BQ40Z80: Integration with USB C PD for full USB 5-20V compatibility.

Chris Hamilton

Part Number: BQ40Z80
Other Parts Discussed in Thread: BQ25708, BQ40Z60, BQ25713, BQ25710

Hi, I would like to build a 1-4 cell USB programmable charger based on the BQ40Z80 and a Cypress based programmable PD chip. I have an early version utilizing the BQ40Z60 and requiring a 20V VBUS, but I would like it to be compatible with all possible USB voltages. Are there any recommended USB C aware buck-boost designs? I am thinking of utilizing the BQ25708/10/13 series, but I believe that would likely involve some redundant charge logic and FETs.

Thanks for any advice!

over 5 years ago

0 Yipeng Su over 5 years ago

TI__Prodigy 420 points

Hi Chris,

BQ25708/710/713 are all our buck-boost charger, which can meet your requirements to support all the PD input voltages (5V, 9V, 15V and 20V) charging 1s~4s battery. The difference is BQ25708 (SMBus) only has the forward charging without OTG feature. And BQ25710 (SMBus) and BQ25713 (I2C) support bi-directional, forward charging and reverse OTG operation.

0 Chris Hamilton over 5 years ago in reply to Yipeng Su

Intellectual 270 points

Thanks for the explanation. I'll definitely be utilizing SMBUS and will be monitoring and configuring through it, I have been studying how best to integrate the BQ40Z80 with the BQ25708. I am hoping to minimize the circuit size to keep it on board. I'll probably not need the predischarge nor the fuse circuit on the BQ40Z80.

The precharge circuits for both seem complimentary, but would the BQ25708 precharge work without the BQ40Z80 FET setup?

Thanks again!

0 Yipeng Su over 5 years ago in reply to Chris Hamilton

TI__Prodigy 420 points

Hi Chris,

BQ25708 is the NVDC architecture with system power path and charging power path management, it has its own BATFET driver. In the pre-charge stage, BQ25708 regulates the pre-charging current though the BATFET in LDO mode, the system voltage is regulated at VSYS_MIN regardless of the battery voltage.

So it does not rely on the gauge FET for the pre-charging.

Thanks.

0 Chris Hamilton over 5 years ago in reply to Yipeng Su

Intellectual 270 points

OK, great thanks!

Power management

Power management forum

BQ40Z80: Integration with USB C PD for full USB 5-20V compatibility.