BQ24172: Power Consumption

Akilarasan R

Part Number: BQ24172

Hi,

In our design, BQ24172 will be used to charge a battery with ISET = 2A and VBATT= 4.2V. Adaptor input voltage will be 12V and load will take around 1A. Please tell me with this configuration, how current will BQ24172 take to charge the battery and what will be the total current driven from adapter.

7 months ago

0 Jeff F 7 months ago

TI__Guru*** 146745 points

Hi Akilarasan,

Using a power balance, eff=VBAT*(CHG/(VIN*IIN) and estimating from the datasheet efficiency curve at 15V below. Since 12V is closer to 8.4V than 15V, efficiency will be slightly better so let's estimate 93%.

0.93=8.4V*2A/(12V*IIN) or IIN = 1.51A.

Regards,

Jeff

0 Akilarasan R 7 months ago in reply to Jeff F

Prodigy 210 points

Hi Jeff,

Let me clarify. You are saying battery charger will take 1.51A just to charge the battery and my load will take 1A. So, total 2.51A will be drawn from the adaptor?

+1 Jeff F 7 months ago in reply to Akilarasan R

TI__Guru*** 146745 points

Hi Aklirasan,

The BQ24172 is traditional powerpath so the system is intended to be connected directly to the 12V rail so yes, you will need 1.51A+1A from the 12V rail.

Regards,

Jeff

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BQ24172: Power Consumption