TPS54228: TPS54228 - How to calculate ON time pluse without Vout sense pin

Jason Dai

Expert 3720 points

Part Number: TPS54228
Other Parts Discussed in Thread: TPS54225,

Hi E2E,

How to calculate ON time pulse without Vout sense pin?

In TPS54225, we can find Vo sense pin in this chip, but no this pin in TPS54228.

As I know, ON time pulse is determined by Vou and Vin.

BR,

Jason

over 7 years ago

0 Yuchang Zhang over 7 years ago

TI__Mastermind 18510 points

Hi Jason,

Two ways for your reference.

1, For D-cap/D-cap2, Rough calculation is Vou/(Vin*Fsw) in steady state.

2, Use simulation tool, do simulation with Tina/Webench to check.

Regards,

Yuchang

0 Jason Dai over 7 years ago in reply to Yuchang Zhang

TI__Expert 3720 points

Yuchang,

Thank you for your reply.

As you mentioned, On time can be got by Vout/(Vin*Fsw). In TPS54228, there are no Vout pin to sense output voltage. the question is how to know the correct and calculate ON time by no Vout information.

BR,

Jason

0 Yuchang Zhang over 7 years ago in reply to Jason Dai

TI__Mastermind 18510 points

Hi Jason,
D-cap2 is added ripple injection circuit by sampling SW node, which is ratio to Vout, and Vout/(Vin*Fsw) can be also used.
Regards,
Yuchang

Power management

Power management forum

TPS54228: TPS54228 - How to calculate ON time pluse without Vout sense pin