SDG

[@mikeselectricstuff]

I designed a multichannel driver like that many years ago - for the switching I used N-channel fets, and drove the gates with pullups to about +15V, so they were always higher than the source regardless of which were on, and open-drain PWM LED drivers, just used as PWM generators.

[@mikeselectricstuff]

Thermal circuit looks a bit complicated - could you not just use an NTC or PTC and resistors to get the required characteristic - overtemp will be basically closed-loop as temp reduces as current goes down, so the temp vs. current slope isn't that important

[@sdgelectronics]

I will probably revisit once I start testing, at the moment I have no feel for the thermal behaviour or even the drive current for the light effect I'm after. If I can simplify it down to a couple of components then that would be ideal.

[@mikeselectricstuff]

You can also reduce the stencil size using the "custom size" option. There can sometimes be issues where they think the printable area is larger than it is, e.g. if the outline is significantly bigger than the printable area, and it refuses to accept the custom size - this can be avoided by doing a seperate stencil order.

[@dascandy]

custom size saves a ton in shipping cost in my experience.

[@lohikarhu734]

Have a look at LP5523, which is a 9-channel "intelligent" LED driver, designed to drive 3 RGB LEDs, or any combination... it's an I2C device, it actually has RAM for 3 LED driver "engines" that have an instruction set, as well as 3 "dimmer potentiometer" controls, temperature compensation separately for each LED driver, 100 uA control steps for 8 bit current control, linear to logarithmic conversion for 12 bit resolution of each PWM control, a multiplex instruction that allows "re-mapping" LED outputs to different controllers, on the fly, and.... It has an automatic charge pump to boost voltage, if battery voltage gets low for any LED output, and ADC (7 bits, I think ) that can be connected to LEDs, charge pump, a "gpio" pin, VCC, so it can be used for self-test function, temperature sensor input, light levels (with phototransistor, for example) , reading a potentiometer... It can be used in a direct control mode, or you generate programs, which you download to RAM, and these programs then run without further CPU overhead, but can provide an I2C interrupt, or toggle a gpio pin... It's a real workhorse, and there is some code for Linux, and an available PC-based "assembler"/download software package.

[@brianwood5220]

Very nice design, Steve. Looking forward to the build. Thanks for sharing with us.

[@akhurash]

Cool project. Looking forward to seeing the assembled board and testing.

[@GodmanchesterGoblin]

Nice! Great vid3o and explanation. The multiple LED control with the LEDs in series and bypassed with a switch is a similar technique to the GS8208 chip used in some 12 volt RGB LED strips. One suggestion... At 19:05 in the video, in the activity detection circuit, I would add a small resistor (say 4.7k...?) between the diodes and the 1uF capacitor so that on start up from the idle state, the capacitor doesn't try to clamp the PWM drive signals.

[@Dutch-Maker]

Have look at MBI6673 4 Channel RGBW led driver SIMO (single inductor multi output)

[@jensschroder8214]

I would use N channel fets and an optocoupler to drive them.

[@tomvleeuwen]

There is a function in WLED that controls an output pin to switch off the power supply to the LEDs. This probably won't work if you want to keep the bottom LEDs on, but would be much simpler than rectifying all PWM signals.

[@TheEmbeddedHobbyist]

Nice, i want to wi-fi some up/down outside lights. would be nice to add some colour.

[@andymouse]

Interesting project....cheers.

[@WR3slo]

I often put 47R / 100R resistor in series with feedback pin. You can easily pull the pin down to ground with 1k resistor for temperature fallback. Having analog power reduction and PWM input on Ctrl pin does not work so nice.

[@sdgelectronics]

The control pin will only have the analogue voltage and the on/off signal, no PWM.

[@Vladimir-hq1ne]

You look much younger with this haircut 😀

[@DarkStormPhoenix]

Do you offer repairs please.?

[@sdgelectronics]

Not really - I hardly have enough time as it is.