hi all,
i have a project to create 600 output on off, as i know arduino don have that much of output,
so that i come in to using TLC5940, there is alot of example i can find,
but did any one know what are the maximum output to connect TLC5940 in series?
(can reach about 600? mean 38 unit of TLC5940 connect in series.)
thank you.
There's no technical reason 38 won't work.
But ... the limit in reality it will depend on the quality of your cables and PCBs and how fast you try to send the data (if it doesn't work then you can slow down the data transmission a bit).
http://www.ti.com/lit/an/slva242/slva242.pdf page 2
The maximum number of cascading TLC5940 devices depends on the application system and is in the range of 40 devices.
i have a project to create 600 output on off,
If that is true and you just want on / off control then the TLC5940 is the wrong chip to use.
You need a shift register like the 74HC595.
The App Note is quoting page 20 of the datasheet:
see page 20 of datasheet
SERIAL DATA TRANSFER RATE
Figure 22 shows a cascading connection of n TLC5940 devices connected to a controller, building a basic
module of an LED display system. The maximum number of cascading TLC5940 devices depends on the
application system and is in the range of 40 devices. Equation 10 calculates the minimum frequency needed:
BTW,
While perusing the datasheet I noticed some interesting things, like led open detection, thermal error flag,
and storing DOT CORRECTION in the built-in EEPROM to adjust the brightness of each of the 16 channels
in 64 steps using a 6-bit word. I also notice the App note that Techstep linked had a schematic for the
22V EEPROM programming supply from the TLC5940 EVM (Evaluation Module ) schematic.
Mike's right. You need to use 74HC595. You might want to check out the TPIC6595 (eight channels of 250 mA each.