Admiral Akhtar Posted June 12 Report Share Posted June 12 Hello, I have wired a couple of low side driven LEDs to the spare Ignition drivers on my Xtreme ECU, but due to them being fly-wheeled Open collectors when in Auxillary output mode, the LEDs are still dimly lit when off My question is what do I need to do in order to prevent this? Wire a pair of pullup/pulldown resistors? Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 13 Report Share Posted June 13 The ignition outputs arent flywheeled or pulled up, I think that is a typo in the help file. I think the chipset that is used probably does have a weak bias internally for the fault and short detection strategy however. The general idea is you want the same voltage or higher on the negative side of the LED when "off" so no current flows through it. If the voltage on the negative side is lower than the positive side when off then you will have a current flow and therefore light generated. What is the otherside of the LED connected to? Quote Link to comment Share on other sites More sharing options...
Admiral Akhtar Posted June 13 Author Report Share Posted June 13 Ah thanks for clarifying The positive side is connected to a switch 12v source, and the negative side runs directly to Aux outs. They are being used to power a sort of shift light array within the cluster, so IGN7 has 2 LEDs connected, IGN8 has 2 LEDs connected and INJ7 has 1 LED connected They are all exactly the same LEDs and all 5 are fed from the same 12v Switch source, but weirdly this issue isn't present on the INJ7 LED, which is why I assumed it was a possibly Aux out difference Quote Link to comment Share on other sites More sharing options...
Admiral Akhtar Posted June 13 Author Report Share Posted June 13 11 hours ago, Adamw said: The ignition outputs arent flywheeled or pulled up, I think that is a typo in the help file. I think the chipset that is used probably does have a weak bias internally for the fault and short detection strategy however. The general idea is you want the same voltage or higher on the negative side of the LED when "off" so no current flows through it. If the voltage on the negative side is lower than the positive side when off then you will have a current flow and therefore light generated. What is the otherside of the LED connected to? Could it be anything to do with having 2 LEDs on one IGN out? Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 13 Report Share Posted June 13 Connect a pull-up to 12V should solve it. Try something like 1-5Kohm. The injector drives wont need it as they dont have the fault detection stuff. Admiral Akhtar 1 Quote Link to comment Share on other sites More sharing options...
Admiral Akhtar Posted June 13 Author Report Share Posted June 13 Perfect, will give that a go shortly Quote Link to comment Share on other sites More sharing options...
Admiral Akhtar Posted June 13 Author Report Share Posted June 13 For anyone that may experience similar issues and come across this thread, a 1k pullup to 12v worked perfectly Quote Link to comment Share on other sites More sharing options...
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