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UC2825: Max Duty Cycle

Idan Simhi
Prodigy 10 points
Part Number: UC2825

From the datasheets it can be seen that the maximum duty cycle for this part is 80%

I work in voltage mode, open loop  and cant achieve more than 50% D.C. 

Does the controller really have the ability to work at 80%?

please your advise 

  • 0
    TI__Mastermind 27885 points

    Idan,

    How are you determining the max duty cycle to be less than 50% - are you looking at OUTA or OUTB only? of, OUTA is limited to ~40% and OUTB is also limited to ~40% but when you consider the total duty cycle of both outputs you get 80% max. Duty cycle definition for a dual output PWM is defined this way.

    Regards,

    Steve

  • 0 in reply to Steven Mappus1
    Prodigy 10 points

    Thank you for your answer.

    Each output of the controller is connected to a power MOSFET through a driver.

    I'm looking for a controller that can supply 80% or above thus creating an overlap between the outputs

    Can you recommend TI part that can be suitable?

    Regard,

    Idan

  • 0 in reply to Idan Simhi
    TI__Mastermind 27885 points

    Idan,

    Your application sounds unique in that it is not regulating output voltage of a switching power converter. I don't know of an analog PWM operating the way you describe. I found some examples of similar E2E threads asking about overlapping PWM signals. In almost all cases the control for this is coming from a microcontroller (MSP430). You might try submitting a new E2E thread targeting the microcontroller team support by mentioning MSP430?

    Regards,

    Steve