EYE ON NPI for this week (videoHe is the owner of bright eyes and a bushy tail, who can juggle multiple tasks simultaneously: he Richtek RT4539 36 V I²C 6-Channel WLED Controlled Driver!
This chip can do everything: it’s a boost converter, it’s a calibrated DC sink, it’s a PWM controller, it’s a gamma corrector, and it has I2C to control all settings. It’s designed for use in laptop or tablet backlight control, and all the little extras it’s built into make it excellent for other types of lightning drivers – just because it says it’s for white LEDs doesn’t mean you have to use it just for that purpose!
The first feature of this chip is the boost converter. Since most LED taillights (and even some large LED assemblies) have sequential LEDs to maintain their current balance, we often need to increase the battery voltage up to 20V+, this chip can go up to 36V from the input 2.7 to 24V – Which means it can handle up to 10 LEDs at 3.3V front drops, and still has little headroom.
The booster FET switch is internal, so only an inductor and a diode are required. Since this is a constant current chip, the output voltage will fluctuate as necessary to support the required current draw. The booster frequency can be set to I2C to balance flickering/beat frequencies and efficiency against low power usage.
The second feature is the constant current series motor. As mentioned earlier, large taillights attempt to string the LEDs together to balance the current, but once you go over about 3-5″ diagonally, there is usually more than one cascade. Now you want to make sure that each chain is balanced. On the inside are the comparator/differential drivers that use matched transistors and resistors with an inverting current setting to make sure you get the exact same current through each string.
The third advantage of RT4539 is PWM driver. Yes, you can reduce the current through the strings, but it’s easier to get a wide range of brightness values by maintaining a constant current and then PWMing the motors sink the output. It’s normal to see linear PWM drivers: you can go from 0-255, say for an 8-bit controller and that translates to a linear duty cycle.
This slide goes above and beyond and provides “Gamma correctedOutput control curve if desired. This gives a more natural and advantageous brightness curve as there is more detail at lower brightness values, often used in night modes.
The fourth (and final?) feature that should be highlighted is that all the capability settings are available via I2C! From boost frequency to sink current, to PWM pattern and duty cycles to extras like smooth dimming transition features, there’s a registration map for easy configuration and modification, making its chips trivial to integrate into any design using a microcontroller or microcomputer.
The Richtech RT4539 It’s super duper new, so it’s not yet available for purchase on the Digi-Key website – stay tuned when this chip becomes available or contact your Digi-Key sales representative and they’ll be able to discuss some samples for you!
Catch up with Richtek Technologies on Youtube
Stop breading and soldering – start building right away! Adafruit’s Circuit is filled with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with MakeCode Drag and Drop Programming SiteLearn Computer Science with the CS Discoveries class at code.org, go to Circle To learn Python and hardware together, TinyGO, or even use the Arduino IDE. Speed Circuit Stadium It is the latest and best circuit board board, with support for CircuitPython, MakeCode and Arduino. It has a powerful processor, 10 NeoPixels, a mini speaker, an InfraRed transmitter and receiver, two buttons, a switch, 14 alligator clip pads, and a lot of sensors: capacitive touch, near-infrared, temperature, light, motion and sound. A vast world of electronics and coding awaits, and it fits in the palm of your hand.
Do you have a great project to share? The Electronics Show and Tell Every Wednesday at 7 PM ET! To join, head over to YouTube and check out the show’s live chat – we’ll post the link there.
Join us every Wednesday at 8pm ET for Ask an engineer!
No comments yet.
Adafruit has a “Be excellent to each other” comment policy. Help us keep the community here positive and helpful. Stick to the topic, and respect crafters of all ages and skill levels. Be kind, and don’t spam – thank you!
#Richtek #RT4539 #I²C #6Channel #WLED #Driver #EYEonNPI #DigikeyDigiKeyAdafruit #Adafruit #Industries #Makers #Hackers #Artists #Designers #Engineers