LM3466 Datasheet | National Semiconductor

LM3466 Smart Linear LED Driver for Multi-Channel LED Systems PRELIMINARY June 1, 2011 Smart Linear LED Driver for Multi-Channel LED Systems General Description The LM3466 integrates a linear LED driver for lighting systems which consist of multiple LED strings powered by a constant current power supply. The current provided by the supply is equalized in a pre-set ratio to each active LED string (an active LED string refers to a fully turn-on LED string) disregarding the number of string connected to the supply, even the forward voltage of each LED string is different. If any LED string opens during operation, the LED current of all remaining active LED strings can equalize the current of the supply automatically. As a result, the overall brightness of the lighting system is maintained even if some LED strings open during operation. The lighting system using the LM3466 is simple to design owing to a proprietary control scheme. To minimize the ponent count, the LM3466 integrates a 70V, 1.5A N-channel MOSFET. To add one more LED string to the system, only a resistor, a capacitor and an LM3466 are required. Other supervisory Features of the LM3466 include under-voltage lockout, current limit, fault reporting, and thermal shutdown protection. The LM3466 consists of only linear circuitry so that the EMI of the application circuit is not deteriorated. The LM3466 is available in the PSOP-8 exposed DAP packages. Features - Easy to design and use for lighting systems consists of - - - - - - - - - - multiple LED strings Works with a Constant Current power supply. No munication to/from the constant current power supply is required Automatically equalizes the current of every active LED string, even the forward voltage of each string is different Total luminance output of the system is nearly not affected if some LED strings open during operation Wide input voltage range from 6V to 70V Integrated 70V 1.5A MOSFET with 2A current limit Operating with minimum...