TL103WB: delay function

The opamps have a typical input bias current of 15 nA. When flowing through 180 kΩ, this indeed results in a voltage drop of 2.7 mV.

What is the purpose of U5? This appears to be a const-voltage/constant-current circuit similar to that shown in the datasheet, but then you would not need a second reference.

What function do you want to delay? It appears to be related to the current limit, but do you want to raise or lower the limit during power up?

Hi Rock,

Please tell us more about the circuit as Clemens points out. I do not even see TL103WB op amp in the schematic. UM601 is voltage and current controller (UTC product?).

Best,

Raymond

The UM603A is a clone of the TL103WA.

Hi Raymond,

The customer used our TL103WB as the second source, but after this issue is fixed, it will be the first source, so please help to check. Thanks.

The UM603A has a worse input bias current (20 nA), so these two devices will not behave in exactly the same way.

Hi Rock, 

Could you replace UM603A with TL103WA op amp and provide us the feedback first?

In addition, I need to know how long is your delay requirements. There are many techniques to increase the power on delay in a circuit, such as soft start, RC timing delay, current limiting delay etc.. 

We do not support our competitors' product generally. I did not know that TL103WA has a clone until Clemens pointed out. The original schematic part notation is fuzzy. 

Best,

Raymond