555 Timer Phase Shift

Thread Starter

HighVoltageJoe

Joined Jun 1, 2017
36
Hi all,

I, since I don't have a signal generator with enough outputs, want to make my own crude 555 timer signal generator with 3 outputs each 60 degrees apart from one another. Creating the square waves is no problem, but where I hit a wall was the phase shift part. I know that I will have three 555s to create my signals but after that, I'm lost.

Does anyone know if it is even possible to effectively create phase shifts with them? I imagine that there has to be a circuit that can do this task. The good thing is that I only need, giving myself a lot of room here that I probably don't need, maybe up to 500Hz. I doubt I'll crest 100Hz. Does anyone have any ideas on how to do this?

Thank you and stay safe,
Joe M
 

Danko

Joined Nov 22, 2017
928
Simplest, easy tuned 3-phase generator,
but without 555 timer, sorry:
1586494495827.png

EDIT:
Used 1 chip CD4093B (U1) and 2 chips CD4013 (U2 and U3).
U1A is oscillator, its frequency depends on R1 and C1 values.
U2B, U3A and U3B - are counter.
Input of counter is "Sin".
Circuit feeds from 12V.
+12V to pin #14, Ground to pin #7 of every chip.
Not used inputs of chips are connected to Ground.
 
Last edited:

crutschow

Joined Mar 14, 2008
24,978
You remove U!A, R1, and C1, and feed Sin (CLK) from a 555 timer with a frequency 3 times the 3-phase frequency you need.

Here's a circuit using just two chips instead of three.

1586496371378.png
 

WBahn

Joined Mar 31, 2012
25,764
Hi all,

I, since I don't have a signal generator with enough outputs, want to make my own crude 555 timer signal generator with 3 outputs each 60 degrees apart from one another. Creating the square waves is no problem, but where I hit a wall was the phase shift part. I know that I will have three 555s to create my signals but after that, I'm lost.

Does anyone know if it is even possible to effectively create phase shifts with them? I imagine that there has to be a circuit that can do this task. The good thing is that I only need, giving myself a lot of room here that I probably don't need, maybe up to 500Hz. I doubt I'll crest 100Hz. Does anyone have any ideas on how to do this?

Thank you and stay safe,
Joe M
First thing to do is to give up on the notion of using three separate 555's, one per phase, and then trying to get them to have a particular phase relationship between them. The very notion of three such signals operating with a specific phase relationship between them presupposes that all three signals are operating at EXACTLY the same frequency, at least when averaged over even a very short period of time (a small fraction of a cycle). That's not going to happen with three 555's, in fact it's not going to happen with any three sources unless they are mechanically or electrically servoed to a single governing signal.

Since you appear to be using squarewaves, it is pretty straightforward to run an oscillator (a 555 in astable mode may work perfectly find for your purposes) at a multiple of 3x the frequency you are looking for and then use the resulting six pulses to set and reset suitable latches to generate your three waveforms. There are many ways to do this.
 

Thread Starter

HighVoltageJoe

Joined Jun 1, 2017
36
First thing to do is to give up on the notion of using three separate 555's, one per phase, and then trying to get them to have a particular phase relationship between them. The very notion of three such signals operating with a specific phase relationship between them presupposes that all three signals are operating at EXACTLY the same frequency, at least when averaged over even a very short period of time (a small fraction of a cycle). That's not going to happen with three 555's, in fact it's not going to happen with any three sources unless they are mechanically or electrically servoed to a single governing signal.

Since you appear to be using squarewaves, it is pretty straightforward to run an oscillator (a 555 in astable mode may work perfectly find for your purposes) at a multiple of 3x the frequency you are looking for and then use the resulting six pulses to set and reset suitable latches to generate your three waveforms. There are many ways to do this.
So either of the circuit suggested above will do the trick effectively? I'm not looking for perfection even if it's +/- 5 degrees I'm fine with it.
 

WBahn

Joined Mar 31, 2012
25,764
So either of the circuit suggested above will do the trick effectively? I'm not looking for perfection even if it's +/- 5 degrees I'm fine with it.
Yes, both of those circuits should work. I haven't looked at them in fine detail, but the basic approach in both is fine. The second one also looks like it's taken from a manufacturer's data sheet or app note.
 

Thread Starter

HighVoltageJoe

Joined Jun 1, 2017
36
Yes, both of those circuits should work. I haven't looked at them in fine detail, but the basic approach in both is fine. The second one also looks like it's taken from a manufacturer's data sheet or app note.
Ok thank you very much. I'll add some gates to my Digikey cart here and get building! :)

Stay safe and best regards,
Joe
 

danadak

Joined Mar 10, 2018
4,057
For future consideration, a general purpose logic platform, as well as a lot of analog capability.

This is a single chip design. clock freq accuracy (w/o a crystal) is +/- 2% over T and V, no external
R & C needed. With crystal << .1%.

This is codeless design, even though core has ARM M0 in it. You drag and drop components
onto IDE schematic, wire them up, right click and configure. A component in PSOC terminology
is an onchip resource. A catalog of components on the chip attached file.

If you work your way up to coding much more sophisticated designs can be done, for example
DSP filtering, advanced PWM/Counter/Timer stuff, display.... In fact its quite easy to do a 3 phase
sinewave generator, all on one chip.

This design uses a registered LUT ( I was lazy) to do the clock and phase generation. Could have
just as easily done the other two posters designs.

You can see in right hand window resources used/left in the chip.

1586517558329.png


Dev board, simple usb interface, is ~ 10. You can do many designs on this, as well as multiple designs.

IDE (PSOC Creator) is free.


Regards, Dana.
 

Attachments

Last edited:

Thread Starter

HighVoltageJoe

Joined Jun 1, 2017
36
For future consideration, a general purpose logic platform, as well as a lot of analog capability.

This is a single chip design. clock freq accuracy (w/o a crystal) is +/- 2% over T and V, no external
R & C needed. With crystal << .1%.

This is codeless design, even though core has ARM M0 in it. You drag and drop components
onto IDE schematic, wire them up, right click and configure. A component in PSOC terminology
is an onchip resource. A catalog of components on the chip attached file.

If you work your way up to coding much more sophisticated designs can be done, for example
DSP filtering, advanced PWM/Counter/Timer stuff, display.... In fact its quite easy to do a 3 phase
sinewave generator, all on one chip.

This design uses a registered LUT ( I was lazy) to do the clock and phase generation. Could have
just as easily done the other two posters designs.

You can see in right hand window resources used/left in the chip.

View attachment 204006


Dev board, simple usb interface, is ~ 10. You can do many designs on this, as well as multiple designs.

IDE (PSOC Creator) is free.


Regards, Dana.
So I can essentially do this with an FPGA? I'm just starting to use FPGAs so I still have a long way to go as far as coding goes lol.
 

danadak

Joined Mar 10, 2018
4,057
So I can essentially do this with an FPGA? I'm just starting to use FPGAs so I still have a long way to go as far as coding goes lol.
Cypress PSOC is FGFA like but with a lot of Analog in it as well as logic, both basic
and advanced functions. You can see whats in it in the catalog of components I
posted earlier. Note a component in PSOC is an onchip resource. Each component
has a number of prewritrten APIs you can call in code to manipulate. A number
of designs can be done codeless as well.

A low cost starter board is PSOC 5LP, $ 10, you can do quite a lot just with this low end
board.

https://www.cypress.com/documentation/development-kitsboards/cy8ckit-059-psoc-5lp-prototyping-kit-onboard-programmer-and

IDE and Compiler free - https://www.cypress.com/products/psoc-creator-integrated-design-environment-ide

Lots of wizards for setting up components, DSP, DMA, state machine, display.......

Some codeless and almost codeless designs -

https://forum.allaboutcircuits.com/threads/mixed-signal-solution-codeless-and-almost-codeless-design.159970/

https://forum.allaboutcircuits.com/threads/cd4060-plus.165245/

https://forum.allaboutcircuits.com/threads/64-bit-demux-single-chip-or-64-bit-mux.165733/

https://forum.allaboutcircuits.com/threads/multi-channel-dds-drive-wavedac.158357/

https://forum.allaboutcircuits.com/threads/variable-pwm-generator.167309/



Regards, Dana.
 
Last edited:

danadak

Joined Mar 10, 2018
4,057
Thank you for recommending that Dana. I might have to order myself one of those.
Lots of videos on website, start with "PSOC Creator 101" https://www.cypress.com/video-library/PSoC-Software/psoc-creator-101-lesson-1-introduction-0/108116


Tons of projects, listed in tool and done outside Cypress -

https://www.element14.com/community/thread/23736/l/100-projects-in-100-days

https://github.com/cypresssemiconductorco/PSoC-4-BLE/tree/master/100_Projects_in_100_Days


Besides the components in the tool catalog there are a number done by community and validated. https://www.cypress.com/validated-components
Mostly done in verilog (users can create their own components from scratch, either from schematic capture and/or verilog).


Regards, Dana.
 
Last edited:

danadak

Joined Mar 10, 2018
4,057
In post # 11 I had the LUT table set with some errors.

As its a registered LUT the outputs for a given state must show the next state address. I was one address off.

Here is corrected version.


1586560932936.png


Regards, Dana.
 
Top