LED lights make new vehicles look sharp and colorful. Today's vehicles use LEDs to distinguish themselves from other manufacturers and older models. With the flexibility that LED lighting design gives us, many possibilities arise. Learn more about Analog Devices and their featured Power products.
Transcript below
Hi, my name is Keith Szolusha.
I am an Applications Engineering Section Leader at Analog Devices Power by Linear. I'm going to talk about the LT3952, a new 60 volt LED driver with an internal 4-amp switch that can be used in many automotive
LED lighting applications. The LT3952 is a compact 60 volt multi-topology LED driver that powers various LED strings at up to 55 volts from a 3 to 42 volt input.
It features adjustable switching frequency from 100 kilohertz to 2.5 megahertz and pseudorandom spread spectrum frequency modulation for reduced EMI. It also has short circuit and open LED protection and fault output flags for each as well as under and overvoltage lockout. The LT3952 can be used as an automotive boost LED driver.
Here it is used to power a 16 watt LED string with 93% efficiency at 350 kilohertz. This is a short-circuit-proof boost and has an output fault flag to indicate a short. It also has open LED protection and an output fault flag to show. 350 kilohertz is a great choice for high efficiency operation and passing stringent automotive EMI requirements.
But this IC can also be run at 2 megahertz for an ultra small solution that also avoids the AM band EMI. With 2 megahertz switching frequency, the LT3952 boost LED driver solution is even smaller. At 40 volts and 330 milliamps, this compact LED driver still has 90% efficiency and gets up to 3,000 to 1 flicker-free PMW dimming at 120 hertz.
This high-end tail and brake light has no EMI in the AM band between 530 kilohertz and 1.8 megahertz with its 2 megahertz switching frequency. The LT3952's high-power switch can be used to drive up to 2 amps through 1 or 2 LEDs in a step-down topology. In addition to the short and open LED protection features of the boost topology, the buck topology has very high PWM dimming ratio.
Unlike, competitor parts Analog Devices Power by Linear's LED drivers can be run at high PWM dimming ratio without flicker. This buck converter gets up to 4,000 to 1 brightness at 120 hertz. No flicker is evident.
Even with the spread spectrum turned on, the LED current remains repetitive and does not flicker. Analog Devices' Power by Linear excels in high dimming ratio, flicker-free PWM dimming, and low EMI as evidence of the PWM dimming performance of the LT3952. A new patent pending topology gives us a combination of step-up and step-down topology, as well as low input and low output ripple.
This LT3952 boost-buck LED driver can drive a string of LEDs at any voltage within the automotive battery range. Its input and output facing inductors give low ripple EMI on both load and lines. This novel step-up and step-down converter allows us to power LEDs of various string voltages as shown here with a varying number of LEDs on our daytime running light.
We can add in an amber signal light as well. And we can PWM dim the signal light to vary its brightness while leaving the daytime running light brightness unchanged. The flexibility that this low ripple step-up and step-down circuit gives to us can help eliminate the need for extra LED drivers in a headlight or taillight assembly.
I hope you enjoyed watching our LT3952 demonstrations. It is clear that this compact LED driver is both versatile and effective in driving different types of automotive LED lights. Please visit us at analog.com for more information.
Thank you.
See related product
See related product
See related product