LM2707 Datasheet | National Semiconductor

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 .. LM2707 output and the low-voltage feedback pin (0.515V). The LM2707 requires only a few small external ponents. 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 acmodates single-cell Lithium-Ion batteries and battery chargers. The LM2707 features 18V output capability, PFM regulation, and a high-current switching transistor (400m A peak). These characteristics allow the part to drive a series string of 2-to-4 LEDs with forward currents between 0 and 40m A. LED brightness can be adjusted dynamically simply by applying a PWM signal to the enable (EN) pin. The PWM signal can be as fast as 50k Hz because the LM2707 has a fast turn-on time. In addition to LED-drive applications, the LM2707 can also be used as a general purpose DC-DC voltage regulator in boost converter applications. The LM2707 is available in a SOT23-8 surface mount package. Features n Excellent LED Drive Capability: 3 LED String: 30m A 4 LED String: 20 m A 6 LEDs (2 strings of 3): 15 m A n Very High LED Drive Efficiency: > 80% n Low Feedback Voltage: 515m V n Low-Resistance NMOS Power Switch: 0.6Ω n High-Speed PWM Brightness Control Capability n Over-Voltage Protection (18V min, 19V typ, 20V max) n Inrush and Inductor Current Limiting n 2.3V - 7V Input Voltage Range n Requires Only a Few...