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Title: High Powered LED - PWM Controlled Circuit - Suggestions Post by: ikefu on September 14, 2013, 11:13:40 23:13 Hi all,
I'm working on a light controller board for a laminar fountain project. I need some help getting started figuring out how to drive a high powered LED (1 Amp+) utilizing a PWM signal from a PIC18F26K22. Most of the circuits I have found either don't allow for PWM dimming or don't support the current output I need. If anyone has some suggestions to point me towards certain ICs or schematics I would greatly appreciate it. Extra info: I'm using this to add RGB lighting effects to a Laminar Fountain I built a few years ago and recently resumed working on. I'll be feeding the light output into fiber-optic cable that carries the light to base of the water nozzle. The high powered LEDs are required to light the entirety of the stream. You can find my fountain here: http://laminar.forumotion.com/t162-ike-s-prototype-project-my-first-laminar-nozzle That forum is a great resource if you are interested in building a laminar forum. Title: Re: High Powered LED - PWM Controlled Circuit - Suggestions Post by: Gallymimu on September 15, 2013, 12:21:09 00:21 I've done this with 300mA using AP8800 from Diodes inc.
you should be able to find a 1A+ buck regulator that can do this (assuming you are starting with a higher voltage). Either PWM the enable on the regulator, or set the current with a filtered PWM to get a roughly analog setpoint. this IC will work for instance: http://www.allegromicro.com/Products/Regulators-And-Lighting/LED-Drivers-For-Lighting/A6211.aspx Title: Re: High Powered LED - PWM Controlled Circuit - Suggestions Post by: Old_but_Alive on September 15, 2013, 02:34:30 02:34 I design LED lighting for a living, and Linear Tech have many suitable IC's
http://www.linear.com/products/led_driver_ics Title: Re: High Powered LED - PWM Controlled Circuit - Suggestions Post by: dezso on September 15, 2013, 04:03:33 04:03 I designed and built 4 LED module with 10 channel PWM using CAT4101
http://www.onsemi.com/pub_link/Collateral/CAT4101-D.PDF I was driving the LEDs with 700ma max so no heatsink required just a larger heat pad. The last image all 30 led running at 50% iPhone camera couldn't take it properly. This picture are from the fits prototype using PCA9685 i2c (http://imgur.com/coHKbYQ) (http://imgur.com/nQkWJgy) (http://imgur.com/3S3vhOa) (http://imgur.com/9d8RMTE) (http://imgur.com/EMYLSYA) (http://imgur.com/Ekm900H) Title: Re: High Powered LED - PWM Controlled Circuit - Suggestions Post by: Old_but_Alive on September 15, 2013, 04:39:38 04:39 the CAT4101 is a linear constant current device, so not efficient, and requires heatsink.
most LED driver IC's are switch mode devices, so have >80% efficiency, and thus low power dissipation. I use the LT3476 Title: Re: High Powered LED - PWM Controlled Circuit - Suggestions Post by: Catcatcat on September 15, 2013, 01:32:04 13:32 CAT4101 be correctly connected, there is no need for the radiator. I would recommend not to use the PWM controller and the standard PWM drivers who use inconsistent counters, and the output drivers install a powerful current...
Title: Re: High Powered LED - PWM Controlled Circuit - Suggestions Post by: chandra2sekhar2000 on September 15, 2013, 01:47:00 13:47 why cant u try power psoc Controllers
Title: Re: High Powered LED - PWM Controlled Circuit - Suggestions Post by: Luigo on September 21, 2013, 06:25:35 18:25 This is an exelent project http://picprojects.org.uk/projects/bigmosfetrgb/index.htm
You can find a lot of good information http://picprojects.org.uk/projects/picprojects.htm |