LM2707

LM2707 Inductive-Boost Series LED Driver with Programmable Oscillator Frequency February 2005 LM2707 Inductive-Boost Series LED Driver with Programmable Oscillator Frequency General Description The LM2707 is a magnetic boost regulator specifically designed for white LED drive applications. Tightly regulated LED currents, exceptional LED brightness uniformity, and very high LED-drive power efficiency ( > 80%) can all be achieved by stacking the LEDs in series between the www.DataSheet4U.com LM2707 output and the low-voltage feedback pin (0.515V). The LM2707 requires only a few small external components. A small inductor with a low saturation current rating can safely be used because the tightly controlled current limit circuit prevents large inductor current spikes, even at startup. The output capacitor can also be small due to the tightly controlled output over-voltage protection circuit. The LM2707 is an excellent choice for display backlighting and other general-purpose lighting functions in battery powered applications. The 2.3V-to-7V input voltage range of the device easily accommodates single-cell Lithium-Ion batteries and battery chargers. The LM2707 features 18V output capability, PFM regulation, and a high-current switching transistor (400mA peak). These characteristics allow the part to drive a series string of 2-to-4 LEDs with forward currents between 0 and 40mA. LED brightness can be adjusted dynamically simply by applying a PWM signal to the enable (EN) pin. The...