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TPS54560: The Eco-Mode threshold of TPS54560

takahiko yokota

Mastermind 7135 points

Part Number: TPS54560

Hi

I think the following I(DCM) is the threshold from PWM to DCM or from DCM to PWM.

Is this understand correct?

Or are there different thresholds them respectively?

I(DCM) = ((Vout / Vin) * (Vin - Vout) / (Fsw * Lout)) / 2

Best regards,

Yokota

over 7 years ago

0 JohnTucker over 7 years ago

TI__Guru**** 191445 points

Not necessarily for TPS54560. The DCM to CCM threshold is where the load current is equal to one half the peak to peak switch current. The pulse skipping threshold is where the COMP pin voltage is at it's minimum clamp value. see this app note for details:
www.ti.com/.../slva388

0 takahiko yokota over 7 years ago in reply to JohnTucker

Mastermind 7135 points

Hi

Let me confirm you about it just in case.

Is my following understand correct?

The threshold of CCM to DCM : I(DCM)

The threshold of DCM to CCM : One half the peak to peak swtich current

The threshold of to Enter pulse skipping Eco-Mode : the peak switch current equal to a nominal COMP voltage of 600 mV

Best regards,

Yokota

0 JohnTucker over 7 years ago in reply to takahiko yokota

TI__Guru**** 191445 points

That is the way I understand it. I wrote that app note based on the ICs referenced within, So far as I know TPS54560 has the same behavior.

0 takahiko yokota over 7 years ago in reply to JohnTucker

Mastermind 7135 points

Are there the formula to calculate the peak switch current comparable to a nominal COMP voltage of 600 mV?

Best regards,

Yokota

0 JohnTucker over 7 years ago in reply to takahiko yokota

TI__Guru**** 191445 points

if you read the app note, you can see it is difficult to predict accurately. It is probably +/- around 30 %, depending on the actual application.