PCA9451A single phase config for buck1 & buck3

[danipower]

hi, i am using the NXP PCA9451A and i try to figure out how i can (and if it can done at all) to operate buck 3 as a standalone converter and not as part of the dual phase with buck 1.

buck 1 work great when i disconnect it for buck 3 (j36 on EVK) but buck 3 wont work (and i checked the remote sense config).

thanks.

[danipower2]

hi, (answering from my newer user) i did connected the R_SNSP3_CFG pin to BUCK3 output? By setting the J30 to 2-3 position. and also removed J36 that connect the converters but still there is no output voltage at BUCK3, only in BUCK1.

* input power is ok (3.3V)

*there is valid communication with the computer

* the rest of the converters work well

there is something i am missing?

[JozefKozon]

Hi Dan,

I have just tested the BUCK1 and BUCK3 single phase regulators and setting the J30 to 2-3 position and removing the J36 jumper is sufficient to enable it. I suspect that the BUCK3 on your board is damaged. Do you have another board at hand? Could you please test it on another board? 

With Best Regards,

Jozef

[danipower2]

hi Jozef, 

I have two boards and in both I did the described process we talked about (the one you attached) and still BUCK3 doesn't work as it should  (no output voltage or right switching waveforms). I can't understand what the problem is.

[JozefKozon]

Hi Dan,

I just want to inform you, that I work on this case. So far I haven't found a solution. As soon as I will have an update I will definitely reply to you.

Thank you for your patience.

With Best Regards,

Jozef

[JozefKozon]

Hi Dan,

I have tested the PCA9451A-EVK for single and dual-phase. While the board was unpowered changing the J30 and J36 was sufficient to change the phase from dual to single-phase and vise versa. 

Later I tested the same under power. I have destroyed the PCA9451A-EVK by trying to set the BUCK1 and BUCK3 from dual-phase to single-phase, while the EVK was under power. I have ordered another one and confirmed the test above with unpowered PCA9451A-EVK, powering it after the J30 and J36 was set either for single or dual-phase. I confirm, that changing the J30 and J36 is sufficient to change the BUCK1 and BUCK3 settings. Please make sure, that you follow the section 3. Configure Hardware in the Getting Started with the PCA9451A-EVK Evaluation Board

When you have the board configured for BUCK1 and BUCK3 for single or dual phase, please follow the points from beginning. When you will want to change the BUCK1 and BUCK3 configuration, please follow in reverse order from point 5. to point 2. for turning off an from point 2. to point 5. for powering in the new configuration. 

If your current PCA9451A-EVK still cannot set the BUCK3 for single phase, please order a new board and test it on new board. In this case, I suspect that something is broken on your current EVK.

With Best Regards,

Jozef

[JozefKozon]

Hi Dan,

yes, the PCA9451A support BUCK1 and BUCK3 single-phase configuration. To avoid misunderstanding, please confirm, have you connected the R_SNSP3_CFG pin to BUCK3 output? By setting the J30 to 2-3 position. The remote sensing.

With Best Regards,

Jozef