The LM3554 is a 2-MHz fixed-frequency, current-mode synchronous boost converter. The
device is designed to operate as a dual 600-mA (1.2 A total) constant-current driver for
high-current white LEDs, or as a regulated 4.5-V or 5-V voltage source.
The main features include: an I2C-compatible interface for
controlling the LED current or the desired output voltage, a hardware flash enable input for direct
triggering of the flash pulse, and dual TX inputs which force the flash pulse into a low-current
torch mode allowing for synchronization to RF power amplifier events or other high-current
conditions. Additionally, an active high hardware enable (HWEN) input provides a hardware shutdown
during system software failures.
Five protection features are available within the LM3554 including a software selectable
input voltage monitor, an internal comparator for interfacing with an external temperature sensor,
four selectable current limits to ensure the battery current is kept below a predetermined peak
level, an overvoltage protection feature to limit the output voltage during LED open circuits, and
an output short circuit protection which limits the output current during shorts to GND.
For all available packages, see the orderable addendum at the
end of the data sheet.
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