• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 502 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

TLV757P: Interface forum

BADAL KUMAR6
Prodigy 130 points
Part Number: TLV757P

Hello,

one of my customer is  using LDC TLV75733 to supply wifi-module which require  600mA and 3.3 v input but LDO current capacity is only 500mA. so they want to supply this additional 100 mA from capacitor which i shown in below block diagram.

so my question is for meeting above current demand what should be the capacitor value?.it is given wifi-module will  be off when voltage dip to 2.8V

  thank you,

badal

  • 0
    TI__Guru 55940 points
    Hi Badal,

    My understanding of your application is that your Wifi-module requires 600 mA only during short periods of time. While your theory of using a capacitor to supply the Wifi-module during the peak current makes sense, please note that the TLV757P family is rated for up to 1 A continuous current. Do you mean that the first block labeled DC-DC convereter can only source 500 mA?

    In order to size the output capacitor you would need to determine the length of time that the Wifi-module requires 600 mA and the amount of voltage deviation your application can tolerate (the output voltage will reduce as the capacitor is discharged). With this information we can use Ohm's Law for a capacitor to calculate the capacitance required:

    i = C x (dv / dt)

    It is important to keep in mind that the above equation will help calculate the ideal capacitance rather than the capacitor value that your application will require. To learn more about capacitor vs capacitance, please see Chapter 2 of our LDO Basics E-book:

    www.ti.com/.../slyy151.pdf

    Very Respectfully,
    Ryan