A flash LED driver with Automatic Vf and ESR Detection for Mobile Camera Systems

The LM3550 device is a low-noise, switched-capacitor DC-DC converter designed to operate as a current-limited and adjustable (up to 5.3 V) super-capacitor charger. The LM3550 features user-selectable termination voltages and provides one adjustable constant current output (up to 200 mA) and one NFET controller ideal for driving one or more high-current LEDs in a high-power flash mode or a low-power torch mode.

The LED current and flash pulse duration of the LM3550 can be programmed via an I2C-compatible interface. The STROBE pin allows the flash to be toggled via a flash-enable signal from a controller or camera module. The EOC pin sinks current when the output voltage reaches 95% of the final value.

The ALD/TEMP input pin allows either a light sensor to adjust the flash-current level based on the ambient light conditions, or it allows for over-temperature detection and protection of the LED during high-power operation or high ambient-temperature conditions.

For all available packages, see the orderable addendum at the end of the data sheet.