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    Full bridge DCDC converter

    hi,
    i need to verify by some one, the Duty cycle variation from 1% to 45% .
    it should be time shifted two PWM pulses is required.

    Click image for larger version. 

Name:	PWM pulses for DCDC full bridge converter.jpg 
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    Re: Full bridge DCDC converter

    An alternative switching pattern uses two 180 degree duty cycle signals and phase shift to control the output duty cycle.



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    Re: Full bridge DCDC converter

    you are trying to tell that phase shift full bridge configuration.

    Quote Originally Posted by FvM View Post
    An alternative switching pattern uses two 180 degree duty cycle signals and phase shift to control the output duty cycle.
    i am asking to verify for Hard switched full bridge configuration



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    Re: Full bridge DCDC converter

    your first post seems correct - what is the question?



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    Re: Full bridge DCDC converter

    hi,
    this question arises for half bridge IC PWM pulses.
    For Hard switching Full bridge converter, is this type of Time shifted PWM pulses is enough to generate the controlled output voltage?

    (or)

    Full complementary pulses is required to generate for Half bridge driver IC?
    (like, in leading leg, exact complementary pulses is required for top and bottom switches is required? )

    Assume i applying 20% duty cycle, (using Full complementary PWM pulses) at S1(top switch 20%) and S2 (bottom switch 80%) will this type of pulses will generate regulated output voltage?



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    Re: Full bridge DCDC converter

    yes - the feedback loop reduces the pwm to stop the Vo going too high - and increases it when load is applied...



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    Re: Full bridge DCDC converter

    Quote Originally Posted by senthilp_1 View Post
    Full complementary pulses is required to generate for Half bridge driver IC?
    (like, in leading leg, exact complementary pulses is required for top and bottom switches is required? )
    When an inductor is in the path, then it should not have abrupt current shutoff. Usually the full H-bridge is switched so it grounds the inductor at one end, while the opposite end gets the rapid PWM. This continues for 1/2 cycle, then it turns the situation around for the last half of the cycle.



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    Re: Full bridge DCDC converter

    i need to verify by some one, the Duty cycle variation from 1% to 45% .
    Yes it looks fine.
    Think of the full bridge as just being two "interleave switched" two transistor forward converters.
    (Each 2TF converter having just less than 50% max duty cycle).
    So yes you comply with that with your waveforms.

    - - - Updated - - -

    If in doubt, you can always do a checking sim in the free ltspice.....one of your scenario is attached here.



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