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Re: Achieving 98% efficiency in a boost converter, inducement

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  Re: Achieving 98% efficiency in a boost converter, inducement Winfield Hill <hill@rowland.harvard.edu> - 2017-03-09 07:21 -0800
    Re: Achieving 98% efficiency in a boost converter, inducement Winfield Hill <hill@rowland.harvard.edu> - 2017-03-09 08:29 -0800
      Re: Achieving 98% efficiency in a boost converter, inducement Don Kuenz <g@crcomp.net> - 2017-03-09 21:30 +0000
        Re: Achieving 98% efficiency in a boost converter, inducement Winfield Hill <hill@rowland.harvard.edu> - 2017-03-09 13:59 -0800
          Re: Achieving 98% efficiency in a boost converter, inducement Winfield Hill <hill@rowland.harvard.edu> - 2017-03-10 05:30 -0800
      Re: Achieving 98% efficiency in a boost converter, deadline Winfield Hill <hill@rowland.harvard.edu> - 2017-03-10 05:34 -0800
        Re: Achieving 98% efficiency in a boost converter, deadline sea moss <danluster81@gmail.com> - 2017-03-10 21:10 -0800
          Re: Achieving 98% efficiency in a boost converter, deadline Winfield Hill <hill@rowland.harvard.edu> - 2017-03-11 05:40 -0800
            Re: Achieving 98% efficiency in a boost converter, RIS-767, new 11-page document Winfield Hill <hill@rowland.harvard.edu> - 2017-03-16 07:55 -0700
    Re: Achieving 98% efficiency in a boost converter, inducement Joerg <news@analogconsultants.com> - 2017-03-16 08:08 -0700
      Re: Achieving 98% efficiency in a boost converter, inducement Winfield Hill <hill@rowland.harvard.edu> - 2017-03-16 08:54 -0700
        Re: Achieving 98% efficiency in a boost converter, inducement Joerg <news@analogconsultants.com> - 2017-03-16 09:36 -0700
          Re: Achieving 98% efficiency in a boost converter, inducement Winfield Hill <hill@rowland.harvard.edu> - 2017-03-16 10:42 -0700
            Re: Achieving 98% efficiency in a boost converter, inducement legg <legg@nospam.magma.ca> - 2017-03-19 17:58 -0400
              Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-03-19 15:38 -0700
                Re: Achieving 98% efficiency in a boost converter, RIS-767 legg <legg@nospam.magma.ca> - 2017-03-22 21:49 -0400
                Re: Achieving 98% efficiency in a boost converter, RIS-767 legg <legg@nospam.magma.ca> - 2017-04-12 11:52 -0400
                  Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-04-12 10:12 -0700
                    Re: Achieving 98% efficiency in a boost converter, RIS-767 Joerg <news@analogconsultants.com> - 2017-04-12 10:26 -0700
                      Re: Achieving 98% efficiency in a boost converter, RIS-767 legg <legg@nospam.magma.ca> - 2017-04-12 17:24 -0400
                        Re: Achieving 98% efficiency in a boost converter, RIS-767 Joerg <news@analogconsultants.com> - 2017-04-13 07:13 -0700
                    Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-04-12 10:29 -0700
                      Re: Achieving 98% efficiency in a boost converter, RIS-767 legg <legg@nospam.magma.ca> - 2017-04-12 17:07 -0400
                        Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-04-13 08:22 -0700
                          Re: Achieving 98% efficiency in a boost converter, RIS-767 legg <legg@nospam.magma.ca> - 2017-04-22 16:58 -0400
                          Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-05-01 15:08 -0700
                            Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-05-05 13:27 -0700
                              Re: Achieving 98% efficiency in a boost converter, RIS-767 Don Kuenz <g@crcomp.net> - 2017-05-06 05:31 +0000
                            Re: Achieving 98% efficiency in a boost converter, RIS-767 dagmargoodboat@yahoo.com - 2017-05-07 14:49 -0700
                              Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-05-08 12:05 -0700
                                Re: Achieving 98% efficiency in a boost converter, RIS-767 sea moss <danluster81@gmail.com> - 2017-05-08 18:50 -0700
                                  Re: Achieving 98% efficiency in a boost converter, RIS-767 Winfield Hill <hill@rowland.harvard.edu> - 2017-05-08 19:27 -0700
    Re: Achieving 98% efficiency in a boost converter, inducement George Herold <gherold@teachspin.com> - 2017-03-22 19:38 -0700

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#450978 — Re: Achieving 98% efficiency in a boost converter, inducement

Winfield Hill wrote...
>
> dagmargoodboat@yahoo.com wrote...
>>
>> On November 9, 2016 at 6:54:04 PM UTC-5, Winfield Hill wrote:
>>> Anybody care to speculate about the most important aspects to consider
>>> when trying to achieve 98% efficiency in a low-power (20mW) boost
>>> converter?  Most available step-up converter circuits seem to perform
>>> in the 85 to 90% region.
>>> 
>>> I'm finishing a PCB "test bed" layout, which allows jumper-selection
>>> of different inductors, synchronous switches, and adjustable controller
>>> parameters.  I'm hoping not to forget something important before
>>> sending it off to the PCB house.  Just for fun I thought I'd make it
>>> in the form of an Arduino shield; giving an option for the processor
>>> to control the parameters and take measurements.
>>
>> Too many degrees of freedom to answer you Win [ snip ]
>
> Thanks, your comments are right on target and can kick
> off the discussion I was hoping to see.  I'll get into
> that conversation tomorrow.  But in the meantime I've
> updated my draft schematic and PCB layout, adding more
> features and items relevant to the discussion.
>
> Here's an inducement: anyone who'd like to experiment
> with issues and concepts embedded in the RIS-767
> board, I'll send you two blank PCBs to play with.
> You just have to talk about what you learn, should
> you get around to learning anything!

 The design has been updated and is ready to order.
https://www.dropbox.com/s/hhl1mwq7mjeo622/RIS-767_b_sch%2Blayouy-pics.pdf?dl=0

 Here's what my document says, achieving a 98% result:
 One test condition: 600mV input from a solar cell,
 2.4V out at 10mA load = 24mW.  Boost converter 
 operation at 250kHz.  Critical for success: an RM8
 inductor, low-loss winding, measured DCR 0.018 Ω,
 calculated loss 0.03mW, and AC loss 1.3 Ω, 0.06mW.
 Best estimated CMOS switch, TS3A24159 powered from
 Vcc = 3.3V. Ron 0.10 Ω, loss 0.16mW.  Calculated
 switch loss, switching 2.4V with Coss=150pF, 0.21mW.

 Continuous total loss 0.46mW = 2% of 24mW (not
 counting 0.18mW in sense resistors).

 I had only one email about a free PCB, but with no
 followup to my answer.  My offer still stands.


-- 
 Thanks,
    - Win

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#450991

Winfield Hill wrote...
>
> The design has been updated and is ready to order.
>https://www.dropbox.com/s/hhl1mwq7mjeo622/RIS-767_b_sch%2Blayouy-pics.pdf?dl=0
>
> Here's what my document says, achieving a 98% result:
> One test condition: 600mV input from a solar cell,
> 2.4V out at 10mA load = 24mW.  Boost converter 
> operation at 250kHz.  Critical for success: an RM8
> inductor, low-loss winding, measured DCR 0.018 Ω,
> calculated loss 0.03mW, and AC loss 1.3 Ω, 0.06mW.
> Best estimated CMOS switch, TS3A24159 powered from
> Vcc = 3.3V. Ron 0.10 Ω, loss 0.16mW.  Calculated
> switch loss, switching 2.4V with Coss=150pF, 0.21mW.
>
> Continuous total loss 0.46mW = 2% of 24mW (not
> counting 0.18mW in sense resistors).
>
> I had only one email about a free PCB, but with no
> followup to my answer.  My offer still stands.

 My RIS-767 testbed is not meant to be a full-blown
 boost converter, instead it's meant to evaluate
 inductors and synchronous switches, under various
 conditions, by independently setting the switching
 frequency, the PWM duty cycle, and the load current.
 Fix two parameters and step a third, plot data points.


-- 
 Thanks,
    - Win

[toc] | [prev] | [next] | [standalone]

#451047

Winfield Hill <hill@rowland.harvard.edu> wrote:
> Winfield Hill wrote...
>>
>> The design has been updated and is ready to order.
>>https://www.dropbox.com/s/hhl1mwq7mjeo622/RIS-767_b_sch%2Blayouy-pics.pdf?dl=0
>>
>> Here's what my document says, achieving a 98% result:
>> One test condition: 600mV input from a solar cell,
>> 2.4V out at 10mA load = 24mW.  Boost converter
>> operation at 250kHz.  Critical for success: an RM8
>> inductor, low-loss winding, measured DCR 0.018 &#937;,
>> calculated loss 0.03mW, and AC loss 1.3 &#937;, 0.06mW.
>> Best estimated CMOS switch, TS3A24159 powered from
>> Vcc = 3.3V. Ron 0.10 &#937;, loss 0.16mW.  Calculated
>> switch loss, switching 2.4V with Coss=150pF, 0.21mW.
>>
>> Continuous total loss 0.46mW = 2% of 24mW (not
>> counting 0.18mW in sense resistors).
>>
>> I had only one email about a free PCB, but with no
>> followup to my answer.  My offer still stands.
>
> My RIS-767 testbed is not meant to be a full-blown
> boost converter, instead it's meant to evaluate
> inductors and synchronous switches, under various
> conditions, by independently setting the switching
> frequency, the PWM duty cycle, and the load current.
> Fix two parameters and step a third, plot data points.

The enigma of the long delay to receive your pcb is cleared up at last.
By process of elimination the one email that you received belongs to me.
Another email was just sent to you with my address in it.

Thank you,

--
Don Kuenz KB7RPU

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#451051

Don Kuenz wrote...
>
>The enigma of the long delay to receive your pcb is cleared up at last.
>By process of elimination the one email that you received belongs to me.
>Another email was just sent to you with my address in it.
>
>Thank you,

 OK, Don, great, you'll get two boards to play with.
 The file on DropBox has changes (errors fixed), so
 over-write the old one.


-- 
 Thanks,
    - Win

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#451155

Winfield Hill wrote...
>
> The file on DropBox has changes (errors fixed),
> since last year, so over-write the old one.

 Assembly parts location images added.


-- 
 Thanks,
    - Win

[toc] | [prev] | [next] | [standalone]

#451157 — Re: Achieving 98% efficiency in a boost converter, deadline

Winfield Hill wrote...
>
>Winfield Hill wrote...
>>
>> The design has been updated and is ready to order.
>>https://www.dropbox.com/s/hhl1mwq7mjeo622/RIS-767_b_sch%2Blayouy-pics.pdf?dl=0

 Folder includes assembly info:
https://www.dropbox.com/sh/6dnpm6muic6st2c/AACSpd3gJEjWT1SYyxS_wutga?dl=0

 My order is going in shortly; I need to know how many
 boards I'll be shipping, so place your (free) orders.

>> Here's what my document says, achieving a 98% result:
>> One test condition: 600mV input from a solar cell,
>> 2.4V out at 10mA load = 24mW.  Boost converter 
>> operation at 250kHz.  Critical for success: an RM8
>> inductor, low-loss winding, measured DCR 0.018 Ω,
>> calculated loss 0.03mW, and AC loss 1.3 Ω, 0.06mW.
>> Best estimated CMOS switch, TS3A24159 powered from
>> Vcc = 3.3V. Ron 0.10 Ω, loss 0.16mW.  Calculated
>> switch loss, switching 2.4V with Coss=150pF, 0.21mW.
>>
>> Continuous total loss 0.46mW = 2% of 24mW (not
>> counting 0.18mW in sense resistors).
>>
>> I had only one email about a free PCB, but with no
>> followup to my answer.  My offer still stands.
>
> My RIS-767 testbed is not meant to be a full-blown
> boost converter, instead it's meant to evaluate
> inductors and synchronous switches, under various
> conditions, by independently setting the switching
> frequency, the PWM duty cycle, and the load current.
> Fix two parameters and step a third, plot data points.


-- 
 Thanks,
    - Win

[toc] | [prev] | [next] | [standalone]

#451273 — Re: Achieving 98% efficiency in a boost converter, deadline

On Friday, March 10, 2017 at 6:34:57 AM UTC-7, Winfield Hill wrote:
> Winfield Hill wrote...
> >
> >Winfield Hill wrote...
> >>
> >> The design has been updated and is ready to order.
> >>https://www.dropbox.com/s/hhl1mwq7mjeo622/RIS-767_b_sch%2Blayouy-pics.pdf?dl=0
> 
>  Folder includes assembly info:
> https://www.dropbox.com/sh/6dnpm6muic6st2c/AACSpd3gJEjWT1SYyxS_wutga?dl=0
> 
>  My order is going in shortly; I need to know how many
>  boards I'll be shipping, so place your (free) orders.
> 
> >> Here's what my document says, achieving a 98% result:
> >> One test condition: 600mV input from a solar cell,
> >> 2.4V out at 10mA load = 24mW.  Boost converter 
> >> operation at 250kHz.  Critical for success: an RM8
> >> inductor, low-loss winding, measured DCR 0.018 Ω,
> >> calculated loss 0.03mW, and AC loss 1.3 Ω, 0.06mW.
> >> Best estimated CMOS switch, TS3A24159 powered from
> >> Vcc = 3.3V. Ron 0.10 Ω, loss 0.16mW.  Calculated
> >> switch loss, switching 2.4V with Coss=150pF, 0.21mW.
> >>
> >> Continuous total loss 0.46mW = 2% of 24mW (not
> >> counting 0.18mW in sense resistors).
> >>
> >> I had only one email about a free PCB, but with no
> >> followup to my answer.  My offer still stands.
> >
> > My RIS-767 testbed is not meant to be a full-blown
> > boost converter, instead it's meant to evaluate
> > inductors and synchronous switches, under various
> > conditions, by independently setting the switching
> > frequency, the PWM duty cycle, and the load current.
> > Fix two parameters and step a third, plot data points.
> 
> 
> -- 
>  Thanks,
>     - Win



On Friday, March 10, 2017 at 6:34:57 AM UTC-7, Winfield Hill wrote:
> Winfield Hill wrote...
> >
> >Winfield Hill wrote...
> >>
> >> The design has been updated and is ready to order.
> >>https://www.dropbox.com/s/hhl1mwq7mjeo622/RIS-767_b_sch%2Blayouy-pics.pdf?dl=0
> 
>  Folder includes assembly info:
> https://www.dropbox.com/sh/6dnpm6muic6st2c/AACSpd3gJEjWT1SYyxS_wutga?dl=0
> 
>  My order is going in shortly; I need to know how many
>  boards I'll be shipping, so place your (free) orders.
> 
> >> Here's what my document says, achieving a 98% result:
> >> One test condition: 600mV input from a solar cell,
> >> 2.4V out at 10mA load = 24mW.  Boost converter 
> >> operation at 250kHz.  Critical for success: an RM8
> >> inductor, low-loss winding, measured DCR 0.018 Ω,
> >> calculated loss 0.03mW, and AC loss 1.3 Ω, 0.06mW.
> >> Best estimated CMOS switch, TS3A24159 powered from
> >> Vcc = 3.3V. Ron 0.10 Ω, loss 0.16mW.  Calculated
> >> switch loss, switching 2.4V with Coss=150pF, 0.21mW.
> >>
> >> Continuous total loss 0.46mW = 2% of 24mW (not
> >> counting 0.18mW in sense resistors).
> >>
> >> I had only one email about a free PCB, but with no
> >> followup to my answer.  My offer still stands.
> >
> > My RIS-767 testbed is not meant to be a full-blown
> > boost converter, instead it's meant to evaluate
> > inductors and synchronous switches, under various
> > conditions, by independently setting the switching
> > frequency, the PWM duty cycle, and the load current.
> > Fix two parameters and step a third, plot data points.
> 
> 
> -- 
>  Thanks,
>     - Win

I will take one, if you haven't placed the order yet.  I'll email my address.

What's the prize for best efficiency?  Do I get shamed if I can't achieve 95%?

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#451302 — Re: Achieving 98% efficiency in a boost converter, deadline

sea moss wrote...
>
> I will take one, if you haven't placed the order yet.
> I'll email my address.

 OK, two boards for you.

> What's the prize for best efficiency?  Do I get
> shamed if I can't achieve 95%?

 95%, you're supposed to aim for 98%!


-- 
 Thanks,
    - Win

[toc] | [prev] | [next] | [standalone]

#452110 — Re: Achieving 98% efficiency in a boost converter, RIS-767, new 11-page document

Winfield Hill wrote...
>
>sea moss wrote...
>>
>> I will take one, if you haven't placed the order yet.
>> I'll email my address.
>
> OK, two boards for you.
>
>> What's the prize for best efficiency?  Do I get
>> shamed if I can't achieve 95%?
>
> 95%, you're supposed to aim for 98%!

 The design has been further updated, more capability,
 now with 18 flip-chip daughterboards.  There's a new
 11-page document describing the project, and with
 five possible simplified build schematics.

https://www.dropbox.com/sh/6dnpm6muic6st2c/AACSpd3gJEjWT1SYyxS_wutga?dl=0

 I'll be placing PCB orders shortly. 


-- 
 Thanks,
    - Win

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#452114

On 2017-03-09 07:21, Winfield Hill wrote:
> Winfield Hill wrote...
>>
>> dagmargoodboat@yahoo.com wrote...
>>>
>>> On November 9, 2016 at 6:54:04 PM UTC-5, Winfield Hill wrote:
>>>> Anybody care to speculate about the most important aspects to consider
>>>> when trying to achieve 98% efficiency in a low-power (20mW) boost
>>>> converter?  Most available step-up converter circuits seem to perform
>>>> in the 85 to 90% region.
>>>>
>>>> I'm finishing a PCB "test bed" layout, which allows jumper-selection
>>>> of different inductors, synchronous switches, and adjustable controller
>>>> parameters.  I'm hoping not to forget something important before
>>>> sending it off to the PCB house.  Just for fun I thought I'd make it
>>>> in the form of an Arduino shield; giving an option for the processor
>>>> to control the parameters and take measurements.
>>>
>>> Too many degrees of freedom to answer you Win [ snip ]
>>
>> Thanks, your comments are right on target and can kick
>> off the discussion I was hoping to see.  I'll get into
>> that conversation tomorrow.  But in the meantime I've
>> updated my draft schematic and PCB layout, adding more
>> features and items relevant to the discussion.
>>
>> Here's an inducement: anyone who'd like to experiment
>> with issues and concepts embedded in the RIS-767
>> board, I'll send you two blank PCBs to play with.
>> You just have to talk about what you learn, should
>> you get around to learning anything!
>
>   The design has been updated and is ready to order.
> https://www.dropbox.com/s/hhl1mwq7mjeo622/RIS-767_b_sch%2Blayouy-pics.pdf?dl=0
>

"That file isn’t here anymore
Someone might’ve deleted the file or disabled the link"

:-(


>   Here's what my document says, achieving a 98% result:
>   One test condition: 600mV input from a solar cell,
>   2.4V out at 10mA load = 24mW.  Boost converter
>   operation at 250kHz.  Critical for success: an RM8
>   inductor, low-loss winding, measured DCR 0.018 Ω,
>   calculated loss 0.03mW, and AC loss 1.3 Ω, 0.06mW.
>   Best estimated CMOS switch, TS3A24159 powered from
>   Vcc = 3.3V. Ron 0.10 Ω, loss 0.16mW.  Calculated
>   switch loss, switching 2.4V with Coss=150pF, 0.21mW.
>
>   Continuous total loss 0.46mW = 2% of 24mW (not
>   counting 0.18mW in sense resistors).
>

That is a very good achievement!


>   I had only one email about a free PCB, but with no
>   followup to my answer.  My offer still stands.
>
>


-- 
Regards, Joerg

http://www.analogconsultants.com/

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#452123

Joerg wrote...
>
>"That file isn’t here anymore
>Someone might’ve deleted the file or disabled the link"
>
>:-(

 Hmm.  See my post this morning, it should work.

>>   Here's what my document says, achieving a 98% result:
>>   One test condition: 600mV input from a solar cell,
>>   2.4V out at 10mA load = 24mW.  Boost converter
>>   operation at 250kHz.  Critical for success: an RM8
>>   inductor, low-loss winding, measured DCR 0.018 Ω,
>>   calculated loss 0.03mW, and AC loss 1.3 Ω, 0.06mW.
>>   Best estimated CMOS switch, TS3A24159 powered from
>>   Vcc = 3.3V. Ron 0.10 Ω, loss 0.16mW.  Calculated
>>   switch loss, switching 2.4V with Coss=150pF, 0.21mW.
>>
>>   Continuous total loss 0.46mW = 2% of 24mW (not
>>   counting 0.18mW in sense resistors).
>
> That is a very good achievement!

 Well, the inductor is an achievement, the rest will be
 calculation / speculation until the testbed arrives.


-- 
 Thanks,
    - Win

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#452127

On 2017-03-16 08:54, Winfield Hill wrote:
> Joerg wrote...
>>
>> "That file isn’t here anymore
>> Someone might’ve deleted the file or disabled the link"
>>
>> :-(
>
>   Hmm.  See my post this morning, it should work.
>

Thanks, that link works. It hadn't shown up in my news server yet before 
walking the dogs.


>>>    Here's what my document says, achieving a 98% result:
>>>    One test condition: 600mV input from a solar cell,
>>>    2.4V out at 10mA load = 24mW.  Boost converter
>>>    operation at 250kHz.  Critical for success: an RM8
>>>    inductor, low-loss winding, measured DCR 0.018 Ω,
>>>    calculated loss 0.03mW, and AC loss 1.3 Ω, 0.06mW.
>>>    Best estimated CMOS switch, TS3A24159 powered from
>>>    Vcc = 3.3V. Ron 0.10 Ω, loss 0.16mW.  Calculated
>>>    switch loss, switching 2.4V with Coss=150pF, 0.21mW.
>>>
>>>    Continuous total loss 0.46mW = 2% of 24mW (not
>>>    counting 0.18mW in sense resistors).
>>
>> That is a very good achievement!
>
>   Well, the inductor is an achievement, the rest will be
>   calculation / speculation until the testbed arrives.
>

If the MPPT is a required part of the game you'd have to add in the 
Arduino power consumption. Maybe use a MSP430 instead? Those can be 
operated on small drops of power.

-- 
Regards, Joerg

http://www.analogconsultants.com/

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#452149

Joerg wrote...
>
> If the MPPT is a required part of the game
> you'd have to add in the Arduino power
> consumption. Maybe use a MSP430 instead?
> Those can be operated on small drops of power.

 Of course.  But my rule is that none of the
 controller power consumption counts.  Why?
 We assume with effort you could drive that
 as far down as you want, but that's not
 the point.  The point is to achieve very
 efficient power conversion, period.  Any
 wild control scheme you dream up is OK.


-- 
 Thanks,
    - Win

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#452619

On 16 Mar 2017 10:42:09 -0700, Winfield Hill
<hill@rowland.harvard.edu> wrote:

>Joerg wrote...
>>
>> If the MPPT is a required part of the game
>> you'd have to add in the Arduino power
>> consumption. Maybe use a MSP430 instead?
>> Those can be operated on small drops of power.
>
> Of course.  But my rule is that none of the
> controller power consumption counts.  Why?
> We assume with effort you could drive that
> as far down as you want, but that's not
> the point.  The point is to achieve very
> efficient power conversion, period.  Any
> wild control scheme you dream up is OK.

Scaling assumptions that approach an order of magnitude are often
troublesome. Two orders of magnitude will require more than just
serious thought.

RL

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#452624 — Re: Achieving 98% efficiency in a boost converter, RIS-767

legg wrote...
>
> Winfield Hill wrote:
>> Joerg wrote...
>>>
>>> If the MPPT is a required part of the game
>>> you'd have to add in the Arduino power
>>> consumption.  Maybe use a MSP430 instead?
>>> Those can be operated on small drops of power.
>>
>> Of course.  But my rule is that none of the
>> controller power consumption counts.  Why?
>> We assume with effort you could drive that
>> as far down as you want, but that's not
>> the point.  The point is to achieve very
>> efficient power conversion, period.  Any
>> wild control scheme you dream up is OK.
>
> Scaling assumptions that approach an order of
> magnitude are often troublesome. Two orders
> of magnitude will require more than just
> serious thought.

 Yes, right.  And also bench experimenting.
 Hence my offer for free RIS-767 boards.


-- 
 Thanks,
    - Win

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#453168 — Re: Achieving 98% efficiency in a boost converter, RIS-767

On 19 Mar 2017 15:38:27 -0700, Winfield Hill
<hill@rowland.harvard.edu> wrote:

>legg wrote...
>>
>> Winfield Hill wrote:
>>> Joerg wrote...
>>>>
>>>> If the MPPT is a required part of the game
>>>> you'd have to add in the Arduino power
>>>> consumption.  Maybe use a MSP430 instead?
>>>> Those can be operated on small drops of power.
>>>
>>> Of course.  But my rule is that none of the
>>> controller power consumption counts.  Why?
>>> We assume with effort you could drive that
>>> as far down as you want, but that's not
>>> the point.  The point is to achieve very
>>> efficient power conversion, period.  Any
>>> wild control scheme you dream up is OK.
>>
>> Scaling assumptions that approach an order of
>> magnitude are often troublesome. Two orders
>> of magnitude will require more than just
>> serious thought.
>
> Yes, right.  And also bench experimenting.
> Hence my offer for free RIS-767 boards.

Is there a recommended 600mV source, or are input filter components
considered adequate impedance stabilization?

RL

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#455905 — Re: Achieving 98% efficiency in a boost converter, RIS-767

On 19 Mar 2017 15:38:27 -0700, Winfield Hill
<hill@rowland.harvard.edu> wrote:

>legg wrote...
>>
>> Winfield Hill wrote:
>>> Joerg wrote...
>>>>
>>>> If the MPPT is a required part of the game
>>>> you'd have to add in the Arduino power
>>>> consumption.  Maybe use a MSP430 instead?
>>>> Those can be operated on small drops of power.
>>>
>>> Of course.  But my rule is that none of the
>>> controller power consumption counts.  Why?
>>> We assume with effort you could drive that
>>> as far down as you want, but that's not
>>> the point.  The point is to achieve very
>>> efficient power conversion, period.  Any
>>> wild control scheme you dream up is OK.
>>
>> Scaling assumptions that approach an order of
>> magnitude are often troublesome. Two orders
>> of magnitude will require more than just
>> serious thought.
>
> Yes, right.  And also bench experimenting.
> Hence my offer for free RIS-767 boards.


What's the solar cell source unloaded output voltage?

With 600mV loaded, I'd expect >900mV?

If so,

https://datasheets.maximintegrated.com/en/ds/MAX17220-MAX17225.pdf

RL

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#455912 — Re: Achieving 98% efficiency in a boost converter, RIS-767

legg wrote...
>
>On 19 Mar 2017 15:38:27 -0700, Winfield Hill
><hill@rowland.harvard.edu> wrote:
>
>>legg wrote...
>>>
>>> Winfield Hill wrote:
>>>> Joerg wrote...
>>>>>
>>>>> If the MPPT is a required part of the game
>>>>> you'd have to add in the Arduino power
>>>>> consumption.  Maybe use a MSP430 instead?
>>>>> Those can be operated on small drops of power.
>>>>
>>>> Of course.  But my rule is that none of the
>>>> controller power consumption counts.  Why?
>>>> We assume with effort you could drive that
>>>> as far down as you want, but that's not
>>>> the point.  The point is to achieve very
>>>> efficient power conversion, period.  Any
>>>> wild control scheme you dream up is OK.
>>>
>>> Scaling assumptions that approach an order
>>> of magnitude are often troublesome.  Two
>>> orders of magnitude will require more than
>>> just serious thought.
>>
>> Yes, right.  And also bench experimenting.
>> Hence my offer for free RIS-767 boards.
>
> What's the solar cell source unloaded output
> voltage?  With 600mV loaded, I'd expect >900mV?
> If so,
>
>https://datasheets.maximintegrated.com/en/ds/MAX17220-MAX17225.pdf

 Right.  Quite a few boost converters claim to
 achieve 95% under certain circumstances. 
 I purchased eval boards for about 10 of them,
 but wasn't able to get better than 90% for my
 2.0 to 2.4-volt boost.  One did 92-94% at 25mW 
 with 0.8 volts in, but strangely deteriorated
 at 2.0 volts in.  In many cases it appeared the
 eval board inductors were too small.  First,
 too low a value, and second, too much core loss.
 It seems the manufacturers just want to prove
 how small their overall used space will be.
 
 So I have footprints for about a dozen inductor
 types.  I also wound an RM8-core inductor, that
 measured to fit into a 98% budget (next post),
 so I think that part of the scene is possible.  

 Another big part is the MOSFET's tradoff, for
 Ron and Coss.  Low Ron goes along with high
 Coss, and thus high C V^2 f losses. 

 Having a variable frequency with load, as the
 Maxim parts do, helps out with that problem.


-- 
 Thanks,
    - Win

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#455917 — Re: Achieving 98% efficiency in a boost converter, RIS-767

On 2017-04-12 10:12, Winfield Hill wrote:
> legg wrote...
>>
>> On 19 Mar 2017 15:38:27 -0700, Winfield Hill
>> <hill@rowland.harvard.edu> wrote:
>>
>>> legg wrote...
>>>>
>>>> Winfield Hill wrote:
>>>>> Joerg wrote...
>>>>>>
>>>>>> If the MPPT is a required part of the game
>>>>>> you'd have to add in the Arduino power
>>>>>> consumption.  Maybe use a MSP430 instead?
>>>>>> Those can be operated on small drops of power.
>>>>>
>>>>> Of course.  But my rule is that none of the
>>>>> controller power consumption counts.  Why?
>>>>> We assume with effort you could drive that
>>>>> as far down as you want, but that's not
>>>>> the point.  The point is to achieve very
>>>>> efficient power conversion, period.  Any
>>>>> wild control scheme you dream up is OK.
>>>>
>>>> Scaling assumptions that approach an order
>>>> of magnitude are often troublesome.  Two
>>>> orders of magnitude will require more than
>>>> just serious thought.
>>>
>>> Yes, right.  And also bench experimenting.
>>> Hence my offer for free RIS-767 boards.
>>
>> What's the solar cell source unloaded output
>> voltage?  With 600mV loaded, I'd expect >900mV?
>> If so,
>>
>> https://datasheets.maximintegrated.com/en/ds/MAX17220-MAX17225.pdf
>
>   Right.  Quite a few boost converters claim to
>   achieve 95% under certain circumstances.
>   I purchased eval boards for about 10 of them,
>   but wasn't able to get better than 90% for my
>   2.0 to 2.4-volt boost.  One did 92-94% at 25mW
>   with 0.8 volts in, but strangely deteriorated
>   at 2.0 volts in.  In many cases it appeared the
>   eval board inductors were too small.  First,
>   too low a value, and second, too much core loss.
>   It seems the manufacturers just want to prove
>   how small their overall used space will be.
>
>   So I have footprints for about a dozen inductor
>   types.  I also wound an RM8-core inductor, that
>   measured to fit into a 98% budget (next post),
>   so I think that part of the scene is possible.
>
>   Another big part is the MOSFET's tradoff, for
>   Ron and Coss.  Low Ron goes along with high
>   Coss, and thus high C V^2 f losses.
>

This may be one of the rare occasions where GaN FETs might make sense.


>   Having a variable frequency with load, as the
>   Maxim parts do, helps out with that problem.
>

Unless there is zero stock a few weeks down the line :-)

-- 
Regards, Joerg

http://www.analogconsultants.com/

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#455945 — Re: Achieving 98% efficiency in a boost converter, RIS-767

On Wed, 12 Apr 2017 10:26:03 -0700, Joerg <news@analogconsultants.com>
wrote:

>On 2017-04-12 10:12, Winfield Hill wrote:
<snip>
>>   Another big part is the MOSFET's tradoff, for
>>   Ron and Coss.  Low Ron goes along with high
>>   Coss, and thus high C V^2 f losses.
>>
>
>This may be one of the rare occasions where GaN FETs might make sense.

something like EPC2014 offers 16mR with total gate charge of 2nC.
only 1/3 of that is Qgs.

The trouble would be getting it to run at 600mV.

At least in this app, there are no heatsink considerations.

RL

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