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BQ25792: Stop 2s BAT to over discharge @6V

Part Number: BQ25792

Hi Team,

 

Customer want to realize when VBAT drops to 6V

  • BAT stop discharge when BAT only
  • Or BAT can left Supplement mode and stop discharge even when VBus power < SYS power.

 

But the problem is they don’t have a Ship FET on board, any SW way to realize it?

 

I noticed in default charging current setting,  VBAT_LOWV can be set to 71.4% * VREG = 0.714 * 8.4V = 6V and this can stop BAT to over discharge. And I think maybe this is a way to solve it.

 

But the real test, the voltage will still drops to around 5.6V and the IPRECHG is around 10+ mA only while setting to 40mA. Do you have any comments here?

Looking forward to your comments. Thank you!

Marc

  • Hi Marc,

    Unfortunately, there is no way to prevent battery discharge without the shipFET on the BQ2579x family.  Changing VBAT_LOWV only affects the transition point from pre-charge to fast charge.

    Regards,

    Jeff