topic Re: PF3000: Different skipping behaviour in Power Management

PF3000: Different skipping behaviour

corono — Thu, 14 Nov 2019 10:22:24 GMT

On a custom board design, I'm using the PF3000A1 for the power supply of an IMX7D. The VDD_ARM voltage is connected to SW1A (1.1V), the VDD_SOC is connected to SW1B (1V). I'm measuring the current through the inductance and found a strange skipping behavior of the PMIC.

VDD_ARM:

Under no load condition, the VDD_ARM voltage is in skipping mode:

Increasing the load shifts from skipping mode to continuous mode:

Everything as expected.

VDD_SOC:

The behavior of VDD_SOC is quite different. Under no (extra) load condition:

This does not look like skipping mode for me, more like a current limit. Increasing the load increases the peak current, but the behavior is still the same.

Can anyone explain this behavior?

Thanks!

Sebastian

Re: PF3000: Different skipping behaviour

guoweisun — Fri, 15 Nov 2019 02:15:07 GMT

Do you try to test in NXP PF3000 evkit at same condition?

Which output channel about VDD_SOC on corresponding on PF3000?

Re: PF3000: Different skipping behaviour

corono — Fri, 15 Nov 2019 13:34:52 GMT

Thanks for your answer. The voltage is connected to the SW1B output.

The current waveform from the sabre board looks normal. It seems that something with my board is broken, but only with this one I'm testing at the moment.Probabley I broke something with soldering.

I've tested two others of my boards this morning and both work. So everything should be alright.

Sebastian