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UCD90160: Power Cycle Issue

Part Number: UCD90160


Hi,

 

I have a question regarding UCD90160 controller. I have used this controller in a power supply for monitoring voltages and currents, and to turn on/off voltage rails. The circuit normally works fine but sometimes the controller itself does not turn on when a power cycle is provided. It happens randomly, for instance, out of 15 or 20 tries the controller does not respond for only one time or maybe even after 30 tries this incident happens. The problem is ambiguous and difficult to diagnose unless the fault behavior is consistent.

Anyhow, I tested the power supply in temperature chamber to check whether it is a heating issue or not and found out that the controller is not starting up upon giving a power cycle at 70 degrees, instead it is randomly turning on and off even without providing power cycle. The device temperature at that time was 81 degrees and the ambient temperature was about 71 degrees. The device operating temperature range in datasheet is -40 to 110 degrees. Please find the attached schematics for your information.

Should I use heat sink on IC to solve this problem? Or to use power-on reset IC on reset pin? Or is there any suggestions by anyone in regards to solving this issue. Your cooperation will be appreciated. Thanks in advance.

7875.UCD90160.pdf

 

  • Hello

    Have you checked the our schematics guideline, especially section 2.2

    The TRST pin must have 10-kohms pull down but in your case the pin is floating.

    V33A need 0.1uf and 4.7uf in parallel.

    RESET pin must have a 10-kohm pull up  and 1-nF decoupling capacitor.

    Please make sure all these.

    Regards

    yihe

  • Hello

    We haven't heard back from you and assumed that the issue has been solved. Please reply if further help is needed.

    Regards

    Yihe

  • Thank you for your response.

    I could not get back to you as i was busy in testing. I have made those changes and haven't encountered that problem yet but I am still observing it because the issue was not consistent so I want to make sure that it has been resolved or otherwise. I will reconfirm the status after further three days of testing.