TINA/Spice/TPS40040: TPS40040 Average Model Issue relevant to CCM & DCM Operation

Janayya Hiremath11

Part Number: TPS40040
Other Parts Discussed in Thread: TINA-TI, , TPS40041

Tool/software: TINA-TI or Spice Models

Hello All,

I have downloaded TPS40040_AVG model from TI website & ran the encrypted model in OrCad PSpice 16.6.
My question is that, does model auto-toggle between CCM & DCM or visa versa?

Looks like model works only in CCM. Please clarify. Waveforms are fyr..

1. Vin=5.5V Vout=1.8V Rload=36ohm Fsw=600kHz wf1

2. Vin=5.5V Vout=1.8V Rload=0.3ohm Fsw=600kHz wf1

Kind Regards,

Janayya

over 5 years ago

0 Mathew Jacob1 over 5 years ago

TI__Expert 5900 points

Janayya,

The models works for CCM. For bode plots etc that is the point of interest anyway.

Regards,

Mathew

0 Janayya Hiremath11 over 5 years ago in reply to Mathew Jacob1

Prodigy 50 points

Okay. But device works in CCM & DCM as per datasheet description. Is published average model has limitation?

0 Mathew Jacob1 over 5 years ago in reply to Janayya Hiremath11

TI__Expert 5900 points

Hello,

Are we talking about the same part? I do not see DCM in the description in the datasheet for TPS40040.

Regards,

Mathew

0 Janayya Hiremath11 over 5 years ago in reply to Mathew Jacob1

Prodigy 50 points

Hi Mathew,

Yes, I am talking about same part(TPS40040).
Regarding CCM & DCM operation info, please refer the page no.25 of Application Report SLVA301–April 2008.

Best Regards,
Janayya

0 Mathew Jacob1 over 5 years ago in reply to Janayya Hiremath11

TI__Expert 5900 points

Hi,

I think that is a typo. Looking at the block diagram I do not see any DCM operation blocks.

Description from datasheet:

The TPS40040 (300 kHz) and TPS40041 (600 kHz) are fixed-frequency voltage-mode synchronous buck controllers. In operation, the synchronous rectifier (SR) is allowed to conduct current in both directions, allowing a converter to operate in continuous mode, even under no load conditions, simplifying feedback loop compensation requirements. During startup, internal circuitry modulates the switching of the synchronous rectifier to prevent discharging of the output if a pre-biased condition exists.

Regards,

Mathew

0 Janayya Hiremath11 over 5 years ago in reply to Mathew Jacob1

Prodigy 50 points

Mathew, Thank you so much for clarifying my doubt. Is it possible to share with me the unencrypted average model of TPS40040?

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TINA/Spice/TPS40040: TPS40040 Average Model Issue relevant to CCM & DCM Operation