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TPS61026: Pre-charge current

Y.Ottey
Mastermind 6145 points
Part Number: TPS61026
Other Parts Discussed in Thread: TPS61020

Dear TI Team,

I would like to ask about pre-charge current of TPS61020.

By the way, the data sheet describes the pre-charge current as follows.

1. When starting operation under the condition of Vin=6.4V, Vout=3.3V, is it OK to recognize that the above state of Pre-Charge current will be maintained until Vout rises to 3.3V?

2. Our customer is using TPS61020EVM.
When Vout-GND is short-circuited under the condition of Vin=6.4V, Vout=3.3V, both input current and output current were clamped to 180mA.
(At this time, Vin drops to 5V)
We think this is the effect of pre-charge current.
However, when Vin=5V, the data sheet Figure.12 shows that the value of 0.2-0.25A is the pre-charge current.
Is it possible to think that the value of 0.18A clamped above is the Pre-Charge current when Vin=5V?

3. Is the output current always clamped at the value of Pre-charge current when started in a short-circuited state?
(Or may a current higher than the pre-charge current flow for a moment at startup?)
Is the above the same even when the output capacitor is changed from a tantalum capacitor to a ceramic capacitor (a resistor is connected in series)?

  • 0
    TI__Mastermind 46905 points

    Hi Y.Ottey,

    1. yes. i think so.

    2. there would be variation on this current limit value, so i would suggest no loading during startup process

    3. yes. your are correct.

    could we suggest a buck-boost converter this application. although this device supports down mode, it is not designed for application with such high voltage gap between VIN and VOUT.