MPM3650 - output shutting off at certain input voltages

DC-DC Power Converters
11

From 2A upwards, the output was stable again:

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12

Even at 5A, the output was stable:

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13

Hello danltec,

It is very strange to me that it shuts off only at ~1.6-2.0A, but not at the higher currents… I will need to check with the PL. This will take a couple of days.

Thank you,
Vinh Tran
Field Applications Engineer

2 Likes
14

Go get a resistor, they don’t have fancy control loops.

15

Waiting for answer
resistor not working too

16

Hello all,

An update to this question. I will be getting an EVM to test myself. If possible could you provide SW node captures?

Can you try with R3=20k and R4=1.54k?

Thank you,
Vinh Tran
Field Applications Engineer

1 Like
17

Thank you Vinh.
I can’t try SW node captures as this device has an integrated inductor, SW node is not available externally.
I’ll aim to try the altered R3 and R4 values in the coming week. Please keep me posted on your progress too.

18

Hello danltec,

There are SW node pins you can measure from.

Thank you,
Vinh Tran

19

Hello danltec,

Just an update on this. I have been able to recreate your issue on my end. Still trying to figure out what is causing this issue.

Thank you,
Vinh Tran

1 Like
20

I have the same problem.
With 12V input and 5V output, the shutoff is about 14mS with about 3A load.

21

Hello All,

The issue is related to a DCM and CCM transition issue. This issue will be fixed in the next revision.

It is recommended to switch over the MPM3650C if your output voltage is below 3.3V. The MPM3650C has FCCM.

If work is needed at no load conditions the MPM3632S or the MPM3683-7 are recommended.

If you need high efficiency at light load conditions it is recommended to use the MPM3630 or the MPM3683-7.

If your operation stays in CCM or DCM, then it is fine to keep using this device.

Thank you,
Vinh Tran
Field Applications Engineer

2 Likes
22

Thank you Vinh, great to hear you’ve identified the source of the issue.
May I ask when the next MPM3650 revision is planned?

I intend to switch to the MPM3630 in our next PCB revision, as I have the EVM for it, and it appears to be working very well in our application. However, it would be great to know when a revised MPM3650 would be available, as it would allow us to use our current PCB’s. It’s a great device too in terms of high current output in a small package, and ease of use, so it’d be great to have the option to use it with variable loads in the future.

23

Hello danltec,

Our next revision for this device will be around 2-3 months. If you would like more business/technical support please reach out to MPS NOW Remote Support.

Thank you,
Vinh Tran
Field Applications Engineer

1 Like
24

Thank you for all your help Vinh!

25

Hi Vinh,
I was just wondering if you had any updates regarding the next revision of this device?
Will the next revision have a new part number, suffix, or another way to identify newer Vs older revisions?

26

Hi danltec,

The new revision is expected around Q3.

Thank you,
Vinh Tran

1 Like
27

Hello, curious if this new revision has released. Thanks.

28

I am also curious, as we’re past Q3 2022 now, and I’d like to avoid a redesign of my PCB if I can help it.

Vinh, has the new revision been released, and if so, how can we identify it compared to the older version?

1 Like
29

Hi Vinh, I’m considering using this device again in a different application - has the new revision been released, correcting this bug relating to the DCM and CCM transition?

30

Hello @danltec ,

Happy to report that the DCM CCM transition issue was fixed near the end of 2022!

Regards,
Jonathan

1 Like