NS High Frequency White LED Driver

National Semiconductor Corporation (National Semiconductor Corporation) has announced a high-speed pulse width modulation (PWM) brightness control of small high-frequency white LED driver. The drive model LM3519 chips for handheld systems, for up to four white LEDs to provide a stable drive current. Mobile phones, MP3 players, barcode scanners and TC4427COA datasheet and other portable electronic devices can use this drive for high-definition display backlighting.

LM3519 driver chip is a high efficiency LED driver, an internal steady flow function, eliminating the need for an external resistor can also be provided for each light-emitting diode drive current of 20mA. Simply drive PWM signal input chip enable pin, can effectively control the brightness of the input signal frequencies up to 30kHz, the human ear can be identified in order to avoid the noise.

LM3519 drives the PWM chip is unique to the steady flow structure, the switching frequency range between 2MHz and TC4427COA price and 8MHz, so you can use smaller inductors.

The LM3519 chip with a voltage protection circuit, but also to high-frequency operation, so the system can lower cost, smaller output capacitor. When the shutdown mode, the output and TC4427COA suppliers and input completely disconnected in order to avoid leakage current will flow through the light-emitting diodes to ground.

LM3519 chips main features:
respectively 2 to 4 LEDs up to 20mA of drive current efficiency of over 80%
switching frequencies up to 8MHz
the PWM dimming up to 30kHz Control
of small external components: 1μH - 3.3μH (typically 2.2μH) of the inductor and output capacitor 1μF real insulation
overvoltage shutdown
wider input voltage range: 2.7V to 5.5V

LM3519 chip is a small SOT23-6 package, but in addition to lead-free package options, purchasing 1,000-unit quantities price 0.70 U.S. dollars, has been a lot of stock.