LM3466MREVAL

The LM3466 integrates a linear LED driver for lighting systems which consist of multiple LED strings powered by a constant current power supply. The LM3466 equalizes the current provided by the supply in a pre-set ratio for each active LED string, where an active string is a fully turned on LED string, regardless of the number of strings connected to the supply or the forward voltage of each LED string. If any LED string opens during operation, the LM3466 automatically equalizes the supply current through all of the remaining active LED strings. As a result, the overall brightness of the lighting system is maintained even if some LED strings open during operation.

The LM3466 consists of only linear circuitry so that the EMI of the application circuit is not deteriorated. This application note details the design of an LM3466 evaluation board that drives 5 LED strings, each of which consists of 14 LEDs. The input current IS (of the constant current power supply) is 1.75A such that the LED current is 0.35A per string. The evaluation board schematic, PCB layout, Bill of Materials, and circuit design procedures are shown. Typical performance and operating waveforms are also provided for reference.

照明 LED ドライバ