bq24170 charging issue

Jake Jung

Expert 1915 points

Other Parts Discussed in Thread: BQ24170

Hi Tiers.

We are using bq24170 in our device and using 4.2V 1cell Li-Ion battery.

At Normal contion, bq24170 operation is good working.

But only below charging issue occured. Please let me know what is debugging point.

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[ Condition ]

-. Battery voltage = about 2.9V

-. Battery's dischrging cutoff voltage spec is 2.9V

1. Case 1 : Charging NG

-. 2.9V Battery is already inside our device

-. When DC 5V is suppied to bq24170, charging is NG. VBAT voltage is measured 4.2V.

2. Case 2 : Charging OK

-. DC 5V is already supplied to bq24170.

-. When 2.9V battery is inserted in the device, charging is OK, VBAT voltage is measured about 3.0V.

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[ Question ]

I think this issue is battery deteciton is failed.

Why Case1 issue is occured? and What is debigging Point?

over 9 years ago

0 Smriti B over 9 years ago

TI__Expert 5565 points

Are you using the same battery pack for case 1 and case 2?

0 Jake Jung over 9 years ago in reply to Smriti B

Expert 1915 points

Yes. Same Battery Pack.
In Case1, If use 2.4V Cutoff Voltage battery, charging is OK.
I think this issue is related battery's cutoff voltage (2.9V) or PCM circuit.
Why this simptom is occured?

0 Smriti B over 9 years ago in reply to Jake Jung

TI__Expert 5565 points

In case 1, if the SRN pin measured 4.2V and there is no charging, that means the IC did not detect a battery. This could be because the battery protection circuitry in the pack is keeping the battery disconnected due to low voltage, which is why the bq24170 cannot detect the battery. Since the 2.4V cutoff battery is working, that helps support the battery protection circuit theory.

0 Jake Jung over 9 years ago in reply to Smriti B

Expert 1915 points

Thank you.
In case 1, SRN pin measured 4.2V. I think this is bq24170 did not detect battery too.
But in case 2, the IC did detect the battery and charging OK. Why this symptom is occured?

0 Smriti B over 9 years ago in reply to Jake Jung

TI__Expert 5565 points

I am not sure as to why that would be happening. Are you taking the battery pack from your test setup in case 2 and plugging it into the charger in the test condition for case 1?

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bq24170 charging issue