BQ24640： BQ24640:Problems with ultracapacitors charging below VFB voltage

6034867

Part Number: BQ24640

When the voltage of the ultracapacitor is less than 2.1V, the output current is only 25mA. Is there any solution to make the capacitor charge according to the set current even when the voltage is less than 2.1V

over 3 years ago

0 Kedar Manishankar over 3 years ago

TI__Mastermind 24075 points

Hi,

BQ24640 charges according to CC-CV charge profile without precharge current. If sensed battery voltage is < 2.1V then there should be no issue as is it can charge at fast charge from 0V battery.

0 6034867 over 3 years ago in reply to Kedar Manishankar

Prodigy 20 points

Thanks for your reply, but the current will be very small at the beginning of charging the capacitor from 0V. Is it because of the short circuit protection

0 ezhao over 3 years ago in reply to 6034867

TI__Genius 10240 points

Hi there,

Please refer to the Figure 14 on the datasheet. It could be due to the soft start.

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BQ24640： BQ24640:Problems with ultracapacitors charging below VFB voltage