BQ24031 - TS=OFF with no-load

What do you mean by TS=OFF?  What is the voltage on the TS pin?

Hi Jeff San,

We aplogize that we diid not explain enough.
TS = off means that  TS pin is L(low level).

Kind regards

Hirotaka Matsumoto

Matsumoto-san,

With PSEL=AC and TS=GND (or TS=LDO), the IC enters an unplanned state where OUT regulation is reset to 4.4V during the transition from USB to ACIN power.  If you monitor the TMR pin voltage, you will see that it oscillates.   This implies that the internal control loops are interferring with each other.

May I ask why TS is being pulled low?

 Regards,

Jeff

Matsumoto-san,

May I also ask for your settings for PSEL, ISET2, ISET1 resistor, DPPM resistor, TMR resistor and the load conditions on OUT?  This info may be on the schematic.

Regards,

Jeff

Hi Jeff San,

Thank you for your updata!

<Setting of PSEL ISET2, ISET1 and DPPM resistor>
Please refer to following attached file;
0741.Schematic.pdf

<The reason which TS-Pin is Low>
In order to prohibit charging without timer reset, TS-Pin is Low.
According to /CE operation(to prohibit charging), timer resets.

Kind regards,

Hirotaka Matsumoto

Matsumoto San,

How will TS be pulled low in final application?  Is it possible to use the /ACPG signal to toggle TS (take TS high then return low) after AC_IN is up?  This will return VOUT to expected regulation level.

Regards,

Jeff