ADN8834

Question

My Application circuit like this 
 
 I tested the voltage of IN1N,OUT1,and use the pin TMPGD drives a LED, 
 
 V(IN1N)= V(1N1P),V(OUT1)= V(IN2P),As 
 
 I changed the valtage of TempSet V(IN2P),Vout1 changed,according to the fomula,Rth changed, 
 but V(1N1N) still equals to Vref/2,As the voltage divider, 
 V(IN1N) =Vref* (Rth+Rx)/(R+Rth+Rx) 
 V(IN1N) not changed,Rth Neither. 
 So it is contradict.I can not understand. 
 Besides,when I tested the voltage of IN1N,the LED always twinkle. 
 Thanks for your explaination.

ntenorio · Accepted Answer

Hi bai1390529449 ,

Hope you are doing great. 
 Based on what I can see, you are trying to check the chopper amplifiers functionality first. What I can suggest here is try to test the stage one by one and see if it is working. Example, try to test the chopper amplifier 1 first before connecting it to chopper amplifier 2. That way, it would be easier for you to identify if the stages are working. 
 However, on your circuit, what value of RFB did you use? can you share to me your actual schematic so I can check? 
 
 Regards.)