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UC3825A: Average Current Mode control ICs that have 2 Error Amplifiers

Jonathan Navor
Genius 9475 points
Part Number: UC3825A
Other Parts Discussed in Thread: UC1823A, , TL494, UCC28070

Hi Experts,

Good day! As per customer request, I am posting this query to help them find the right device for them.Here is the full details of inquiry below.

If you need more information please let us know.

I am looking for Average Current Mode control ICs that have 2 Error Amplifiers inside in order to implement an external voltage loop as well.

The ICs I found for "current mode control" e.g. UC3825A, UC1823A etc, have 1 Error Amplifier. Is there any IC that have 2 Erorr Amplifiers ?

Thank you in advance. 

Best regards,

Jonathan

  • 0
    TI__Expert 7900 points

    Hi Jonathan,

    To answer customer question - the TL494 has two error amplifiers.

    I don't understand exactly why they need two error amplifiers?  Every current mode controller has an error amplifier to control the output voltage which feeds a PWM comparator to control the peak current (basically two loops).

    Regards,

    Eric

  • 0 in reply to Eric Reicher
    TI__Genius 9475 points

    Hi Eric,

    Thank you. Here is the customer's feedback.

    Every Peak Current mode control IC has 1 Error Amplifier and 1 PWM

    comparator to control the peak current, but we want to control the
    average current, which is made with an additional Error Amplifier, apart
    from the comparator, same way is done in PFC (e.g. UCC28070).

    I was wondering why there are no ICs to control the average current and
    voltage having already built in 2 Error Amps + 1 Comparator. TI
    portfolio is wide in Peak Current Control (1 EA + 1 Comparator).

    Maybe I did not find them or just use 1 EA + 1 Comparator like UC3825A,
    UC1823A etc and then add additional error amp externally?

    Best regards,

    Jonathan

  • +1 in reply to Jonathan Navor
    TI__Expert 7900 points

    Hi Jonathan,

    Adding an external error amp is a good option.

    Peak current mode control has the benefit of limiting the peak current to prevent damage.

    Regards,

    Eric