TPS61178: TPS61178 Duty MAX/MIN

Rock Shao

Part Number: TPS61178

Hi,

I have two questions of TPS61178

1. What is this IC DUTY MAX & DUTY MIN?

2. When 12.5V boost to 13V, the DUTY is about 4%, can this IC be used in such a low DUTY range? Whether it is over design in the actual application of the IC?

The SPEC as the follow

Vin(min)	7V
Vin(max)	12.5V
Vout	13V
Iout	3A

Thanks and best regards

Rock Shao

over 3 years ago

0 Minqiu Xie over 3 years ago

TI__Mastermind 21565 points

Hi Rock:

The duty is not a problem to deliver 13V when Vin=12.5V. If Vin is close to Vout, the TPS61178 can operate in PFM mode.

0 Rock Shao over 3 years ago in reply to Minqiu Xie

Expert 2800 points

Hi Minqiu,

Thanks for your answer, My customer interested in TPS61178 and it has a maximum of 90%, but the minimum? Can I found that in the datasheet?

Are there any design or application documents for reference?

Best regards

Rock

0 Minqiu Xie over 3 years ago in reply to Rock Shao

TI__Mastermind 21565 points

Hi Rock:

In the test in our lab, the min Ton is around 105nS, and min Toff is 140nS. It's typical value for reference.

So the min duty will change with varied frequency you select.

0 Rock Shao over 3 years ago in reply to Minqiu Xie

Expert 2800 points

Hi Minqiu,

Thank you, in the duty is not a problem to deliver 13V when Vin=12.5V, and the output voltage also can stable in 13V3A?

Will there be problems with voltage instability or falling?

Regards,

Rock

0 Minqiu Xie over 3 years ago in reply to Rock Shao

TI__Mastermind 21565 points

Hi Rock:

It should have such capability with proper design, so the Vout won't fall.

I'm not sure if the loop will be unstable, as the VIN range is wide, Modify the compensation parameters will do some help.

Power management

Power management forum

TPS61178: TPS61178 Duty MAX/MIN