Inverting Dc

[Airskout]

So i am trying to upload an image of the display that has to be powered and the preexisting board on witch it mounts but i cant at the moment i ll try again later .
The project is an upgrade of this existing board witch is feed by an external supply witch provides it with either +24or-24V it is used in elevators . The reason i want to know how to reverse the polarity is so i can create the circuit in order to not need a different board witch it does at the moment. it uses either +or - as common .
So i dont need to make different ones i want to take the polarity that i am given and always make it for example possitive

 

[Airskout]

For example this is an other one i need to upgrade as you can see it has 3 "pins" 1 is common witch is either possitive or negetive voltage and the other ones are for the direction of the arrow . I want to replace the common pin with 2 others 1 receiving negetive and one receiving positive voltage so it works either way.

 

[rjenkinsgb]

That is a very different application and not one that needs a dual-polarity power supply to work?

According to the description, the arrow LEDs work on either polarity.

If I understand what you are saying, you want to use two wires and have one arrow working on one polarity and the other with the opposite polarity.

I think that should be possible just by adding two rectifier diodes from the two inputs to common, both the same way around (eg. both cathodes to common or both anodes to common).

You should then just be able to use the other two terminals and the lights should be controlled by the power polarity.


For info, that same board here, about a third of the way down the page:
**broken link removed**

Translation of the description:

Code: TOXO 4020

Direction arrow type indicator
Power supply: 12/24 AC or DC Volt
Dimensions: 40x64,7x20mm (Low Profil 13mm)
Mounting distance: 45.5 to 64.5 φ35

 

[shortbus=]

To keep a high side N-Channel FET on?

If the voltages are appropriate and you configure it in voltage doubler mode, it should be suitable - you could generate eg. 15V above the main circuit positive supply.

If the supply is higher than 18V, possibly put a 15V zener across the IC with positive direct and a resistor for the negative input?

Yes, using a high side N mosfet requires a boot strap circuit and they need to be refreshed frequently, using that IC could allow one to stay on longer. I'm talking about a 12V gate voltage. In my original post I forgot to mention it was a Nmos, sorry.

 

[Airskout]

That is a very different application and not one that needs a dual-polarity power supply to work?

According to the description, the arrow LEDs work on either polarity.

If I understand what you are saying, you want to use two wires and have one arrow working on one polarity and the other with the opposite polarity.

I think that should be possible just by adding two rectifier diodes from the two inputs to common, both the same way around (eg. both cathodes to common or both anodes to common).

You should then just be able to use the other two terminals and the lights should be controlled by the power polarity.


For info, that same board here, about a third of the way down the page:
**broken link removed**

Translation of the description:

Bro that's my page

 

[Airskout]

That is a very different application and not one that needs a dual-polarity power supply to work?

According to the description, the arrow LEDs work on either polarity.

If I understand what you are saying, you want to use two wires and have one arrow working on one polarity and the other with the opposite polarity.

I think that should be possible just by adding two rectifier diodes from the two inputs to common, both the same way around (eg. both cathodes to common or both anodes to common).

You should then just be able to use the other two terminals and the lights should be controlled by the power polarity.


For info, that same board here, about a third of the way down the page:
**broken link removed**

Translation of the description:

Also they are two boards 1 for positive common and 1 for negative i reverse the diodes in the input for each one.

 

[Airskout]

Also I dont care about the power supply outside the board it comes from a building panel

 

[dr pepper]

If you have a processor or some electronics on the board then you can use a bridge rectifier to supply it with a constant polarity regardless, then you could detect the polarity of your signal using either a couple of transistors or a couple of opto isolators back to back.

 

[rjenkinsgb]

Please clarify *exactly* what you are trying to do, the target seems to have moved repeatedly since your first post re. a 5V unit..

 

[Airskout]

Please clarify *exactly* what you are trying to do, the target seems to have moved repeatedly since your first post re. a 5V unit..

I know but i wasn't sure about all the info and i didn't exactly understand the problem my self

 

[Airskout]

So most of your ideas are pretty helpful but the problem is i want something compact because on most of the designs i want to upgrade i need 6 -12 inputs inverted if you go on my page ( https://www.sheltek-electronics.eu/lift-electronics )and see those codes DT404627ABCD or DT404627ABCD you ll see i need almost every input to be reversed therefore i cant have a big support circuit .
I cant fix the bolt above so you have to bear with me.
If you want i could upload the schematic of some design to better understand it's use if you need it to provide me with a solution.

 

[Les Jones]

Are you trying to make boards to replace the one in the link or are you trying to use them an a system they are not designed to work with.
What is the power supply voltage (The + & -) Which of the signals are inputs and which are outputs ? (A, B, C, D Up, Down.) It is better if we understand exactly what you are trying to do.

Les.

 

[Airskout]

The supplied voltage is either 24 or -24V I am trying to improve existing designs so i dont have to assemble 2 different boards as i do at the moment. So i sort of want to replace the existing ones

 

[Airskout]

Are you trying to make boards to replace the one in the link or are you trying to use them an a system they are not designed to work with.
What is the power supply voltage (The + & -) Which of the signals are inputs and which are outputs ? (A, B, C, D Up, Down.) It is better if we understand exactly what you are trying to do.

Les.

The ABDC and arrows are the inputs the outputs go straight to the display not used elsewere

 

[rjenkinsgb]

I am trying to improve existing designs so i dont have to assemble 2 different boards as i do at the moment.

Why not just put a bridge rectifier around each LED, so the whole thing works regardless of polarity?
That would be far simpler and cheaper!

 

[Diver300]

You've got a processor in there. Fit a bridge rectifier on the power input. Label the power inputs "Gnd" and "Supply". Measure the supply (before the rectifier) and if is -ve, get the program in the processor to invert all of the 6 - 12 signals.

I've designed some circuits to go in vehicles which need to have a supply, and need to have an ignition input. There are 3 wires, for ground, power and ignition, and it doesn't matter which is connected to which, to simplify installation. There is a 3-phase bridge with 6 diodes on the wires, so the circuit is powered from the most positive and the most negative of the wires. The processor in my circuit measures the three voltages, and arranged to be able to measure slightly negative voltages as well as positive ones. The lowest voltage is taken to be ground, the highest one to be the supply. The one that's in between is the ignition voltage, and if that is high the ignition is assumed to be on.