Simplifying complex LED matrix designs

Linear Technology has released the LT3965, an LED bypass switching device for dimming and diagnosing up to eight individual LEDs or LED segments. The LT3965 works in conjunction with an LED driver circuit configured as a current source and features eight individually controlled floating 17V/330mO NMOS switches.

Typical applications include automotive matrix LED headlights, industrial lighting and LED display lighting. The I2C serial interface is claimed to provide 256:1 dimming ratios with or without the 11-bit resolution fade transition between the dimming states. Each switch can control and monitor a single LED or a segment of up to 16V series-connected LEDs. The LT3965’s 8 to 60V input voltage range can accommodate LED drivers used in automotive and industrial applications.

When multiple LT3965s are used for larger applications, the I2C serial interface communicates between the master microcontroller and the LT3965s configured as slaves. The LT3965 provides an internal clock generator and also supports an external clock source for PWM dimming. Additionally, each channel of the LT3965 offers both open LED and shorted LED fault reporting and protection.

The device is offered in a 28-lead TSSOP thermally enhanced package. An industrial temperature version, the LT3965IFE, is tested and operates across a -40 to 125°C temperature range.