LP87702-Q1: LP87702 boost disable

Hi lanjie,

I have assigned this to the device expert. In the meantime, the LP87702's Boost converter is enabled by the control pin EN1 per the LP87702 TRM (www.ti.com/.../snvu593a.pdf). To disable it, the BOOST_EN bit can be written to '0'. To not connect the BOOST, this would have to be done before setting EN1 high, is this an option for your board?

Dear Kevin:

We want to disable in hardware mode, the software mode,thanks.

EN1 is Buck1 and Boost enable together pins. If no hareware solution,

we need to conform the input and output folat or connect to groud/ input work ability, thanks a lot.

Hi Lanjie,

LP87702 device is designed to be 2 BUCK's and BOOST converter, but BOOST can be disabled as Kevin already told by writing BOOST_EN bit = 0 via I2C and that is the suggested and proved by design way.

If you leave BOOST input floating without any external components, after startup BOOST will be disabled and give short circuit detection, interrupt flag and PG1 fault. Not affect to BUCKx

From interest, what is the application or use case for the LP87702 device?

Thanks

Tuomo

I need conform of the pins can float or pull high or low

Hi Lanjie,

Correct way to disable BOOST is thru I2C. But if you connect SW_BST pin to the GROUND, it should give short circuit detection and BOOST should disabled. This will happen if SW_BST pin is connected to ground during startup sequence and there should not be BOOST external components populated.

Tuomo

Dear Tuomo:
as you say, the boost part need full schematic component, couldn't float or connect to ground or input, thanks.
That may control schematic internal that connnect to BST, I will keep component design and disable with software mode.