Problem Facing while Multiple Circuit is connected After Bridges.

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Bjtpower

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Hello All,

I have attached my circuit here where i am not able to understand why circuit is behaving like This.

Separately all circuits are working fine,But by integrate all this i am facing problem.

Can someone have clue which is right approach of the correct circuit..??



Regards
Marx
 

Hi,

Safety first: your circuit is connected to mains voltage. This is dangerous. Especially here because all the dangerous voltage is fed back to the "external power supply". Connectors, wiring and all other devices connected to this power supply usually are not made for live voltage. I doubt your circuit is according safety rules.

****

You don't say "what" problem you see.

Please explain what you mean with "multiple circuits".

Klaus
 

Hi Klaus

Problem is
When i connect the circuit as attached in the above post,for 100vac the VIN rises linearly and when we go to the Higher voltage it goes to rail voltage ie 3.8V

i used the Window comparator to make the output high at 120vac and 170VAC

Once it goes to +3.8V, it does not come down till we remove external power supply.

Window comparator is working seperately.

Lytswitch circuit is attached.
 

Hi,

Again: Please explain what you mean with "multiple circuits".

Schematic form post#1:
* What is Vref´? What voltage? Where does it come from? Where is it referenced to? What is it´s source impedance?
* What is Vref? What voltage? Where does it come from? Where is it referenced to? What is it´s source impedance?
* Where does the output of your window comparator go to? What load?
* Missing capacitor at OPAMP supply.

Your schematic of post#3:
A schematic without values it is about as useful as a map without text (city names, river names...)

Klaus
 

Hi Klaus,
There are 2 circuits..??
1) Lytswitch
2) Window Comparotor.

Vref:1.12V (For 120VAC Detections) GND is same in all circuit that is the Bridge -ve Points.
Vref':1.59V (For 170VAC Detections)

Where does the output of your window comparator go to? What load?
Output of OPAMP goes to M1 & M2 MOSFET Gates for Current varying of Lytswitch.

Missing capacitor at OPAMP supply.
Opamp is powered with the stable external power supply.
 

Output of OPAMP goes to M1 & M2 MOSFET Gates for Current varying of Lytswitch.
Click to expand...
Unfortunately you didn't manage to show the circuit interdependency in your schematics, instead hiding it behind an abstract switch symbol.

This should work if M1 and M2 are opto isolated analog switches, but I guess they aren't.
 

M1 and M2 are the N-Mos (DMN3070)

They are just for the Shunt to come into the Picture(Drive of Gates are Complementary)

So that we could have the Variable current Limit.

As well whole system is non-isolated as the Costing of project.

I would like the hints which i can troubleshoot in the same.

Regards
Marx
 

M1 and M2 are the N-Mos (DMN3070)

They are just for the Shunt to come into the Picture(Drive of Gates are Complementary)
Click to expand...
Means you believe that the transistor switches are operated with useful voltage range?

Unfortunately we can't check the assumption.
 

I checked it by driving gate from the External gate drive and it is working..

Now i am Integrating it with the OP-AMP DRIVES.?

i DINT GET YOUR QUESTIONS
 

Hi,

giving only half the informations makes it difficult to give good answers. You wast your time. And ours, too. Don´t be surprised if you get no response.
There still are questions not answered.

There are 2 circuits..??
1) Lytswitch
2) Window Comparotor.
Click to expand...
(For you this may be clear. But I see a rectifier circuit, a LED circuit, a voltage divider circuit....and additionally you hide some circuit. Maybe you speak of several Lytswitch circuits...)

--> Now I understand you talk about Lytswitch circuit and Window comparator circuit only.

I doubt that the Lytswitch (assuming a suitable PCB layout) circuit influences the window comparator.
But a bad layout may cause ripple on the supply lines ... and the ripple may be pushed to the capacitor via the diode.

Another problem may be:
The ouput voltage of the OPAMP is fed back to the capacitor via the 47k resistor. And there´s nothing to pull the capacitor voltage down.

BTW: I don´t like the "mis-use" of an OPAMP as comparator. A discussion about this was last week.

The circuit could be improved.
But again (annoying) the question about the sources (circuit, impedance or any other specification) of the two "Vref".

Klaus
 

Yes,

You understand it clearly.

There are only 2 circuits (Lytswitch Followed by Leds (Load)) and another is the voltage divider for the AC Voltage detection followed by the Hystresis comparator)

One thing is that How to pull down the Capacitor Voltage..??

Also need help how it can get corrected as you have an idea now..
 

Hi,

One thing is that How to pull down the Capacitor Voltage..??
Click to expand...
Currently the capacitor is chrged via the diode.
And it is discharged only when the comparator output is low. ... via the 47k resistors.
But as soon as the comparator output is HIGH...it can´t be discharged anymore ... instead it is charged to about the comparator output voltage.

Also need help how it can get corrected as you have an idea now..
Click to expand...
--> I need to see how you generated the Vrefs (the third time now)

For sure I can design the complete circuit for you. But this is not what a forum is for. We want to give you the informations that you can modify/improve your circuit by yourself. Today and in future.

Klaus
 

Hi Klauss,

the Vref is generated by the Fixed supply of +5V of op-amp by using the Voltage dividers

- - - Updated - - -

Here is the circuit of vref and vref'

 

Hi,

I think there´s something wrong:

Let´s call the output of the upper OPAMP "A"
and the output of the lower OPAMP "B".

Below 120V both "A" and "B" are low. --> output (collector of BC547) is LOW
Between 120V...170V "A" is LOW and "B" is HIGH --> output (collector of BC547) is LOW
above 170V both "A" and "B" are HIGH --> output (collector of BC547) is LOW

So the collector voltage is always LOW? Never HIGH. Didn`t you say you measured the correct output voltage?

Klaus
 

HI,

Its complementary output..??

Output for the Mosfet M1 & M2 are take from the Base and Collector.

So when base is low,Collector Voltage would be High.

When base is high, Collector Votage would be Low.
 

But the collector never is HIGH.
Click to expand...
True if Vref < Vref' as claimed in post #5. You want Vref > Vref' to make a window comparator.

The transistor should have a base current limiting resistor b.t.w.
 

Lets take a example.
Vref'=1.2V(120V)
Vref=1.7v(170V)

Now when vin is 1.21V
Upper opamp will be high because Vref'<Vin and lower Op-amp (Input of Base)=0V COZ VREF(1.6V)>VIN(1.2V)->Bjt is in off state so collector voltage would be high

When VIN =1.71V
Lower opamp will be High ie Base of opamp is high (Opamp o/p is provided to M1)

Now when Base is high so BJT will turn on and collector voltage would be VCESAT=0.3V (Low)

So we will get complementary output.

Now i am facing problem in window comparator..??
Can someone help me in that Hystresis.. how to avoid when Vin>Vref', that timr Vin become Opamp output voltage
so both the opamp o/p is getting high in my case..

Marx
 

Hi,

Post#5:
Vref:1.12V (For 120VAC Detections) GND is same in all circuit that is the Bridge -ve Points.
Vref':1.59V (For 170VAC Detections)
Click to expand...

Post#18:
Vref'=1.2V(120V)
Vref=1.7v(170V)
Click to expand...

Now it´s the opposite and new values. We don´t know what´s correct.
That´s repeatedly the problem with your given data. They change, they are incomplete and sometimes wrong.

Klaus
 

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