BQ25070: Vin-DPM for solar application

Dave Willetts

Part Number: BQ25070
Other Parts Discussed in Thread: BQ25071, BQ24210

The datasheet for the BQ25070 briefly mentions Vin-DPM which I believe would make it suitable as a solar charger for LiFePO4 single cells.

Can you confirm the suitability of the BQ25070 for a solar charging application?
There is no mention of the Vin-DPM voltage, can you please confirm what it is pre-set to?
The pulse control Table 1 doesn't specify how to control Vin-DPM and whether it is enabled by defualt. Can you please confirm?
Does the BQ25071 also have the Vin-DPM feature (it is not mentioned in the datasheet but [this](https://e2e.ti.com/support/power-management/f/196/p/743001/2744499#2744499?jktype=e2e) states the only difference is the CTRL/EN pin7)?

Thank you for your time.

over 3 years ago

0 Dave Willetts over 3 years ago

Prodigy 40 points

Additionally, is there a TI product that is similar to the BQ2407x family with Vin-DPM and DPPM that is suitable for LiFePO4 chemistry?

0 Nick Brylski over 3 years ago in reply to Dave Willetts

TI__Mastermind 19195 points

Hi Dave,

1. We do not recommend this part for solar as no MPPT

2/3. Going to have to look into this

4. BQ25071 does not have a Vin-DPM feature

5. Currently no LiFePO4 part with both Vin-DPM and DPPM

Best,

0 Dave Willetts over 3 years ago in reply to Nick Brylski

Prodigy 40 points

Hi Nick,

Thanks for looking into this for me. I am aware that it is not MPPT however it seems from my research that for low power solar charging applications, where the solar panel MPP is close to battery voltage, the linear charger I/Cs perform equally well if not better.

The BQ24210 seems a good option for LiPo, or the BQ2407x, both of which feature Vin-DPM (BQ2407x with DPPM pass-through as a bonus). Similarly, I'm hoping the BQ25070 with Vin-DPM will be equally up to the task for solar charging LiFePO4.

Thanks again,

Dave

0 Nick Brylski over 3 years ago in reply to Dave Willetts

TI__Mastermind 19195 points

Hi Dave,

The VIN-DPM function is not enabled by default or possibly may not be available on the BQ25070. There is no option to enable/disable vin-dpm on the evm, current will be reduced at the dropout voltage.

Best,

0 Dave Willetts over 3 years ago in reply to Nick Brylski

Prodigy 40 points

Ok, that doesn't sound very promising. I'll keep looking. Thanks for your time!

Regards,

Dave

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BQ25070: Vin-DPM for solar application