Problem with IR2110 to drive an H-Bridge

Discussion in 'Embedded Systems and Microcontrollers' started by jean120, Apr 15, 2016.

  1. jean120

    Thread Starter Member

    Jan 24, 2016
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    Hello everybody,I have a problem which made me to spend two weeks trying to find the error but not find,please can you help me to handle??

    I am making an H-bridge which is controlled by the IR2110(2) but I am not getting the HO (output high) on all the driver(IR2110) but the LO are there.
    With oscilloscope in order to obtain the HO ,I have to use the second probe and connect its ground to the ground of the circuit.
    My circuit configuration is like the one of Tahmid blog on this link http://tahmidmc.blogspot.com/2013/01/using-high-low-side-driver-ir2110-with.html .
    Please help me to handle this problem.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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  3. jean120

    Thread Starter Member

    Jan 24, 2016
    75
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    Is the switching frequency causing this problem I have?I am using the PWM freq of 16KHZ.
    I am not obtaining the High side output,only the low side output is visualized on the oscilloscope for the two IR2110 I used.

    Please help.

    Thx
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    What is the measured voltage on the HO pin of the IC?
    What load do you have connected across the bridge?
    What is your Vcc voltage (if it's too low the under-voltage protection in the chip will kick in and prevent HO going high)?
     
    Last edited: Apr 16, 2016
  5. jean120

    Thread Starter Member

    Jan 24, 2016
    75
    1
    hello,no load connected yet on the H-bridge.
    On the HO,the output voltage is zero.The VCC is +12V DC and Vss is +5V dc
    Please help
     
  6. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Your problem may lie in those two quotes. For the bootstrap to work it must go to ground at some point in the cycle. With no load ,a motor or even a resistor or light bulb, there is no path to ground to charge the boot capacitor.

    Are you sure the boot circuit diode is inserted in the correct direction?
     
  7. MaxHeadRoom

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    Jul 18, 2013
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    +1 on load.
    The Vboost relies on a complete circuit to common.
    Max.
     
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  8. Alec_t

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    Why is Vss 5V? Normally, Vdd would be 5V and Vss would be 0V.
     
  9. MaxHeadRoom

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    My HIN & LIN are both opto isolated so this enables using 15v for both VCC & VDD if you wish, which is what I use generally.
    Max.
     
  10. jean120

    Thread Starter Member

    Jan 24, 2016
    75
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    Sir,You want to mean that for getting the HO,I have to connect the load?When measuring the voltage Gnd to pin 5 and Gnd to pin 6(positive side of bootstarp) I find the same voltage.
     
  11. jean120

    Thread Starter Member

    Jan 24, 2016
    75
    1
    Sir,will the connection of VCC&VDD to +15V solve the problem so that I can measure the HO and get it on the oscilloscope?
    Best Regards,
     
  12. jean120

    Thread Starter Member

    Jan 24, 2016
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    The Vcc is +12V and no load connected on the circuit.
     
  13. Alec_t

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    Sep 17, 2013
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    Which one of Tahmid's blog circuits have you built, and is it exactly as he shows?
    Make sure you have a load (e.g. a ~1k resistor) connected when you test the circuit.
    The Vs pin needs to be pulled repeatedly high and low for the bootstrap to work. Without that action HO will not pulse high.
     
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  14. MaxHeadRoom

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    Jul 18, 2013
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    I think you mean the Vsource has to be low, In my case I switch the lower fet on continuously (Lin) and use the PWM into upper input (Hin).
    This conforms to the typical Microchip CCP PWM output.
    Max.
     
  15. jean120

    Thread Starter Member

    Jan 24, 2016
    75
    1
    I add the load and test again hope I get the good output.

    Thank you!!
     
  16. jean120

    Thread Starter Member

    Jan 24, 2016
    75
    1
    Hello,as Alec_t has advised I added a load on my circuit but I get no output,still the HO is not obtained;I ma measuring with the oscilloscope and digital voltmeter.

    Please help!!

    Thx
     
  17. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Which one of Tahmid's blog circuits have you built, and is it exactly as he shows?
    Why?
     
  18. jean120

    Thread Starter Member

    Jan 24, 2016
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    Not Vss at +5V but VDD=+5V.
    Please help
     
  19. Alec_t

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    Still waiting for answers.
     
  20. MaxHeadRoom

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    Jul 18, 2013
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    Also what PWM circuit/device/method are you driving with?
    Max.
     
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