TPS53622: The power on sequence for TPS532622 is OK or not

user5074120

Part Number: TPS53622

HI sir，

The power secquence for TPS53622A is 5V（PS_EN pull up to 5V）->3.3V->12V->VR_EN,is it oK or not? How about 12V->5V(PS_EN)->3.3V->VR_EN?

Is there a time interval requirement between 5V and 3.3V?

Thanks!

over 6 years ago

0 Chasel Chen over 6 years ago

TI__Expert 5830 points

Hi,

5V（PS_EN pull up to 5V）->3.3V->12V->VR_EN

In this manner, pre-bias start up function may not work, at the moment 5V and PS_EN is high, PWM pin will be low due to 3.3V is absence, Vout might be pulled down to 0V before 3.3V ramps up.

12V->5V(PS_EN)->3.3V->VR_EN

In this manner, pre-OVP not works because 12V is the first power rail to the system.

If pre-bias start up and pre-OVP function are not a concern to the design, there is no issue for power up as long as VR_EN is the latest one asserted.

Thanks,
Chasel