• State TI Thinks Resolved
  • Locked Locked
  • Replies 9 replies
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 1835 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS563208: High current consumption even when load is turned off

Pradeep Mohan
Intellectual 725 points
Part Number: TPS563208
Other Parts Discussed in Thread: TPS563201, TPS54240, TPS563200, TPS54302, TPS564201, TPS54327, TPS54326, TPS54339, TPS54329, TPS54328, TPS54325

Hello TI,

please find attached the schematics for our 12V to 3.8V DC DC convertor to power the EC21 modem.

The DC/DC convertor consumes nearly 19mA at 12V even when the connected modem is turned off. This offsets any advantage we may have using the sleep mode of the EC21 where it consumes less than a mA at 12V.

Is this normal with this part?

Of course the current consumption is negligible when V_EN is turned off. 

For our previous series production part we used the TPS54240 and here even when V_EN is present the device consume barely any current.

How can I reduce this current consumption under no load conditions?

If this is impossible with the TPS563208, could you kindly recommend another DC/DC convertor where I'd have to make minimal changes to the design? Thank you!

  • 0
    TI__Expert 5745 points

    Even if the load is turned off, the part is still switching. So the current in mA is not an issue. But 19mA is a little big in 530KHz. You can change the new IC(TPS563208) to double check this phenomenon.

    If you want to work with uA, please disable the EN to turn off all the MOS to decrease the current.

  • 0
    TI__Expert 4875 points

    Hi Pradeep,

    TPS563208 is FPWM mode part which still get fixed switching frequency during light load. The device is not working under sleep mode. TPS54240 is a PSM mode part which will skip pulse during light load. Please try to switch to TPS563201 or TPS563200 for better light load efficiency. They are skip mode part and will consume minimum current during light load. 

  • 0 in reply to Anthony Lang
    Intellectual 725 points
    Hello Anthony,

    thanks for the quick reply. The TPS563201 looks promising and the TPS563200 even better with the advanced ECO mode. However, I'm having trouble with the availability of these components on the usual websites we purchase from. These products are active though right?

    If I'm not able to secure these components for testing, what other alternatives would you recommend? Our requirements are VIN=12V, VOUT=3.8V and IOUT=3A.

    Thanks again!
  • 0 in reply to Pradeep Mohan
    TI__Expert 4875 points

    Hi Pradeep,

    It seems that the sample room has a long lead time for TPS563201. Have you checked on store.ti.com? I found TPS563200 is available for sample request. Another devices you could try is TPS564201 which is 4A version of TPS563201. Also, TPS54302 which is eco mode and has ULQ may also be a good choice for you. I checked on ti store and found they are both available. TPS54302 is a 28Vin device so its cost will be higher and different from TPS56320x, it is a current mode device not DCAP2 device. Please let me know whether it work for you. 

  • 0 in reply to Anthony Lang
    Intellectual 725 points
    Hello Anthony,

    thank you for the suggestions!

    Could you suggest any application note explaining the differences between DCAP and current mode devices?

    Am I correct in assuming that the TPS54302 would also require more space on the PCB?

    Finally do most DC/DC convertors have a delivery time of 30 weeks? If there are convertors available with the usual 16 weeks delivery time, we might consider our design for a newer, more easily available component.

    Thanks again for your time!
  • 0 in reply to Pradeep Mohan
    TI__Expert 4875 points
    Hi Pradeep,

    TPS54302 is pin to pin with TPS56320x. The PCB layout space should be similar. Here is a link for a training video that introduces all the control mode: training.ti.com/survey-control-modes-step-down-converters-and-controllers

    For the lead time, I don't have any comments here. TPS56320x is a very popular device so the lead time could be longer than others. I would recommend you to connect with local sales team or distributors to quote and ask for the lead time. They should be more aware of what is going on for the production. Thanks!
  • 0 in reply to Anthony Lang
    Intellectual 725 points
    Hello Anthony,

    thank you again for the response. Our distributor doesn't seem to have any of the products available to sample. The lead times are all around 30 weeks!

    The TPS54302 seems to be a good choice too. The switching frequency is 400 kHz which is lower than that of the 563208 with which we have tested until now. What effect would this have? The EC21 modem datasheet mentions spikes upto 400 mV during GSM burst transmissions. Can
  • 0 in reply to Pradeep Mohan
    Intellectual 725 points

    Another query:

    Is there a 3A variant of the TPS54240DGQR? 

    The most promising alternative now seems to be the TPS564201 which has a lead time of 6~10 weeks.

  • 0 in reply to Pradeep Mohan
    TI__Expert 4875 points
    HI Pradeep,

    1. For TPS54302, it is current mode device. The load transient is not as good as TPS563208 which is DCAP2. And TPS54302 is not easy to use for Vout lower than 1.2V. It request big output cap to support low Vout.

    2. I also know some other devices for 17Vin, 3A and are DCAP2. But the cost will be higher and the package will be bigger. In return, their thermal performance will be better. The device list are: TPS54325, TPS54326, TPS54327, TPS54328, TPS54329, TPS54339.