ADP5090

I am working with ADP5090 -2-EVALZ to generate voltage using Teg(SP1848) as a input source. The issue i am facing is with Cold start voltage i.e 380 mV ,the output only generates if my TEG provides input voltage greater than 380 mV.i used external battery to bypass this as you mentioned in data sheet.i connected 400mV dc supply to Back_up battery terminal acting as battery.but still no output was coming to my Vout(sys pin).My super cap voltage was 1.48v at that time.Why the output is not coming at my Vout ?.like it gives when input voltage reaches above 380 mV. The super cap i am using is 5v/2.5f.

  • You need a high back_up battery voltage to bypass the cold start. so you can try to increase the voltage.

    Btw, ADP5091 is more suitable for supercap storage as charging efficiency is much better than ADP5090.

  • How much high you are referring to ? and if it works well.then in my Practical application i will be requiring a backup power source (which is not a good thing to me if i wanna power a RF sensor). Is there any module which do not have Cold Start. as issue i am facing is that my Teg will be generating around 270-320 mV in practical environment .due to this Cold start condition until and unless the input reaches to 380 mV no Vout will be there.How to Tackle this SItuation ?, is there any other way?

  • LTC3108 can support this kind of low voltage  level TEG.

  • That i will look thank you for info.But in the  ADP5090 datasheet you have mentioned following :

    With the internal cold-start circuit, the regulator
    can start operating at an input voltage as low as 380 mV. After
    cold startup, the regulator is functional at an input voltage range
    of 80 mV to 3.3 V.

    so that means once input voltage to harvester reaches 380 mV the Vout will start coming up,also means if after sometime my input voltage goes below upto 80 mV the Vout should still be coming.But when i did the same experiment the Vout starts going down. i kept my Vinput after some time  at 92mV and vout starts decreasing from 400 mv to 15mv and from there dec furthur at a very slow rate. why it is happening ? as according to statement once it completes the cold start staze even if i dec the input the Vout should be increasing .

  • That depends on the input power and output power. Only if the input power is greater than output, the output can be charged up.