TPS62110: TPS62110

Hello Bill,

You can find in this Application Note more information regarding how to choose an appropriate Pull-up resistor for PG: www.ti.com/.../slva485.pdf

Thank you very much for reaching out to us!

Best Regards,

Dorian

Hello Bill,

I haven’t heard back from you.
Do you have any follow up questions?
Otherwise I will assume you were able to resolve your issue. If not, just post a reply below .

Thank you,

Dorian

Hello Dorian,

Thank you very much for suggesting the appnote. It helps me to calculate the range of the pullup resister range. I just would like to confirm my calculation with you.

Based on Eq 2 in the appnote (slva485),
Rpullup max = (Vout - VIH)/Ipullup = (3.3 - 1.3)Volt/(10+0.07)uA=198kohm, where Vout = 3.3V, VIH = 1.3V (TPS62110 data sheet), Ipullup = IEN + ILKG (Eq 1), and IEN = 10uA, ILKG = 0.07uA (data sheet)

Based on Eq 4 in the appnote,
Rpullup min = Vout/I pullup, whete I pullup = IOL - IEN = 1 mA = 10uA (data sheet) = 3.33kohm

Therefore the pullup resister value should be between 3.33kohm and 198 kohm.

Discussion: According to the appnote, if 2.2kohm is used as Rpullup value, it causes a higher current than the test condition current to flow in Q1. If a current higher than the test condition current flows through Q1, the voltage drop across Q1 is higher and no longer ensured.

Question: Could you elaberate this "no longer ensured"?

Hello Bill,

In the Datasheet you can find

A typical value is given for PG voltage. If your the pull-up resistor is inferior to R=3.3k ohm then this trip voltage can no longer be ensured.

Thank you very much!

Best Regards,

Dorian