IR2110 half bridge help needed.

Discussion in 'General Electronics Chat' started by Salvador1, Nov 30, 2015.

  1. Salvador1

    Thread Starter New Member

    Jan 9, 2015
    Hi, folks
    So I have two identical half bridge smps , each uses two mosfets and one IR2110 which drives the mosftets, both IR2110 are powered from a single small transformer and rectifier/voltage regulator.
    both IR2110 are driven from an SG3525AN oscillator.
    Now heres the funny thing , when I made the first half bridge and put in the first IR2110 to drive the two mosfets of that half bridge it worked fine, now I installed the other two mosfets in the other half bridge which has a separate transformer , I inserted the second IR2110 which is also driven from the same SG3525 from which the first one gets its signal, but now when I attempt to drive both only one of them works , the other one doesnt work at all.
    in other words the second half bridge i finished later works but the first one doesnt , and quite frankly because the first IR2110 is not driving the mosftets but its not dead or anything when i change the two IR2110 places they both work but only one at a time.
    why is that ?

    I have attached the schematic for my smps , the schematic shows only one full half bridge but my layout for each half bridge is exactly like in the schematic only that both IR2110 are driven from a single power supply and from the same SG3525 chip.
  2. ronv

    AAC Fanatic!

    Nov 12, 2008
    It should work. After all it is just another 2 inputs be driven. The second one won't be regulated of course.
  3. Salvador1

    Thread Starter New Member

    Jan 9, 2015
    Ok , heres a question , i checked everything twice and to be honest the driving cirucit is not that complicated since most of it is inside the IC's there is nothing wrong but everytime i try to run them together they just dont , one IR2110 works fine while the other one doesnt work, when i measure the output from the IR2110 to the mosfet gates it's the output of one of the IR2110 high side gate drive that is very low , about 0.17 volts while all the other ones are at about 6.5, this is done when the mosfets have no voltage across their D-S.

    but then I thought maybe , i could either run 4 mosfets , two in pairs parallel from one IR2110, or maybe as I have done in the attached schematic , since i have two separate transformers just get some really high current mosfets and use two to drive both transformers , what do you guys think ?