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Topic: Boosting Logic Voltage (LED Strips on Teensy) (Read 7684 times) previous topic - next topic

Qdeathstar

should the outputs be grouned too, or just floating?
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

Wawa


Grumpy_Mike

http://www.aliexpress.com/item/2015-Hot-sales-High-quanlity-addressable-digital-led-strip-LPD8806-5m-led-digital-strip-36LEDs-M/32275782496.html
The strip may be high quality but their data is not. If you put 12V into that strip you will probably blow it up. It needs 5V according to Adafruit. I can not see any 5V regulator or zener on that photograph, but you have the real thing so check that the power connector on the chip is connected directly to the power at the joins between sections. If it is then it is not a 12V system. I would strongly advise against running the first section at a different voltage than the rest of the chip.

You need a library to drive this chip, the Adafruit mentions an Arduino one, down load it and check that it is compatible with the Teensy.


Wawa

Mike, the circuit seems to follow the datasheet's recommendation, third page.
https://frack.nl/w/images/3/33/LPD8806_datasheet.pdf

Only the LED rail is connected to 12volts. (3x 3.3volt LED in series?)
And every single chip is supplied from a resistor and 5v1 zener to ground.
The IC's supply pin is roughly in the middle, left hand side.
You can just see the connection to the resistor and melf (zener?) diode.

I think this strip uses six 5050 LEDs per IC. Each package containing three LED chips of the same colour.
And the Adafruit strip uses two RGB 5050 LEDs per IC.
Single LED explains the 5volt LED rail.
Adafruit's strip can mix colours (RGB LEDs). This strip can't.
But I could be wrong...
Maybe the owner can confirm this.
Leo..



Qdeathstar

the two strips work the same, with the exception that the one I linked too has a lower resolution.

that is, on this strip every three leds can be independently controlled to get to any color.

I'm using the fastLED library and drive them with no problem using the default lpd8806 library on an arduino... the reason I want to use a teensy though, is the added sram and smaller footprint.
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

Wawa

Ahh, got that part wrong. So three RGB 5050s in series, running from 12volt.
One IC can drive two of these sets.
Leo..

Grumpy_Mike

While the 74LS14 is an old chip it is not obsolete in the accepted electronic sense of the word of no longer being manufactured.

This one is even ROSH certified so the changes to that must have been done in the last eight years.
74LS14
Showing that development of the chip is still ongoing.

Qdeathstar

Thanks Grumpy and Wawa... Though, i think the non-inverting chip is more practical...
A creaking creeping shadow
stiff against the freezing fog
glares at a tickless watch.

Time has failed him -- all things shall pass.

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