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Could you tell me about LMZ31530's circuit configuration ?

Pokkun
Genius 4695 points
Part Number: LMZ31530
Other Parts Discussed in Thread: LMZ31520, PMP, TMS320C6678, , LM10010

Hi member.

I proposed LMZ31520/30 to the following specifications for customer.

VIN：12V
　VOUT：1.1V / IOUT_MAX：20A
　VOUT：1.0V / IOUT_MAX：20A
　VOUT：1.5V / IOUT_MAX：20A
　VOUT：1.8V / IOUT_MAX：20A

We are planning to use it for the core of DSP (TMS320C6678) and we are trying to design with reference to the following document (PMP 7256).
Http://www.tij.co.jp/jp/lit/df/snvr131/snvr131.pdf

So, I have a question.

Could you teach me about this?

＜Question＞

Since the FB pin is not set in the LMZ 31530, it is not known whether the following circuit can be constructed.

However, looking at the internal circuit, it seems that it can be realized because only the high side of the FB divider resistance is built in.

From the conclusion ....

Is it possible to realize the PMP7256 circuit with LMZ31530?

※We already propose LM10010 too.

Could you help us?

Best Regards,

Pokkun

  • 0
    TI__Mastermind 28020 points

    It is not recommended to add the external feedback and compensation components to the VADJ pin of the LMZ31530.

    If output voltage adjustment is required, reference the app-note below (SNVA709).

  • 0 in reply to J Arrigo
    Genius 4695 points
    Hi, Arrigo-san.

    Thank you very much for the answer.

    I compared the SNVA709 with PMP7256.
    Is this thing correct with the following idea?
    ・The principle that the output voltage is changed by the current injected to the FB pin using the D-A Converter is the same.
    ・Since LMZ315x0 is a product that does not require loop compensation, compensation circuits mustn't connect.

    (When the answer is YES ...)
    By understanding this principle and referring to the data of SNVA 709,
    Is it possible to propose LMZ315x0 as a power supply for DLP using LM10010?

    Best regards,
    Pokkun
  • 0 in reply to J Arrigo
    Genius 4695 points
    For this thing, I reproposed it again with LMZ31530 and LM10010 with reference to SNVA709.
    So, would you tell me the confirmation point of the above post?
  • 0 in reply to Pokkun
    TI__Mastermind 28020 points
    Yes, injecting current into the FB pin will change the output voltage. It is not recommended to apply external compensation components to this device.
  • 0 in reply to J Arrigo
    Genius 4695 points
    Thank you very much for your help, Arrigo-san.

    I'm advancing it with this proposal (LMZ31530 and LM10010 with reference to SNVA709).

    Please help me again if there is any doubt.

    Best regards,
    Pokkun