• State TI Thinks Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 2 answers
  • Subscribers 63 subscribers
  • Views 438 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

TPS63002: Circuit configuration for starting up with an input voltage of 3.6V

TPS63002: Power-On Current Consumption at VINA Pin

Y.Ottey
Mastermind 6145 points
Part Number: TPS63002
Other Parts Discussed in Thread: TPS63802

Dear all,

I would like to ask about Power-On Current Consumption at VINA Pin.

In the data sheet, there is the following quiescent current (Iq), but there is no description of the current consumption when the IC is started.

Please tell me the VINA current consumption when the IC is starting up.

(especially load (Iout) is 500mA).

Best Regards,

Y.Ottey

  • 0
    TI__Mastermind 21565 points

    Hi Y.Ottey:

    The VINA is mainly for inner circuit, and consumes a little current during the normal operation with 500mA load.

    May I know why you care about that value?

  • 0 in reply to Minqiu Xie
    Mastermind 6145 points

    Hi Miniqiu

    My customer is trying to output Vout = 5V / Iout = 500mA at Vin = 4 ~ 5.5V with this device.
    In addition, they are trying to enable the IC at Vin = 3.6 V at startup by placing a voltage divider resistor as in the following circuit

    (Because the threshold of UVLO of VINA is max1.8V)

    * Connect a 0.1μF capacitor before VINA.

    When the following circuit starts up, VINA current consumption causes a voltage drop in the voltage divider resistor, which causes the voltage on the VINA pin to drop, and there is concern that UVLO will be applied after startup.
    Also, customers have asked us how much the voltage divider resistor is recommended.
    I would like to tell you about the current consumption of VINA.
    If there is a recommended value of the voltage divider, please let me know.

    Best Regards,

    Y.Ottey

  • 0 in reply to Y.Ottey
    TI__Mastermind 21565 points

    Hi Y.Ottey:

    I got your point. 

    I don't have exact value of the VINA current. And our team for this is all on vocation for Christmas. 

    May I know what's the precision of the threshold the customer wanted? We have TPS63802, and it's much suitable with high accuracy for the threshold of enable . 

  • 0 in reply to Minqiu Xie
    TI__Expert 7925 points

    Hi Y.Ottey,

    The correct way to do what you want is like this:


    R3/C4 make a filter for VINA, and R3 should not be larger than 100 Ω. You should set the input voltage threshold with a separate voltage divider R4/R5.

    However, as discussed in your previous thread, EN threshold of the TPS6300x is not precise and cannot be used for defining a precise Vin level to turn the device on. The threshold is not 1.2 V, but anywhere between 0.4 V and 1.2 V.

    Please use an additional voltage supervisor circuit, or another device with a precise EN threshold, such as TPS63802.

    Best regards,
    Milos

  • 0 in reply to Milos
    Mastermind 6145 points

    Dear Moniq, Milos,

    Thank you for your reply.

    For example, if the device is activated in the following circuit, it is considered that the voltage drop at R3 causes a difference between the voltage at the VIN pin and the voltage at the VINA pin.

    If there is a voltage difference between the VIN pin and the VINA pin, is there any abnormality in operation?

    Also, is there a tolerance for the voltage difference between the VIN pin and the VINA pin?

    Best Regards,

    Y.Ottey

  • 0 in reply to Y.Ottey
    TI__Expert 7925 points

    Hi Y.Ottey,

    We did not characterize the device for voltage difference between VIN and VINA. VINA is the supply for the internal control circuit, and must be at the same voltage as VIN. 

    Best regards,
    Milos