TPS53681EVM-002: DCM mode

Max Zhu

Part Number: TPS53681EVM-002

Hi,

I want to test DCM 1-phase operation on this EVM. The setting in Fusion I used are shown below. With 2A load current, only phase one has PWM signal. However, the phase one still works in CCM from measured inductor current. Please let me know what parameters I should set in Fusion to make circuit work in DCM 1-phase operation.

over 4 years ago

0 Max Zhu over 4 years ago

Prodigy 40 points

Hi,

Any expert could help with this issue?

0 Anne Ngo77 over 4 years ago in reply to Max Zhu

TI__Genius 9310 points

Hi, Max,

Please try the below to see if it works:

DSP_DCM_EN dropdown box: select DCM in 1-ph.

0 Max Zhu over 4 years ago in reply to Anne Ngo77

Prodigy 40 points

Hi Anne,

Please see the screenshot in my first message. I tried the same setting, but it didn't work.

0 Anne Ngo77 over 4 years ago

TI__Genius 9310 points

Did you try "Disable 2-to-1 phase transition"? Check to enable single-phase operation during normal
operation (single-phase operation continues to occur in PS2 Mode).

Make sure to save to NVM and power cycles device after the changes.

0 Max Zhu over 4 years ago in reply to Anne Ngo77

Prodigy 40 points

Should I check "disable 2-to-1 phase transition" or not? Based on my understanding, the circuit won't work in one-phase mode if I check the "disable 2-to-1 phase transition", since it won't allow the circuit to transit from two-phase to one-phase.

When I check "disable 2-to-1 phase transition", phase one and two both have PWM signals. It's not DCM-1-phase mode.

0 Derrick Su over 4 years ago

TI__Intellectual 2845 points

Hi Max,

Could you share the config. code with me then I can check for you. It's should be straightforward and your understanding is right. Just in case, maybe you can check CSPx-VREF voltage to make sure the loop should enter DCM already.