BQ24616: BQ24616 not Charging the battery

Hello,

Please describe your setup more.

First, I am correcting the calculated values.

1. VISET1 = 808 mV, so ICHG = 4.04 A.

2. VISET2 = 596 mV  so IPRECHG = 596 mA. If your battery is discharged such that the FB pin is below VLOWV (1.55 V) you battery will be in precharge.

3. VACSET = 300 mV so IDPM = 1.5 A.

If PG is on, that means power is good.

Please confirm if the schematic is updated. Your TS voltage from the schematic would be 3.23 V which would put the part into a TS charge suspension. If TS if 57% of VREF, then the output charge voltage will be limited. Please bias the TS pin correctly.

Thanks,

Mike Emanuel

Please click "Resolved" if this answered your question.

Hi Mike Emanuel,

Thank you for correcting me on the calculation, i have measured the voltage on pin of ISET1, 2 and ACSET and did the calculation. ISET2 calculation, you're right, it is 596mA.

The resistor divider connected in TS pin was updated with new value(R13 - 13.7K, R14 - 10.2K) which yields 1.892 volts which is 57.3% of  VREF.

I have connected the battery(6S1P Li-Ion) on J1 and ensure the voltage on VFB is 2.065(using 10K variable resistor) before connecting the RPS, the input supply to this circuit. I did set the voltage of RPS to 22.5V, 24V, 26V.

What is the status now?

Thanks,

Mike Emanuel

Not charging the battery, not sure what is missing still.

Hello,

What is your exact input voltage exactly? Please make sure it is 1.5-2V above your battery regulation.

Can you please explain how you are calculating/setting the battery regulation voltage?

Thanks,

Mike Emanuel

Hi,

The input voltage is 24V. battery pack voltage is 22.2 when each cell voltage is ~3.7V. Full charge voltage of cell is 4.2V.

Hello,

If you have 22.2 V with 3.7 V/cell, you will already be pushing it trying to charge the batteries at that voltage. 6 cells at 4.2 V is 25.2 V, which is above the input voltage. This charger is a buck converter and we recommend the input voltage to be at least 1.5 V to 2 V above the full battery voltage.

Thanks,

Mike Emanuel

Please click "Resolved" if this answered your question.

Hi,

I changed the input voltage to 27V and checked, there was no current drawn from power supply to charge the battery. the battery voltage is 23.7v. when i checked the Gate signal of Q10 there was no pulse and then i checked at pin 19(LODRV), i can see pulse so the issue is with resistor R67, i replaced it with 0 ohm and connected the PS and Battery pack again. Now the Gate is triggered properly but the PG keeps toggling.

When i tried to check the Gate signal Q7 with oscilloscope probe it blown the charger IC BQ24616.

May i know what is causing the issue. another similar post in the forum but was answered in private.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/996303/bq24616-blowing-for-unknown-reason

The schematic is same as in the EVM but not working. I checked other post related to this part, seems like the device failed to operate with 6S configuration. Could you please check the schematic again and suggest if any additional protection necessary?

Hello,

I am not aware of the value of R12, in relation to the FB pin, but it looks like the upper resistor for the FB pin is 909 kOhm and the lower resistor is 100 kOhm. This means the battery regulation is (909/100+1)*2.1 or 21.189 V. You will not charge the 23.7V battery if your battery is already above the 21.2 V regulation voltage when you insert it.

Thanks,

Mike Emanuel

Please click "Resolved" if this answers your question.

Hi,

We updated the feedback network resistor in the board  and make sure the charger get 2.1V when 6s battery pack is full 25.2V. I have already mentioned this in one of my previous message. Could you please help us to overcome the actual issue? i couldn't relate your last reply with the chip failure issue we faced. I will update the schematic with values of parts what we have used in the board and share,  then it will be easier for your understanding.

Hi Mike,

the schematic is updated with part values as in the board. please refer this one.

BATT_CHARGER.pdf

Please report your current problem. Are you able to charge the battery to regulation, or are you concerned about the ESD event, or both?

If the first, please start the battery with lower voltage, say 10 V, and observe the charge cycle. See if the battery charges to regulation and if not 25.2 V what does it charge to?

If the second, please observe if you shorted any pins when making the probe you made. The probe tip could have shorted something.

What did you change on the input to make the PG pin toggle? Is your input stable?

Can you please show waveforms of the input voltage, PH voltage, output voltage, and output current with and without a battery? How can you regulate the output voltage without a battery, but not with a battery? Is your battery configured to charge?

Thanks,

Mike Emanuel

You're welcome!