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BQ2002 charging at C/10 and C/5

Other Parts Discussed in Thread: LM317, BQ2002

Hi Folks,

I am working on a emergency LED based charger design. Since the design is based in India and targeted for Indian customers the input is 220V to 230V AC 50Hz, My design is divided into two stages.

Stage1:

Converting 230VAC to 5.0VDC without transformer, which is working fine and I have tested it.

Stage2:

Using this 5.0VDC to charge a NiMH battery of 4.8V 80mAh. Now here is the point where I need some suggestion. I looked at various internet sites and suggestion is go with C or 2C or C/2 charging. I understand with the TM pin of BQ2002 and LM317 I get the charging of C or C/2 or 2C by pulling it up or down or VCC/2.

But I request you please suggest which is the best charging methodology to be followed for charging 4.8V 80mAh NiMH. Some links suggest the charging of 0.1C or 0.5C to increase the battery life and it may take 10-14 hours to charge the battery.

Is it possible to use BQ2002 to set 0.1C or 0.5C charging? If not, what are the suggested TI alternates which support 0.1C or 0.5C charging for NiMH battery.

Any suggested in highly appreciated. Thanks in advance.

Regards

-Anand