A single switch to make multiple circuits. But how?

Thread Starter

fieryfire

Joined Feb 14, 2017
106
Hi Everyone, I am looking for a single switch to make multiple circuits. Currently i can only find circuit selector switches like the one below.
Is there a switch out there that i can turn on or off 10 circuits with a single switch. Like the application shown in image 2.

upload_2019-7-25_17-23-47.png

upload_2019-7-25_17-29-19.png
 

Thread Starter

fieryfire

Joined Feb 14, 2017
106
Hello member,

Thank you for the response. I am aware of this option. But how do i bridge the toggles to be on the same switching motion though?

The immediate thing that came in my mind is using a ruler/scale and than placing the alignment on all the switches at once. yes i suppose this could be an option. But for my test procedure i might have to constantly wrestle with the thought of doing it correctly. Is there an alternate option. If not i will go for the one as proposed
 

crutschow

Joined Mar 14, 2008
24,928
Here's one.

Alternately you could use one single-pole switch to control some 4 pole or 6 pole relays, or some MOSFET switches.

What is the nature of the signals you want to switch?
 

narkeleptk

Joined Mar 11, 2019
461
I'm surprised there is nothing on the market to fit over those dip switches already to bridge x amount. If I was a 3d printer type guy I might would try and make some molds.
 

Thread Starter

fieryfire

Joined Feb 14, 2017
106
Hello Crutshow,

Thank you , but it seems like something that cannot be used on a PCB and would require manual wiring? And could you explain more about the mosfet switches?
My object is as shown below - I would want a single switch to control multiple(76) circuits of the below diagram, to be able to simply short the circled paths.

upload_2019-7-25_17-50-50.png
 

Thread Starter

fieryfire

Joined Feb 14, 2017
106
I'm surprised there is nothing on the market to fit over those dip switches already to bridge x amount. If I was a 3d printer type guy I might would try and make some molds.
Me too. And i am more surprised that no one had the requirement for such a switch since the dawn of electronic circuits?????
 

crutschow

Joined Mar 14, 2008
24,928
I would want a single switch to control multiple(76) circuits of the below diagram, to be able to simply short the circled paths.
If you are simply shorting those points to ground then, depending upon how low a resistance switch you need, an N-MOSFET, such as a 2N700x (x= 0 or 2), should work.
They can be turned on with a 10-12V gate-source voltage, and have an on-resistance of about 5 ohms.
They draw no gate current so all the gates to be switched can be connected in parallel (as long as all the MOSFET source terminals are connected to ground).
 

Thread Starter

fieryfire

Joined Feb 14, 2017
106
If you are simply shorting those points to ground then, depending upon how low a resistance switch you need, an N-MOSFET, such as a 2N700x (x= 0 or 2), should work.
They can be turned on with a 10-12V gate-source voltage, and have an on-resistance of about 5 ohms.
They draw no gate current so all the gates to be switched can be connected in parallel (as long as all the MOSFET source terminals are connected to ground).
This seems like quite a feasible idea. Thanks. My internal system has a +-12V power supply. I since the nmos draws next to no current . I can put like 76 of them(as i want) and then be able to control the on or off switch with an SPST. Could you please tell me why all the sources HAVE to be connected grounded? cant i place them in between two different potentials?

By the way thanks alot for this advice :D I think this should be feasible for my application
 

crutschow

Joined Mar 14, 2008
24,928
tell me why all the sources HAVE to be connected grounded? cant i place them in between two different potentials?
Because it's the gate-source voltage that determines if the MOSFET is on or off.
If the source is not at ground potential but at some different potential, then you have to apply a control signal that provides either 0V (off), or 10V-12V (on) between the gate and source terminals.
For example, if the source were at 5V, then you would have to apply 5V (or less) to the gate for turn-off and 15V for turn-on.

If you really want to float the switch, then you could use a CMOS switch, such as the CD4066 (4 switches in one package), which can switch a signal anywhere from ground to the supply voltage.
But it has an on-resistance of about 300 ohms maximum with a 12V supply.
If you need a lower resistance, there are other CMOS gates available (but generally more expensive).

What is the maximum voltage level you need to switch?
 
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Analog Ground

Joined Apr 24, 2019
394

Vinnie90

Joined Jul 7, 2016
86
as @crutchshow said you can use N-MOS (maybe it's better if you buy them in a more compact packaging with source and gate already connected) like this:
https://www.diodes.com/assets/Datasheets/DMN1250UFEL.pdf
you can also use a bus switch like this one so that you have a compact solution:
http://www.ti.com/lit/ds/symlink/sn74cb3t16211.pdf
that has 24 switches and can be controlled with an EN pin. It is technically for digital signals but if you just need to connect it to ground.

If you need to go higher than 5V probably the MOS array solution will be the most convenient

Cheers ;)
 

Thread Starter

fieryfire

Joined Feb 14, 2017
106
Because it's the gate-source voltage that determines if the MOSFET is on or off.
If the source is not at ground potential but at some different potential, then you have to apply a control signal that provides either 0V (off), or 10V-12V (on) between the gate and source terminals.
For example, if the source were at 5V, then you would have to apply 5V (or less) to the gate for turn-off and 15V for turn-on.

If you really want to float the switch, then you could use a CMOS switch, such as the CD4066 (4 switches in one package), which can switch a signal anywhere from ground to the supply voltage.
But it has an on-resistance of about 300 ohms maximum with a 12V supply.
If you need a lower resistance, there are other CMOS gates available (but generally more expensive).

What is the maximum voltage level you need to switch?
Thank you very much for this explaination. It is very clear now.
To me i dont really mind about the on resistance at all, i can simply modify the resistance value preceding it to get the correct voltages that i need. Since i still havent designed the PCB from your idea. I can take a look at CD4066 or even other higher density switches. For example my design uses about 39x2(78 switches) but ill seperate it into two pcbs as 39 circuits are connected from different sides. So any switch that is integrated with 39 would be great for my application. Or as you mentioned i can either use
-39*nmos(2n7000)
-10*CD4066
or if you are aware of another option. that would be great too :)
 

Thread Starter

fieryfire

Joined Feb 14, 2017
106
How about an "Analog Switch". There are many different switching arrangements. See the ICs at this link. The control input is a logic signal but the signal path can be anywhere within the power supply range.

https://www.analog.com/en/products/switches-multiplexers/analog-switches-multiplexers.html

https://www.analog.com/media/en/news-marketing-collateral/product-selection-guide/Choosing_Switches_or_Muxes.pdf
Thank you once again Analog Ground :) . I just took a look at the analog switches. And i suppose that 4xSPST switches can be a good option. For my application as mentioned in the comment above
I could use 10xAD5412 for my application. I am guessing if all the inputs are shorted like the picture shown below. And the control to turn on or off are equally applied. Then i am able to simultanesously control the on or off switches for the 4 switches. This should help. I tried to look for more than 4 x SPST switches if possible. But the catalogue doesnt have it. Never the less, this seems like a good option too :)
upload_2019-7-26_9-56-20.png
 

Thread Starter

fieryfire

Joined Feb 14, 2017
106
as @crutchshow said you can use N-MOS (maybe it's better if you buy them in a more compact packaging with source and gate already connected) like this:
https://www.diodes.com/assets/Datasheets/DMN1250UFEL.pdf
you can also use a bus switch like this one so that you have a compact solution:
http://www.ti.com/lit/ds/symlink/sn74cb3t16211.pdf
that has 24 switches and can be controlled with an EN pin. It is technically for digital signals but if you just need to connect it to ground.

If you need to go higher than 5V probably the MOS array solution will be the most convenient

Cheers ;)
I like the idea of the 8 in 1 N channel mosfet as @crutchshow mentioned. I can have more switches with one component this way. moreover less leads to be connected which is really great. The solution seems quite compact and i appreciate this one . Thanks alot. With this i would need only 5xDMN1250UFEL for my application.

I am fairly new to the bus IC you mentioned. It looks very interesting since it has 24 switches. which means i only need 2XSN74CB3T16211. Even better. But it looks quite complicated. Ill read through the datasheet to understand more about buses. Im a noob :)
 

Vinnie90

Joined Jul 7, 2016
86
I like the idea of the 8 in 1 N channel mosfet as @crutchshow mentioned. I can have more switches with one component this way. moreover less leads to be connected which is really great. The solution seems quite compact and i appreciate this one . Thanks alot. With this i would need only 5xDMN1250UFEL for my application.

I am fairly new to the bus IC you mentioned. It looks very interesting since it has 24 switches. which means i only need 2XSN74CB3T16211. Even better. But it looks quite complicated. Ill read through the datasheet to understand more about buses. Im a noob :)
The BUS switches basically work as normal switch, they are just very fast when switching and don't load much the system in terms of load capacitance.
It also depends on you budget...you can almost can find anything you want if you don't mind the price :p
 

Thread Starter

fieryfire

Joined Feb 14, 2017
106
The BUS switches basically work as normal switch, they are just very fast when switching and don't load much the system in terms of load capacitance.
It also depends on you budget...you can almost can find anything you want if you don't mind the price :p
Price doesnt matter :) Im trying to build a test bench. So i wouldnt need to fabricate 100s of these units. As long as these work as advertised they should work then its ok. Would you happen to know of an option that has 40 switches? That would be the Best :) . Else i can go for the bus or the 8 in 1 nmosfet. Both look quite fit for my application
 

crutschow

Joined Mar 14, 2008
24,928
If you only need to switch 5V, then the SN74CB3T16211, which has an on-resistance of <10Ω should work fine.

I don't believe you ever stated what maximum voltage you need to switch(?).
 

danadak

Joined Mar 10, 2018
4,057
Here is an approach using PSOC. I was able to route 48 channels onto one chip.
Resources left (right window) looks like I could squeeze another 16. Would have to
try it to see if it routes.

Plenty of resources left, could add a debouncer and a button input to control the array.
Could make it latching.....push to go on, push to go off. Button could be a cap sense
button to eliminate mechanical button.

Only code that has to be written is one line of code for each 8 inputs to turn them on/off
so 6 lines of code for the 48 outputs shown. So there would be a small latency between
turn on of the first 8 channels and the last 8 channels, I am guessing << 50 uS.

So everything is on 1 chip as shown. So top component (a component is an onchip
resource inside PSOC) is actual analog switch array, next is pins array for connecting
mux to external world, and below control registers to write to in code to turn on/off
analog switches channels.

upload_2019-7-29_16-17-14.png

So this is one analog signal in, distributed to 48 outputs. Could also add a OpAmp
buffer (also onchip) to the signal input. Or could use the onchip 4 opamps and buffer
the outputs in groups (for this exampe) of 12. Many possibilities. One chip.

Regards, Dana.
 
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