struggling to figure out power flags.
I have the following circuit power. have input power errors bottom and top. put power flag on the bottom and that resolved part of them.
I am trying to ERC check a schematic and keep getting Input power not driven.
I tried putting power flag on top of this section, then moved it to the battery, then to jack, no luck. I just keep moving the errors around, sometimes to the power flag itself. What am I missing?
Put a PWR_FLAG on the +9V rail too.
I don’t run ERC so I’m not sure what I write.
Error arrow not exactly points where error is (it is what you probably are missing). If there are 10 pins needing power (power inputs) at the net and there is 0 pins being power output at that net then arrow points at one of those power inputs pins showing you that this net has no power output pin at it.
It is better to get one such error that can be resolved by one PWR_FLAG then to get 10 errors pointing to each power input pin at that net.
I tried putting it on 9V rail, it takes flag off IC power and moves it to the power flag.
this error is pins of power output and open collector are connected.
without the power flag the ic power gets error.
So two possibilities are:
It’s a design error because you’re not supposed to connect an open collector to the power rail because if you turn on the transistor, then kablooey, right? In this case ERC has saved you from a costly mistake.
The pin has the wrong type which could be the case if you got the symbol from some random library not the KiCad library.
You might want to post the software version and an archive of your project, if it’s not a secret, for less guesswork. Although if it’s an electronics design issue it’s outside the scope of this KiCad forum.
Thanks everyone for the help.
I ended up having to put a power flag on the 9V rail and right before the VCC out.
The circuit is essentially a tube screamer overdrive pedal. I know it works or has for at least the last 50 years. I am using it to learn kicad before I do my own designs. Kicad did not like that I had no resistor before the BJT transistor’s collector. This BJT is being used as a buffer and works without the resistor on the collector. I put a 1 ohm resistor on the collector and the error went away.
BTW I am using Kicad 7.0.8
Normally a BJT’s pin types are Input for the base and Passive for the emitter and collector in the KiCad symbol libraries so you are free to abuse the transistor any way. Open collector type is usually used for IC pins that are, well, open collector.
If remember well some time ago (moth, two,…) someone used npn symbol destined for Spice simulation and he was asking here about its ‘Open collector’ (and probably ‘Open Emitter’ ??) pins.
This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.
