BQ24072: Problem battery not charge BQ24072

Daniele Cortellazzi

Part Number: BQ24072

Hello,

i have the BQ24072 on my system, my schematics is

and i have problem with some device when they are in charge. On some device happen that after some hour in charge i have the pin CHG high (that indicate battery charged) but when i disconnect the usb and measure the battery this is not at 4.2V but in this last test was at 3.60V.

Before the test i have check that the pin PGOOD was VSS (that indicate a power supply).

Can you help me?

Thanks

over 7 years ago

0 Daniele Cortellazzi over 7 years ago

Prodigy 110 points

PS: my battery is a 1000mAh li-po 3.7V

0 Rafael Herrera Mangones over 7 years ago

Prodigy 70 points

you must use the BQ24072RGTR Marked as CKP.
The bq24072TRGTR Marked as PAP, presents the problems that you mention.

0 Daniele Cortellazzi72 over 7 years ago in reply to Rafael Herrera Mangones

Prodigy 20 points

Hello, and sorry for the delay in the reply. Yes we know the difference and this is not the case.
Others tips?

Thanks

0 Daniele Cortellazzi over 7 years ago in reply to Daniele Cortellazzi72

Prodigy 110 points

UP... we need help

0 Daniele Cortellazzi over 7 years ago in reply to Daniele Cortellazzi

Prodigy 110 points

No support from texas?!

We tried to find the problem measuring the current. The battery begin to be charged with 500mA when you connect the usb, after 2 hour we reach the battery charge. If i power up the device (that consume 120mA ) i see that the device recieve 20mA from the usb so the other current will be bring by the battery. After 30min the current from the usb increase because the Vbat will drop the limit for re-begin the charge. After one night with the usb connected the battery was 3V only and from the CHARGE pin i read a frequency of 2HZ, so the chip indicate an error.

Why this happen?! The mosfet shoudn't power the device using the usb without discarghe the battery?!?!

Thanks

0 Bill Johns over 7 years ago in reply to Daniele Cortellazzi

TI__Guru* 75916 points

The CHARGE pin freq of 2Hz is probably charge timer fault (Dynamic Charge Timer section 9.3.5.6) the unit did not complete charge in 6.5 hours.
A way to check this is to connect the TMR pin 14 to ground, this will disable the timer.

A couple of other things to try:
1.) Does the input voltage stay at 5V or does it possibly drop triggering power limiting?
2.) Using an external power supply does the charging current and system current look correct?

0 Daniele Cortellazzi72 over 7 years ago in reply to Bill Johns

Prodigy 20 points

Hello,

we will do other test using a power supply with data logger so to check the current during the time.
I will post the result as soon as possible

Thanks

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BQ24072: Problem battery not charge BQ24072