BQ24079: BQ24079 application for protect IC

Brian Chan

Expert 6970 points

Part Number: BQ24079
Other Parts Discussed in Thread: LM3658, BQ25170

Tool/software:

Hi Team

my customer will use below Protect IC.

FS326-DS-20_EN.pdf

However the protection IC will trigger protection when over discharge happen and it will leave the protection when the charger is higher than 2.7V~2.9V.

Can BQ24079 provide a higher voltage than 2.7V ~2.9V when the protection trigger protection? or BQ24079 direct provide Vbus when the protection happen,

below is spec:

Vin ~ 5V and 1S battery.(4.1V)

BRs

Brian

over 1 year ago

0 Garrett Kreger over 1 year ago

TI__Mastermind 32280 points

Hi Brian,

When protection IC is open due to over discharge and an input source is plugged into BQ24079 the device will run the battery detection routine (example waveform shown in figure 10-3 on datasheet page 36).

During this BQ24079 will apply precharge current at BAT pin for approx. 250ms in an attempt to close the protector. This process should result in BQ24079 providing sufficient voltage at BAT to close protection IC and allow battery to begin charging.

Best Regards,

Garrett

0 Brian Chan over 1 year ago in reply to Garrett Kreger

TI__Expert 6970 points

Hi Garrett

do you have any recommendation like LM3658? which only have BATT power rail?

customer side don't need the BQ24079 VSYS feature. because they already have another battery charger to support it.

BRs

Brian

0 Alec Lehman over 1 year ago in reply to Brian Chan

TI__Genius 9235 points

Hello Brian,

If the customer wants a non-power path charger, then I would recommend BQ25170. Are there any other features the customer wants as well?

Regards,

Alec Lehman

0 Brian Chan over 1 year ago in reply to Alec Lehman

TI__Expert 6970 points

Hi Alec

Thanks for your advise

However customer side need to match their requirement to avoid the over discharge protection.

I think V bat_short can't match this requirement.

do you have any other recommendation?

BRs

Brian

+1 Alec Lehman over 1 year ago in reply to Brian Chan

TI__Genius 9235 points

Hello Brian,

Garrett Kreger said:
During this BQ24079 will apply precharge current at BAT pin for approx. 250ms in an attempt to close the protector.

When BQ24079 applies pre-charge current to the BAT pin during its battery detection routine, the output cap on the BAT pin charges up to V_BAT(REG). For BQ24079, V_BAT(REG) is 4.1V (refer to page 6 of the datasheet). Therefore, the output cap will provide more than the 2.7V - 2.9V required to close the protector.

Best Regards,

Alec

0 Brian Chan over 1 year ago in reply to Alec Lehman

TI__Expert 6970 points

Hi Alec

Thanks for your support!

do you have any other solution which have EN pin? they need to control battery charger open/close.

BRs

Brian

0 Garrett Kreger over 1 year ago in reply to Brian Chan

TI__Mastermind 32280 points

Hi Brian,

To double check customer wants EN pin to be able to put charger in standby/suspend state with input power applied?

On BQ25170 customer can disable charge (i.e. enter suspend state) by pulling TS pin to GND. Is this acceptable?

Best Regards,

Garrett

0 Brian Chan over 1 year ago in reply to Garrett Kreger

TI__Expert 6970 points

Hi Garrett

Thanks for your reply!

it's good idea for us

BRs

Brian

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BQ24079: BQ24079 application for protect IC