BQ24092 charger IC getting heated .

rimpul chawada

Other Parts Discussed in Thread: BQ24092

Dear All,

I am using BQ24092 charger IC to charge my battery (Li-ion,3.7v,1800mAh). When i switch on the 5v to charge the battery, Charger IC is getting heated up like anything.

I have used thermal pad beneath the IC in my PCB board to protect from the heat but i am not successfull .It takes nearly 6hrs to charge from 0v to 3.8v, but as per the datasheet it should be less than 3hrs. Please help in this situation,

Details of the charger IC and circuit are as follows:

O/p voltage and current from charger IC is: 4.04v and 800mA

ISET resister used is: 680ohm.

preterm resistor used: 2K ohm

TS resistor used: 10K

Regards,

Rimpul

over 11 years ago

Charles Mauney over 11 years ago

TI__Mastermind 31120 points

Does your layout look like the EVM? The PCB should be 0.031" thick and use 2 oz copper (0.0028") and have multiple vias. The copper area extending from the IC should be at least 1 to 2 sq inches.

ANIS BEN SLIMANE1 over 9 years ago in reply to Charles Mauney

Prodigy 50 points

Hi Charles,

Please I need your help. I'm using the BQ24092 on my bluetooth PC ECG for charging an 1400mAh Li-ION battery. my broblem is the programmed charge current is 800mA (R ISET=680). when I measure the voltage on the Iset pin the value is 200mA. But, when I look at the FUNCTIONAL BLOCK DIAGRAM on the datasheet (page 9) the right value must be equal to 1.5V. What is wrong?

Please see the attached schematic file

Thank in advance

Wenjia Liu over 9 years ago in reply to ANIS BEN SLIMANE1

TI__Expert 7730 points

What is your battery voltage at that point? The ISET voltage is only regulated to 1.5V in constant current mode. If the battery voltage is close to regulation and charge current already starts tapering down, ISET voltage will be reduced too. The charging will terminate once VISET drops to the voltage at PRETERM pin.

Thanks,

Wenjia

ANIS BEN SLIMANE1 over 9 years ago in reply to Wenjia Liu

Prodigy 50 points

Hi,

Thank you for the response.

The battery voltage is about 3.8v

Thanks

Wenjia Liu over 9 years ago in reply to ANIS BEN SLIMANE1

TI__Expert 7730 points

Can you measure the voltage at the OUT pin instead of at the positive terminal of the battery? Sometimes the voltage drop over the trace will cause the VOUT much higher than the battery voltage.

Thanks,

Wenjia

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BQ24092 charger IC getting heated .