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UCC28051: error amplifier output voltage

Shinichi Inoue
Guru 19671 points
Part Number: UCC28051

Dear Specialists,

My customer is evaluating UCC28051 and has a question.

I would be grateful if you could advise.

---

We're in a final test before mass production and there is a output voltage drop in some board. 

Could you please advise following questions.

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(1) Tolerance of maximum output voltage of error amplifier

⇒ Is it "V comp high: 4.5V --5.5V" described in the data sheet P5 VCOMP high in VOLTAGE AMPLIFIER (VO_SNS) ?

(2) Related to Question(1),

When the error amplifier is saturated, the output will be the maximum COMP IN value of 3.8V, or will be the maximum output voltage of the error amplifier of 4.5V?

Which value should be used for 3.8V or 4.5V in the equation at datasheet of 7.3.6 Multiplier Block.

0.67 × VMULTIN × (VCOMP − 2.5 V)

(3) How much does the Multiplier gain constant (k) change with temperature?


Are 0.43Vmin and 0.87Vmax included temperature fluctuations?

---

I appreciate your great help in advance.

Best regards,

Shinichi

  • 0
    TI__Guru 65965 points

    Hello,

    1. Vo_sns is set to 2.1 for the test condition to see how high VCOMP will go.

    2. When the amplifier is saturated VCOMP will be 4.5V or greater.

    3. According to the data sheet the specification range for the multiplier is 0.43 to 0.87 over temperature.

    4. Yes

    Regards,

  • 0 in reply to Mike O'
    Guru 19671 points

    Hi Mike,

    Thank you for your reply.

    I'll share these information with the customer.

    I appreciate your great help and cooperation.

    If the customer has an additional question, I consult you again.

    Best regards,

    Shinichi