SGM3781.pdf
No.10925
● Input Voltage Range: 3V to 5V
● Dual Flash LED Outputs
● Drive Up to Total 1.5A or 0.75A per Channel
● High Efficiency LED Driver (Up to 90%)
● 2MHz Step-Up Converter
● Very Small Inductor: 1.0μH
● Independent Flash Mode Enable and Movie/Torch Mode Enable Pins
● Flash Mode or Movie/Torch Mode Dimming via PWM Control
● 10kHz to 200kHz PWM Dimming Frequency
● One Resistor Sets Flash Mode LED Current
● One Resistor Sets Movie/Torch Mode LED Current
● Integrated Thermal Regulation Control
● 330kΩ Pull-Down Resistor on ENM or ENF Pin
● LED Open or Short Protection
● Output Over-Voltage Protection
● Cycle-by-Cycle Inductor Current Limit
● Less than 1μA Shutdown Current
● Available in Green TDFN-3×2-14L Package
● Temperature Range: -40℃ to +85℃
The SGM3781 is the ideal power solution for highpower flash LEDs used with cell phone camera modules or digital still cameras. It is a highly integrated step-up DC/DC converter with very high switching frequency, fixed at 2MHz, providing a very small total solution for portable photo flash. The SGM3781 has separate Flash mode and Movie/Torch mode enable pins for maximum flexibility. The Flash mode and Movie/Torch mode LED current is programmed by external resistors respectively, making the flash LED solution simple to control. If both enable pins are at logic high, the LED current will be programmed by the Movie/Torch mode setting resistor.
The two LED output sinks can be shorted together externally for higher power single flash LEDs, up to 1.5A continuous LED current. Thermal regulation is integrated in Flash mode to limit the IC’s temperature and continuously provide the maximum allowed output current. Various protection features are built into the SGM3781, including cycle-by-cycle input current limit protection, output over-voltage protection, LED fault (open or short) protection and thermal shutdown protection. The leakage current in shutdown is less than 1μA.
