The above circuit I am using for reverse polarity and charger detection circuit for a Battery Management System. Here, I have represented +56V as my charger output. So, I have used two Optocouplers, Left one for reverse polarity detection and right one for charger detection. I have provided two logic output such that the left one should be High when the circuit is detecting reverse polarity connection. The right side logic output is for the charger detection such that if the charger is connected, which I have represented +56V, the logic output is Low and if the charger is not detected Logic is high. Is this circuit correct?

 

So do you have a question, or are you just posting your design for the general interest?

 

Small, low-res image is difficult to read.

Where does the 5 V come from, and does it share a common GND with the 56 V source?

Please add a unique reference designator to each component. without them, the circuit is very difficult to discuss

ak

 

Please avoid showing dotted conductors unless that is used to indicate the active part of some circuit. The difference between circuit and "just lines" is clear to most of us.
Please describe the operation of the circuit as to what happens when:
A no charger is connected),
BReveresd polarity is applied),
Cthe charger polarity applied is correct.)
THAT will assure that I understand and can provide a correct evaluation. Presently I do not see how those different conditions will provide signals.

 

hi Aj,
This is what LTSpice simulation shows for your circuit.
Check the layout for accuracy.
E
Edited to show more clearly polarity change.

 

View attachment 370182

The above circuit I am using for reverse polarity and charger detection circuit for a Battery Management System. Here, I have represented +56V as my charger output. So, I have used two Optocouplers, Left one for reverse polarity detection and right one for charger detection. I have provided two logic output such that the left one should be High when the circuit is detecting reverse polarity connection. The right side logic output is for the charger detection such that if the charger is connected, which I have represented +56V, the logic output is Low and if the charger is not detected Logic is high. Is this circuit correct?

What is the input voltage (Vin) of this circuit?

 

hi lc,
The TS posted.
have represented +56V as my charger output.

The 56V charge voltage is the ;Input' No Vin

E

 

https://www.falstad.com/s.php?s=ZzhNGx with some modifications

 

Certainly the circuit functions, but all it provides is data outputs.
Enable input /disable input actual functions are missing.
For actual use, we need to ENABLE a system whe the inputs are correct. THAT portion is missing.

 

no it does not function...

why would anyone think that this can work as reverse polarity detector? if the 56V is reversed, the optocouplers will blow...
the LEDs in them cannot tolerate such high reverse bias (it is 10 times what it can handle)


you need something like this (observe that D1 and D4 connection is antiparallel with optos LED):

 

OK, the circuit shown is not able to provide any USEFUL FUNCTION! !
ACTUAL reverse polarity and over-voltage circuits are quite different in most aspects. The best circuits provide isolation until both the correct voltage and polarity are sensed, AND they are usually able to withstand excess voltages.
OFTEN that protection includes both a series resistor and a voltage clamping arrangement to protect rest of the sensor/protection circuit. THAT can be as simple as a resistor and a shunting zener diode.

 

OK, the circuit shown is not able to provide any USEFUL FUNCTION! !

Hi B,

You obviously, once again, have not read the TS's original requirement

He is using the Output Logic Signals in determine the 56V charge voltage state BEFORE switching the power to the BMS

Quote:
The above circuit I am using for reverse polarity and charger detection circuit for a Battery Management System.
I have provided two logic output such that the left one should be High when the circuit is detecting reverse polarity connection. The right side logic output is for the charger detection such that if the charger is connected, which I have represented +56V, the logic output is Low and if the charger is not detected Logic is high. Is this circuit correct?

E

 

OK, I suppose. The over-voltage protection packages that I have seen tended to include the portions that prevent excess voltage or reversed polarities from entry. The circuit shown could provide notification, but as sown it provides no mechansm for actual protection, but only a logic level state change.
My apology for being a bit critical. OPtical isolation would probably be appropriate, but it is not likely that the setpoint would be repeatable thru a production run.