Matthias, good sugestion! Indeed, those guys (vitzrocell) are the first ones (in the internet) to give detailed data. Varta and others give just the basics. First time I see something about "initial voltage delay". Its important thing about this battery technology. Now have to think about a way to waste large current for few seconds in my application when it wake-up first time... Just to mention the information in the web, the battery pointed by Matthias would be SB-AA02: Specifications: 1/2 AA Size Nominal Voltage ---- 3.6V STD Discharge Current ------------------------------- 0.5mA Max. Continuous Current ---------------------------- 15mA Max. Pulse Current 40mA Nominal Capacity ------------------ 1200mAh(at 0.5mA to 2.0V @20) Weight ------------------ 8.8g Operating Temperature Range --------------------- -55 ~ +85 Reaction Surface Area -------------------------------- 7cm2 But, you see, the maximum pulse current should be around 40mA so, need big caps to deliver 170mA during Frederic's TX.... (or multiple batteries in parallel) Augusto -----Mensagem original----- De: Matthias Weingart [mailto:msp430@msp4...] Enviada em: sexta-feira, 10 de dezembro de 2004 22:26 Para: msp430@msp4... Assunto: Re: RES: [msp430] DC-DC converter design 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 > > > > > > > > > > > > . > > > Yahoo! Groups Links > > > > > > > Matthias . Yahoo! Groups Links
DC-DC converter design
Started by ●December 10, 2004
Reply by ●December 10, 20042004-12-10
Reply by ●December 10, 20042004-12-10
A better choice for battery, found after sending previous email, and keep in the Matthias' suggestion: Vitzrocell SW-AA02. Its 2.4A/h with up to 400mA continuous current and operation downto -55C. Or, for big guys, SW-D02: 14A/h with 1.8A continuous.... that Teckraft made a hell of a battery... The best battery I know. -Augusto -----Mensagem original----- De: Matthias Weingart [mailto:msp430@msp4...] Enviada em: sexta-feira, 10 de dezembro de 2004 22:26 Para: msp430@msp4... Assunto: Re: RES: [msp430] DC-DC converter design 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 > > > > > > > > > > > > . > > > Yahoo! Groups Links > > > > > > > Matthias . Yahoo! Groups Links
Reply by ●December 11, 20042004-12-11
That may well be so, but they are incapable of delivering more than a
few milliamps at these temperatures. In fact even at higher temperatures
the peak currents of coin cells are not suitable for 170mA.
Al
augusto einsfeldt wrote:
>
> CR2032 goes to -40C. VARTA's CRAA (2A/h) goes to -30C.
> Caps must be tantalum.
>
>
>
> -----Mensagem original-----
> De: onestone [mailto:onestone@ones...]
> Enviada em: sexta-feira, 10 de dezembro de 2004 16:24
> Para: msp430@msp4...
> Assunto: Re: [msp430] DC-DC converter design
>
>
>
>
> 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
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>>__________________________________
>>>>
>>>
>>>
>>
>>
>>__________________________________
>>
>>
>>
>>
>>
>>
>>
>>
>>.
>>
>>
>>Yahoo! Groups Links
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
>
> .
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
>
>
> .
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
Reply by ●December 11, 20042004-12-11
> 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 will certainly try these tantalum cap! Even with 2 Energizer Lithium L91 in parallel, it is possible that not enough current is supply to Dc-Dc converter? Is there power consumption consideration in having 2 cell like this in parallel? I read somewhere that they can self-discharge. > 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 > > > > > > > > > > > > > > > > > > > > > > > __________________________________ >
Reply by ●December 11, 20042004-12-11
On Fri, 2004-12-10 at 15:18, Frederic Beaulieu wrote:
> Why low ESR is so important in the voltage
regulation?
> I used ceramic X5R capacitor.
There are two reasons for this...
1) When your circuit suddenly demands more current and the battery is
unable to source this current, it gets drawn from the capacitor. If the
capacitor doesn't have a low ESR, then this current will induce a
voltage across the ESR of the cap and the voltage input to the supply
might not be maintained.
2) Any time you have a significant change in load current on your
switcher, it takes the supply controller some amount of time to adjust
the switching parameters to maintain the voltage. This causes ripple on
your input and output - which is normally handled by the capacitors. But
if your capacitors have a high ESR, then problem 1 happens and you end
up with a significant ripple voltage.
Dave
Reply by ●December 13, 20042004-12-13
>From: "onestone" <onestone@ones...> > >This is not a Li-poly or Li-ion. These output 3.6V and >are capable of >very high discharge currents at low temperatures. I >regularly use these in systems drawing up to 1A. Which one exactly do you use? Are they expensive? How do you regularize it for a 3V output voltage? I can see for 5V output (switcher) but I'm not sure for 3V. > 170mA is very high for many >battery >technologies. > >Al __________________________________
Reply by ●December 14, 20042004-12-14
On nearly all my designs I use a regulator of some kind, mainly to get
the most out of a battery while retaining the same supply voltage
enabling high speed operation and flash writing. The MAX1724 has an
extremely low quiescent current at only 1.5uA, but is limited to 150mA.
IT takes input of 0.8 to 5.5V and comes in a range of fixed voltages.
For high current I use the MAX1674. It's quiescent current is 16uA, but
it can output 1A from an input of 0.7V to Vout. It works with slight
overvoltage.
I get my batteries from Taiwan. 3.3Ah costs me US$7 in low volume US$5
in 100 off. I get mine through a friend in Asia. The company is called
HEcell. The free trade magazine 'ELECTRONIC COMPONENTS ASIA' is an
absolute gold mine for stuff like this.
Al
Frederic Beaulieu wrote:
>>From: "onestone"
<onestone@ones...>
>>
>>This is not a Li-poly or Li-ion. These output 3.6V
>
> and >are capable of
>
>>very high discharge currents at low temperatures. I
>>regularly use these in systems drawing up to 1A.
>
>
> Which one exactly do you use? Are they expensive?
> How do you regularize it for a 3V output voltage? I
> can see for 5V output (switcher) but I'm not sure for
> 3V.
>
>
>>170mA is very high for many >battery
>>technologies.
>>
>>Al
>
>
>
>
>
>
> __________________________________
>
>
>
>
> .
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
Reply by ●December 14, 20042004-12-14
Al,
Can you direct me to where I can subscribe to the magazine.
Cheers,
Peter.
onestone wrote:
> On nearly all my designs I use a regulator of some
kind, mainly to get
> the most out of a battery while retaining the same supply voltage
> enabling high speed operation and flash writing. The MAX1724 has an
> extremely low quiescent current at only 1.5uA, but is limited to 150mA.
> IT takes input of 0.8 to 5.5V and comes in a range of fixed voltages.
> For high current I use the MAX1674. It's quiescent current is 16uA,
but
> it can output 1A from an input of 0.7V to Vout. It works with slight
> overvoltage.
>
> I get my batteries from Taiwan. 3.3Ah costs me US$7 in low volume US$5
> in 100 off. I get mine through a friend in Asia. The company is called
> HEcell. The free trade magazine 'ELECTRONIC COMPONENTS ASIA' is
an
> absolute gold mine for stuff like this.
>
> Al
>
> Frederic Beaulieu wrote:
>
>
>>>From: "onestone" <onestone@ones...>
>>>
>>>This is not a Li-poly or Li-ion. These output 3.6V
>>
>>and >are capable of
>>
>>
>>>very high discharge currents at low temperatures. I
>>>regularly use these in systems drawing up to 1A.
>>
>>
>>Which one exactly do you use? Are they expensive?
>>How do you regularize it for a 3V output voltage? I
>>can see for 5V output (switcher) but I'm not sure for
>>3V.
>>
>>
>>
>>>170mA is very high for many >battery
>>>technologies.
>>>
>>>Al
>>
>>
>>
>>
>>
>>
>>__________________________________
>>
>>
>>
>>
>>.
>>
>>
>>Yahoo! Groups Links
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
>
>
> .
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
>
>
--
------------------------------
Web: www.homanndesigns.com
email: homann@homa...
Phone: +61 421 601 665
www.homanndesigns.com/DigiSpeedDeal.html - DC Spindle control
www.homanndesigns.com/TurboTaig.html - Taig Mill Upgrade board
Reply by ●December 14, 20042004-12-14
My apologies Peter, but I had my subscription set up for me. I haven't
got one lying around. A new one is due soon, but if you can give me a
business address I will try and organise one to be sent to you.
Al
Peter Homann wrote:
> Al,
>
> Can you direct me to where I can subscribe to the magazine.
>
> Cheers,
>
> Peter.
>
> onestone wrote:
>
>
>>On nearly all my designs I use a regulator of some kind, mainly to get
>>the most out of a battery while retaining the same supply voltage
>>enabling high speed operation and flash writing. The MAX1724 has an
>>extremely low quiescent current at only 1.5uA, but is limited to 150mA.
>>IT takes input of 0.8 to 5.5V and comes in a range of fixed voltages.
>>For high current I use the MAX1674. It's quiescent current is 16uA,
but
>>it can output 1A from an input of 0.7V to Vout. It works with slight
>>overvoltage.
>>
>>I get my batteries from Taiwan. 3.3Ah costs me US$7 in low volume US$5
>>in 100 off. I get mine through a friend in Asia. The company is called
>>HEcell. The free trade magazine 'ELECTRONIC COMPONENTS ASIA'
is an
>>absolute gold mine for stuff like this.
>>
>>Al
>>
>>Frederic Beaulieu wrote:
>>
>>
>>
>>>>From: "onestone" <onestone@ones...>
>>>>
>>>>This is not a Li-poly or Li-ion. These output 3.6V
>>>
>>>and >are capable of
>>>
>>>
>>>
>>>>very high discharge currents at low temperatures. I
>>>>regularly use these in systems drawing up to 1A.
>>>
>>>
>>>Which one exactly do you use? Are they expensive?
>>>How do you regularize it for a 3V output voltage? I
>>>can see for 5V output (switcher) but I'm not sure for
>>>3V.
>>>
>>>
>>>
>>>
>>>>170mA is very high for many >battery
>>>>technologies.
>>>>
>>>>Al
>>>
>>>
>>>
>>>
>>>
>>>
>>>__________________________________
>>>
>>>
>>>
>>>
>>>.
>>>
>>>
>>>Yahoo! Groups Links
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>.
>>
>>
>>Yahoo! Groups Links
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
Reply by ●December 14, 20042004-12-14
For higher power take a look at the National LM2623 switcher. US $0.81 in 1k pcs quantities. 0.8 to 14v at up to 2A. 80uA running. < 2.5uA over temp standby. Regards Shaun Parsons -----Original Message----- From: onestone [mailto:onestone@ones...] Sent: Tuesday, December 14, 2004 5:13 AM To: msp430@msp4... Subject: Re: [msp430] DC-DC converter design On nearly all my designs I use a regulator of some kind, mainly to get the most out of a battery while retaining the same supply voltage enabling high speed operation and flash writing. The MAX1724 has an extremely low quiescent current at only 1.5uA, but is limited to 150mA. NOTICE OF CONFIDENTIALITY The information contained in this e-mail message and in the documents attached herewith (hereinafter "the message") is intended only for the individual or the entity named above and is intended to be confidential. The reading of the message or any retention, copying, dissemination, distribution, disclosure of the existence of the message or of its contents, or any other use of the message or any part thereof, by anyone other than the intended recipient is strictly prohibited. If you received this message and you are not the intended recipient or agent responsible for the delivery of this message to the intended recipient, please refrain from reading it and notify us immediately by telephone +27 (11) 921-7900, so that we can co-ordinate with you, erasure of the message. Although this e-mail and its attachments are believed to be free of any virus or other defect, it is the responsibility of the recipient to ensure that they are virus-free, and no responsibility is accepted by this firm for any loss or damage arising from receipt or use thereof.
