TPS61060: Startup with resistive load

Daisuke Higa

Part Number: TPS61060

Hi support team.

Could you please tell me why you have to keep it below the precharge current when startup with resistive load as described in the data sheet below?
Currently, my customer is experiencing startup failure due to a resistive load.

Best regarsds,

Higa

over 3 years ago

0 Frank Qiu over 3 years ago

TI__Genius 15776 points

10.1 -10.7 is Chinese notional holiday, our expert will reply you after 10.8. if it's an urgent case, please directly communicate with the person who is assigned.

0 Daisuke Higa over 3 years ago in reply to Frank Qiu

Genius 3765 points

Hi support team.

Do you have any update?

Regards,

Higa

0 Daisuke Higa over 3 years ago in reply to Daisuke Higa

Genius 3765 points

Hi support team.

Could you give us information on the current situation?

Best regards,

Higa

0 Mason Wang over 3 years ago in reply to Daisuke Higa

TI__Genius 9630 points

hi Daisuke, I'm still working on this, and will get back to you ASAP.

0 Mason Wang over 3 years ago in reply to Daisuke Higa

TI__Genius 9630 points

hi Daisuke

Per my understanding, if the start up loading current is larger than precharge current, the precharge voltage will never increase to satisfy Vo=Vin-0.3V due to resistive load, this means the converter will stay in the soft start stage and not enter into normal switching mode. This will not happen if start up loading current is smaller than precharge current.

Can I ask the operation condition? and detailed information regrading the start up failure?

0 Daisuke Higa over 3 years ago in reply to Mason Wang

Genius 3765 points

Hi Mason-san

Thank you for your answer.

My customer has the issue of startup with resistive load.

They are using under condition below.

Rs=2.1ohm

Rload=50ohm(resistive load)

Vin=3.3V

ILED=H level(connected to VIN)

Best regards,

Higa

+1 Mason Wang over 3 years ago in reply to Daisuke Higa

TI__Genius 9630 points

hi Daisuke

According to your setting(ILED= H level, Rs=2.1ohm), the minimum loading current will be larger than the precharge current 100mA. As there is no outside pin to modify the soft-start logic, we may need to decrease the loading current for pure resistive load or add capacitor at output side.

Mason

Power management

Power management forum

TPS61060: Startup with resistive load