Please does anyone have in their scrap book; a circuit for a toggle flip-flop using 2 comparators?

Its going to be power management switching for a LED driver - but I haven't done that bit of the design yet.

Its for 6V, but its a basic principles circuit block that I can re calculate component values if needed.

Thanks.

 

Just use a 555 without the timing cap. It already has two compare circuits with one referenced to 1/3Vcc and the other referenced to 2/3Vcc.

 

Are you -

1) Trying to toggle a single F-F from two different voltage set points asynchronously ?
2) Trying to toggle a F-F for a range of V, like a window comparator ?
3) Trying to toggle a F-F with one comparator, reset it with another ?
4).....

As you can see maybe a little more description of what is needed, like range of V's,
logical behavior, speed, timing.....would be useful.

Regards, Dana.

 

Are you -

1) Trying to toggle a single F-F from two different voltage set points asynchronously ?
2) Trying to toggle a F-F for a range of V, like a window comparator ?
3) Trying to toggle a F-F with one comparator, reset it with another ?
4).....

As you can see maybe a little more description of what is needed, like range of V's,
logical behavior, speed, timing.....would be useful.

Regards, Dana.

It was a simple question - till you got your hands on it!

If you don't have what I'm looking for in your scrap book - don't confuse those who might.

 

Does this help....

 

Do you need a toggle (one input to alternate the state) or latch with two inputs (set and reset)?
What will toggle the circuit -- a switch, or a logic signal?

 

Does this help....


View attachment 153514

Considering I could do that with a couple of transistors...……...

 

Do you need a toggle (one input to alternate the state) or latch with two inputs (set and reset)?
What will toggle the circuit -- a switch, or a logic signal?

It all seemed so simple to me, toggling is latching by definition and a toggle flip-flop isn't a S/R flip-flop.

 

Considering I could do that with a couple of transistors...……...

You could make a T flip flop with a couple transistors too.

 

You could make a T flip flop with a couple transistors too.

Doesn't that have steering diodes and commutating capacitors?

 

Doesn't that have steering diodes and commutating capacitors?

And some resistors.

 

Please does anyone have in their scrap book; a circuit for a toggle flip-flop using 2 comparators?

Its going to be power management switching for a LED driver - but I haven't done that bit of the design yet.

Its for 6V, but its a basic principles circuit block that I can re calculate component values if needed.

Thanks.

It's unclear what the constraints are. Do you require a circuit that uses ONLY two comparators and nothing else? Or two comparators plus passive components? Are opamps allowed in addition to the comparators? Other logic components?

Do you need a reset ability, or just the ability to toggle the state every time a signal rises above a certain threshold and it doesn't matter what state the circuit initializes in?

It would help if you described why you need such a circuit as opposed to just using a standard D or JK FF configured as a T FF.

 

Doesn't that have steering diodes and commutating capacitors?

It wouldn't have to have anything of the sort? You could build it as a pure CMOS circuit and it would have nothing but transistors, albeit more than "a couple".

 

Please does anyone have in their scrap book; a circuit for a toggle flip-flop using 2 comparators?

Its going to be power management switching for a LED driver - but I haven't done that bit of the design yet.

Its for 6V, but its a basic principles circuit block that I can re calculate component values if needed.

Thanks.

Hi,

How fast does it have to toggle?

 

I have one with one comparator. I don't know what the other comparator is for.

You seem determined to use comparators. Is it an impertinent waste of your time to ask why? For example, is an open collector output needed for some downstream circuit function?

ak

 

I have one with one comparator. I don't know what the other comparator is for.

You seem determined to use comparators. Is it an impertinent waste of your time to ask why? For example, is an open collector output needed for some downstream circuit function?

ak

Hi,

I think he wants the input to work at a circuit voltage threshold. Standard logic has standard threshold levels but i you use a comparator you can get whatever level you want. You can also do that with a comparator and standard logic though, so maybe he just has two comparators left over and wants to be able to use them.

 

It's unclear what the constraints are. Do you require a circuit that uses ONLY two comparators and nothing else? Or two comparators plus passive components? Are opamps allowed in addition to the comparators? Other logic components?

Do you need a reset ability, or just the ability to toggle the state every time a signal rises above a certain threshold and it doesn't matter what state the circuit initializes in?

It would help if you described why you need such a circuit as opposed to just using a standard D or JK FF configured as a T FF.

I set out to make the question as simple as possible - and have been soundly thwarted.

just a simple toggle flip flop with a push button.

I figured a simple circuit using an SOIC8 package dual comparator would just about fit the available space.

there is a simple textbook circuit - if I knew the search string to Google, I'd have it without a third degree.

 

I set out to make the question as simple as possible - and have been soundly thwarted.

just a simple toggle flip flop with a push button.

I figured a simple circuit using an SOIC8 package dual comparator would just about fit the available space.

there is a simple textbook circuit - if I knew the search string to Google, I'd have it without a third degree.

Since asking whether you need to be able to put this flip flop into a known state or whether the circuit is allowed to use any components at all other than the two comparators is "a third degree" and not even worthy of an answer, I have to conclude that the solution I've come up with is not acceptable. I won't waste any more of your time or my time trying to help you.

Good luck.

 

I set out to make the question as simple as possible - and have been soundly thwarted.

That would seem to be self-inflicted.

 

Like this?
How are you debouncing the switch?