LT1160 Not Working Accordng to Datasheet

Discussion in 'General Electronics Chat' started by ashkarmalik, Aug 28, 2016.

  1. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    I have Build a H-Bridge Using 2 LT1160 Mosfet Drivers.When I apply Signal on diagonal side of the drive then the motor (1Amp 24v) Starts to run in an start-stop Oscillating fasion.
     
  2. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    What kind of signal do you apply? You cannot keep the upper mosfet on all the time, because C1 gets discharged and you don´t have enough voltage to keep the mosfet on. You need to use PWM with less than 100% duty cycle, for example 95%.
     
  3. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    In your schematic R8,R9 and R10 are 10 Ohm.
    This will not work, the optocouplers likely will burn out.

    Bertus
     
  4. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    @bertus-R8,R9&R10 are 1k each,There was an error in the schamatic.
    @kubeek I am Applying constant 5v signal on the upper side and lower side.
     
  5. kubeek

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    Sep 20, 2005
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    As I said before, you cannot keep have the upper mosfets constantly on with this kind of driver.
     
  6. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    1)You mean ,If I am using Bootstrap Circuit to turn the upper mosfet then the Upper Mosfet would drain its stored charge with time!
    2)I'll supply the gate driver with pwm on higher side and will let you know what is happening.
    3)Are Mosfet gate driver available which can be continously kept on i.e High and Low Side ,And they uses Bootstarp circuit also?
     
  7. kubeek

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    Sep 20, 2005
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    You would either have to make a boost converter or charge pump to provide rougly 12V above the 24V rail, or use a P-channel mosfet for the upper transistors.
     
  8. crutschow

    Expert

    Mar 14, 2008
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  9. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    Thank you for clearing my doubt and pointing out the mistake,Really Appericiate you Effort,Once I would connect PWM on Upper side and run the setup then I'll Update the results.
     
  10. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    I have Applied the 50%~95% Duty Cycle to Turn on the Upper side,But the same Response is been generated from the H-Bridge.
     
  11. kubeek

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    Sep 20, 2005
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    What response exactly? Also I noticed you have R16 connected wrong, it should go to the source not to the next gate, but that should not cause too much trouble.
     
  12. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    "R16 " is an error in the Schematic,It is connected to gate and Source.
    Motor runs In jerking like fashion.i.e Speed up quickly and stops and keeps doing this repeatedly.
    But I noticed some thing more on the H-bridge,When I switches the Other half of the Bridge then Sometimes the Drivers (LT1160)heats up quickly and I stops the test.
    I have Changes the Bootstrap Cap to 0.1uF also.and tested the same result.(Just to know what is going on with the driver)
     
  13. Kjeldgaard

    Member

    Apr 7, 2016
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    Values for R7, R8, R9 and R10 does not look right?
     
  14. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    Values of R7,8,9,10 are all 10K,It is just a mistake in the schematic
     
  15. Kjeldgaard

    Member

    Apr 7, 2016
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    And if there should be "symmetry" in the schematic, then R11 may also be 10K.
     
  16. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    I have corrected the Schematic now.
     
  17. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Post details (preferably 'scope traces or simulations) of the side 1 and side 2 driving signals.
     
  18. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    Thank you for waiting ,I have captured the specific signals for proper debugging. WP_20161010_006.jpg
    This is the signal captured at the gate side of both the lower and upper side mosfet.
     
  19. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    And is the input signal different from the output?
     
  20. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
    55
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    Yes,I am giving regular 50% duty cycle input at the top gate side ,And this is the result.and the bottom side is been supplied with a constant high signal.
     
    Last edited: Oct 12, 2016
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