TPS54200: Minimum duty cycle+PWM resolution

Pjs

Part Number: TPS54200
Other Parts Discussed in Thread: TPS92200

Hi,

1) Can you confirm the analogue dimming resolution of the TPS54200. The datasheet suggests a PWM signal between 1% and 100% but what resolution can I dim to between these values in analogue mode? Will the TPS54200 resolve the difference in PWM duty cycle of fractions of a percent - e.g. 10.01% and 10.02%?

2) What are the buck regulator duty cycle limitations? Can this comfortably output 10.5V from a Vin=11.5V?

Many thanks

over 4 years ago

0 Frank Qiu over 4 years ago

TI__Genius 15776 points

Robin, please help in this case.

0 Yuting Shao over 4 years ago

TI__Genius 13001 points

Hi Pjs,

TPS92200 is the next generation of TPS54200. How about this device? For your resolution question, I need time to check. The maximum duty cycle of TPS92200 is 99%, which means it supports coverting 11.5V to 10.5V.

Robin

0 Pjs over 4 years ago in reply to Yuting Shao

Intellectual 890 points

Hi Robin,

The TPS92200 is out of stock and looks to be on a 35wk lead time unless you can help me locate some stock?

That's great thank you - can you confirm what the limits of Vin would be with a Vout of 10.5V would be and would this need to consider the switcher efficiency also?

Many thanks

0 Yuting Shao over 4 years ago in reply to Pjs

TI__Genius 13001 points

Hi Pjs,

The main limitation for conversion is the internal voltage drop and internal FET minimum on time and off time.

Robin

0 Pjs over 4 years ago in reply to Yuting Shao

Intellectual 890 points

Thanks Robin :).

So what's the best way to calculate how close to the Vin->Vout limit I would be operating? Are these values in the datasheet? I just need to be sure there's some headroom if I use this device for this step down!

Many thanks

0 Yuting Shao over 4 years ago in reply to Pjs

TI__Genius 13001 points

Hi Pjs,

Understood. But I need bench test before I answer your question. This parameter is not mentioned in TPS54200 datasheet.

Robin

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TPS54200: Minimum duty cycle+PWM resolution