• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 49 subscribers
  • Views 886 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.

Low power\Sleep mode - Current measurment

mayer
Prodigy 95 points

Hello All,

What is the best way to measure very very low current 500nA to 100mA

Sleep mode of MCU - or testing How the current reduced with PLL divider of the main oscillator

Please suggest TI IC and circuit (Schematic)   - Analog out put solution

I saw ACS712 that can be an option but it's too mess to measure current

Thanks in advance,

Mayer

  • 0
    TI__Genius 14825 points

    Mayer,

    Thank you for your inquiry.  Our selection of current shunt monitors have specially designed input structures to measure large currents and have input bias currents and offsets that will overpower your 500nA measurement.  Your application appears to be one that needs wide dynamic range (500nA to 100mA with decent accuracy) and may best be accomplished with something like a low input bias current PGA that is adjustable to best measure your currents.

    If you could provide us a bit more information about your application like the desired resolution, we would be able to assist you further.  I'm also going to push your question over to Precision Amplifiers Forum to get you the additional support for this application.

    Jason Bridgmon

  • 0
    TI__Mastermind 25865 points

    Hello Mayer,

    For such a large range of input current I recommend evaluating a PGA.  Please take a look at the following TI Precision Design:

    http://www.ti.com/tool/tipd135

    This design describes a 10uA-100mA current sensing solution (high side), but after reading the guide I believe you should be able to modify the design to obtain the desired range.  

  • 0 in reply to Jason Bridgmon
    Prodigy 50 points

    Hi Jason,

    Thanks for your answer

    As I wrote - my application is a portable device that controlled by MCU.

    Obviously we want that the app will work as much as possible - Longer time.

    All the system will be in sleep mode including the MCU to get lowest current as possible

    and based on RTC or external interrupt  we will wake up the system and handle the Event

    My battery is 3.7V 1200mAh

    and the range is about 500nA to 10mA - for the sleep mode measurements

    (I wrote the 100mA range because the working current measurement - can be done with a regular Fluke)

    I want to measure the current in sleep mode - as far I knew it's close to range of ~500nA to ~100uA (for msp430 Series)

    If I could to get indication that I am blow 10uA in sleep it's also enough for my application (Due to overpower of 500nA )

    Is there TI's  Ref design for current measure in range of  ~500nA to ~100uA ?

    Is there TI's  App note for MCU sleep mode handle - sleep mode Strategy ?

    Thanks for your help,

    Mayer

  • 0 in reply to Meir Yeru
    TI__Mastermind 25865 points

    Hello Mayer,

    Concerning your question about additional current sensing reference designs, TIPD104 is a simulation-based reference design for low-side sensing from 10uA to 10mA. Both documents go through the design process step-by-step, so you should be able to use them as guides to implement your solution.

    I am unaware of what you mean by "MCU sleep mode handle". Perhaps that question is better suited for the MSP430 microcontroller support forum.