Hi I would like to drive a 7 segment using a shift register and have tried
74LS164 but it could not source enough current. Can anyone recomend me some parts that can drive the 7 segment using serial. I have quite a few common cathode and anode LEDs and I would like to make used of them.Thanks
Richard
Hello Richard,
Have you tried the 74HC164? Or HCT if you need TTL interface? However, if you need more than 5mA per Segment you should use a buffer anyway. Either some big bus driver, a ULN chip or seven FETs.
Regards, Joerg
I'd use a 74HC595. It has an extra register, so you avoid glitching the outputs while you shift in the data. It can also source enough current for typical LEDs.
"Richard" schrieb im Newsbeitrag news:dsj6cv$38u$ snipped-for-privacy@mawar.singnet.com.sg...
serial.
Use a TPIC6B595 from TI
or TPIC6c595 from TI
or from ST
MIKE
-- www.oho-elektronik.de OHO-Elektronik Michael Randelzhofer FPGA und CPLD Mini Module Klein aber oho !
Try Alegro
Richard,
I am not sure why you elected to use the inferior drive 74LS variety but I have used the 74HC164 in smd to drive leds for an outdoor 32 segment bargraph. The problem you may facing is the type of display are you using. Chances are that it is probably very inefficient and you would be better off going to a high-efficiency display. I have run 7seg displays straight off I/O pins that are viewable in daylight without a problem, provided that you use high-efficiency/high-brightness displays.
But if you are trying to drive a large display (~1" and up) I guess you will need more drive than a poor little 164 can handle. Easiest way is just to couple the 164 to external drivers or use a more expensive and harder to get driver like the 5822 serial to parallel type.
But once again, as is common on newsgroups, the OP does not supply any helpful information or parameters on which to base a correct answer.
*Peter*Richard wrote:
I am using MAX7219 for driving LED displays.
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