Author Topic: Eensy weensy switchmode power supplies  (Read 1484 times)

Offline klugesmith

  • High Voltage Engineer
  • ****
  • Posts: 370
  • Karma: +11/-0
    • View Profile
Eensy weensy switchmode power supplies
« on: September 10, 2020, 09:05:18 PM »
Helping with a board bring-up at work, I found SMPS converters smaller than I knew existed.

Little buck converters with 1 uH integrated inductor, switched at 2 MHz.  Input voltage up to 17 V.  Output can be set between 0.9 and 6 volts, with up to 3 A of continuous current.
« Last Edit: September 10, 2020, 09:10:59 PM by klugesmith »

Offline T3sl4co1l

  • High Voltage Technician
  • ***
  • Posts: 168
  • Karma: +9/-0
    • View Profile
Re: Eensy weensy switchmode power supplies
« Reply #1 on: September 11, 2020, 06:49:47 PM »
Cute.  I've seen smaller, but they didn't seem to work very well.  (Some brand acquired by Intel, single chip POL converters -- very high frequency, basically enough logic-level transistors packed together to make a power switch, then a little bit of inductance somewhere.  They were incredibly sensitive to nearby EFT pulses, somehow.)

LT (now ADI) has had modules for quite a while, with even more integration than this -- less critical on external capacitance for example.  Though I've also seen a few that were an EMC nightmare...

Probably we'll be seeing more and more modules, as GaN continues to mature.  It's rather difficult to use transistors so fast, at any kind of power, but all that difficulty can be solved before the customer touches it, using a module.  (You already see integrated half-bridge modules for example, gate drivers and supply bypass included.)

Tim

Offline Weston

  • High Voltage Technician
  • ***
  • Posts: 106
  • Karma: +7/-0
    • View Profile
Re: Eensy weensy switchmode power supplies
« Reply #2 on: September 11, 2020, 10:22:04 PM »
I use this modules on my tesla coil PCBs and research PCBs, mostly to supply the voltage rails for FPGAs. They are pretty great and surprisingly cheap.

They save a lot of design time, which is nice for small quantity stuff where BOM cost is not an issue. However, are not even that much more expensive than a discrete inductor and DC/DC IC. Inductors are strangely expensive in small quantity.

Here is one on the top left of the row of regulators on top of the FPGA on my cuteQCW driver board, it almost blends in with the decoupling capacitors




Offline klugesmith

  • High Voltage Engineer
  • ****
  • Posts: 370
  • Karma: +11/-0
    • View Profile
Re: Eensy weensy switchmode power supplies
« Reply #3 on: September 13, 2020, 05:42:52 PM »
Very pretty, Weston.  My first view of actual part, because the board I'm dealing with is accessible only from back side.

What drew my attention was output voltage ripple in the application (power for some clock fanout buffers).
Roughly -53 dBm at 2.1 MHz and a few harmonics; that's around 1 millivolt each.
« Last Edit: September 13, 2020, 05:44:54 PM by klugesmith »

Offline rikkitikkitavi

  • High Voltage Experimenter
  • **
  • Posts: 89
  • Karma: +1/-0
    • View Profile
Re: Eensy weensy switchmode power supplies
« Reply #4 on: September 15, 2020, 08:20:37 AM »
Qute. And quite useful. The ripple is quite amazing, I wonder if they use a post filter?
A man can not have too many variacs

Offline klugesmith

  • High Voltage Engineer
  • ****
  • Posts: 370
  • Karma: +11/-0
    • View Profile
Re: Eensy weensy switchmode power supplies
« Reply #5 on: September 16, 2020, 06:19:24 PM »
Sometimes the ripple is not good enough.  Here is the measured spectrum of a reference clock, shown with two different sources of Vcc for a distribution buffer IC.
Yellow:  a TPS82130.  The spurs are at Vcc ripple frequency and its harmonics, and represent deterministic jitter and/or AM.
Blue: a benchtop lab supply.

Fortunately, it appears that when the Enable pin of TPS buck converter is pulled low, the main Up and Down FETs are both turned off.  So V_out is not clamped to ground, and can be driven to normal voltage by another source.

« Last Edit: September 16, 2020, 08:11:07 PM by klugesmith »

Offline johnf

  • High Voltage Technician
  • ***
  • Posts: 160
  • Karma: +5/-0
    • View Profile
Re: Eensy weensy switchmode power supplies
« Reply #6 on: September 16, 2020, 09:49:17 PM »
Yes at 68 ish dB down it is in spec
But boy would i not want that in a radio!!!

Offline T3sl4co1l

  • High Voltage Technician
  • ***
  • Posts: 168
  • Karma: +9/-0
    • View Profile
Re: Eensy weensy switchmode power supplies
« Reply #7 on: September 17, 2020, 06:56:59 AM »
If the sidebands are in phase, it really is AM, and that's the definition of what you're looking at -- a square wave with varying height.  Input thresholds vary proportionally, so it's no problem for local timing.  It may be a problem crossing supply domains (AM-PM mixing), or for a reference standard (making a nice clean e.g. 10MHz sine), where I guess you should use very quiet supplies and a DDS?

Tim

Offline klugesmith

  • High Voltage Engineer
  • ****
  • Posts: 370
  • Karma: +11/-0
    • View Profile
Re: Eensy weensy switchmode power supplies
« Reply #8 on: September 17, 2020, 07:46:08 PM »
Yeah, spectrum analyzer doesn't show the +/- sideband phasing, which could let us separate AM from PM.  Was plumbed to one side of a differential PECL signal, whose common mode ripple stands out in spectrum at baseband, and whose voltage swing sensitivity to Vcc could be measured.  Looking forward to view with differential input on oscilloscope (plumbed, not probed).  How clearly can we resolve the 2.1 MHz perturbation, whose amplitude is less than 1 ps even if entirely PM?  Mainly for academic interest, because it's no big deal to get rid of the switching Vcc source.

Offline T3sl4co1l

  • High Voltage Technician
  • ***
  • Posts: 168
  • Karma: +9/-0
    • View Profile
Re: Eensy weensy switchmode power supplies
« Reply #9 on: September 18, 2020, 08:19:19 AM »
Ahh, PECL, then my assessment isn't quite true; I had CMOS in mind.  Though I think either the difference between levels, or the mean, or both, still varies with supply, so it might not be that far off after all?  And yep, a full differential measurement might help, too.

Agreed, a few inductors and capacitors are quite a bit cheaper than a picosecond resolution scope. ;D

Tim

High Voltage Forum

Re: Eensy weensy switchmode power supplies
« Reply #9 on: September 18, 2020, 08:19:19 AM »

 


* Recent Topics and Posts

post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
Today at 12:44:31 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
Today at 12:41:33 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
Today at 12:11:13 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 13, 2021, 11:52:11 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 11:38:44 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 10:26:51 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 13, 2021, 09:57:56 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 09:29:08 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 13, 2021, 08:53:25 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 07:22:05 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 13, 2021, 07:02:28 PM
post Re: HFSSTC with fixed crystal-controlled frequency
[Solid State Tesla Coils (SSTC)]
Steve Ward
June 13, 2021, 06:25:20 PM
post First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 02:48:59 PM
post OpenTheremin v3 loosing calibration after minutes
[Electronic Circuits]
gianpaolo
June 13, 2021, 12:00:09 PM
post Re: What is the guidence on SpaceX rockets based on ? PID's?
[General Chat]
Mads Barnkob
June 12, 2021, 07:28:03 PM
post Re: Rocket engine questions
[General Chat]
klugesmith
June 12, 2021, 07:23:12 PM
post Re: Rocket engine questions
[General Chat]
rikkitikkitavi
June 12, 2021, 12:24:06 PM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
Da_Stier
June 12, 2021, 10:06:18 AM
post Re: Rocket engine questions
[General Chat]
plasma
June 12, 2021, 10:01:29 AM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
Twospoons
June 12, 2021, 08:47:08 AM
post Re: What is the guidence on SpaceX rockets based on ? PID's?
[General Chat]
Patrick
June 12, 2021, 07:03:10 AM
post Re: Complications in the design of the first DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
PEDRO HENRIQUE
June 12, 2021, 06:42:56 AM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
davekni
June 12, 2021, 04:20:53 AM
post Re: SKM100 Mini DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Willsmith001
June 11, 2021, 11:08:24 PM
post Re: How much propagation delay is too much propagation delay
[General Chat]
Willsmith001
June 11, 2021, 11:07:00 PM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
Da_Stier
June 11, 2021, 12:33:55 PM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
futurist
June 11, 2021, 12:03:24 PM
post Re: How much propagation delay is too much propagation delay
[General Chat]
davekni
June 11, 2021, 06:47:52 AM
post Re: How much propagation delay is too much propagation delay
[General Chat]
Power-Max
June 11, 2021, 06:32:02 AM
post Re: How much propagation delay is too much propagation delay
[General Chat]
davekni
June 11, 2021, 05:16:03 AM
post Re: SKM100 Mini DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 11, 2021, 04:53:50 AM
post Re: Why are SGT50T65FD1PN soo cheap on lcsc?
[General Chat]
Hydron
June 10, 2021, 11:51:17 PM
post Re: Rocket engine questions
[General Chat]
MRMILSTAR
June 10, 2021, 09:52:59 PM
post Re: Rocket engine questions
[General Chat]
Patrick
June 10, 2021, 09:16:25 PM
post Re: Why are SGT50T65FD1PN soo cheap on lcsc?
[General Chat]
Weston
June 10, 2021, 08:19:40 PM
post Fujifilm PMT module PMT12A, reverse engineering
[Detection, Counting and Measurements]
Mads Barnkob
June 10, 2021, 08:05:27 PM
post Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
alan sailer
June 10, 2021, 07:46:12 PM
post Re: Is it possible to go fully CW with a DRSSRC?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Uspring
June 10, 2021, 06:31:40 PM
post Re: Why are SGT50T65FD1PN soo cheap on lcsc?
[General Chat]
rikkitikkitavi
June 10, 2021, 02:12:07 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic Circuits]
T3sl4co1l
June 10, 2021, 05:14:41 AM
post How much propagation delay is too much propagation delay
[General Chat]
Power-Max
June 10, 2021, 05:10:24 AM
post Re: Why are SGT50T65FD1PN soo cheap on lcsc?
[General Chat]
Power-Max
June 10, 2021, 04:50:34 AM
post Re: SKM100 Mini DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
June 10, 2021, 01:36:31 AM
post Re: Why are SGT50T65FD1PN soo cheap on lcsc?
[General Chat]
Steve Ward
June 09, 2021, 09:15:22 PM
post Re: Is it possible to go fully CW with a DRSSRC?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Power-Max
June 09, 2021, 08:02:15 PM
post Re: Complications in the design of the first DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
PEDRO HENRIQUE
June 09, 2021, 07:17:27 PM
post Re: Analog HFBR amplifier
[Electronic Circuits]
Max
June 09, 2021, 06:58:33 PM
post Aisler PCB Manufacturer
[Printed Circuit Board]
Max
June 09, 2021, 06:58:12 PM
post [WTS] (US) Large Ferrite U and E Cores, assorted types
[Sell / Buy / Trade]
Steve Ward
June 09, 2021, 05:44:06 PM
post Re: Complications in the design of the first DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
AstRii
June 09, 2021, 02:35:47 PM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
SimplePortal 2.3.6 © 2008-2014, SimplePortal