BQ24038: BQ24038RHLT

user1649982

Prodigy 100 points

Part Number: BQ24038
Other Parts Discussed in Thread: BQ24083

We are using BQ24038 as a lithium-ion battery charger

Part No : BQ24038RHLT

Marking : BOW

Package : QFN

batch No : TI 65KF9E3

Lithium-ion Battery Rating : 20Ah, Battery max charging voltage 4.2Vdc

Pin configuration

VBSEL=5V;

ISET1 = 5V;

USB = SET1 = 0V;

charging time set at 10hrs

OUTPUT1 pin 2 battery charging indication pull up of 47K at 4.2vdc

OUTPUT2 pin 3 battery full charging indication pull up of 47K at 4.2vdc

Problem:

when we connect discharged battery to charger then it charges battery properly with OUTPUT1 low (STAT1=0) indication and OUTPUT12 high (STAT2=1)but when it reached to battery full charging threshold that is 4.2V then instead of OUTPUT2 low (STAT2=0)indication it give OUTPUT1 as well as OUTPUT2 indication ,

if STAT2=0 then STAT1=1

if STAT2=1 then STAT1=0

oscillating with frequency of approx 17Hz

This condition is similar to no battery connected to Pin_6 and pin_7 of BQ24038.

In this condition, the battery voltage remains at 4.12V to 4.15V.

This problem is observed in ICs which carry batch no TI 65KF9E3 only.

When we replace same IC with another one with Ic batch No : TI 25JP6LL, it is giving proper indication for charging and full charge indication. Also the battery is getting full charge voltage within expected time.

Note -- Updated Sept 20, Removed bq24083 reference after input from customer.

over 6 years ago

0 Bill Johns over 6 years ago

TI__Guru 69916 points

Is this problem related to the bq24083 (CFZ) or only the bq24038 (BOW). The two parts are very different.

0 user1649982 over 6 years ago in reply to Bill Johns

Prodigy 100 points

Hi Bill,

Thanks for your reply.

sorry for typographical error .

This Problem is related to bq24038(BOW).

Thanks,

Vinayak

0 Bill Johns over 6 years ago in reply to user1649982

TI__Guru 69916 points

Thanks for the reply I have updated the original post. We will look into this and advise the best way to proceed.

0 user1649982 over 6 years ago in reply to user1649982

Prodigy 100 points

Hi Bill,

waiting for your reply.

Thanks,

Vinayak Waingankar.

0 Bill Johns over 6 years ago in reply to user1649982

TI__Guru 69916 points

Sorry for the delay.

I am trying to duplicate the problem in the lab, will configure and EVM to simulate this. Can you provide a schematic?
Is the battery description correct 20Ah?

0 user1649982 over 6 years ago in reply to Bill Johns

Prodigy 100 points

Thanks for the reply.

Our R&D server is not directly connected to internet & also I have to take permission of senior to copy the schematic. It will take while. I will be in touch with you shortly.

Mean while there is one observation. When the indicators are dancing between “FULL CHARGE” & “CHARGING” and then if you remove the battery and reconnect again then it shows “FULL CHARGE” indication. Also we purchased new lot of 25 pieces. Out of them only two had this problem. Lastly what I observed is the non working ICs in currently used PCB are working fine in old PCB with exactly same schematic. Do you suspect layout issue?

Battery rating is 20Ah

Thank you

Vinayak

0 Bill Johns over 6 years ago in reply to user1649982

TI__Guru 69916 points

Can you describe how the device is configured, resistor used or pins pulled high or low?
What charging current are seeing with the unit?

0 user1649982 over 6 years ago in reply to Bill Johns

Prodigy 100 points

Hi Bill,

Device configuration as below,

Pin No	Pin Name	Configuration
19	VBSEL	pull low .
9	CE	High On POWER ON
4	Vin(VCC)=5V	Charging input from AC ADAPTER
5,6	BAT	Battery ip/op
13	DPPM	33K to GND
10	ISET1	pull low
7	ISET2	680Ohm to VCC
15,16,17	OUT	Power out to System
8	PSEL	Pull High
2	STAT1	Pull High
3	STAT2	Pull High
14	TMR	68K to GND
12	TS	10K to GND
20	USB	Pull LOW

Battery charging current : 1A

Thanks,

Vinayak

0 Bill Johns over 6 years ago in reply to user1649982

TI__Guru 69916 points

Double check the connection of Pin10 (ISET1) this should be a resistor value of around 1k ohms for 1A battery charge current

0 user1649982 over 6 years ago in reply to Bill Johns

Prodigy 100 points

Hi Bill,

Yes , there is 1K at pin 10(ISET1) .

it is not directly shorted to GND.

Thanks,

Vinayak

0 user1649982 over 6 years ago in reply to user1649982

Prodigy 100 points

Hi Mr. Bill,

I am waiting for your reply.

Thanks,

Vinayak Waingankar.

0 Bill Johns over 6 years ago in reply to user1649982

TI__Guru 69916 points

Hi Mr Vinayak Waingankar

I am trying to understand the design and need your assistance.
With ISET1 at 1k ohms to ground the charge current is 1A.
With TMR at 68k ohms to ground the safety timer is set to 6.8 hours.
But battery is a 20Ah battery and the design can only provide 6.8Ah of the 20Ah required to charge the battery before the safety timer fault stops charging.
The design should not work with this large a battery pack. Is there some points on this design that you have not mentioned?

0 user1649982 over 6 years ago in reply to user1649982

Prodigy 100 points

Hi Bill,

This is reply on your last main on oc08,2018

it is correct .
but we dont't understand why itis is showing both indication(charging and full chage) simultaneously

Thanks,
Vinayak Waingankar

Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

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BQ24038: BQ24038RHLT