuits, including integrated 38.5V over-voltage protection (OVP), soft-start, cycle-by-cycle current limiting, and thermal shutdown protection circuitry.
SGM3740 supports 3V to 18V input voltage, and then SGM3740 can be used in one cell or two-cell battery equipments.
