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TPS543B20: About output voltage setting

Part Number: TPS543B20
Other Parts Discussed in Thread: LM10011

Hi,

Let me talk about the TPS543B20 output voltage setting.
Customers are considering TPS543B20.
In that situation, I got the following question.

1.Can TPS543B20 changing the voltage by applying external bias?
   I would like to know both patterns using Feed buck resistors and VSEL.

2.About Remote Sensing With Feedback Resistors
   Could you tell me the calculation formula of the output voltage setting.
  
   

Best Regards,
Yusuke/Japan Disty

  • I am getting someone to look at this.
  • 1. Designer can use external supply connecting to the output resistor divider for margin up/down the output voltage. VSEL is only read at the initial start up (similar pin strapping as other devices) and set the reference voltage at RSP pin.

    2. The output resistor divider network can be calculate as normal voltage divider from output voltage to the reference voltage at VSEL set.

  • Nguyen-san,Jhon-san,

    Thank you for your support.
    Please let me reconfirm this to make sure.

    〉1. Designer can use external supply connecting to the output resistor divider for margin up/down the output voltage. VSEL is only read at the initial start up
    〉(similar pin strapping as other devices) and set the reference voltage at RSP pin.

    Is this supposed to be the case using Remote Sensing With Feedback Resistors?
    Assuming that's the case, Is my image correct?



    〉2. The output resistor divider network can be calculate as normal voltage divider from output voltage to the reference voltage at VSEL set.

    Rtop=(Vout‐VSEL) / VSEL*Rbottom
    ※VSEL: Voltage set with RVSEL
    Is my understanding correct?

    Best Regards,
    Yusuke/Japan Disty

  • Hello Yusuke-san,

    1) There are a few methods to do the margin circuit. It depends how the customer want to implement it. I lists 2 more with drawing pictures in addition to your drawing. If the pictures can not display, I will contact local FAE then he/she gets in touch with you.

    a) Simple Margin circuit:

    b) Use LM10011: It produces the current source into the FB network. Please refer the datasheet for more information.

    2) For the output voltage with no margin: the equation to calculate the resistor as---VSEL = Vout*Rbot/(Rbot+Rtop). Select a Rbot or Rtop then solve for another one.

  • Nguyen-san,

    Thank you for your kind support.
    Let me ask you one more thing.

    a) Simple Margin circuit:
    Question:
    Is it recommended to change only VSEL directly with Bias?
    If not recommended, could you tell me the reason?

    b) Use LM10011: It produces the current source into the FB network
    Question:
    When LM10011 is used,
    Is the connection destination RSN pin?
    Will you give me advice on the connection point?

    Best Regards,
    Yusuke/Japan Disty

  • Hello Yusuke-san,

    a) VSEL is used to select the reference voltage at RSP pin (with respect to RSN). The IC detects the voltage at this pin and set the reference voltage prior the start up process.  So, it is not recommend to change at VSEL pin.

    b) From the LM10011 datasheet, IDAC_OUT is connect to FB pin. RSP pin can be consider same as FB pin function when using the external resistor divider network.

    Kit

  • Kit-san,

    Thanks for your detailed explanation, which I understood.
    I will inform it to customers.

    Best Regards,
    Yusuke/Japan Disty

  • Kit-san,

    I have an additional question.
    Could you tell me the Rtop and Rbot recommended values when using Remote Sensing With Feedback Resistors?
    Customer want advice on resistor renge (10k range etc..) and accuracy.



    Best Regards,
    Yusuke/Japan Disty

  • Hello Yusuke-san,

    Using 10K range is fine. Since the accuracy of output voltage also depends on the tolerance of those resistors. Less tolerance has better accuracy. Customer can choose 0.1% tolerance or standard 1% tolerance. It is up to the customer choice.

    Kit

  • Kit-san,

    Thank you for your kind support.
    I understand your explanation.
    I will inform the customer about output setting resistor.

    Best Regards,
    Yusuke/Japan Disty