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Original question:

TPS61220: TPS61220

TPS61220: Did TPS61220 support 1.2V output

Lumina Gui
Genius 3610 points
Part Number: TPS61220
Other Parts Discussed in Thread: TPSM82822, TPS82085, TPS61094, TPSM82823, TLV627432

Hi Sir,

In our new project, there is a requirement for DC to DC. The input voltage is required to be 0.9V~2.7V, and the output voltage need to be 1.2V or 1.5V fixed output, but if the feedback resistance is adjustable (we tend to adjust it to 1.2V) ).

We learned that the minimum output voltage of the TPS61220 is 1.8V, but the feedback voltage is 0.5V. And we want to use the 1Mohm and 1.4Mohm resistors to divide the voltage to achieve a 1.2V output. Can u help to confirm whether this is feasible? The calculated value is OK, but does not meet the minimum output of the chip.

Thanks,

Kind Regards

  • 0
    TI__Genius 9046 points

    Hi Lumina,

    Thanks for reaching to us. Please based on electrical characteristics to use this device. With low output voltage there might be some internal block mal-functioned. Boost converter is not like to buck converter, which typically as minimum Vout as same as reference voltage. As some of internal block is supplied by Vout and Vin is only used for start-up, so Vout has typically higher minimum Vout than reference.

    What is your output load requirement? TPS61011 may be a good choice, but i need to know if you have more specific requirement like device package, output current.

    -Wenhao

  • 0 in reply to Wenhao Wu
    Genius 3610 points

    Hi Wenhao,

    The end equipment is cap pencil and the load current is no more than 300mA. We fristly thinking about the buck converter, but found no buck products with 1.2V output on TI's official website. Can u give us some better suggestion?

    Thanks,

    Best Regards

  • 0 in reply to Lumina Gui
    TI__Genius 9046 points

    Hi Lumina,

    I think may be you have improper search setting. There are a lot of buck devices supporting down to even 0.6V output, like TPS82085, TPSM82822/3, etc, but which needs higher input voltage than 0.9V to 2.7V so you may need a boost converter to boost up bus voltage for down streaming loads. This is the first thing that strikes me.

    However, considering you are design cap pencil which may need lower solution size. (I would appreciate you can share some image link of the product or similar, just curious. ) I need to check if there is any single stage solution which could support your application so that you can save your size at maximum.

    I will feedback to you before tomorrow. Thanks!

    -Wenhao

  • 0 in reply to Wenhao Wu
    Genius 3610 points

    Hi Wenhao,

    Our cap pencil is similar with Apple pencil and the width of PCBA is about 4*4mm, so there are certain requirements for the package size of DC to DC.

    I have checked the datasheet of TPS82085 and TPSM82822/3 on TI website, but the height is not suitable.

    Thanks,

    Kind Regards

  • 0 in reply to Lumina Gui
    TI__Genius 9046 points

    Hi Lumina,

    What is the input power of the cap pencil? Supercapacitor? Or battery or from an adapter?

    -Wenhao

  • 0 in reply to Wenhao Wu
    Genius 3610 points

    Hi Wenhao,

    The input power of the cap pencil is supercapacitor, and the voltage range from 0.9V to 2.7V.

    Thanks,

    Kind Regards

  • 0 in reply to Lumina Gui
    TI__Genius 9046 points

    Hi Lumina,

    Got it. I checked internally and there is no Boost or Buck-boost converter available at such a low voltage operation. I would recommend TPS61094+Buck converter/module or LDO.

    Do you have specific requirement on height? Since you have said TPSM82823 does not meet your requirement. I can help check if any Buck converter can meet your requirements.

    -Wenhao

  • 0 in reply to Wenhao Wu
    TI__Genius 9046 points

    Hi Lumina,

    Per we talked, I would recommend customer a boost converter solution + a buck converter solution

    TPS610992+TLV627432 remains the smallest and the lowest input solution which can help you in their device. We will try to touch with your customer for further information. Thanks!

    -Wenhao

  • 0 in reply to Wenhao Wu
    Genius 3610 points

    Hi Wenhao,

    Thanks a lot. I will pass on your suggestion to our customer.

    Best Regards