About multi-chemistry, multi-cell battery charger

Tsukui Yusuke

Guru 21930 points

Other Parts Discussed in Thread: BQ25730, BQ25723, BQ25171-Q1

Hi,

We are looking for a NiMH compatible multi-cell charger.
And I found TI's mulch chemistry charger series.
For example, BQ25730, BQ25723 etc..
Let me ask you two questions about multi chemistry charger.

１．Could you tell me the meaning of "multi-chemistry support" that TI intends?
　　I learned from the following threads that host control such as MCU is essential.
　　https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/948162/bq25790-about-nimh-battery-charging/3503433?tisearch=e2e-sitesearch&keymatch=NiMH%2525E3%252580%252580charger#3503433

　　However, no specific control method or example has been commented.
　　Does the multi-cell charger series only cover the charging voltage range and charge current?

２．Is there a case where BQ257xx was actually used for NiMH chargers?
　　If so, how was host control realized?
　　Is there sample software or code for NiMH charge control?

Best regards
Yusuke

over 3 years ago

0 Gautham over 3 years ago

TI__Genius 12485 points

Hi Yusuke-san,

What are your charging rates? If they are pretty low, we also have a device dedicated for NiMH chemistry- BQ25171-Q1. More details about the charging profile are present on the datasheet.

You would pick how many cells and the chemistry using the VSET and CHM_TMR pins.

Regards,

Gautham

0 Tsukui Yusuke over 3 years ago in reply to Gautham

Guru 21930 points

Hi Gautham-san,

Thank you for your support.

>What are your charging rates?

Charging rate is undecided.
However Input voltage is 5V and 4cell NiMH.
In that background they are looking for a boost charger or buck boost charger.

Could you give me some advice on questions 1 and 2?

Best regards
Yusuke

+1 ezhao over 3 years ago in reply to Tsukui Yusuke

TI__Genius 10240 points

Hi Yusuke-san,

The host control chargers offer the flexibility for a host to program the charging profile. The application note below is a good reference for the control flow. It was implemented with MCU ADC and GPIO control for 3S NiMH configuration. With the host communication, there are more flexibility to enable/disable charging, charging voltage and current control etc. We could not provide the sample code due to the liability reason and hope the flow chart can help you for the control method. https://www.ti.com/lit/an/slua843/slua843.pdf?ts=1644421495475&ref_url=https%253A%252F%252Fwww.google.com%252F

Best regards,

Eric

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About multi-chemistry, multi-cell battery charger