The LM3553 is a fixed frequency, current mode step-up DC/DC converter with two regulated current sinks. The device is capable of driving loads up to 1.2A from a single-cell Li-Ion battery.
One or more high current flash LEDs can be driven in series either in a high power Flash mode or a lower power Torch mode controlled by either an internal register or the FEN pin. Additionally a low current (20mA) indicator mode and a fixed output voltage mode are also available.
The LM3553 has 128 current levels and 176 flash safety timer durations that are user adjustable via an I2 C compatible interface. Internal soft-start eliminates large inrush currents at start-up. Over-voltage protection circuitry and 1.2MHz switching frequency allow for the use of small, low-cost output capacitors with lower voltage ratings.
The LM3553 is an asynchronous step-up DC/DC converter with an I2C compatible control interface designed for white LED Flash applications. The evaluation board is setup to drive two white flash LEDs with a series flash current of 500mA. Flash duration and current can both be configured by adjusting values stored in the internal control registers. The LM3553 is available in a 3 mm by 3mm LLP package.