EYE on NPI: Richtek RT4539 36 V I²C Controlled 6-Channel WLED Driver #EYEonNPI #Digikey @DigiKey
This week’s EYE ON NPI is a bright-eye’d and bushy-tailed go-getter, who can juggle multiple tasks at once: it’s the Richtek RT4539 36 V I²C Controlled 6-Channel WLED Driver ()! This chip can do it all: it’s a boost converter, it’s a calibrated constant-current sink, it’s a PWM controller, it’s a gamma-corrector, and it’s got I2C for controlling all the settings. It’s designed for use in laptop or tablet backlight control, and all the little extras that were designed in make it excellent for other sorts of lighting drives - just cause it says its for white LEDs doesn’t mean you have to only use it for that purpose!
The first feature of this chip is the boost converter. Since most LED backlights (and even some large LED clusters) have the LEDs in series to keep them current balanced, we often need to boost the battery voltage up to 20V , this chip can go up to 36V output from 2.7 to 24V input - which means it can handle up to 10 LEDs at forward drops, and still have a little headroom. The boost FET switch is internal so only an inductor and diode are required. Since this is a constant-current chip, the output voltage will fluctuate as necessary to support the current draw needed. The booster frequency can be adjusted over I2C to balance flickering/beat frequencies and efficiency vs low power usage.
The second feature is the constant current string driver. As mentioned, large backlights try to string LEDs together to balance the current, but once you get past about 3-5“ diagonal, there’s usually more than one string. So now you want to make sure each string is balanced. Inside are comparator/differential drivers that use matched transistors and resistors with current mirroring setup to make sure you get the same exact current through each string.
The third feature of the RT4539 is the PWM driver (). Yes you can reduce the current through the strings but its easier to get a wide range of brightness values by keeping a constant current and then PWMing the output sink drivers. It’s normal to see linear PWM drivers: where you can go from 0-255, say for 8-bit control and that translates to a linear duty cycle. This chip goes above-and-beyond and provides an exponential “gamma corrected“ () output control curve if desired. This gives a more natural and useful brightness curve where there’s more granularity at low brightness values, often used for night modes.
The fourth (and final?) feature to highlight is that all of the settings for the capabilities are available over I2C! From the booster frequency to sink current, to the PWM style and duty cycles to extras like smooth dimming transition features, there’s a register map for easy configuration and adjustment, making his chip trivial to integrate into any design with a microcontroller or microcomputer.
The Richtek RT4539 () is super-duper new, so it’s not yet available for purchase on Digi-Key’s website - keep an eye out for when this chip becomes available or contact your Digi-Key sales rep and they’ll be able to wrangle you some samples!
1 view
257
91
3 weeks ago 00:02:20 1
Gears of War: E-Day | Official Announce Trailer (In-Engine)
3 weeks ago 00:04:03 1
Deep Purple - Pictures of You (Official Music Video)
3 weeks ago 00:02:20 1
Gears of War: E-Day | Official Announce Trailer (In-Engine) - Xbox Games Showcase 2024
3 weeks ago 00:00:00 1
Hellgate Ospreys Nest Cam | Cornell Lab | University of Montana
3 weeks ago 00:00:59 1
Black cat on the floor
3 weeks ago 00:26:17 1
How to be a HIGH VALUE MAN without saying a single word -Stoicism
3 weeks ago 00:03:37 1
Student gets kicked out of class
3 weeks ago 00:48:45 1
Why You Wouldn’t Survive Life in Nazi Germany
3 weeks ago 00:12:29 1
Heartworm Disease - Plain and Simple
3 weeks ago 00:08:28 1
Eric Clapton - My Father’s Eyes (Official Music Video) | Warner Vault
3 weeks ago 00:42:55 1
BATTLE OF ROBOTS 2024 SUPERFINAL - Robot Combat’s 1st World Championship since 2003! | TCC BREAKDOWN
3 weeks ago 00:01:19 1
I Spy With My Eye... Homophones! | StoryBots: Learn to Read | Netflix Jr
3 weeks ago 00:04:38 1
Video For Practicing Eye Contact
3 weeks ago 02:01:32 1
Расшифровка Событий 🟣 Живой Эфир
3 weeks ago 00:04:43 1
Pleasure Business Ft. ViRG - Deja Vu
3 weeks ago 01:27:15 1
How the Wests grandiose illusions collapse in Russia
3 weeks ago 00:03:22 1
IZ*ONE (아이즈원) - 환상동화 (Secret Story of the Swan) MV
3 weeks ago 00:02:23 1
DipX Coral Dip – Safely introduce new corals to your tank.
3 weeks ago 00:05:29 1
Madonna - Frozen (Official Video) [HD]
3 weeks ago 00:01:37 1
UK: Rishi Sunak’s popularity down by 12%; Farage more popular than Sunak, says survey | WION
3 weeks ago 00:01:43 1
Marvel Studios’ What If…? – An Immersive Story | Official Trailer | ILM Immersive & Disney+
3 weeks ago 00:03:28 1
The Turning Point
3 weeks ago 01:21:50 1
Кукла Лол/Lol doll
3 weeks ago 00:02:02 1
Blumhouse Games Summer Game Fest 2024 Reveal - The Horror Starts Here