Help with Begginer Circuit

Discussion in 'The Projects Forum' started by John Brkic, Nov 24, 2014.

  1. John Brkic

    Thread Starter New Member

    Nov 20, 2014
    5
    0
    Hi,

    I have created a dc-dc booster using the AS1326 which has been designed specifically for this purpose. The problem is that I want to put 4 of these circuits into one PCB and I need the output to be unified. For example:I will have 4 dual inputs (+, -). The input for one single IC (AS1326) will vary from 0.7 to 5V and the outpt will be a fixed 3.3V. The problem is that I dont know how to connect the 4 outputs and add their voltaged together into one output. Is conecting the ICs together an option? Should I use a component that will unify all the 4 outputs and add them together to fom an output of 13.2V? I know that connection in series will give me added voltages and connection in parallel will gve me added current. But is there a way to add any additional components to get the most out of both? Thanks in advance and apologies if my question is a too begginer one. Pleasee see icon and datasheet attached.

    PS The circuit I did (on Eagle) is exactly the same a shown on figure 19, at page 11 of the datasheet.

    Regards
    John
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,137
    1,786
    It seems unlikely that your scheme will work as drawn. It would require each device to have the inputs isolated from the outputs AND for the outputs to be floating with respect to GND.

    You will be better off designing a boost converter with 0.7V-5V input and 13.2V output. To do this you will need to be VERY careful with the HIGH currents required to go from 0.7V to 13.2V if any appreciable load current is required. For 13.2V @ 500 mA you will need almost 12 Apperes from the 0.7 volt supply.
     
    Last edited: Nov 24, 2014
  3. DickCappels

    Moderator

    Aug 21, 2008
    2,648
    632
    I think the application note from Texas Instruments (first published by Unitrode before T.I. boght them) at the link below will tell you everything you need to know about load sharing among power converters, including the advice to not do it unless for some reason you can't do it with a single converter, as per Papabravo's advice.

    www.ti.com/lit/ml/slup094/slup094.pdf
     
    Last edited: Nov 25, 2014
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