BQ25792: If we use BQ25792 as a standalone charger, will the 5V input be sufficient to operate for the PMIC?

sAHEB Mandal

Part Number: BQ25792
Other Parts Discussed in Thread: BQ25886

Hi There,

We are checking on possibilities to configure BQ25792 as a standalone charger for autonomous charging with the host controlling the charger IC. As I got from the datasheet, the default charging current is set by resistor at PROG pin. We want to set it at 8.2Kohm. Also it shoes in datasheet that VSYSMIN will be automatically set for 7V. My doubt is that, If I have a 5V USB Input running the system, will this setting work and charge the battery at a rate of 2A? Please suggest your expertise on this.

Regards,

Saheb

over 2 years ago

0 Jeff F over 2 years ago

TI__Guru**** 165856 points

Hi Sahed,

With 5V input and 3.3A max input current, there is 16.5W of input power. For a 8.4V battery charging at 2A, the charger needs 16.8W of output so no, the charger will not charge at 2A.

Regards,

Jeff

0 sAHEB Mandal over 2 years ago in reply to Jeff F

Prodigy 20 points

Hi Jeff, Thanks for your reply. It will be fine for us if the charging current will be less than 2A. We can go as low as 1A also. I was having a doubt regarding the VSYSMIN which is mentioned as 7V for 2S configuration. In 2S configuration with default PROG resistor and Input Voltage of 5V, will the charging process work?

0 Jeff F over 2 years ago in reply to sAHEB Mandal

TI__Guru**** 165856 points

Yes, BQ25792 is a buck-boost charger. It will boost when SYS and BAT are less than VBUS.

Regards,

Jeff

0 sAHEB Mandal over 2 years ago in reply to Jeff F

Prodigy 20 points

Oh ok great. One doubt, we are going to use BQ25792 as a standalone charger, not using any HOST communication. So, in that scenario also these things work I hope but the charge current will be less than 2A.

0 Jeff F over 2 years ago in reply to sAHEB Mandal

TI__Guru**** 165856 points

Hi Saheb,

The charger will function and operating in input current limit, with the charge current reduced. You might also consider BQ25886. It is intended to be a standalone charger for up to 2S battery.

Regards,

Jeff

Power management

Power management forum

BQ25792: If we use BQ25792 as a standalone charger, will the 5V input be sufficient to operate for the PMIC?