Adjust the DC votage to LOC111

Thread Starter

superway

Joined Oct 19, 2009
125
Hi,

I enclosed a schematic by hand drawing.
I applied 10vdc at R1 and tried to adjust R2 to bring TP1 down to 1.3Vdc to get the correct voltage, but somehow and sometimes the TP1 can not go low 1.3vdc, it always about 1.8v or 1.9v that is lowest point even I tried to adjust the R1 all the way down and noticed a small click on R2. According LOC111 specs, can be 1.2V - 1.4Vdc on LED voltage drop
http://www.clare.com/home/pdfs.nsf/www/LOC111.pdf/$file/LOC111.pdf

Is that problem related to linear optocoupler? On data sheet, it shows K3 sort Bin table with Bin A to Bin J version, and what all the numbers on second column stand for? should Bin A, Bin B, Bin C... change different reading?

Please help. Thanks
Thanks
 

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bertus

Joined Apr 5, 2008
20,528
Hello,

Did you read the application note for this chip?
I have attached it.
Take a look at page 3 for the schematic.
It looks a bit different as the schematic you posted.

Bertus
 

Attachments

Thread Starter

superway

Joined Oct 19, 2009
125
On data sheet, What does it mean below:
K3 Sorted Bins​
Bin A = 0.550-0.605
Bin B = 0.606-0.667
Bin C = 0.668-0.732
Bin D = 0.733-0.805
Bin E = 0.806-0.886
Bin F = 0.887-0.974
Bin G = 0.975-1.072
Bin H = 1.073-1.179
Bin I = 1.180-1.297​
Bin J = 1.298-1.426

Does one of it affect the voltage reading on my schemactic if we change from one to antoher one?

Thanks
 

crutschow

Joined Mar 14, 2008
24,912
K3 is the transfer gain between the input and the output (see Electrical Characteristics). It means the input current versus the output current can be different, depending upon the device you get.

And as bertus noted, use the input circuit shown in the Application Note for proper operation.
 
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