Electrical isolation for the I2C bus with optocouplers


Posted on Jul 10, 2012

When the lines SDA (Serial DAta) and SDA 'are logical '1', the circuit is at rest with the result that optocouplers IC 1 and IC2 can not convey absolutely no information. But once the SDA line become the 'O', then the LED the IC 1 becomes conductive through the resistor R2. At that time the line SDA 'and it becomes reasonable' O 'because of conductivity of the transistor of IC 1 and D2. This logic state remains on the right side of the channel. After the LED of IC2 can not properly polarized, and therefore unable to transfer back to the left. In this way, ensure that the circuit will never be 'stuck' to logical 'O'. As you noticed, the circuit is symmetrical.


Electrical isolation for the I2C bus with optocouplers
Click here to download the full size of the above Circuit.

Thus, if the line SDA 'lead to logical' O ', then the SDA line will also acquire. The lower part of the circuit works like the above, except that here the signal moving is the SCL (Serial CLock). The R 1, A4, A5 and A8 are the usual restraint Elements 3.3 KO which should always be placed on the lines of bus 12C. If the resistors are already co-dedemenes elsewhere in the channel, they can be received by this circuit. The current absorbed by the Bus lines are a little higher than expected due to the presence of LED diodes that optocouplers are parallel with the resistance straps. Nevertheless, the value is still consistent with standard specifications 12C.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

A Low Cost 4Mbps IrDA Receiver
Line-level preamplifier
How to design A class amplifier
Soft Circuit Singing Pig with Wigs Part 2 Circuit
The UC3825BN as DC/DC Converter Central Processor Circuit Schematic and Datasheet
digital logic purpose of diode in this 555 timer application
Schematic Diagram Of LED Sequencer Based On The 555 Timer IC
GPS-Disciplined 10 MHz Frequency Standard / GPS-Based Universal Time Clock
SemiAutonomous Submersible robot for underwater research
GBluer(Slayer) Exiter
PIC12F629 based IR decoder
Current sensing of the rails circuit diagram
Mains under voltage voltage protection circuit



Top