-----Mensagem original-----
De: Frederic Beaulieu [mailto:Frb78@Frb7...] 
Enviada em: sexta-feira, 10 de dezembro de 2004 16:46
Para: msp430@msp4...; onestone@ones...
Assunto: Re: [msp430] DC-DC converter design




I used already a Lithium battery, the Energizer L91 AA
1.5V (see attachement), which is supposed to opperate
down to -40oC. The only thing I can see is that the
discharge current at lower temp is too low, but 170mA
is not that high ...

--- onestone <onestone@ones...> wrote:
> 
> I would change to a battery capable of lower
> temperature operation.
> Li-poly tends to be a lot better than alkaline, and
> is rechargable. LTC 
> is not rechargable but operates down to -40C.
> 
> Al
> 
> Frederic Beaulieu wrote:
> 
> > 
> > After few tests, I think it's the battery which
> cannot
> > support the current load at lower temperature.
> > I have put my board (without battery) in a freezer
> > (~-10oC) for about half a hour then I have
> inserted
> > the warm battery in it. All work fine! However, if
> I
> > let the device working in the freezer, after 20
> > minutes, the Tx problem occurs.
> > Is there a way to solve this problem? Can I put
> bigger
> > cap in front of the switcher (input capacity - C67
> > (see attachement)) and/or after it (output
> capacity -
> > C68)? Is there side effect to do that?
> > 
> > Your help is very appriciated!
> > Fred
> > 
> > 
> > --- David Rea <dave@dave...> wrote:
> > 
> > 
> >>I don't see the voltage scale on those TIFs, but
> you
> >>say the ripple is
> >>only 3mV. Unless you're driving a VCO directly
> with
> >>the output of the
> >>power supply, I don't see how that could possibly
> >>cause the transmitter
> >>to glitch. The XE1203 datasheet reports (at a
> quick
> >>glance) that it
> >>works from 2.4 to 3.6VDC, so 3mV ripple in the
> >>supply really shouldn't
> >>bother it.
> >>
> >>I see that the operating temp of the XE1203 is
> >>-40~85.
> >>
> >>Here are a few things to consider:
> >>
> >>1) Does the circuit exhibit the same behavior when
> >>powered by a bench
> >>supply at low temperatures?
> >>
> >>2) A can of "Freeze Mist" or other electronics
> >>cooling spray can be
> >>helpful in troubleshooting this type of problem -
> >>you can spray
> >>refrigerant onto each chip and see which one
> causes
> >>your problem:
> >>
> > 
> >
>
http://www.unicornelex.com/newunicorn/subcategory.php?catK04&
> > 
> >>Dave
> >>
> >>Quoting Frederic Beaulieu <frb78@frb7...>:
> >>
> >>
> >>>I'm working with a RF transceiver Xemics XE1203.
> >>
> >>When
> >>
> >>>it is in Rx mode all operate correctly, but when
> >>
> >>it
> >>
> >>>turn in Tx mode (which require 50 mA more), the
> >>>message  is not sent correctly. The switcher
> >>
> >>output
> >>
> >>>voltage seem to take longer to stabilize (1400us
> >>>instead of 300us) but the ripple isn't bigger
> >>
> >>(3mV).
> >>
> >>>I send you in attachment the output of the
> >>
> >>switcher at
> >>
> >>>room temperature, which work correctly, and at
> low
> >>>temperature, where at think there is the problem.
> >>>
> >>>Fred
> >>>
> >>>--- David Rea <dave@dave...> wrote:
> >>>
> >>>
> >>>>>I use a LTC3401 with typical reference design
> >>
> >>and
> >>
> >>>>I
> >>>>
> >>>>>have few problems at low temperature (-10oC).
> >>
> >>This
> >>
> >>>>>seem to appear when a higher current is
> >>
> >>request by
> >>
> >>>>the
> >>>>
> >>>>>device (from 120mA to 170mA) and the battery
> >>
> >>(2 X
> >>
> >>>>>Energizer L91 AA 1.5V in parallel) should
> >>
> >>support
> >>
> >>>>this
> >>>>
> >>>>>increase.
> >>>>
> >>>>Can you be more specific about what problem is
> >>>>occuring? Is the output
> >>>>voltage dropping out? Problems with the
> >>
> >>switching?
> >>
> >>>>Excessive ripple?
> >>>>
> >>>>Dave
> >>>>
> >>>>
> >>>
> >>>
> >>>
> >>>__________________________________
> >>>
> >>
> >>
> > 
> > 
> > 		
> > __________________________________
> >  
> >  
> > 
> > 
> > [Non-text portions of this message have been
> removed]
> > 
> > 
> > 
> > .
> > 
> >  
> > Yahoo! Groups Links
> > 
> > 
> > 
> >  
> > 
> > 
> > 
> > 
> 
> 
> 
> .
> 
>  
> Yahoo! Groups Links
> 
> 
>     msp430-unsubscribe@msp4...
> 
>  
> 
> 
> 
> 


		
__________________________________ 
 





.

 
Yahoo! Groups Links



 

Frederic,
These batteries has a big series resistence. 170mA is a high current even
for the best ones.
You may have a big voltage drop.
I have a design with MSP430 + Xemics DP1203 working at near -40C. Tx time is
less than 10ms, duty cycle less than 1%. The Tx current is supplied by two
47uF tantalum capacitors. 
No DC-DC in my case.
The only problem I've got was the 32KHz XT1 stopping when the temperature
arise above 0C. Some umidity in the air, during MSP assembly, condensated in
the XT1 terminals.... Solution was to use hot air before sealing the board.

Augusto


-----Mensagem original-----
De: Frederic Beaulieu [mailto:Frb78@Frb7...] 
Enviada em: sexta-feira, 10 de dezembro de 2004 16:46
Para: msp430@msp4...; onestone@ones...
Assunto: Re: [msp430] DC-DC converter design




I used already a Lithium battery, the Energizer L91 AA
1.5V (see attachement), which is supposed to opperate
down to -40oC. The only thing I can see is that the
discharge current at lower temp is too low, but 170mA
is not that high ...

--- onestone <onestone@ones...> wrote:
> 
> I would change to a battery capable of lower
> temperature operation.
> Li-poly tends to be a lot better than alkaline, and
> is rechargable. LTC 
> is not rechargable but operates down to -40C.
> 
> Al
> 
> Frederic Beaulieu wrote:
> 
> > 
> > After few tests, I think it's the battery which
> cannot
> > support the current load at lower temperature.
> > I have put my board (without battery) in a freezer
> > (~-10oC) for about half a hour then I have
> inserted
> > the warm battery in it. All work fine! However, if
> I
> > let the device working in the freezer, after 20
> > minutes, the Tx problem occurs.
> > Is there a way to solve this problem? Can I put
> bigger
> > cap in front of the switcher (input capacity - C67
> > (see attachement)) and/or after it (output
> capacity -
> > C68)? Is there side effect to do that?
> > 
> > Your help is very appriciated!
> > Fred
> > 
> > 
> > --- David Rea <dave@dave...> wrote:
> > 
> > 
> >>I don't see the voltage scale on those TIFs, but
> you
> >>say the ripple is
> >>only 3mV. Unless you're driving a VCO directly
> with
> >>the output of the
> >>power supply, I don't see how that could possibly
> >>cause the transmitter
> >>to glitch. The XE1203 datasheet reports (at a
> quick
> >>glance) that it
> >>works from 2.4 to 3.6VDC, so 3mV ripple in the
> >>supply really shouldn't
> >>bother it.
> >>
> >>I see that the operating temp of the XE1203 is
> >>-40~85.
> >>
> >>Here are a few things to consider:
> >>
> >>1) Does the circuit exhibit the same behavior when
> >>powered by a bench
> >>supply at low temperatures?
> >>
> >>2) A can of "Freeze Mist" or other electronics
> >>cooling spray can be
> >>helpful in troubleshooting this type of problem -
> >>you can spray
> >>refrigerant onto each chip and see which one
> causes
> >>your problem:
> >>
> > 
> >
>
http://www.unicornelex.com/newunicorn/subcategory.php?catK04&
> > 
> >>Dave
> >>
> >>Quoting Frederic Beaulieu <frb78@frb7...>:
> >>
> >>
> >>>I'm working with a RF transceiver Xemics XE1203.
> >>
> >>When
> >>
> >>>it is in Rx mode all operate correctly, but when
> >>
> >>it
> >>
> >>>turn in Tx mode (which require 50 mA more), the
> >>>message  is not sent correctly. The switcher
> >>
> >>output
> >>
> >>>voltage seem to take longer to stabilize (1400us
> >>>instead of 300us) but the ripple isn't bigger
> >>
> >>(3mV).
> >>
> >>>I send you in attachment the output of the
> >>
> >>switcher at
> >>
> >>>room temperature, which work correctly, and at
> low
> >>>temperature, where at think there is the problem.
> >>>
> >>>Fred
> >>>
> >>>--- David Rea <dave@dave...> wrote:
> >>>
> >>>
> >>>>>I use a LTC3401 with typical reference design
> >>
> >>and
> >>
> >>>>I
> >>>>
> >>>>>have few problems at low temperature (-10oC).
> >>
> >>This
> >>
> >>>>>seem to appear when a higher current is
> >>
> >>request by
> >>
> >>>>the
> >>>>
> >>>>>device (from 120mA to 170mA) and the battery
> >>
> >>(2 X
> >>
> >>>>>Energizer L91 AA 1.5V in parallel) should
> >>
> >>support
> >>
> >>>>this
> >>>>
> >>>>>increase.
> >>>>
> >>>>Can you be more specific about what problem is
> >>>>occuring? Is the output
> >>>>voltage dropping out? Problems with the
> >>
> >>switching?
> >>
> >>>>Excessive ripple?
> >>>>
> >>>>Dave
> >>>>
> >>>>
> >>>
> >>>
> >>>
> >>>__________________________________
> >>>
> >>
> >>
> > 
> > 
> > 		
> > __________________________________
> >  
> >  
> > 
> > 
> > [Non-text portions of this message have been
> removed]
> > 
> > 
> > 
> > .
> > 
> >  
> > Yahoo! Groups Links
> > 
> > 
> > 
> >  
> > 
> > 
> > 
> > 
> 
> 
> 
> .
> 
>  
> Yahoo! Groups Links
> 
> 
>     msp430-unsubscribe@msp4...
> 
>  
> 
> 
> 
> 


		
__________________________________ 
 





.

 
Yahoo! Groups Links



 

Hi,

David Rea wrote:
> Ripple isn't caused as much by the value of the capacitors as it is
> by the Equivalent Series Resistance (ESR).

Depends, does not if PDN is correctly designed.

Additional note, for ceramic capacitors at low temperatures, you may
want to use ones with tighter tolerance dielectrics (X5R, X7R or C0G).
Good example: 10uF specified Z5V capacitor is around 0.5uF at -24C,
measured at 1kHz, with 10% of nominal voltage.

Indrek

-- 
  Indrek Rebane           |      Borthwick-Pignon
  Electronics Engineer    |    Tartu Science Park
  Phone: (+372) 7 302 641 | Riia 185, 51014 Tartu
  Fax:   (+372) 7 383 041 |               Estonia
  indrek@indr...        |         www.bps.co.ee

> Frederic,
> These batteries has a big series resistence. 170mA
> is a high current even
> for the best ones.
> You may have a big voltage drop.

I don't see it at the switcher output.

> I have a design with MSP430 + Xemics DP1203
working
> at near -40C. Tx time is
> less than 10ms, duty cycle less than 1%. The Tx
> current is supplied by two
> 47uF tantalum capacitors.

Why low ESR is so important in the voltage regulation?
I used ceramic X5R capacitor.

> No DC-DC in my case.
> The only problem I've got was the 32KHz XT1 stopping
> when the temperature
> arise above 0C. Some umidity in the air, during MSP
> assembly, condensated in
> the XT1 terminals.... Solution was to use hot air
> before sealing the board.
> 
> Augusto
> 
> 
> -----Mensagem original-----
> De: Frederic Beaulieu [mailto:Frb78@Frb7...] 
> Enviada em: sexta-feira, 10 de dezembro de 2004
> 16:46
> Para: msp430@msp4...;
> onestone@ones...
> Assunto: Re: [msp430] DC-DC converter design
> 
> 
> 
> 
> I used already a Lithium battery, the Energizer L91
> AA
> 1.5V (see attachement), which is supposed to
> opperate
> down to -40oC. The only thing I can see is that the
> discharge current at lower temp is too low, but
> 170mA
> is not that high ...
> 
> --- onestone <onestone@ones...> wrote:
> > 
> > I would change to a battery capable of lower
> > temperature operation.
> > Li-poly tends to be a lot better than alkaline,
> and
> > is rechargable. LTC 
> > is not rechargable but operates down to -40C.
> > 
> > Al
> > 
> > Frederic Beaulieu wrote:
> > 
> > > 
> > > After few tests, I think it's the battery which
> > cannot
> > > support the current load at lower temperature.
> > > I have put my board (without battery) in a
> freezer
> > > (~-10oC) for about half a hour then I have
> > inserted
> > > the warm battery in it. All work fine! However,
> if
> > I
> > > let the device working in the freezer, after 20
> > > minutes, the Tx problem occurs.
> > > Is there a way to solve this problem? Can I put
> > bigger
> > > cap in front of the switcher (input capacity -
> C67
> > > (see attachement)) and/or after it (output
> > capacity -
> > > C68)? Is there side effect to do that?
> > > 
> > > Your help is very appriciated!
> > > Fred
> > > 
> > > 
> > > --- David Rea <dave@dave...> wrote:
> > > 
> > > 
> > >>I don't see the voltage scale on those TIFs, but
> > you
> > >>say the ripple is
> > >>only 3mV. Unless you're driving a VCO directly
> > with
> > >>the output of the
> > >>power supply, I don't see how that could
> possibly
> > >>cause the transmitter
> > >>to glitch. The XE1203 datasheet reports (at a
> > quick
> > >>glance) that it
> > >>works from 2.4 to 3.6VDC, so 3mV ripple in the
> > >>supply really shouldn't
> > >>bother it.
> > >>
> > >>I see that the operating temp of the XE1203 is
> > >>-40~85.
> > >>
> > >>Here are a few things to consider:
> > >>
> > >>1) Does the circuit exhibit the same behavior
> when
> > >>powered by a bench
> > >>supply at low temperatures?
> > >>
> > >>2) A can of "Freeze Mist" or other electronics
> > >>cooling spray can be
> > >>helpful in troubleshooting this type of problem
> -
> > >>you can spray
> > >>refrigerant onto each chip and see which one
> > causes
> > >>your problem:
> > >>
> > > 
> > >
> >
>
http://www.unicornelex.com/newunicorn/subcategory.php?catK04&
> > > 
> > >>Dave
> > >>
> > >>Quoting Frederic Beaulieu <frb78@frb7...>:
> > >>
> > >>
> > >>>I'm working with a RF transceiver Xemics
> XE1203.
> > >>
> > >>When
> > >>
> > >>>it is in Rx mode all operate correctly, but
> when
> > >>
> > >>it
> > >>
> > >>>turn in Tx mode (which require 50 mA more), the
> > >>>message  is not sent correctly. The switcher
> > >>
> > >>output
> > >>
> > >>>voltage seem to take longer to stabilize
> (1400us
> > >>>instead of 300us) but the ripple isn't bigger
> > >>
> > >>(3mV).
> > >>
> > >>>I send you in attachment the output of the
> > >>
> > >>switcher at
> > >>
> > >>>room temperature, which work correctly, and at
> > low
> > >>>temperature, where at think there is the
> problem.
> > >>>
> > >>>Fred
> > >>>
> > >>>--- David Rea <dave@dave...> wrote:
> > >>>
> > >>>
> > >>>>>I use a LTC3401 with typical reference design
> > >>
> > >>and
> > >>
> > >>>>I
> > >>>>
> > >>>>>have few problems at low temperature (-10oC).
> > >>
> > >>This
> > >>
> > >>>>>seem to appear when a higher current is
> > >>
> > >>request by
> > >>
> > >>>>the
> > >>>>
> > >>>>>device (from 120mA to 170mA) and the battery
> > >>
> > >>(2 X
> > >>
> > >>>>>Energizer L91 AA 1.5V in parallel) should
> > >>
> > >>support
> > >>
> > >>>>this
> > >>>>
> > >>>>>increase.
> > >>>>
> > >>>>Can you be more specific about what problem is
> > >>>>occuring? Is the output
> > >>>>voltage dropping out? Problems with the
> > >>
> > >>switching?
> > >>
> > >>>>Excessive ripple?
> > >>>>
> > >>>>Dave
> > >>>>
> > >>>>
> > >>>
> > >>>
> > >>>
> > >>>__________________________________
> > >>>
> > >>
> > >>
> > > 
> > > 
> > > 		
> > > __________________________________
> > >  
> > >  
> > > 
> > > 
> > > [Non-text portions of this message have been
> > removed]
> > > 
> > > 
> > > 
> > > .
> > > 
> > >  
> > > Yahoo! Groups Links
> > > 
> > > 
> > > 
> > >  
> > > 
> > > 
> > > 
> > > 
> > 
> > 
> > 
> > .
> > 
> >  
> > Yahoo! Groups Links
> > 
> > 
> >     msp430-unsubscribe@msp4...
> > 
> >  
> > 
> > 
> > 
> > 
> 
> 
> 		
> __________________________________ 
>  
> 
> [Non-text portions of this message have been
> removed]
> 
> 
> 
> .
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
> 
> 



	
		
__________________________________ 

What is PDN?

--- Indrek Rebane <indrek@indr...> wrote:

> Hi,
> 
> David Rea wrote:
> > Ripple isn't caused as much by the value of the
> capacitors as it is
> > by the Equivalent Series Resistance (ESR).
> 
> Depends, does not if PDN is correctly designed.
> 
> Additional note, for ceramic capacitors at low
> temperatures, you may
> want to use ones with tighter tolerance dielectrics
> (X5R, X7R or C0G).
> Good example: 10uF specified Z5V capacitor is around
> 0.5uF at -24C,
> measured at 1kHz, with 10% of nominal voltage.
> 
> Indrek
> 
> -- 
>   Indrek Rebane           |      Borthwick-Pignon
>   Electronics Engineer    |    Tartu Science Park
>   Phone: (+372) 7 302 641 | Riia 185, 51014 Tartu
>   Fax:   (+372) 7 383 041 |               Estonia
>   indrek@indr...        |         www.bps.co.ee
> 
> 



	
		
__________________________________ 

Hi,

Frederic Beaulieu wrote:
> What is PDN?

Power Delivery Network aka PDS, Power Delivery System.

Indrek

-- 
  Indrek Rebane           |      Borthwick-Pignon
  Electronics Engineer    |    Tartu Science Park
  Phone: (+372) 7 302 641 | Riia 185, 51014 Tartu
  Fax:   (+372) 7 383 041 |               Estonia
  indrek@indr...        |         www.bps.co.ee

> Frederic,
> These batteries has a big series resistence.

What is the impact of a such high battery's serie
resistance?

>  170mA is a high current even
> for the best ones.
> You may have a big voltage drop.
> I have a design with MSP430 + Xemics DP1203 working
> at near -40C. Tx time is
> less than 10ms, duty cycle less than 1%. The Tx
> current is supplied by two
> 47uF tantalum capacitors. 
> No DC-DC in my case.
> The only problem I've got was the 32KHz XT1 stopping
> when the temperature
> arise above 0C. Some umidity in the air, during MSP
> assembly, condensated in
> the XT1 terminals.... Solution was to use hot air
> before sealing the board.
> 
> Augusto
> 
> 
> -----Mensagem original-----
> De: Frederic Beaulieu [mailto:Frb78@Frb7...] 
> Enviada em: sexta-feira, 10 de dezembro de 2004
> 16:46
> Para: msp430@msp4...;
> onestone@ones...
> Assunto: Re: [msp430] DC-DC converter design
> 
> 
> 
> 
> I used already a Lithium battery, the Energizer L91
> AA
> 1.5V (see attachement), which is supposed to
> opperate
> down to -40oC. The only thing I can see is that the
> discharge current at lower temp is too low, but
> 170mA
> is not that high ...
> 
> --- onestone <onestone@ones...> wrote:
> > 
> > I would change to a battery capable of lower
> > temperature operation.
> > Li-poly tends to be a lot better than alkaline,
> and
> > is rechargable. LTC 
> > is not rechargable but operates down to -40C.
> > 
> > Al
> > 
> > Frederic Beaulieu wrote:
> > 
> > > 
> > > After few tests, I think it's the battery which
> > cannot
> > > support the current load at lower temperature.
> > > I have put my board (without battery) in a
> freezer
> > > (~-10oC) for about half a hour then I have
> > inserted
> > > the warm battery in it. All work fine! However,
> if
> > I
> > > let the device working in the freezer, after 20
> > > minutes, the Tx problem occurs.
> > > Is there a way to solve this problem? Can I put
> > bigger
> > > cap in front of the switcher (input capacity -
> C67
> > > (see attachement)) and/or after it (output
> > capacity -
> > > C68)? Is there side effect to do that?
> > > 
> > > Your help is very appriciated!
> > > Fred
> > > 
> > > 
> > > --- David Rea <dave@dave...> wrote:
> > > 
> > > 
> > >>I don't see the voltage scale on those TIFs, but
> > you
> > >>say the ripple is
> > >>only 3mV. Unless you're driving a VCO directly
> > with
> > >>the output of the
> > >>power supply, I don't see how that could
> possibly
> > >>cause the transmitter
> > >>to glitch. The XE1203 datasheet reports (at a
> > quick
> > >>glance) that it
> > >>works from 2.4 to 3.6VDC, so 3mV ripple in the
> > >>supply really shouldn't
> > >>bother it.
> > >>
> > >>I see that the operating temp of the XE1203 is
> > >>-40~85.
> > >>
> > >>Here are a few things to consider:
> > >>
> > >>1) Does the circuit exhibit the same behavior
> when
> > >>powered by a bench
> > >>supply at low temperatures?
> > >>
> > >>2) A can of "Freeze Mist" or other electronics
> > >>cooling spray can be
> > >>helpful in troubleshooting this type of problem
> -
> > >>you can spray
> > >>refrigerant onto each chip and see which one
> > causes
> > >>your problem:
> > >>
> > > 
> > >
> >
>
http://www.unicornelex.com/newunicorn/subcategory.php?catK04&
> > > 
> > >>Dave
> > >>
> > >>Quoting Frederic Beaulieu <frb78@frb7...>:
> > >>
> > >>
> > >>>I'm working with a RF transceiver Xemics
> XE1203.
> > >>
> > >>When
> > >>
> > >>>it is in Rx mode all operate correctly, but
> when
> > >>
> > >>it
> > >>
> > >>>turn in Tx mode (which require 50 mA more), the
> > >>>message  is not sent correctly. The switcher
> > >>
> > >>output
> > >>
> > >>>voltage seem to take longer to stabilize
> (1400us
> > >>>instead of 300us) but the ripple isn't bigger
> > >>
> > >>(3mV).
> > >>
> > >>>I send you in attachment the output of the
> > >>
> > >>switcher at
> > >>
> > >>>room temperature, which work correctly, and at
> > low
> > >>>temperature, where at think there is the
> problem.
> > >>>
> > >>>Fred
> > >>>
> > >>>--- David Rea <dave@dave...> wrote:
> > >>>
> > >>>
> > >>>>>I use a LTC3401 with typical reference design
> > >>
> > >>and
> > >>
> > >>>>I
> > >>>>
> > >>>>>have few problems at low temperature (-10oC).
> > >>
> > >>This
> > >>
> > >>>>>seem to appear when a higher current is
> > >>
> > >>request by
> > >>
> > >>>>the
> > >>>>
> > >>>>>device (from 120mA to 170mA) and the battery
> > >>
> > >>(2 X
> > >>
> > >>>>>Energizer L91 AA 1.5V in parallel) should
> > >>
> > >>support
> > >>
> > >>>>this
> > >>>>
> > >>>>>increase.
> > >>>>
> > >>>>Can you be more specific about what problem is
> > >>>>occuring? Is the output
> > >>>>voltage dropping out? Problems with the
> > >>
> > >>switching?
> > >>
> > >>>>Excessive ripple?
> > >>>>
> > >>>>Dave
> > >>>>
> > >>>>
> > >>>
> > >>>
> > >>>
> > >>>__________________________________
> > >>>
> > >>
> > >>
> > > 
> > > 
> > > 		
> > > __________________________________
> > >  
> > >  
> > > 
> > > 
> > > [Non-text portions of this message have been
> > removed]
> > > 
> > > 
> > > 
> > > .
> > > 
> > >  
> > > Yahoo! Groups Links
> > > 
> > > 
> > > 
> > >  
> > > 
> > > 
> > > 
> > > 
> > 
> > 
> > 
> > .
> > 
> >  
> > Yahoo! Groups Links
> > 
> > 
> >     msp430-unsubscribe@msp4...
> > 
> >  
> > 
> > 
> > 
> > 
> 
> 
> 		
> __________________________________ 
>  
> 
> [Non-text portions of this message have been
> removed]
> 
> 
> 
> .
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
> 
> 



		
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Quoting Frederic Beaulieu <Frb78@Frb7...>:

> What is the impact of a such high battery's
serie
> resistance?

Imagine the battery were actually two components - an "ideal" battery
that always outputs the exact voltage on its discharge curve, in series
with a resistor. This is the series resistance of the battery.

The result is that as you draw more current out of the battery, you
observe a voltage drop as if there were a resistor in series with the
battery. This voltage drop might be affecting the performance of your
boost converter.

A good example of series resistance being a real-world problem is in the
world of flashlights. I'm a total flashlight geek... :) In typical
incandescent flashlights, the bulb draws relatively little current, so
the series resistance of your typical AA battery isn't a big deal. But
in high-intensity tactical flashlights, the xenon bulb requires more
current. Most of them like to run at 6V. So why not just put in 4 AA
batteries? The bulb draws so much current that the series resistance of
the batteries would a) drop a significant voltage and b) cause unsafe
heating (due to power dissipation of the ESR) of each individual
battery.

So, most of your high-intensity tactical lights and weaponlights use 3V
lithim batteries.

Dave

High series (internal) resistence reduces the capability of the battery to
deliver current. 
It is also called "dynamic performance".
I did try to find some specs to you but none found.
 
Since you have it working with worm battery and not working with frozen
battery the only answer is the battery. Since battery only deliver some
current at some voltage you should have only a drop in the voltage or in the
current (delivered to your DC-DC circuit).
So, even if you have not detected it doesn't mean it is not there.
Tantalum capacitors (they can sustain their capacitance at verey low
temperatures) may help you to deliver more current to DC-DC circuit during
Tx. 

I would use a digital scope triggered with TX Enable signal to analyse the
supply voltage before and after DC-DC (in high frequency as well to detect
very short supply interruptions).
A series resistor (after and before DC-DC) would help to measure the current
surge when TX Enabled.


Hope it helps,

Augusto


-----Mensagem original-----
De: Frederic Beaulieu [mailto:Frb78@Frb7...] 
Enviada em: sexta-feira, 10 de dezembro de 2004 19:12
Para: msp430@msp4...
Assunto: Re: RES: [msp430] DC-DC converter design



> Frederic,
> These batteries has a big series resistence.

What is the impact of a such high battery's serie
resistance?

>  170mA is a high current even
> for the best ones.
> You may have a big voltage drop.
> I have a design with MSP430 + Xemics DP1203 working
> at near -40C. Tx time is
> less than 10ms, duty cycle less than 1%. The Tx
> current is supplied by two
> 47uF tantalum capacitors.
> No DC-DC in my case.
> The only problem I've got was the 32KHz XT1 stopping
> when the temperature
> arise above 0C. Some umidity in the air, during MSP
> assembly, condensated in
> the XT1 terminals.... Solution was to use hot air
> before sealing the board.
> 
> Augusto
> 
> 
> -----Mensagem original-----
> De: Frederic Beaulieu [mailto:Frb78@Frb7...]
> Enviada em: sexta-feira, 10 de dezembro de 2004
> 16:46
> Para: msp430@msp4...;
> onestone@ones...
> Assunto: Re: [msp430] DC-DC converter design
> 
> 
> 
> 
> I used already a Lithium battery, the Energizer L91
> AA
> 1.5V (see attachement), which is supposed to
> opperate
> down to -40oC. The only thing I can see is that the
> discharge current at lower temp is too low, but
> 170mA
> is not that high ...
> 
> --- onestone <onestone@ones...> wrote:
> > 
> > I would change to a battery capable of lower
> > temperature operation.
> > Li-poly tends to be a lot better than alkaline,
> and
> > is rechargable. LTC
> > is not rechargable but operates down to -40C.
> > 
> > Al
> > 
> > Frederic Beaulieu wrote:
> > 
> > > 
> > > After few tests, I think it's the battery which
> > cannot
> > > support the current load at lower temperature.
> > > I have put my board (without battery) in a
> freezer
> > > (~-10oC) for about half a hour then I have
> > inserted
> > > the warm battery in it. All work fine! However,
> if
> > I
> > > let the device working in the freezer, after 20
> > > minutes, the Tx problem occurs.
> > > Is there a way to solve this problem? Can I put
> > bigger
> > > cap in front of the switcher (input capacity -
> C67
> > > (see attachement)) and/or after it (output
> > capacity -
> > > C68)? Is there side effect to do that?
> > > 
> > > Your help is very appriciated!
> > > Fred
> > > 
> > > 
> > > --- David Rea <dave@dave...> wrote:
> > > 
> > > 
> > >>I don't see the voltage scale on those TIFs, but
> > you
> > >>say the ripple is
> > >>only 3mV. Unless you're driving a VCO directly
> > with
> > >>the output of the
> > >>power supply, I don't see how that could
> possibly
> > >>cause the transmitter
> > >>to glitch. The XE1203 datasheet reports (at a
> > quick
> > >>glance) that it
> > >>works from 2.4 to 3.6VDC, so 3mV ripple in the
> > >>supply really shouldn't
> > >>bother it.
> > >>
> > >>I see that the operating temp of the XE1203 is
> > >>-40~85.
> > >>
> > >>Here are a few things to consider:
> > >>
> > >>1) Does the circuit exhibit the same behavior
> when
> > >>powered by a bench
> > >>supply at low temperatures?
> > >>
> > >>2) A can of "Freeze Mist" or other electronics
> > >>cooling spray can be
> > >>helpful in troubleshooting this type of problem
> -
> > >>you can spray
> > >>refrigerant onto each chip and see which one
> > causes
> > >>your problem:
> > >>
> > > 
> > >
> >
>
http://www.unicornelex.com/newunicorn/subcategory.php?catK04&
> > > 
> > >>Dave
> > >>
> > >>Quoting Frederic Beaulieu <frb78@frb7...>:
> > >>
> > >>
> > >>>I'm working with a RF transceiver Xemics
> XE1203.
> > >>
> > >>When
> > >>
> > >>>it is in Rx mode all operate correctly, but
> when
> > >>
> > >>it
> > >>
> > >>>turn in Tx mode (which require 50 mA more), the
> > >>>message  is not sent correctly. The switcher
> > >>
> > >>output
> > >>
> > >>>voltage seem to take longer to stabilize
> (1400us
> > >>>instead of 300us) but the ripple isn't bigger
> > >>
> > >>(3mV).
> > >>
> > >>>I send you in attachment the output of the
> > >>
> > >>switcher at
> > >>
> > >>>room temperature, which work correctly, and at
> > low
> > >>>temperature, where at think there is the
> problem.
> > >>>
> > >>>Fred
> > >>>
> > >>>--- David Rea <dave@dave...> wrote:
> > >>>
> > >>>
> > >>>>>I use a LTC3401 with typical reference design
> > >>
> > >>and
> > >>
> > >>>>I
> > >>>>
> > >>>>>have few problems at low temperature (-10oC).
> > >>
> > >>This
> > >>
> > >>>>>seem to appear when a higher current is
> > >>
> > >>request by
> > >>
> > >>>>the
> > >>>>
> > >>>>>device (from 120mA to 170mA) and the battery
> > >>
> > >>(2 X
> > >>
> > >>>>>Energizer L91 AA 1.5V in parallel) should
> > >>
> > >>support
> > >>
> > >>>>this
> > >>>>
> > >>>>>increase.
> > >>>>
> > >>>>Can you be more specific about what problem is
occuring? Is the 
> > >>>>output voltage dropping out? Problems with the
> > >>
> > >>switching?
> > >>
> > >>>>Excessive ripple?
> > >>>>
> > >>>>Dave
> > >>>>
> > >>>>
> > >>>
> > >>>
> > >>>
> > >>>__________________________________
> > >>>
> > >>
> > >>
> > > 
> > > 
> > > 		
> > > __________________________________
> > >  
> > >  
> > > 
> > > 
> > > [Non-text portions of this message have been
> > removed]
> > > 
> > > 
> > > 
> > > .
> > > 
> > >  
> > > Yahoo! Groups Links
> > > 
> > > 
> > > 
> > >  
> > > 
> > > 
> > > 
> > > 
> > 
> > 
> > 
> > .
> > 
> >  
> > Yahoo! Groups Links
> > 
> > 
> >     msp430-unsubscribe@msp4...
> > 
> >  
> > 
> > 
> > 
> > 
> 
> 
> 		
> __________________________________
>  
> 
> [Non-text portions of this message have been
> removed]
> 
> 
> 
> .
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
> 
> 



		
__________________________________ 
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.

 
Yahoo! Groups Links



 

tekcell (i think they call itself now vitcrocell or similar) have
a new wire wound Li AA battery (3.6V) that is able to deliver 1A or more
and work down to -55degC. If you need very low temp. operation you
should drop your converter and use this one.

M.

On Fri, Dec 10, 2004 at 05:48:34PM -0200, augusto
einsfeldt wrote:
> 
> Frederic,
> These batteries has a big series resistence. 170mA is a high current even
> for the best ones.
> You may have a big voltage drop.
> I have a design with MSP430 + Xemics DP1203 working at near -40C. Tx time
is
> less than 10ms, duty cycle less than 1%. The Tx current is supplied by two
> 47uF tantalum capacitors. 
> No DC-DC in my case.
> The only problem I've got was the 32KHz XT1 stopping when the
temperature
> arise above 0C. Some umidity in the air, during MSP assembly, condensated
in
> the XT1 terminals.... Solution was to use hot air before sealing the board.
> 
> Augusto
> 
> 
> -----Mensagem original-----
> De: Frederic Beaulieu [mailto:Frb78@Frb7...] 
> Enviada em: sexta-feira, 10 de dezembro de 2004 16:46
> Para: msp430@msp4...; onestone@ones...
> Assunto: Re: [msp430] DC-DC converter design
> 
> 
> 
> 
> I used already a Lithium battery, the Energizer L91 AA
> 1.5V (see attachement), which is supposed to opperate
> down to -40oC. The only thing I can see is that the
> discharge current at lower temp is too low, but 170mA
> is not that high ...
> 
> --- onestone <onestone@ones...> wrote:
> > 
> > I would change to a battery capable of lower
> > temperature operation.
> > Li-poly tends to be a lot better than alkaline, and
> > is rechargable. LTC 
> > is not rechargable but operates down to -40C.
> > 
> > Al
> > 
> > Frederic Beaulieu wrote:
> > 
> > > 
> > > After few tests, I think it's the battery which
> > cannot
> > > support the current load at lower temperature.
> > > I have put my board (without battery) in a freezer
> > > (~-10oC) for about half a hour then I have
> > inserted
> > > the warm battery in it. All work fine! However, if
> > I
> > > let the device working in the freezer, after 20
> > > minutes, the Tx problem occurs.
> > > Is there a way to solve this problem? Can I put
> > bigger
> > > cap in front of the switcher (input capacity - C67
> > > (see attachement)) and/or after it (output
> > capacity -
> > > C68)? Is there side effect to do that?
> > > 
> > > Your help is very appriciated!
> > > Fred
> > > 
> > > 
> > > --- David Rea <dave@dave...> wrote:
> > > 
> > > 
> > >>I don't see the voltage scale on those TIFs, but
> > you
> > >>say the ripple is
> > >>only 3mV. Unless you're driving a VCO directly
> > with
> > >>the output of the
> > >>power supply, I don't see how that could possibly
> > >>cause the transmitter
> > >>to glitch. The XE1203 datasheet reports (at a
> > quick
> > >>glance) that it
> > >>works from 2.4 to 3.6VDC, so 3mV ripple in the
> > >>supply really shouldn't
> > >>bother it.
> > >>
> > >>I see that the operating temp of the XE1203 is
> > >>-40~85.
> > >>
> > >>Here are a few things to consider:
> > >>
> > >>1) Does the circuit exhibit the same behavior when
> > >>powered by a bench
> > >>supply at low temperatures?
> > >>
> > >>2) A can of "Freeze Mist" or other electronics
> > >>cooling spray can be
> > >>helpful in troubleshooting this type of problem -
> > >>you can spray
> > >>refrigerant onto each chip and see which one
> > causes
> > >>your problem:
> > >>
> > > 
> > >
> >
> http://www.unicornelex.com/newunicorn/subcategory.php?catK04&
> > > 
> > >>Dave
> > >>
> > >>Quoting Frederic Beaulieu <frb78@frb7...>:
> > >>
> > >>
> > >>>I'm working with a RF transceiver Xemics XE1203.
> > >>
> > >>When
> > >>
> > >>>it is in Rx mode all operate correctly, but when
> > >>
> > >>it
> > >>
> > >>>turn in Tx mode (which require 50 mA more), the
> > >>>message  is not sent correctly. The switcher
> > >>
> > >>output
> > >>
> > >>>voltage seem to take longer to stabilize (1400us
> > >>>instead of 300us) but the ripple isn't bigger
> > >>
> > >>(3mV).
> > >>
> > >>>I send you in attachment the output of the
> > >>
> > >>switcher at
> > >>
> > >>>room temperature, which work correctly, and at
> > low
> > >>>temperature, where at think there is the problem.
> > >>>
> > >>>Fred
> > >>>
> > >>>--- David Rea <dave@dave...> wrote:
> > >>>
> > >>>
> > >>>>>I use a LTC3401 with typical reference design
> > >>
> > >>and
> > >>
> > >>>>I
> > >>>>
> > >>>>>have few problems at low temperature (-10oC).
> > >>
> > >>This
> > >>
> > >>>>>seem to appear when a higher current is
> > >>
> > >>request by
> > >>
> > >>>>the
> > >>>>
> > >>>>>device (from 120mA to 170mA) and the battery
> > >>
> > >>(2 X
> > >>
> > >>>>>Energizer L91 AA 1.5V in parallel) should
> > >>
> > >>support
> > >>
> > >>>>this
> > >>>>
> > >>>>>increase.
> > >>>>
> > >>>>Can you be more specific about what problem is
> > >>>>occuring? Is the output
> > >>>>voltage dropping out? Problems with the
> > >>
> > >>switching?
> > >>
> > >>>>Excessive ripple?
> > >>>>
> > >>>>Dave
> > >>>>
> > >>>>
> > >>>
> > >>>
> > >>>
> > >>>__________________________________
> > >>>
> > >>
> > >>
> > > 
> > > 
> > > 		
> > > __________________________________
> > >  
> > >  
> > > 
> > > 
> > > [Non-text portions of this message have been
> > removed]
> > > 
> > > 
> > > 
> > > .
> > > 
> > >  
> > > Yahoo! Groups Links
> > > 
> > > 
> > > 
> > >  
> > > 
> > > 
> > > 
> > > 
> > 
> > 
> > 
> > .
> > 
> >  
> > Yahoo! Groups Links
> > 
> > 
> >     msp430-unsubscribe@msp4...
> > 
> >  
> > 
> > 
> > 
> > 
> 
> 
> 		
> __________________________________ 
>  
> 
> 
> 
> 
> 
> .
> 
>  
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
> 
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> 
> 
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> 
> 
> 
        Matthias