About UsLT Releases New 8-Switch LED Matrix Dimmer
The LT3965 Allows Independent Dimming and Diagnostics of Eight Individual LEDs or LED Segments
Linear Technology (now part of Analog Devices) has released the LT3965, a LED bypass switching device that enables independent dimming and diagnostics of eight individual LEDs or LED segments. The LT3965 works in conjunction with a LED driver circuit configured as a current source. It features eight individually controlled floating 17V/330mΩ NMOS switches. Using these internal power switches and an integrated I²C serial interface, individual LEDs within the string can be turned on or off, or they can be PWM dimmed to offer unique patterns within the LED matrix.
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Typical applications include automotive matrix LED headlights, industrial lighting and large LED display lighting. The I²C serial interface enables digital programming with 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 of series-connected LEDs. The LT3965's 8V to 60V input voltage range can accommodate a wide range of LED drivers commonly used in automotive and industrial applications. For larger LED matrix applications, multiple LT3965s (up to 16) can use a common I²C bus.
The LT3965's eight switches can be connected in parallel and/or in series to bypass current around one or more LEDs in a string. When multiple LT3965s are used, the I²C serial interface enables communication between the master microcontroller and one or more 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. It is offered in a 28-lead TSSOP thermally enhanced package, ensuring a compact solution footprint for matrix dimming applications.
Features of the LT3965 include:
- Eight Independent 17V 330mΩ NMOS Switches
- Independent On/Off/Dimming Control for Each Switch
- I²C Serial Interface with Open LED & Shorted LED Fault Reporting
- Programmable I²C Address
- Vdd Range: 2.7V to 5.5V & Vin Range: 8V to 60V
- Digital Programmable 256:1 PWM Dimming
- Fade Transition Between PWM Dimming States
- Optional Internal Clock Generator or External Clock Source for PWM Dimming
- Slew Rate Limited Switching for Noise Reduction
- Programmable Open LED & Shorted LED Threshold
- Open LED Overvoltage Protection
For more information on the LT3965 8-Switch LED Matrix Dimmer, visit the Analog Devices website at Linear Technology LT3965 product page.
The Analog Devices website address is www.analog.com
[Reprinted with kind permission from Linear Technology - Release Date: 9th December, 2015]