Dual channel buck LED driver with I2C dimming control

30th November 2017
Posted By : Alice Matthews
Dual channel buck LED driver with I2C dimming control

A dual channel, 36V, high efficiency, synchronous, step-down LED driver with internal 40V, 1.6A power switches and an I2C interface that simplifies LED dimming control, has been announced by Analog Devices. The Power by Linear LT3964 operates with a wide 4-36V input range, and features two independently controlled LED drivers that switch at up to 2MHz, resulting in a highly integrated, compact solution with small external components.

The LT3964 employs fixed frequency, current mode control and operates as a constant-current and constant-voltage source with accurate current regulation to provide optimal LED lighting in automotive, industrial and architectural lighting applications. Synchronous operation results in efficiencies above 94% with both channels at full current load.

Its 400kHz I2C interface greatly simplifies digital PWM dimming. A PWM signal from a microcontroller to the LED driver is not necessary; instead, internal registers are programmed with the desired dimming duty cycle, which is synchronised to the internal clock. This provides dimming ratios up to 8192:1 and eliminates beat frequencies caused when the PWM signal and the internal oscillator are not synchronised.

Alternatively, with analog dimming, an I2C settable 8-bit scale factor sets the control voltage-to-LED current ratio allowing more control of analog dimming adjustments. 1000:1 external PWM dimming and 10:1 analogue dimming are also provided.

The LT3964’s switching frequency is programmable from 200kHz to 2MHz or it can be synchronised to an external clock signal. LED driver protection features include open LED and short-circuit LED fault detection, and LED overcurrent and overvoltage detection, all of which can be reported via the I2C interface. Thermal shutdown provides an added layer of protection.

The LT3964EUHE is available in a thermally enhanced 36-lead 5x6mm QFN package. Three temperature grades are available, with operation from –40 to 125°C (junction) for the extended and industrial grades, and a high temperature grade of –40 to 150°C.

Downloads


You must be logged in to comment

Write a comment

No comments




Sign up to view our publications

Sign up

Sign up to view our downloads

Sign up

Maintec 2018
6th November 2018
United Kingdom NEC, Birmingham
electronica 2018
13th November 2018
Germany Messe Munchen
SPS IPC Drives 2018
27th November 2018
Germany Nuremberg
International Security Expo 2018
28th November 2018
United Kingdom London Olympia
The Security Event 2019
9th April 2019
United Kingdom NEC, Birmingham