TPIC6B595N or 74HC595 for 7-segment display?

[dacflyer]

tried to post in Smileys workshop..but no one's home..


i am wanting to build me another clock using 7-segment large led displays.

i am wanting advice on whats better to use. i am thinking to use the TPIC6B595N's

i see they use less lines ( connections ) and can handle more power, but i am not sure which is easier for code ( uses less memory )

if using the 74HC595, there is more connections and you have to have another ic to handle the higher current.. again, not sure on how much code is needed to control them v/s the TPIC6B595N

[haklesup]

it would be helpful if you can post links to datasheets for the devices you are discussing

[dyarker]

Saw your post over there. I downloaded the spec sheets for both those ICs. They both looked the same as far logic and IO "lines". Seemed like exact same programming to control them, so figured I was missing something.

The main difference is one IC has open drain FET for output. Handy for larger output current. But also allows LED supply voltage to higher than IC supply voltage (you can put more LEDs in series). How many LEDs per segment are you planning?

[dyarker]

(haklesup posted while I working on my previous. good idea though)

Both easily found at Digikey -
http://www.ti.com/lit/ds/symlink/tpic6b595.pdf
http://www.nxp.com/documents/data_sheet/74HC_HCT595.pdf

[dacflyer]

i plan to use it for larger led displays ( bigger clocks ) but i kind of liked the TPIC6B595N
1 chip instead of 2.
It looked like there was less connections if i saw it right..
i found some interesting pre-made modules on "Sparkfun" site. all you do is add your CA display.
http://www.kr4.us/sparkfun-large-digit-driver.html
i have ordered a few of these,,, hope they come in soon.

i used a board i found online, it can handle up to 12 of the TPIC6B595N chips, but i am only using 6 of them for my GPS clock. (12-digit, or 96 Bit, LED driver.)
the board was designed for use in a dual sided scoreboard. CROSSROADS has them for sale, you can find him on the Arduino site, he has a lot of other boards as well..
http://www.crossroadsfencing.com/BobuinoRev17/

[dyarker]

How do you figure 6 TPIC6B595Ns for 12 digits?

That IC is just an 8 bit shift register with high current outputs. You need 7 bits per digit, UNLESS a binary to 7 segment decoder logic is on each digit. That would change the bits required to 4 bits per digit, BUT then the high current driver needs to be after (or part of) the 7 segment decoder. So it still does not make sense to me.

I hope it is something I'm missing, but looks like you intend to send binary to 7 segments.

[dacflyer]

no not 6 chips for 12 digits,,, i ment that i am only using 6 for 6 digits, i do not need to use all 12 on the board,,in fact they are not even installed..
but the board is capable to drive 12 digits.