LP8864S-Q1: PFM MODE

Koji Hayashi92

Mastermind 7030 points

Part Number: LP8864S-Q1

Hi TI-team

This IC has PFM mode.

If the SW waveform looks like the following, does that mean it is not in PFM mode ?

The frequency is set to 400 kHz.

I am measuring the phase margin.

I think that a measurement under these conditions would be meaningless if it were in PFM mode.

Best Regards,

Koji Hayashi

over 4 years ago

0 Charles-Chen over 4 years ago

TI__Genius 11836 points

Hi Koji,

It is in DCM mode rather than PFM mode.

0 Koji Hayashi92 over 4 years ago in reply to Charles-Chen

Mastermind 7030 points

Hi Charles-san

Thank you for response.

I understand.

Do you have a SIM for the LP8864S-Q1 phase margin ?

Best Regards,

Koji Hayashi

0 Charles-Chen over 4 years ago in reply to Koji Hayashi92

TI__Genius 11836 points

Hi Koji-san,

I suggest to test it in practice since it is also related to the characteristic of LED string.

0 Koji Hayashi92 over 4 years ago in reply to Charles-Chen

Mastermind 7030 points

Hi Charles-san

Thank you for quick response.

After evaluation, the phase margin is 46° and the unity gain frequency is as low as a few hundred Hz, so we were thinking of considering using the SIM.

Best Regards,

Koji Hayashi

0 Charles-Chen over 4 years ago in reply to Koji Hayashi92

TI__Genius 11836 points

Hi Koji-san,

We will plan to release the model soon but it is not available now.

Power management

Power management forum

LP8864S-Q1: PFM MODE