• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 79 subscribers
  • Views 1314 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.

msp430l092 comparator

tillmann scheibe
Prodigy 25 points
Other Parts Discussed in Thread: MSP430L092, BQ25504

hello,

i'm new to microcontrollers and have a question dealing with the integrated comparator of the msp430l092.

i want to build a dcdc-converter which together with the msp430 should perform maximum power point tracking of solar cells.

for that a hysteresis control should trigger the mosfets dependently to the converters input voltage.  as the msp430 has an integrated comparator it would be nice using it instead of external schmitt-trigger for this purpose. that for the comparator should constantly compare the external voltage with an internal reference (changing due to hysteresis) from an dac an give the comparators output to an external pin. the output signal has to be be in a range of frequencies from 20kHz to 100kHz. i was wondering if this is to fast for the  comparator cause all applications i have read about use the comparator only for slow detection of treshholds.

i hope someone can help me with that.

greeting and thank you

tillmann

  • 0
    Prodigy 40 points

    hey, 

    Did your problem get resolved. Cuz even I am kind of facing the same problem. I am trying to change the MPPT of LTC3105 using MSP430 5438 but cant really figure out the code to do this. I read up on ADC but still, using the ADC to change the MPPT,cant really figure that out. Code,idea anything to give me a start would be really helpful. 

    Thank you,

    Hemant. 

  • 0 in reply to Hemant
    Prodigy 25 points

    hey hernant,

    yes in the end i used the internal comparator. my MPPT works kind of this way:

    i sample the open circuit voltage of the solar cells and calculate a mpp reference voltage. (umpp=0.8*uoc)

    now this reference voltage an the voltage of solar cells are inputs for the integrated comparator.

    comparators output trigger the mosfet of a buck converter. 

    i didn't use hysteresis cause propagation delay of the comparator an switching time of mosfet create a natural hysteresis. 

    first i was thinking of using ltc3105 too, but finally i decided against cause i couldn't find a way to manipulate mpp voltage from external mcu.

    the ltc3105 has just a 10uA current source which serve for programming a mpp-voltage with a resistor. 

    if your decision isn't made yet i would recomend  TI's bq25504. it is basically the same functions but you can program mpp voltage with external mcu.

    efficiency is also much better...

    if you need further help feel free to contact me. i could also send you my code an even the documentation (german) if required.

    good look.

    tillmann 

     

**Attention** This is a public forum