TPS54202: Current condition of Figure 27 to Figure30 and Pulse skip mode

Hirotaka Matsumoto

Part Number: TPS54202
Other Parts Discussed in Thread: TPS561208,

Hi all

Would you mind if we ask TPS54202?

<Question1>
We have questions of the test condtion of Figure 27 to Figure30.
How much is the current condition(Iout) about Figure 27 to Figure30? Iout=0A? or 1A?

<Question2>
We would like to confirm "Pulse skip mode peak inductor current threshold".
Does this threshold depend on peak inductor current only?

For example, in case of TPS561208, threshold depends on L, Fsw, Vin and Vout as follows;
-Iout(LL)=(1/(2×L×fsw))×((Vin-Vout)×Vout/Vin)
So, is there any formula for TPS54202's Pulse skip mode?

And if you have the more detail document about TPS54202's Pulse skip mode, could you share us?
(If it contains confidential contents, please let us know threshold's formula only.)

Kind regards,

Hirotaka Matsumoto

over 6 years ago

0 Shawn Nie over 6 years ago

TI__Genius 10070 points

Hi,

1. the load is 5 Ω. Please refer to "TPS54202EVM-716 2-A Regulator Evaluation Module User's Guide".

2. Please refer to "7.3.2 Pulse Skip Mode". When the peak inductor current is lower than 300 mA typically, the device enters pulse skipping mode.

Best Regards,
Shawn

0 Hirotaka Matsumoto over 6 years ago in reply to Shawn Nie

Guru 27585 points

Shawn san

Thank you so much for your cooperation.
We would like to confirm the time which device enters to pulse skip mode.

Is this deglitch time 1/Fsw?
When the peak inductor currrent is less than 300mA During 1/Fsw, does the device enter to pulse skip mode?
Is our recognition correct?

Kind regards,

Hirotaka Matsumoto

0 Shawn Nie over 6 years ago in reply to Hirotaka Matsumoto

TI__Genius 10070 points

Hi,

you can calculate the inductor current ripple by using iL_ripple=(1/(L×fsw))×((Vin-Vout)×Vout/Vin), If the load current is lower than 1/(2*iL_ripple), the device would enter DCM. In DCM, if the load current is reduced continuously, the duty cycle would be reduced, and so is the current ripple of inductor. When the peak inductor currrent is less than 300mA, the device will enter pulse skip mode.

Best Regards,

Shawn

0 Hirotaka Matsumoto over 6 years ago in reply to Shawn Nie

Guru 27585 points

Shawan san

Thank you for your reply!

We would like to know the timing which the device will enter pulse skip mode.
Each duty, the device checks the peak inductor currrent.
The deglitch time is 1/Fsw, is this recognition correct?

Kind regards,

Hirotaka Matsumoto

0 Shawn Nie over 6 years ago in reply to Hirotaka Matsumoto

TI__Genius 10070 points

Hi,

When the peak inductor currrent is less than 300mA, the device will skip next pulse until the inductor currrent is higher than 300mA. And for the on time in skip mode, it is decided by Vcomp.
I am not sure what you want to ask?

Shawn

0 Hirotaka Matsumoto over 6 years ago in reply to Shawn Nie

Guru 27585 points

Shawan san

What we would like to confirm is the deglitch time to enter pulse skip mode.
How much does it require?
In other words, how much of time does it require to detect the the inductor currrent? 1 cycle?

Kind regards,

Hirotaka Matsumoto

0 Shawn Nie over 6 years ago in reply to Hirotaka Matsumoto

TI__Genius 10070 points

Hi,

The device checks it every cycle, and take action immediately.

Shawn

0 Hirotaka Matsumoto over 6 years ago in reply to Shawn Nie

Guru 27585 points

Shawn san

Thank you so much for your reply!

OK, we got it.

Kind regards,

Hirotaka Matsumoto

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TPS54202: Current condition of Figure 27 to Figure30 and Pulse skip mode