EEVblog Electronics Community Forum

Electronics => PCB/EDA/CAD => KiCad => Topic started by: AxelVega on September 22, 2019, 02:58:30 am

Title: Error with regulators in ERC
Post by: AxelVega on September 22, 2019, 02:58:30 am

Hi guys!

When I try to run in ERC I have the next errors and warnings. What are they about? how can I solve it?

(https://imagizer.imageshack.com/img922/3130/GJFUVM.jpg)


(https://imagizer.imageshack.com/img921/5304/6N39WJ.jpg)
Title: Re: Error with regulators in ERC
Post by: Whales on September 22, 2019, 03:14:15 am
Hmm.  You're getting your ground externally.  What's your external power supply look like?

(ie can this ground accept or provide current to things connected to the bridge rectifier?)
Title: Re: Error with regulators in ERC
Post by: T3sl4co1l on September 22, 2019, 03:22:24 am
Set pin types to Passive or Power.

There's very little point in using ERC in analog circuits.  It's a digital logic gate thing.

Tim
Title: Re: Error with regulators in ERC
Post by: Nusa on September 22, 2019, 05:28:54 am
Two warnings and an error. The error is because both lines labeled "out" are considered connected. That's how net names are used in schematics when you don't want to actually draw the wire.
Title: Re: Error with regulators in ERC
Post by: Bassman59 on September 22, 2019, 07:09:57 pm
Quote from: AxelVega on September 22, 2019, 02:58:30 am

Hi guys!

When I try to run in ERC I have the next errors and warnings. What are they about? how can I solve it?

(https://imagizer.imageshack.com/img922/3130/GJFUVM.jpg)


(https://imagizer.imageshack.com/img921/5304/6N39WJ.jpg)

You must learn about “Power Flags” (in the Kicad POWER library). They are symbols you attach to a net that provide a Power Output source for Power Input pins on that net.

Your regulators’ input pins are Power Input types, but there’s no power Output driving their nets. The inputs come from the rectifier diodes. The Power Flag fixes the complaint.
Title: Re: Error with regulators in ERC
Post by: AxelVega on September 23, 2019, 05:28:38 am
Quote from: Nusa on September 22, 2019, 05:28:54 am
Two warnings and an error. The error is because both lines labeled "out" are considered connected. That's how net names are used in schematics when you don't want to actually draw the wire.

Thank you! I corrected that error  :D
Title: Re: Error with regulators in ERC
Post by: thinkfat on September 23, 2019, 07:43:21 am
The nets connected to the "+" and "-" pins of the bridge rectifier need a power flag. The schematic symbol likely lists them as "passive" and so they cannot drive the VIN pins of the regulators, which are marked as "Input".
Title: Re: Error with regulators in ERC
Post by: poeschlr on September 23, 2019, 08:39:22 am
There are two distinct errors reported. The not driven error is a common error made by beginners. KiCad checks if every power input pin is driven by a power output pin. This check is however done per net meaning if you have a passive between your power source and your consumer then you need to tell kicad that the "output" of the passive is indeed a source of power. This is done by placing the so called pwr_flag at this "output" pin.

Another place where you likely need the power flag is at the main power connector if you use a generic connector symbol. (The generic connector symbol defines all its pins as passive so kicad has no knowledge about the fact that this connector is the power source of your system)

More details see: https://forum.kicad.info/t/errtype-3-pin-connected-to-some-others-pins-but-no-pin-to-drive-it/10946/

---

The second error is because you directly connect two power outputs. I have not looked at your circuit long enough to determine if you can ignore it. (KiCad warns you because normally connecting two power outputs is quite dangerous as the two supply systems might start fighting over who is allowed to determine the voltage level. Resulting in one of them potentially going up in smoke or resulting in an unwanted voltage level at the net in question. Your circuit needs to somehow ensure that this can not happen.)