Current Limit Exceeded

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Hi All,

I am using a MAX V 5M2210ZF256 CPLD to drive a bunch of LEDs and when I try to compile my program I get the following error:

"Error (169007): Current density too high in I/O bank 2 -- pins combined exceed the limit (130.0 mA) by 10.0 mA"

I do understand that the current capability of the bank (bank 2) is only 130mA and my requirement exceeds it by 10mA. But in an earlier project that I have done using the MAX V 5M2210ZF324C5N CPLD I have connected LEDs to a single bank in such a way that it exceeds the current limit of the bank and successfully compiled and implemented the design. What is the reason I could successfully compile my design earlier and not now? Is there any workaround for the present problem?

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Hi djp,

Maybe you compiled your previous design with a different Quartus version? I have seen stunts like this one before... Or maybe there exists an assignment to tell Quartus that not all your LEDs will be turned on at the same time, in a way that will keep the CPLD always healthy.

Anyway, shouldn't it be a better solution just to move a few leds away from that bank and keep your CPLD working under nominal conditions? Or to introduce series resistors between the CPLD and the LEDs?

What I/O constraints are you setting for these output pins? Post the project's .qsf file for us to look at.

Cheers,

Alex