TPS55288: TPS55288 schematic review

Hello
one more point We are not using the I2C interface; instead, we are using a feedback resistor to achieve the desired 3.7V output.

Regards
hasham

Hi Hasham,

Thanks for reaching out.

What do you mean you don't use I2C interface? The SCL and SDA pins are floating? If so, the buck-boost device will not be enabled.

If I2C interface is used and external output voltage feedback is selected at VOUT_FS register, the output voltage is right to be 920mV as the default FB voltage is 282mV. 282mV/Rfbb*(Rfbb+Rfbt)=920mV. You need to change the VREF at REF register to get the correct output voltage value.

BRs,

Bryce

Hi Hasham,

By the way, for this kind of power level, TPS55289 which is full integrated Buck-boost converter without external MOSFETs is more suitable here.

And recommend to select 4.7uH inductor for fsw=400kHz. The COMP parameters need to be adjusted according to the effective capacitance and ESR of output capacitors.

BRs,

Bryce

Dear Bryce,
Thank you for your response.
Yes, we did not use the I2c and the pins are floating.
without using I2C how can we get the 3.7V output with the FB/INT feedback resistors values?
if i add the pullup resistors on the i2c pins, will the module work?

Regards
hasham

Hi Hasham,

Without I2C, there will be no switching, and the buck-boost can't be enabled. If I2C is not required, you can use TPS552882 which is non-I2C version to get the output voltage.

If I2C version TPS55288 is still needed, you will need MCU to communicate with TPS55288 via I2C.

BRs,

Bryce