0
\$\begingroup\$

I am seeking to drive a seven-segment common anode LED display in which each segment (setting aside the decimal point) should be regulated to 78mA or thereabouts. (The digit is 12" tall, hence the high current.) I'd like to send the data to the driver in some serial format, though I am not particular about which. I'm driving Betlux model BL-SE1200B-11UHR (datasheet); the manufacturer didn't reply to an emailed query.

I have not found any common-anode driver capable of anywhere near the required current. A candidate would've been Maxim ICM7212 (datasheet), but it only drives up to 8mA per segment. Or, the Maxim 7221 (datasheet), which can sink a maximum of –45mA per segment, so is getting closer to ,y current carrying needs—but is configured for common cathode use.

Are there any commercially available chips to do this job? (I'm driving six of these digits, so preferably the chip is available in DIP package for easy hand soldering.) Or must I build a driver, combining a demultiplexer with a series of transistors each switching a current limiter for the segments? Or is there another, simpler approach I'm overlooking?

Thanks!

\$\endgroup\$
  • \$\begingroup\$ DIP power handling is mediocre. Prepare to use a SO package with a huge ground beneath the package. \$\endgroup\$ – Ignacio Vazquez-Abrams Jun 3 '18 at 23:01
  • \$\begingroup\$ @IgnacioVazquez-Abrams, thanks—I was worried about that. If there is an SO package that fits the bill, I'll take what I can get. Are you aware of any for the application? \$\endgroup\$ – R Zach Jun 3 '18 at 23:07
  • \$\begingroup\$ Try TI's TLC* line. \$\endgroup\$ – Ignacio Vazquez-Abrams Jun 3 '18 at 23:07
  • \$\begingroup\$ @IgnacioVazquez-Abrams Bingo. TLC5916/7, 8 outputs, comes in PDIP package, up to 120mA per channel. My parametric searches didn't turn it up for whatever reason. Thanks a million for the advice! If you submit as an answer I'll gladly accept it. \$\endgroup\$ – R Zach Jun 4 '18 at 2:19
  • \$\begingroup\$ @IgnacioVazquez-Abrams I cannot edit my prior comment, so I'm adding to it: the application I have uses 15 LEDs in series, and 4 strings of those in parallel, per segment. This requires a driving voltage 30–33V, and current 20–80mA. The TLC5916 is fine for that current, but can't do more than 20V, so it turns out it won't work, unfortunately. \$\endgroup\$ – R Zach Jun 4 '18 at 5:07

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.