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BQ25723: BQ25723不能给电池包自动充电

Part Number: BQ25723
Other Parts Discussed in Thread: BQ25713, BQ25892, BQ25798, BQ25731

各位专家好:

                    我的问题是这样的,目前我们自己基于BQ25723做了一块验证版,单板验证,没有烧录任何软体的情况下:

                    发现:单插15V适配器,后端加60W负载,可以正常工作,通路是适配器到Vsys这一路;

                                单插11.1V电池包,后端加60W负载,可以正常工作,通路是BAT到Vsys这一路;

                                但是,我们把电池包放电到9.6V后,同时插上适配器和电池板,一直没有触发适配器给电池包充电功能?!

                                这是我们目前遇到的问题,就是裸机状态下(无软体),BQ25723不能自动给电池包进行充电,请问这样的现象正常吗?按我们自己的理解应该是会自动触发的,如果正常的话,针对3S电池组,

                                什么情况在才会使能适配器给电池包进行自动充电功能,需要软体的支持才行吗?

                            

  • 您好,这款芯片降压和升压之间是无缝转换。

    您的电路方便提供一下吗。

  • 您好,正在查询,稍后回复。

  • 您好,BQ25723 is designed to have AUTO_WAKUP_EN=0 by default. That means it disables auto wakeup feature. It requires the host controller to set the charge current in order to charge the battery. 

    If you requires auto wakeup feature, suggest using BQ25713.

  • 首先感谢专家的回复,解决了我目前的困扰。照目前看来,BQ25723可能不能满足我们的产品设计需求,主要因为测下来他的电源转换率达不到93%以上,发热比较严重。

    其实我们之前使用的是你们家的BQ25892充电芯片,它是一款降压带NVDC功能的单节电池充电芯片,电源输入最大3A,充电电流最大5A。

    我们的新产品需求现在是 3串电池包,并且要求支持15V/6.4A电源输入,给3串电池组充电电流可以达到8A,同样需要带NVDC电池包补偿放电功能减轻电源负载压力,最好能够支持电源给电池包自充电功能,基于这样的需求,请问BQ25892同类产品中有合适的高规充电芯片推荐吗?

  • 您好,正在查询,稍后回复。

  • 您好,请参考下面内容:

    TI does not have and likely will never have a single integrated FET charger than provide 8A and 3*4.2V = 12.6V = 100.8W.  The losses in FETs will be too high, resulting in the charger IC clamping its output due to thermal regulation. 

    The closest fit would be two BQ25798's in parallel, with only one being set to provide termination.  The BAT pins are tied together but only one SYS pin can provide the SYS because the SYS pin cannot be tied together, unless with ideal diode circuits like LM5050 ideal diode controller or similar. This solution would also require a switch to isolate each charger's I2C pins since they have the same I2C address.  Once the I2C registers are configured at power up, the charger runs standalone.

    The other. likely best, option is a charge controller plus external FETs like BQ25731 or similar.