LM3551 Datasheet, PDF (14/15 Pages) National Semiconductor (TI) – 1A White LED Driver with Flash Timeout Protection

Application Examples (Continued)
within a system. By setting the T/F pin high, the LM3551/2
will allow the current to flow through the flash LED while still
maintaining the fixed output voltage rail. The flash current is
set by R_F using the equation R_F = [(V_OUT - V_LED) / I_LED] -
0.36Ω , and should not exceed 500mA. The total usable
output current is dependent upon the output voltage se-
lected. If the dual-mode configuration is used, the FTO pin
should be grounded to prevent the voltage rail from being
shutdown at an unwanted time.
www.national.com
14