Pulse detector

On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.
Click to expand...

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?

(The problem isn't very well defined.)



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?


Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver
Click to expand...

That's not very well defined either.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?
Click to expand...

Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver
 
On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?


Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.
Click to expand...

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?
 
On Saturday, April 25, 2020 at 2:57:39 PM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 14:37:51 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?


Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?

Accuracy?
Click to expand...

10%

> Duration/decay time constant?

100ms

> Source impedance?

1K ohm

> Measurement device?

Lm358 and Lm393

> Scale of production?

Low

> Why not rectify it with a diode and a capacitor?

The Op Amp bring it closer to the source voltage without worrying about the variable diode drop, as well as isolating the circuit from the input.
 
On Sat, 25 Apr 2020 14:37:51 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?


Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?
Click to expand...

Accuracy?

Duration/decay time constant?

Source impedance?

Measurement device?

Scale of production?


Why not rectify it with a diode and a capacitor?




--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On Saturday, April 25, 2020 at 2:08:33 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?


Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.
Click to expand...

It's good enough for something called brainstorming. You might try it some time. Lots of people here talk about using it. It's very popular. What do you have to lose? I recommend it.

--

Rick C.

-++ Get 1,000 miles of free Supercharging
-++ Tesla referral code - https://ts.la/richard11209
 
On Saturday, April 25, 2020 at 9:02:59 PM UTC-7, Ricky C wrote:
On Saturday, April 25, 2020 at 5:37:58 PM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail..com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?


Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?

Not completely. What does "rejected" mean? You haven't explained exactly how you want the outputs to behave. Do you want two outputs that detect the presence of two voltages Âą1V and exclude everything else? So if the voltage is 7.5V neither output is active?
Click to expand...

Yes, only the prefined voltage ranges are accepted.

> If the duty cycle is not 10% should neither output be active?

The voltage is more important in this case, even if the duty cycle is off. I was just bringing up the point that averaging is not appropriate, but peak detection. Anyway, averaging is not easy to do in analog, peak detection is simple enough.

> It's interesting watching the analog approach get more complex as it is refined. I'd like to see a BOM.

Lm358 + 2 x Lm393
 
On Saturday, April 25, 2020 at 5:37:58 PM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal..

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?


Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?
Click to expand...

Not completely. What does "rejected" mean? You haven't explained exactly how you want the outputs to behave. Do you want two outputs that detect the presence of two voltages Âą1V and exclude everything else? So if the voltage is 7.5V neither output is active? If the duty cycle is not 10% should neither output be active?

It's interesting watching the analog approach get more complex as it is refined. I'd like to see a BOM.

--

Rick C.

+-- Get 1,000 miles of free Supercharging
+-- Tesla referral code - https://ts.la/richard11209
 
On Sunday, April 26, 2020 at 12:25:42 AM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 9:02:59 PM UTC-7, Ricky C wrote:
On Saturday, April 25, 2020 at 5:37:58 PM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward....@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?


Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?

Not completely. What does "rejected" mean? You haven't explained exactly how you want the outputs to behave. Do you want two outputs that detect the presence of two voltages Âą1V and exclude everything else? So if the voltage is 7.5V neither output is active?

Yes, only the prefined voltage ranges are accepted.

If the duty cycle is not 10% should neither output be active?

The voltage is more important in this case, even if the duty cycle is off.. I was just bringing up the point that averaging is not appropriate, but peak detection. Anyway, averaging is not easy to do in analog, peak detection is simple enough.

It's interesting watching the analog approach get more complex as it is refined. I'd like to see a BOM.

Lm358 + 2 x Lm393
Click to expand...

So the circuit has two outputs from four comparators. Going to use wire ORs to get a high only when within each window?

There will be a number of passives and don't you need a voltage reference? Or will you use the power supply?

Can't compete with the price for sure but for low volumes $0.50 is not much of an issue. I didn't know you could get an op amp/comparator that cheap. But the MCU will be a lot less space on the PCB and have fewer components overall. The programming is just part of the test process when I build boards. I usually design a simple test fixture, but that depends on the product.

What else is on this board?

--

Rick C.

+-+ Get 1,000 miles of free Supercharging
+-+ Tesla referral code - https://ts.la/richard11209
 
On Sunday, April 26, 2020 at 2:25:42 PM UTC+10, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 9:02:59 PM UTC-7, Ricky C wrote:
On Saturday, April 25, 2020 at 5:37:58 PM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward....@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?


Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?

Not completely. What does "rejected" mean? You haven't explained exactly how you want the outputs to behave. Do you want two outputs that detect the presence of two voltages Âą1V and exclude everything else? So if the voltage is 7.5V neither output is active?

Yes, only the prefined voltage ranges are accepted.

If the duty cycle is not 10% should neither output be active?

The voltage is more important in this case, even if the duty cycle is off.. I was just bringing up the point that averaging is not appropriate, but peak detection. Anyway, averaging is not easy to do in analog, peak detection is simple enough.
Click to expand...

Averaging is dead easy in anaolog - it's called "low pass filtering". It can be a bit slow.
It's interesting watching the analog approach get more complex as it is refined. I'd like to see a BOM.

Lm358 + 2 x Lm393
Click to expand...

Plus power supplies, lots of resistors, the occasional capacitor ...

Waht does seem to be missing is an an explicit and more or less complete specification of what the the circuit does. Why is does it is frequently useful too.

--
Bill Sloman, Sydney
 
On Sunday, April 26, 2020 at 12:19:34 AM UTC-7, Ricky C wrote:
On Sunday, April 26, 2020 at 12:25:42 AM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 9:02:59 PM UTC-7, Ricky C wrote:
On Saturday, April 25, 2020 at 5:37:58 PM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward....@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?


Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected..

Is that clear?

Not completely. What does "rejected" mean? You haven't explained exactly how you want the outputs to behave. Do you want two outputs that detect the presence of two voltages Âą1V and exclude everything else? So if the voltage is 7.5V neither output is active?

Yes, only the prefined voltage ranges are accepted.

If the duty cycle is not 10% should neither output be active?

The voltage is more important in this case, even if the duty cycle is off. I was just bringing up the point that averaging is not appropriate, but peak detection. Anyway, averaging is not easy to do in analog, peak detection is simple enough.

It's interesting watching the analog approach get more complex as it is refined. I'd like to see a BOM.

Lm358 + 2 x Lm393

So the circuit has two outputs from four comparators. Going to use wire ORs to get a high only when within each window?
Click to expand...

Yes, actually the ltc2304 can do it in single chip, but expensive.

> There will be a number of passives and don't you need a voltage reference? Or will you use the power supply?

Just resistor divider voltage reference: 2K,1K,1K,1K,1K,6K.

> Can't compete with the price for sure but for low volumes $0.50 is not much of an issue. I didn't know you could get an op amp/comparator that cheap.

Brought 50 lm358 and 100 lm393 for less than $10, including shipping from China. Hopefully, they are open now. I can burn out lots of them doing prototype.

> But the MCU will be a lot less space on the PCB and have fewer components overall. The programming is just part of the test process when I build boards. I usually design a simple test fixture, but that depends on the product.

Space is not a problem. If sale volume is high enough, could do micro.

> What else is on this board?

Power supply and relays.

JL:
This might work as your peak detector. It might be good enough without
D1+R1, especially if you account for the drop of D2 downstream.
Click to expand...

> https://www.dropbox.com/s/yuxsjp8iypvqdxw/Simple_Peak_Det.JPG?raw=1

This is pretty much same as our ideal diode circuit, but just one diode.
Don't understand why you want D2 and bring back the voltage drop problem.
Op amp eliminates the voltage drop error across D1.
 
On Sat, 25 Apr 2020 21:25:36 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 9:02:59 PM UTC-7, Ricky C wrote:
On Saturday, April 25, 2020 at 5:37:58 PM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?


Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?

Not completely. What does "rejected" mean? You haven't explained exactly how you want the outputs to behave. Do you want two outputs that detect the presence of two voltages ą1V and exclude everything else? So if the voltage is 7.5V neither output is active?

Yes, only the prefined voltage ranges are accepted.

If the duty cycle is not 10% should neither output be active?

The voltage is more important in this case, even if the duty cycle is off. I was just bringing up the point that averaging is not appropriate, but peak detection. Anyway, averaging is not easy to do in analog, peak detection is simple enough.

It's interesting watching the analog approach get more complex as it is refined. I'd like to see a BOM.
Click to expand...

More refinement should simplify a design. The popular concept of
"over-engineered" is backwards.

Lm358 + 2 x Lm393
Click to expand...

This might work as your peak detector. It might be good enough without
D1+R1, especially if you account for the drop of D2 downstream.

https://www.dropbox.com/s/yuxsjp8iypvqdxw/Simple_Peak_Det.JPG?raw=1


Incidentally, averaging is really easy: one RC.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On Sunday, April 26, 2020 at 11:30:33 AM UTC-4, edward...@gmail.com wrote:
On Sunday, April 26, 2020 at 12:19:34 AM UTC-7, Ricky C wrote:
On Sunday, April 26, 2020 at 12:25:42 AM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 9:02:59 PM UTC-7, Ricky C wrote:
On Saturday, April 25, 2020 at 5:37:58 PM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail..com
wrote:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?

Not completely. What does "rejected" mean? You haven't explained exactly how you want the outputs to behave. Do you want two outputs that detect the presence of two voltages Âą1V and exclude everything else? So if the voltage is 7.5V neither output is active?

Yes, only the prefined voltage ranges are accepted.

If the duty cycle is not 10% should neither output be active?

The voltage is more important in this case, even if the duty cycle is off. I was just bringing up the point that averaging is not appropriate, but peak detection. Anyway, averaging is not easy to do in analog, peak detection is simple enough.

It's interesting watching the analog approach get more complex as it is refined. I'd like to see a BOM.

Lm358 + 2 x Lm393

So the circuit has two outputs from four comparators. Going to use wire ORs to get a high only when within each window?

Yes, actually the ltc2304 can do it in single chip, but expensive.
Click to expand...

I can't find that device on ADI's web site... it is mentioned in some Russian viewgraphs.


There will be a number of passives and don't you need a voltage reference? Or will you use the power supply?

Just resistor divider voltage reference: 2K,1K,1K,1K,1K,6K.

Can't compete with the price for sure but for low volumes $0.50 is not much of an issue. I didn't know you could get an op amp/comparator that cheap.

Brought 50 lm358 and 100 lm393 for less than $10, including shipping from China. Hopefully, they are open now. I can burn out lots of them doing prototype.
Click to expand...

$25 would buy plenty of MCUs and they'd be reusable, not likely to get burnt out. China is already on Monday, so yeah, they're open, well, shortly.


But the MCU will be a lot less space on the PCB and have fewer components overall. The programming is just part of the test process when I build boards. I usually design a simple test fixture, but that depends on the product.

Space is not a problem. If sale volume is high enough, could do micro.

What else is on this board?

Power supply and relays.

JL:
This might work as your peak detector. It might be good enough without
D1+R1, especially if you account for the drop of D2 downstream.

https://www.dropbox.com/s/yuxsjp8iypvqdxw/Simple_Peak_Det.JPG?raw=1

This is pretty much same as our ideal diode circuit, but just one diode.
Don't understand why you want D2 and bring back the voltage drop problem.
Op amp eliminates the voltage drop error across D1.
Click to expand...

The two diodes connected that way eliminate the saturation of the op amp output which allows a response to shorter pulses which is not needed at all in this design. It also mucks up the diode voltage drop compensation since the two diodes will have different currents when charging up the cap. That was the main variation in the many peak detector circuits I saw, compensating for the diode voltage vs. keeping the op amp out of saturation... to some degree. None of them manage it perfectly. This is the first one I've seen that slacked off on the diode drop compensation.

Analog is messy and requires a lot of iteration to get right. It often also needs various... circuitry to deal with detail issues. The op amp is the first order of this. The diode has a voltage drop, so add the op amp to fix that. The op amp saturates and is slow to respond to the leading edge of the pulse, so add more circuitry to fix that, etc.

You probably can do without the op amp actually. The diode drop can be reduced by using a Schottky diode and even then if the end current is not large it will be near the low end of it's range. With your voltages being large compared to the diode drop it should be no problem to compensate for it in the resistor dividers. You've got a 10% window and 1% resistors. Accounting for a quarter volt diode drop should be pretty trivial.

Instead of designing for 9V Âą1V, design for 8.75V Âą1V.

BAT54J
VF forward voltage[1]
IF= 0.1 mA--240mV
IF= 1 mA--320mV
IF= 10 mA--400mV
IF= 30 mA--500mV
IF= 100 mA--800mV

--

Rick C.

++- Get 1,000 miles of free Supercharging
++- Tesla referral code - https://ts.la/richard11209
 
On Sunday, April 26, 2020 at 9:41:43 AM UTC-7, Ricky C wrote:
On Sunday, April 26, 2020 at 11:30:33 AM UTC-4, edward...@gmail.com wrote:
On Sunday, April 26, 2020 at 12:19:34 AM UTC-7, Ricky C wrote:
On Sunday, April 26, 2020 at 12:25:42 AM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 9:02:59 PM UTC-7, Ricky C wrote:
On Saturday, April 25, 2020 at 5:37:58 PM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?

Not completely. What does "rejected" mean? You haven't explained exactly how you want the outputs to behave. Do you want two outputs that detect the presence of two voltages Âą1V and exclude everything else? So if the voltage is 7.5V neither output is active?

Yes, only the prefined voltage ranges are accepted.

If the duty cycle is not 10% should neither output be active?

The voltage is more important in this case, even if the duty cycle is off. I was just bringing up the point that averaging is not appropriate, but peak detection. Anyway, averaging is not easy to do in analog, peak detection is simple enough.

It's interesting watching the analog approach get more complex as it is refined. I'd like to see a BOM.

Lm358 + 2 x Lm393

So the circuit has two outputs from four comparators. Going to use wire ORs to get a high only when within each window?

Yes, actually the ltc2304 can do it in single chip, but expensive.

I can't find that device on ADI's web site... it is mentioned in some Russian viewgraphs.
Click to expand...

Sorry, tlv2304. Op amp + comparator in single chip.
 
On Sunday, April 26, 2020 at 1:07:28 PM UTC-4, edward...@gmail.com wrote:
On Sunday, April 26, 2020 at 9:41:43 AM UTC-7, Ricky C wrote:
On Sunday, April 26, 2020 at 11:30:33 AM UTC-4, edward...@gmail.com wrote:
On Sunday, April 26, 2020 at 12:19:34 AM UTC-7, Ricky C wrote:
On Sunday, April 26, 2020 at 12:25:42 AM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 9:02:59 PM UTC-7, Ricky C wrote:
On Saturday, April 25, 2020 at 5:37:58 PM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?

Not completely. What does "rejected" mean? You haven't explained exactly how you want the outputs to behave. Do you want two outputs that detect the presence of two voltages Âą1V and exclude everything else? So if the voltage is 7.5V neither output is active?

Yes, only the prefined voltage ranges are accepted.

If the duty cycle is not 10% should neither output be active?

The voltage is more important in this case, even if the duty cycle is off. I was just bringing up the point that averaging is not appropriate, but peak detection. Anyway, averaging is not easy to do in analog, peak detection is simple enough.

It's interesting watching the analog approach get more complex as it is refined. I'd like to see a BOM.

Lm358 + 2 x Lm393

So the circuit has two outputs from four comparators. Going to use wire ORs to get a high only when within each window?

Yes, actually the ltc2304 can do it in single chip, but expensive.

I can't find that device on ADI's web site... it is mentioned in some Russian viewgraphs.

Sorry, tlv2304. Op amp + comparator in single chip.
Click to expand...

That would not accomplish much considering you need four comparators.

If you are running the relays off the same power as the rest of the circuit you might need to filter the reference resistors pretty well to avoid glitches and/or oscillations. Circuit activates causing relay to trip which surges the power supply drooping reference voltage causing comparator to drop out cycling around a few times.

So add some caps to your BOM.

I just would never try to do this with analog devices this way when it is such a simple design for an LDO, an MCU and two transistors - $1 and you are done. I expect for not much more you can buy MCU modules that solder to your board. In fact, I bet you can find relay boards with an MCU ready for you to add your programming.

Why roll your own board when you can buy hardware that will do this?

--

Rick C.

+++ Get 1,000 miles of free Supercharging
+++ Tesla referral code - https://ts.la/richard11209
 
On Sunday, April 26, 2020 at 11:42:16 AM UTC-7, Ricky C wrote:
On Sunday, April 26, 2020 at 1:07:28 PM UTC-4, edward...@gmail.com wrote:
On Sunday, April 26, 2020 at 9:41:43 AM UTC-7, Ricky C wrote:
On Sunday, April 26, 2020 at 11:30:33 AM UTC-4, edward...@gmail.com wrote:
On Sunday, April 26, 2020 at 12:19:34 AM UTC-7, Ricky C wrote:
On Sunday, April 26, 2020 at 12:25:42 AM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 9:02:59 PM UTC-7, Ricky C wrote:
On Saturday, April 25, 2020 at 5:37:58 PM UTC-4, edward...@gmail.com wrote:
On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?

Not completely. What does "rejected" mean? You haven't explained exactly how you want the outputs to behave. Do you want two outputs that detect the presence of two voltages Âą1V and exclude everything else? So if the voltage is 7.5V neither output is active?

Yes, only the prefined voltage ranges are accepted.

If the duty cycle is not 10% should neither output be active?

The voltage is more important in this case, even if the duty cycle is off. I was just bringing up the point that averaging is not appropriate, but peak detection. Anyway, averaging is not easy to do in analog, peak detection is simple enough.

It's interesting watching the analog approach get more complex as it is refined. I'd like to see a BOM.

Lm358 + 2 x Lm393

So the circuit has two outputs from four comparators. Going to use wire ORs to get a high only when within each window?

Yes, actually the ltc2304 can do it in single chip, but expensive.

I can't find that device on ADI's web site... it is mentioned in some Russian viewgraphs.

Sorry, tlv2304. Op amp + comparator in single chip.

That would not accomplish much considering you need four comparators.

If you are running the relays off the same power as the rest of the circuit you might need to filter the reference resistors pretty well to avoid glitches and/or oscillations. Circuit activates causing relay to trip which surges the power supply drooping reference voltage causing comparator to drop out cycling around a few times.
Click to expand...

Solid state relay takes around 25mA to activate, should not cause to much ripple.
 
On Sunday, April 26, 2020 at 3:27:27 PM UTC-4, edward...@gmail.com wrote:
On Sunday, April 26, 2020 at 11:42:16 AM UTC-7, Ricky C wrote:

If you are running the relays off the same power as the rest of the circuit you might need to filter the reference resistors pretty well to avoid glitches and/or oscillations. Circuit activates causing relay to trip which surges the power supply drooping reference voltage causing comparator to drop out cycling around a few times.

Solid state relay takes around 25mA to activate, should not cause to much ripple.
Click to expand...

Ah, the big buck relays. Low voltage/low current switched signal? I know for power line apps magnetic relays are much more cost effective. Obviously the load is not on the same supply or the relay would not be needed.

I want to make a control for my 240 volt, 30-50 amp household devices. No way I'm using a solid state relay for that. Even a magnetic relay goes up in price significantly from a 30 amp unit.

--

Rick C.

---- Get 1,000 miles of free Supercharging
---- Tesla referral code - https://ts.la/richard11209
 
On Sunday, April 26, 2020 at 3:20:53 PM UTC-7, Ricky C wrote:
On Sunday, April 26, 2020 at 3:27:27 PM UTC-4, edward...@gmail.com wrote:
On Sunday, April 26, 2020 at 11:42:16 AM UTC-7, Ricky C wrote:

If you are running the relays off the same power as the rest of the circuit you might need to filter the reference resistors pretty well to avoid glitches and/or oscillations. Circuit activates causing relay to trip which surges the power supply drooping reference voltage causing comparator to drop out cycling around a few times.

Solid state relay takes around 25mA to activate, should not cause to much ripple.

Ah, the big buck relays. Low voltage/low current switched signal? I know for power line apps magnetic relays are much more cost effective. Obviously the load is not on the same supply or the relay would not be needed.

I want to make a control for my 240 volt, 30-50 amp household devices. No way I'm using a solid state relay for that. Even a magnetic relay goes up in price significantly from a 30 amp unit.
Click to expand...

I only need around 120V 6A. It's less than $5.
 
On 2020-04-25, edward.ming.lee@gmail.com <edward.ming.lee@gmail.com> wrote:
On Saturday, April 25, 2020 at 11:08:33 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 11:03:21 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 10:47:16 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Sat, 25 Apr 2020 09:47:46 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Saturday, April 25, 2020 at 7:48:21 AM UTC-7, jla...@highlandsniptechnology.com wrote:
On Thu, 23 Apr 2020 10:48:05 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

Measure the average and multiply by 10.

It's not likely, but possible to have different duty cycles. So, it would get confused with 10% 9V and 15% 6v.

OK, it's not 10%.

Then why not rectify it with a diode and a capacitor?


Yes, that's pretty much an ideal diode and cap:

OpAmp(D),RC -> Comp-(10V),Comp+(8V) -> OpenCollectorDriver

That's not very well defined either.

10% duty cycle 1KHz signal, area of interest at 6V and 9V +/- 1V.
Other duty cycles and voltages upto 12V may be present and rejected.

Is that clear?
Click to expand...

You want to detect peaks in the 6V region reliably and in the 9V region too.
Power-supply is +12V DC

I still have many questions:

How close to 12V is the supply voltage? how much ripple?

You mentiond 10% PWM may increase to 15%, will it ever go above 90%
or below 10%? (and still require correct output)

Is there an output signal requirement if the PWM stops?
if so What constitutes a stop ? do we need to ignore runt pulses?

Your candidate circuit at the beginning was AC coupled.
Is your signal AC coupled or DC coupled?

Do you have output signal requirements for out of range signals?
I'm assuming 7-8V is treat as either 6V or 9V, but what about for
below 4V? what about for for above 11V?

How fast must the circuit respond to a change in signal amplitude?
100 microseconds? 100 milliseconds?

Preferred output is current sinking or sourcing? logic level? (which)

Can I draw 20mA from the signal line or it it high impedance?

--
Jasen.
 
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