BQ24450 With LED Indicator

Bornfree

Other Parts Discussed in Thread: BQ24450

Hi There,

I have designed a charger using BQ24450 but i also want to know the charge status via a LED. I have connected a LED on pin 9 (stat2).

The problem is the LED sometimes works perfectly and sometimes not at all. It is ok if i can only show the status when it's boost charging but nice if i could also show float mode as well.

Why does the LED work only sometimes?

How can i show boost mode and Float mode?

Thanks

over 14 years ago

0 Jeff F over 14 years ago

TI__Guru**** 167196 points

I am not certain why your circuit doesn't work. I have attached a circuit with two separate LEDs and a FET. The LED on the left inidates Boost mode while the LED on the right indicates Bulk or Float mode. To distinguish between Bulk and Float, you would need a buffer or logic gate.

4251.STAT2circuit.pdf

0 Bornfree over 14 years ago in reply to Jeff F

Prodigy 240 points

Hi Jeff,

Is it ok to use Pin 1 (ISNS) with a LED to show the status of I boost and I float ? On page 9 of the datasheet i can see that this can only be indicated by STAT1 and ISNS.

0 Jeff F over 14 years ago in reply to Bornfree

TI__Guru**** 167196 points

Although I have not tested it, I believe this will work. ISNS is open collector output. It is tied to BSTOP which is a high impedance input with its pull up. So, if you sense with another high impedance circuit that doesn't add significant loading to the pull up, that should be okay.

0 Bornfree over 14 years ago in reply to Jeff F

Prodigy 240 points

Hi Jeff,

Thank you very much for you assistance.

0 Dilbagh Singh over 11 years ago in reply to Bornfree

Intellectual 330 points

Hi,

Kindly help with this problem, in dire need.

http://e2e.ti.com/support/power_management/battery_management/f/179/t/292941.aspx

Regards

Dilbagh

Power management

Power management forum

BQ24450 With LED Indicator