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DCPA10505D: Line Regulation

Kenji Ohno1
Genius 5095 points
Part Number: DCPA10505D
Other Parts Discussed in Thread: DCPA10505, DCR010505

Hi Team,

I would like to see my view of power reduction in the actual case.

I'm not asking for a guaranteed value so you can rest assured.

What I would like to know is the assumed worst case value.

I would like to know the voltage at which the output power is 5V no matter how much the input voltage is below 5V.

The conditions are as follows.

　Load 35%

　Temperature condition -15 ℃ ~ 85 ℃

I think that it will be a graph like the one attached, but even if the input drops to 4.9V in this case,

5V can be maintained even in the worst case.

Best Regards,

Kenji

  • 0
    TI__Guru 50120 points

    Hi Kenji-san,

    You can see the line regulation for a 5V output voltage on Figure 16 of the datasheet. At full 100% loading the output voltage of 5V can be maintained given an input voltage of roughly ~4.97. At 10% loading the output voltage of 5V is maintained given an input of roughly 4.75V. Since you are going to load at around 35%, I think the 5V output voltage will still be maintained even if your input voltage drops to 4.9V. 

    Regards,

    Jimmy

  • 0 in reply to Jimmy Hua
    Genius 5095 points

    Hi Jimmy-san,

    Thank you for your reply.

    5.0V output with 4.9V input within the specified temperature range and even with variations.

    Is it okay to understand that 5.0V output may not be possible with 4.8V input?

    Best Regards,

    Kenji

  • 0 in reply to Kenji Ohno1
    Genius 5095 points

    Hi,

    Please tell me one more thing.
    For example, if the input is 4.65V, I would like to know the worst case of the output voltage under the conditions of Tc=-15°C to +85°C and Load = 35%.
    Best Regards,
    Kenji
  • 0 in reply to Kenji Ohno1
    TI__Guru 50120 points

    Hi Kenji-san,

    Below are my comments on your questions:

    1. The Figure 16 you see in the datasheet is tested at ambient temperature of 25C(room). The operating temperature for this device is spec between -40C and 100C. However like you mentioned, there might be some variations at different temperature that could shift the lowest possible input voltage for a given desired output voltage regulation.
    2. Let me check with my colleague to see if he can test your use case condition since I don't have the EVM with me. I'll ask him to test for the lowest possible input voltage given a stable output voltage of 5V for both -15C and 85C @ 35% loading condition. When I get more information on this I'll get back to you.

    Regards,

    Jimmy

  • 0 in reply to Jimmy Hua
    TI__Guru 50120 points

    Hi Kenji-san,

    I was able to get some test results for your specific application. Attached below is the voltage dropout. The DCPA10505 is unregulated. 

    Note that is this only typical data and only has been tested on one device. 

    If you are interested in a regulated output voltage it may be more beneficial if you are using the DCR010505 since this part has a regulated output. You may want to check out the EVM and test for you use case application. 

    Regards,

    Jimmy 

  • 0 in reply to Jimmy Hua
    Genius 5095 points

    Hi Jimmy-san,

    Thank you for the survey.

    Can I understand that Load = 35% is the same for +35mA and -35mA cases?

    Best Regards,

    Kenji

  • 0 in reply to Kenji Ohno1
    TI__Guru 50120 points

    Hi Kenji-san,

    I would expect the graph for -35mA will be the same as the +35mA expect inverted. 

    Regards,

    Jimmy