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  1. Weekly Progress Reports
    1. WPR - Week of 10-16 May 2009
    2. WPR - Week of 26-30 Apr 2009
    3. WPR - Week of 19-25 Apr 2009
    4. WPR - Week of 12-18 Apr 2009
    5. WPR - Week of 5-11 Apr 2009
    6. WPR - Week of 1-4 Apr 2009
    7. WPR - Week of 15-21 Mar 2009
    8. WPR - Week of 8-14 Mar 2009
    9. WPR - Week of 1-7 Mar 2009
    10. WPR - Week of 22-28 Feb 2009
    11. WPR - Week of 15-21 Feb 2009
    12. WPR - Week of 8-14 Feb 2009
    13. WPR - Week of 1-7 Feb 2009
    14. WPR - Week of 25-31 Jan 2009
    15. WPR - Week of 18-24 Jan 2009
    16. WPR - Week of 11-17 Jan 2009
  2. Meeting Notes
    1. 7 June 2009
    2. 10 Apr 2009
    3. 3 Apr 2009
    4. 6 Feb 2009
    5. 30 Jan 2009
    6. 23 Jan 2009
    7. 16 Jan 2009
  3. Notes
    1. Notes: 30 Apr 2009
    2. Notes: 29 Apr 2009 (Initial Design Review)
    3. Notes: 14 Apr 2009 (TI Tech Day)
    4. Notes: 5 Mar 2009
    5. Notes: 20 Feb 2009
    6. Notes: 16 Feb 2009
    7. Notes: 5 Feb 2009
    8. Notes: 3 Feb 2009
    9. Notes: 2 Feb 2009
    10. Notes: 1 Feb 2009
    11. Notes: 22 Jan 2009
    12. Notes: 20 Jan 2009
    13. Notes: 13 Jan 2009
    14. Notes: 11 Jan 2009
  4. Questions
  5. Rejected Parts List

Weekly Progress Reports

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WPR - Week of 10-16 May 2009

Last Week

Next Week

Issues - Further behind every day, need an assistant.

WPR - Week of 26-30 Apr 2009

Last Week

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Issues

WPR - Week of 19-25 Apr 2009

Last Week

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Issues

WPR - Week of 12-18 Apr 2009

Last Week

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Issues

WPR - Week of 5-11 Apr 2009

Last Week

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WPR - Week of 1-4 Apr 2009

Last Week

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WPR - Week of 15-21 Mar 2009

Last Week

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Issues

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WPR - Week of 8-14 Mar 2009

Last Week

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Issues

WPR - Week of 1-7 Mar 2009

Last Week

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Issues

WPR - Week of 22-28 Feb 2009

Last Week

Next Week

Issues

WPR - Week of 15-21 Feb 2009

Last Week

Next Week

Issues

WPR - Week of 8-14 Feb 2009

Last Week

Next Week

WPR - Week of 1-7 Feb 2009

Last Week

Next Week

Issues

WPR - Week of 25-31 Jan 2009

Last Week

Next Week

Issues

WPR - Week of 18-24 Jan 2009

Last week

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Actions Required

Issues

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WPR - Week of 11-17 Jan 2009

Last week

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Actions Required

Issues

Meeting Notes

7 June 2009

Capstone Sunday meeting notes: 7 June 2009 Prefered file format is Office 2007

Report to Taylor

Binder-Tuesday- to David @1pm

    HardCopy Emails
    Datasheets
    Discards list
    WPRs
    Block Diagrams
    Schematics
    Layouts
    Algorithms
    Printed Code


Report Word Copy, email to Scott
    System Level Descriptions (Generic Node[(HAP, SPS, uC)])
        Intro 
        Description of what we did, and how we did it.
        Conclusion
        Lessons Learned
    Issues and Solutions

-

Schedule of Presentation (each slide should start with requirements)

Intro Mike is making Intro Slides (Very Brief - Jeremy)
    goals (Mikes .bmp)
    worked on
    What we thought we would do
    What we did

Hardware
    Ken  (Discuss Process and Issues)
        Brief history (reasons for redisign)
        Generic Node
        SPS
        HAP
        uC
    Scott (Discuss Process and Issues)
        Brief history (reasons for redisign)
        APS
        Power Switches
        HUB
        Umbilical
        Ideal diode
    David (Discuss Process and Issues)
        Brief history (reasons for redisign)
        Battery Selection
        Internal Charger
        External Charger
    Ailing (Discuss Process and Issues)
        Brief history (reasons for redisign)
        Battery Board
        Pressure Sensors        

Software
    General Needs
    General Software outline
    Mike Slides
    Jeremy Slides

10 Apr 2009

Official Notes here : No official Notes again

Additional Notes :

3 Apr 2009

Official Notes here : No official Notes again

Additional Notes :

6 Feb 2009

Official Notes here : No Official Notes this meeting?

Additional Notes :

30 Jan 2009

Official Notes here : No Official Notes this meeting?

Additional Notes :

Note : I realized after the meeting that unfortunately, neither of them will be able to use the LV2b generic node SPS as it stands due to the new higher specs for Imax. The LV2b SPS specs 3.3Vdc @ 400mA, while the new spec is 3.3Vdc and 5Vdc both with 1A max. Also, the 5V shown in the LV2b schematics is unlikely to be 5V, more likely 7.2 or so according to the 2006 final report.

Figure 1: SPS-HAP Option A

Figure 2: SPS-HAP Option B

Figure 3: SPS-HAP Ideal Option

23 Jan 2009

Official Notes here : No Official Notes this meeting?

Additional Notes :

16 Jan 2009

Notes

Notes: 30 Apr 2009

Most redlines completed. Still have the following two lists, the first will just take some time. The second I think I need help with.

Notes: 29 Apr 2009 (Initial Design Review)

Last night was the initial design review. It went relatively well, and though there is a lot left to be fixed before Friday, it should be pretty doable. Some of the results are from ineffective review of the original capstone 2006 design, but most of the results are from incomplete portions of the new circuit. Bigger issues include two reversed FETs (one orginal design, one mine), and the decision to run with the LT3972/LTC4085 combination over the single IC design using the LTC4090. The following is a more detailed list of the redlines that need fixing by Friday....

Redlines to the current node5-frontend-rev2.sch file are as follows:

Notes: 14 Apr 2009 (TI Tech Day)

Another long time between notes. So far the SPS and HAP designs are in EAGLE, though they need to have several more parts built. I have started the IC_LPC2368 microprocessor in EAGLE and it needs to have the symbol shrunk so it fits on the existing node design better. I have started to integrate my SPS design in place of portions of the 2006capstone design.

Today I went to the TI techdays conference in Beaverton. There were 5 classes.

Notes: 5 Mar 2009

Long time no online updates. Time to fix that. As of today I have the SPS IC chosen as the LT3972 (from Linear Technologies), the HAP Charger IC chosen as the SC806 (from Semtech) and the HAP Output Regulator IC chosen as the LTC3441 (also from Linear Technologies). I have used the reference designs in the data sheets to pick initial component values for each section. I have also calculated values for many of the associated resistors and other parts that set values and have a few changes from the reference designs. However until this week I was unable to simulate the parts in LT spice ( And I still can't sim the SC806). Now that the ICs are available in LTSpice I am running some simple simulations using the supplied test fixtures for each of them and substituting in my calculated component values. The first simulation I ran simply checks that the given range of input voltages results in the appropriate voltage outputs. So far so good. The next think I thought to check was the efficiency. Here is a small stumbling block. The efficiency is not as good as I expected from the LT3972 (15Vin, 5Vout, 1Aout). I am running different values to see where it went wrong. Using the default test bench, the efficiency calculates out to 92.1%, but using my components I only get 58%. So far I have found that using a larger Inductor makes a big difference to my efficiency and brings it to 88%. I'll have to play with this more today and have some results and questions for tomorrows meeting.

Notes: 20 Feb 2009

I have finished updating the rejected parts list and moved it down to the bottom of the page. Tomorrow I will select the specific ICs that I will move forward with in the SPS-HAP design. Now that I have the hang of making a list like that and updating it as I search for parts, I think any further parts selections should go much further. The list is big, but it is not as complete as it could be. There were many parts that were briefly looked at and dismissed without comments, not listed as I did not collect data appropriate for the table while looking at them. Initially when starting this project I thought that the IC selection for the SPS and HAP would go quickly so I could move on to more interesting parts of the design. At least now I am more able to quickly examine a datasheet and toss it if it hasn't got what I'm looking for.

Speaking of the rejects, here are the least rejected of the reject list. The following is a listing of the most likely ICs for each of the three major parts of the SPS-HAP.

Likely Buck Converters for the SPS

Likely Chargers for the HAP

Likely Output Buck-Boost Converters for the HAP

Notes: 16 Feb 2009

Long time no updates. Tonight I am putting up a partial list of parts that I have considered. Several look promising, but I have rejected the majority of these for one reason or another. The reason is listed wherever possible, along with other (possibly) applicable notes. Without further fanfare, here it is, "The Reject List"

Notes: 5 Feb 2009

So I attended the PSAS meeting this Tuesday. There was a lot of discussion about the URB and backchannel communication. There was also a great time to talk to Tim about the SPS, the HAP, and battery selection. Lets start with the batteries. They don't need to be big, 250mAH is fine, but if they are bigger for the same size that's ok too. There are batteries that come with solderable tabs (no need for high frequency vibration welding or anything crazy) and are the right size (similar to what was selected for the prior designs). Also, the batteries don't need to have a high max current, a rating of 2C is fine. That said it looks also like a lower Imax is to be expected during battery operation. This is good as it results in a much smaller and lighter weight battery. There was some discussion about how to attach a small board directly to the battery, place a small plastic fuse on it, and have wires run from it to the board. This results in considerable strain relief for the solder tabs on the battery and should make it much easier to reliably attach to the board. Also, using a battery that is designed for some other commercial device would be fine, if it can be found in the right size, cheap, and with wires already attached. No contact pads.

Now for the second part of the discussion I had with Tim. Regarding the rest of the SPS and HAP power supplies, I may have been significantly overcomplicating things. I should be able to use the existing SPS design with little or no modification, simply changing the final output voltage to something closer to 4.2V into the HAP. The hap consists of a battery charger, and maybe a pair of diodes or switches to control the flow of power (depending on the capabilities of the chosen charger). The output of the HAP can feed a linear regulator and still be pretty efficient due to the close voltage relationship between the battery and the desired Vout of 3.3V. As for efficiency, I want to beat the specs Tim wrote on the whiteboard, but it may be harder than I think (50%@10mA, 80%@30mA, AND 750mAmax). I also have a much better understanding of how the split inductor thing works in the existing SPS design. I think what I was missing is that the 3.3V is the controlled source, and the 5V is really pretty unregulated. The 5V will change in value as the 3.3V supply is loaded or unloaded. To deal with this, just set the values such that the 5V line never drops below 5V and regulate it later down to the exact 5V that you are looking for.

I think the big difference between the two approaches is in what gets left out. If you make a generic SPS similar to the one I had on the 3rd, if you don't want the 5V or the HAP, you jumper the appropriate parts and don't populate the components. The same is true here, but there should be a board space savings in that there will be fewer inductors and ICs to not lay out on the board, i.e. the double inductor is a space saver as well as elegant.

Last but not least, a rough block diagram for the potential system could be as follows:

Figure 1: Another SPS-HAP potential block diagram (notice similarities to the existing LV2 and LV2B setups)

Notes: 3 Feb 2009

The block diagram I am working with today looks like the figure below.

Figure 1: SPS-HAP

Still looking for a good 2.9-5.5Vin to 5V out switching converter for use after the battery.

Looked at regulators that specifically claim to be low-noise such as the LT1533, LT1534, LT1534-1, and LT3439 and found that they all miss out on the switching frequency (only sync as high as 375kHz). So if we can lower the sync freq, they would be worth considering.

Parts from other manufacturers also should be considered, but the LT parts are often available for simulation directly in LT spice which will be helpful during any attempted simulations.

The requirements for the Vmid to 3.3V converter are very similar to the Vmid to 5V, the requirements list is below. One thing to note here is that the exact same regulator chosen for the 5V supply would work here. On the other hand, a buck-only supply might be nice since (assuming it has a pass through for Vin <= Vout) it would waste less power as the battery voltage drops. Also having a buck only supply would allow the cpu to track the voltage easily and know when the voltage begins to approach the lower functional limit (ie. give it a chance to send an SOS).

There requirements for the APSinput to Vmid converter are as follows:

Now I need requirements for the charger circuit. Hmm, this is more difficult because I almost need the battery specs first. Which came first, the battery or the charger?

Notes: 2 Feb 2009

Tonight I am going over the specs again and looking for discrpancies, while also trying to cement them in my head. The simplest way to do this was to re-write them here, so I have posted the pyro specific specs here in a slightly different configuration from what went before.

Notes: 1 Feb 2009

Work this weekend covered, yet again, more research into possible parts for the SPS and HAP. I spent a lot of time finding and going through battery data sheets. In fact there I found that many of the batteries that I had thought should work, might not meet the maximum discharge rates in the spec. Currently, for both 3.3V and 5V the node needs to meet (?,30mA,1A). I think that I may need to look into a separate Imax spec for the node during battery power. All of the batteries I have looked at will handle the normal 30mA, but they often fall short of the Imax mark. In fact specifically the one I looked at last could be had at a 500mAH capacity, but could only deal out 900mA max, and thats at 3.7V. If I want to meet the 1A Imax spec, I'll have to spec a battery that is noticeably larger physically.

I also found that one of the simplest ways to go might be to spec a battery that is meant for another device entirely, and use it in the design. I'm not sure about legalities that may arrise from that though. Can I simply call for the battery to be similar(read identical) to that used in the 6th generation I-pods? They are readily available from many sources, and have the 450mAH I am initially looking for. They come ready made with no spot welding of tabs necessary, and since the Ipod will likely be around for a few more years, the replacement parts should be available relatively cheap on ebay with ever increasing capacities.

Yet another battery related issue. In the battery charger IC specs, the IC manufacturer refers to the Lithium polymer charger as having a V-nom of 4.2V, whereas the battery manufacturers often refer to the batteries as having a V-nom of 3.7V. I don't particularly care for this, and I am thinking that even after I have the charger picked, I'm going to have to be very careful about what battery gets chosen. This is especially true after reading the voltage specs for the LPC1248, it must have between 2.9Vdc and 3.6Vdc to prevent Under Voltage Alarms and/or Over Voltage damage.

Several sites had intersting information, they are listed below.

<http://www.powerstream.com/li-pol.htm> Manufacturer of Lithium Polymer cells.

<http://www.globalsources.com/gsol/I/Lithium-polymer-manufacturers/b/2000000003844/3000000181566/22762/20.htm> Online Marketplace that carries a large variety of lithium polymer batteries, some have minimum order of 1 cell.

<http://www.eemb.com/productcenter/Industry/LP/LP.html> Listing of this manufacturers lithium polymer batteries

<http://www.rcgroups.com/forums/showthread.php?t=209187> Info on Lithium failures

In addition I had a go at block diagrams that include some possible part numbers. I'm including them here so they may be soundly criticized and commented upon. Please comment as you see fit. Prior to the friday meeting I should have a decision matrix ready for commenting with many of the relevant parts that I am currently researching. Basically, the APS feeds a DC/DC converter, that feeds More DC/DC converters that handle the actual output voltages. In between them sits the Battery and its charger.

Known issues include the flyback transformer based charging devicein the second diagram. It has been fairly hard to find a charger that has all the protection services I want and is not overly complicated in some other way. I also have not yet found one that can be in sync up to 1.25MHz.

Parts that I particularly like so far, include the LTC3411A, I think I can use it as 3.0-5.5 Vin to 3.3 Vout at 1.25A, it looks pretty efficient and should do the job well for the 3.3V backed up supply. It also has a high maximum frequency and can be in sync across a large range (.4-4 MHz). Keeping it sunk up to the 1.25MHz coming from the processor will allow easy filtering of the switching noise.

Figure 1: SPS-HAP-1

Figure 2: SPS-HAP-2

Notes: 22 Jan 2009

Finally found the missing Maxim IC part, I had emailed it to myself and the email ended up in the junk folder. <http://datasheets.maxim-ic.com/en/ds/MAX1775.pdf> This is not a perfect part, but it does handle many of the jobs that are required. Not sure if it can deal with the 10-20V input though, the spec sheet says IN = -0.3V to +30V, and then says IN = -.03V to +6V on the next line???

Also need to look more in-depth at the following parts... MAX8731A (battery charger) (link to be added later), ST Microelectronics - GS-R400 series switching regulators, <http://www.st.com/stonline/products/literature/ds/2665/gs-r400.htm> or specifically <http://www.st.com/stonline/products/literature/ds/2665.pdf> (not sure these will stay on the board during launch though).

Looks like most of the larger manufacturers have lists of reference designs and such. Some of them look particularly interesting including the following from Maxim <http://www.maxim-ic.com/design_guides/> also <http://www.maxim-ic.com/cookbook/powersupply> (want to look at CB12, CB14, CB81, CB110. Cookbooks are unlikely to have the "perfect" design, but they may also be a great place to start or help generate ideas.)

Just how much power do I need to store in the Pyro HAP? Looks like the most any node could need is (very) roughly 17.5 watts (5V@3.5A), but the pyro node should be much lower than that even.

Notes: 20 Jan 2009

Today is a re-cap of the weekends work. I re-read the SPS information from the 2006Capstone. I have given a lot of time to the existing setup, and I am finding it difficult to re-capture all the various requirements that they actually went for. The following is a list of what I understand the requirements to be so far for the SPS/HAP portion of the desgn:

Now, I have also been reading vast numbers of data sheets for power products, mostly switching regulators, but also different battery management devices. A few key points of general information include: 1. High switching frequency usually leads to high quiescent current draw. 2. Vast Majority of USB solutions won't work due to Amperage requirements 3. Many Automotive related parts will work given the voltage/amperage requirements 4. Many NOtebook power supply solutions may work given the Volt/Amp requirements 5. The LT Micro-Modules, while looking good in some resepects, the Iq usually is higher than desired. 6. I have a lot to learn when it comes to battery charging and selection.

Most questions I have had I have been able to find the answer on the iki or elsewhere on the web. A couple of questions that are still unresolved... 1. Why are we didtributing 16Vdc from the APS? Seems like regulating the APS outputs down to 5 to 5.5V would enable more component oportunities for the node power supplies. 2. Is there a specific manufacturer or part number in mind for the Li-Poly battery?

Notes: 13 Jan 2009

So far I am still doing research on various system components, primarily I have been focused on reading up on the existing design for the SPS. Still need to look into the HAP, and ensure that I have the right voltages and amperages to successfully run the node.

I have looked at several uModules from LT (LTM4606 and LTM4603HV) and compared them to the existing SPS switcher, which is an LT1767EMS8. Initially the existing switcher looks good, especially the price and size (from LT$3.76, and 3mmX5mmX2mm). On the other hand, the uModules ($24 or so, and 15mmX15mmX3mm) have the inductor built in along with a few other components, so the comparison gets a bit more complicated. The most interesting find is that one of the uModules is rated for low EMI and has a noise cancellation circuit built into the device output to silence the switching noise. Next is to read more about the existing SPS design and try to figure out exactly what would be removed with the changeover to a uModule switcher. I'll have to come up with a good comparison chart before proceeding much further in this arena.

Notes: 11 Jan 2009

To do for me:

At this point I still need to do significant amounts of research including but not limited to:

  1. Keep up with any changes to the design specifications requirements
  2. Read Capstone 2006 report focus on items related to SPS design
  3. Lookup old PDF with information on component level design from prior PSAS designs

  4. Find and read resources on general SPS design

  5. Wikipedia

  6. Book: "Modern DC-to-DC Switch mode Converter Circuits" by Severns and Bloom
    • This book is dated 1985, but should still cover the basics. The textbook for my power electronics class is still not in, but the ETA is Monday 12 January 2009
  7. Other Online resources:

  8. Application notes from companies such as LT, ST, Ti, Maxim since they all make integrated converter solutions.

    Linear Technologies uModule Regulators

    Ti general power management

    ST Microelectronics – power management products

    Maxim – power and battery management products

  9. Find and read resources on general HAP design, specifically regarding Lithium Polymer batteries
    • Charging requirements?
    • Costs?
    • Size vs voltage and capacity?
  10. Need to find/determine specific requirements for Pyro node SPS and HAP.
  11. Pyro node SPS:
    • Vin (min,nom,max): (10, 14.2, 20)Vdc
    • Vout1(min,nom,max): (3..075, 3.3, 3.6)Vdc
    • Vout2(min,nom,max): (?,5,?)Vdc
    • Iout1 (0, 30mA, 1.25A)
    • Iout2 (0, 30mA, 1.25A)
    • Required features: Sync (1.5MHz), Shutdown pin, ?
    • Useful extra features:Power good pin
  12. Pyro node HAP:
    • Battery Type: Lithium Polymer.
    • Battery Capacity: ?
    • Battery Charger: ?
    • Vin (min,nom,max)?
    • Vout (min,nom,max)?
    • Required features: ?
    • Useful extra features: ?

Now that I have finished my first battle royal with the iki wiki editor, is there a way to simply type something in notepad (or equivalent) and then paste it in here while preserving the formatting? iki lists are iki.

Questions

Rejected Parts List

Manufacturer Part# Type Vin(,,) Vout(,,)V Iout(,,)A Sync? Why rejected?
Linear LTC4110 battery backup manager Vin(,,)V Vout(,,)V Iout(,,)A PWM flyback dc-dc converter. low frequency 340kHz max. lots of goodies for controlling all sorts of things. big 3mm by 7mm package. i2c and smb bus connectivity. High efficiency accross the load range. complicated datasheet.
Linear LTC3552-1 Battery Charger plus DC-DC Vin(,,)V Vout(,,)V Iout(,,)A no too low on Iout. no sync on switches.
Linear LTC3558 Battery Charger plus DC-DC Vin(,,)V Vout(,,)V Iout(,,)A no too low on Iout. no sync on switches.
Linear LTC3559 Battery Charger plus DC-DC Vin(,,)V Vout(,,)V Iout(,,)A no too low on Iout. no sync on switches.
Linear LTC4080 Battery Charger plus DC-DC Vin(,,)V Vout(,,)V Iout(,,)A no too low on Iout. no sync on switches.
Linear LTC4081 Battery Charger plus DC-DC Vin(,,)V Vout(,,)V Iout(,,)A no too low on Iout. no sync on switches.
Linear LTC408x Battery Charger plus DC-DC Vin(,,)V Vout(,,)V Iout(,,)A no too low on Iout. no sync on switches.
Linear LT1769 charger Vin(,,) Vout(,,)V Iout(,,)A no low frequency operation at only 230kHz max. Elderly part. lots of useful features. no sync.
Linear LTC4002 charger Vin(,,)V Vout(,,)V Iout(,,)A switch freq is low at 500kHz. slightly complicated multipurpose soft start- shutdown - charge begin pin. Few onboard control options. No timer.
Fujitsu MB3878 charger Vin(,,)V Vout(,,)V Iout(,,)A Imax is way too low. SSOP package
Fujitsu MB3887 charger Vin(,,)V Vout(,,)V Iout(,,)A Imax is too low. SSOP package
Fujitsu MB39A107 charger Vin(,,)V Vout(,,)V Iout(,,)A no Imax is too low. frequency is not syncable. SSOP package
Linear LTC3576/LTC3576-1 Charger plus powerpath Vin(,,)V Vout(,,)V Iout(,,)A efficiency at 10mA to load is only 30%.
Linear LTC4009 Charger with buck Vin(,,)V Vout(,,)V Iout(,,)A no no sync. synchronous buck topology looks pretty good outside the lack of sync. low switch freq at 550kHz max.
Linear LTC3101 charger with buck buck-boost linear-powerpath Vin(,,)V Vout(,,)V Iout(,,)A no 1.5MHZ fmax. 800mA buck boost. dual 300mA synchronous bucks. no sync. this is another part that would be useable if it had sync and met the 1A output needs. extra LDO would provide added noise for little benefit.
Linear LTC3556 charger with buck buck-boost switching-powerpath Vin(,,)V Vout(,,)V Iout(,,)A no similar to the LTC3555 but with different switching supply options. no sync. low efficiency unless the supply is allowed to be mode changed on the fly.
Linear LTC3555 charger with buck switching-powerpath Vin(,,)V Vout(,,)V Iout(,,)A no poor efficiency unless the I2C bus is used to switch mode from 10x to 1x on the fly. no sync for the switching supplies.
Linear LTC3567 Charger with buck-boost Vin(,,)V Vout(,,)V Iout(,,)A Charger with buck-boost efficiency is 30% at 10mA unless the mode is switched to low current in which case it is acceptable (60% at 10mA) but no longer reaches the Imax we are looking for. Efficiency reaches into the 90% for high current loads ~80% for 100mA to 200mA. Could be possible to switch current mode on the fly via I2C port. No sync.
Linear LTC3586/LTC3586-1 Charger with buck-boost Vin(,,)V Vout(,,)V Iout(,,)A efficiency is 30% at 10mA unless the mode is switched to low current in which case it is acceptable (60% at 10mA) but no longer reaches the Imax we are looking for. Efficiency reaches into the 90% for high current loads. ~80% for 100mA to 200mA. Could be possible to switch current mode on the fly via I2C port. No sync.
Linear LTC3566 charger with LDO buck-boost switching-powerpath Vin(,,)V Vout(,,)V Iout(,,)A no similar to the LTC3555 but with different switching supply options. no sync.
Linear LTC1960 charger with power path Vin(10,,20) Vout(,,)V Iout(,,)A No audible band noise. low switching frequency 345kHz max. high efficiency. Handles dual batteries which could enable the use of 2 small batteries operating in parrallel to supply the total demand (buy 2 250mAH batteries to get 500mAH is this complication or benefit? allows more flexible use of board space since batteries could be physically stacked). this part is a possibility but is out with no sync and low switch frequency.
Linear LTC3550 charger/switcher Vin(,,)V Vout(,,)V Iout(,,)A 600mA max. output is buck only
Linear LTC3550 charger/switcher Vin(,,)V Vout(,,)V Iout(,,)A 600mA max. output is buck only and the Vin-min is too low
Linear LTC3550-1 charger/switcher Vin(,,)V Vout(,,)V Iout(,,)A 600mA max. output is buck only
Linear LTC3552 charger/switcher Vin(,,)V Vout(,,)V Iout(,,)A 600mA max. output is buck only and the Vin-min is too low
Linear LTC3558 charger/switcher Vin(,,)V Vout(,,)V Iout(,,)A no both outputs only good up to 400mA. No Sync. though the freq is 2.25MHz.
Linear LTC4050 linear charger Vin(,,)V Vout(,,)V Iout(,,)A missing some desired controls. need external amplifiers to program more than 500mA output.
Linear LTC4062 linear charger Vin(,,)V Vout(,,)V Iout(,,)A internal pwr mosfet. a little light ont he Imax. but otherwise perfectly useable
Linear LT3559 linear charger with bucks Vin(,,) Vout(,,)V Iout(,,)A no external pwr fet. Bucks run at up to 2.5MHz and are very efficient at our lighter loads. does not handle the necessary 1Amax needed for the 3.3v supply. switch node slew limiting to reduce radiated EMI. This would be a great part if: they had sync. They had the necessary current handling capabilities. could be used to split the 3.3vout into two 400mA max supplies which would enable partial load shutdown to conserve pwr.
Linear LTC4063 linear charger with LDO Vin(,,)V Vout(,,)V Iout(,,)A this is the same as the LTC4062 but with a 100mA LDO added. Unneccesary LDO would serve to add noise to the system. this is not desireable.
STmicroelectronics STC3100 Battery Monitor Vin(2.7,,5.5)V Vout(,,)V Iout(,,)A N/A Good Battery Monitor with coulomb meter and I2C interface. 3X3 DFN package
Ti BQ24100 Charger Vin(4.35,,16)V Vout(,,4.2)V Iout(,,2)A no QFN package. Switched mode charger. No sync. Synchrounous and 1.1MHz for high efficiency and small components. Host termination control. Lots of good protection features. Good application note for charging the battery while supplying system load. All parts in the series share one datasheet up to BQ24115.
Ti BQ24120 Charger Vin(4.35,,16)V Vout(,,4.2)V Iout(,,2)A no QFN package. Switched mode charger. No sync. Synchrounous and 1.1MHz for high efficiency and small components. Lots of good protection features. Good application note for charging the battery while supplying system load.
Ti BQ24150 Charger Vin(4,,6)V Vout(2.5,,3.3)V Iout(,,1.25)A no BGA package. Switched mode charger. No sync. Synchrounous and 3MHz for high efficiency and small components. I2C
Ti BQ24151 Charger Vin(4,,6)V Vout(2.5,,3.3)V Iout(,,1.25)A no BGA package. Switched mode charger. No sync. Synchrounous and 3MHz for high efficiency and small components. I2C
Ti BQ24152 Charger Vin(4,,6)V Vout(2.5,,3.3)V Iout(,,1.25)A no BGA package. Switched mode charger. No sync. Synchrounous and 3MHz for high efficiency and small components. I2C
Maxim MAX8713 Charger Vin(7.5,,28)V Vout(,,4.2)V Iout(,,2)A no Switched Mode charger. Low Freq. no sync. Confusing datasheet.
Maxim MAX8731A Charger Vin(8,,26)V Vout(,,4.2)V Iout(,,8)A no Switched Mode charger. Low Freq. no sync. Confusing datasheet.
semtech sc20 charger Vin(,,)V Vout(,,)V Iout(,,)A Iq >2mA
Semtech sc811 charger Vin(,,)V Vout(,,)V Iout(,,)A charger enabled and disabled Iq >2mA
semtech sc824 charger Vin(,,)V Vout(,,)V Iout(,,)A doesn't appear to have the necessary Imax. datasheet hard to navigate.
semtech sc908 charger Vin(,,)V Vout(,,)V Iout(,,)A Won't handle Imax
Summit SMB137 Charger Vin(,5.5,)V Vout(,,)V Iout(,,1.5)A maybe 2MHz Switched mode charger. Looks great but for the lack of actual datasheet. Contact a sales rep for datasheet!! BAH!!
Summit SMB339 Charger Vin(4.35,5.5,6.2)V Vout(,,)V Iout(,,1.25)A maybe 3MHz Switched mode charger. Looks great but for the lack of actual datasheet. Contact a sales rep for datasheet!! BAH!!
Linear LTC4099 Charger Vin(4.35,,5.5)V Vout(,4.2,)V Iout(,,1.5)A no 2.25MHz switch rate. No Sync. I2C. Can control another switcher like the LT3480 to be a nearly complete SPS and HAP combo.
Semtech SC801 charger Vin(4.2,,14)V Vout(,4.2,)V Iout(,,1.5)A N/A Looks like a good charger. No bells or whistles
Semtech SC806 charger Vin(3,,6)V Vout(,4.2,)V Iout(,,1)A N/A Looks like a good basic charger. Got bells and whistles (OVP UVLO and Current limit or external termination). Hard to locate a supplier.
Ti TPS65014 Charger PMIC Vin(4.5,,6.5)V Vout(2.5,,3.3)V Iout(,,1)A no This is a big integrated do it all solution that includes the charger and three buck supplies. Will handle 3.3V at 1A in addition to various others. I2C. No sync.
Ti TPS65820 Charger PMIC Vin(4.35,,16.5)V Vout(2.5,,3.3)V Iout(,,1.5)A no Big Do it all. Battery charger with 9 LDOs (.8-3.3V) and 2 Bucks (.6-3.4V at 600mA). 3GPIO ports and I2C interface. No sync.
Linear LTC3780 DC-DC Buck-Boost Vin(4,,36)V Vout(0.8,,30)V Iout(,,20)A yes low freq. synchronous switching allows for very high efficiency. External switches.
Linear LTC3785 DC-DC Buck-Boost Vin(2.7,,10)V Vout(2.7,,10)V Iout(,,10)A no no sync
Linear LTC3785-1 DC-DC Buck-Boost Vin(2.7,,10)V Vout(2.7,,10)V Iout(,,10)A no no sync
Linear LTM4605 DC-DC Buck-Boost Vin(4.5,,20)V Vout(0.8,,16)V Iout(,,5)A yes BIG 15x15mm. low freq
Linear LTM4607 DC-DC Buck-Boost Vin(4.5,,36)V Vout(0.8,,28)V Iout(,,5)A yes BIG 15x15mm. Low freq
Fairchild FAN5361 DC-DC Buck Vin(2.3,,5.5)V Vout(1,,1.8)V Iout(,,0.6)A yes 6MHz Synchronous Synchronizable Buck converter. Not right for this project but still cool.
National LM20242 DC-DC Buck Vin(4.5,,36)V Vout(.8,,32)V Iout(,,2)A no Good looking IC with all the interesting protection features built in. 1MHz freq max. No Sync
National LM20333 DC-DC Buck Vin(4.5,,36)V Vout(.8,,32)V Iout(,,3)A yes Sync up to 1.5MHz. OVP. UVLO. PwrGood. Soft Start. Enable. Internal Synchronous Switches. Iq up to 3mA. Shutdown Iq is minimal. TSSOP package.
National LM20343 DC-DC Buck Vin(4.5,,36)V Vout(.8,,32)V Iout(,,3)A no Good looking IC with all the interesting protection features built in. 1MHz freq max. No Sync
Linear LTM4606 DC-DC Buck Vin(4.5,,28) Vout(0.6,,5) Iout(,,6) yes BIG 15x15mm. Pll sync up to about 1MHz. Low noise version of the uModule. Good and BIG
Linear LTM4614 DC-DC Buck Vin(2.375,,5.5) Vout(0.8,,5) Iout(,,4) no BIG 15x15mm. 1.25MHz operation. Dual Output. No sync
Linear LTM4616 DC-DC Buck Vin(2.375,,5.5) Vout(0.6,,5) Iout(,,8) yes BIG 15x15mm. sync 75kHz to 2.25MHz. (wants to run at 1.5MHz). Dual Output. Good and BIG this would be ideal if it showed efficiency info for low loads and was smaller.
Linear LTM8023 DC-DC Buck Vin(3.6,,36)V Vout(0.8,,10)V Iout(,,2)A yes Low Noise. smaller uModule (11.25mmX9mm) with sync up to 2.4MHz missing datasheet info. could very useable for SPS replacement. high cost at $16.90 in digikey
Linear LTM8032 DC-DC Buck Vin(3.6,,36)V Vout(0.8,,10)V Iout(,,2)A yes Low Noise. smaller uModule (9mmX15mm) with sync up to 2.4MHz missing datasheet info. Is this available yet???
Ti TPS54140 DC-DC Buck Vin(3.5,,42)V Vout(0.8,,39)V Iout(,,1.5)A yes Sync up tp 2.2MHz. Poor efficiency at very low loads. OVP. Adjustable-UVLO. Pwr-Good. Enable. Could be used.
Ti TPS54160 DC-DC Buck Vin(3.5,,60)V Vout(0.8,,58)V Iout(,,1.5)A yes Sync up tp 2.2MHz. Poor efficiency at very low loads. OVP. Adjustable-UVLO. Pwr-Good. Enable. Could be used.
Ti TPS62590 DC-DC Buck Vin(2.5,,5.5)V Vout(0.75,,5)V Iout(,,1)A no QFN package. No Sync. 2.25MHz tiny 2X2 SON package. Simple buck few controls or protections.
Linear LT3680 DC-DC Buck Vin(3.6,,36)V Vout(2.5,,5..5)V Iout(,,3.5)A yes Sync from .2MHz to 2MHz. Looks good. Has most of the required features.
Linear LT3417A-2 DC-DC Buck Vin(2.25,,5.5)V Vout(2.5,,3.3)V Iout(,,1.5)A yes Dual Synchronous Step downs with Sync. Could be used for regulation of the batterry to the multiple loads. Up to 4MHz
Linear LT3480 DC-DC Buck Vin(3.6,,38)V Vout(0.8,,20)V Iout(,,2)A yes Sync from .25MHz to 2MHz. Looks good. Has most of the required features.
Linear LT3972 DC-DC Buck Vin(3.6,,33)V Vout(0.8,,30)V Iout(,,3.5)A yes Sync from .25MHz to 2MHz. Looks good. Has most of the required features.
Linear LTC3411A DC-DC Buck Vin(2.5,,5.5)V Vout(0.8,,5.5)V Iout(,,1.25)A yes Looks like a good Lion to 3.3V regulator.
National LM3668 DC-DC Buck Boost Vin(2.8,,5.5)V Vout(3,,5)V Iout(,,1)A Yes Sync freq up to 2.7MHz. Good Efficiency in forced PWM mode. Low Iq.
National LM5022 DC-DC Buck-Boost Vin(6,,60)V Vout(,,)V Iout(,,)A Yes Standard old school controller. Cap Inductor Diode and FET are all external. Max Freq is 2MHz.
Ti TPS63001 DC-DC Buck-Boost Vin(1.8,,5.5)V Vout(1.2,,5.5)V Iout(,,1.2)A yes Sync .8-1.6MHz. LowIq. Good Efficiency. OVP. Adjustable-UVLO. Pwr-Good. Enable. Could be used.
Ti TPS63030 DC-DC Buck-Boost Vin(2.5,,5.5)V Vout(1.2,,5.5)V Iout(,,0.8)A yes Sync 2.2-2.6MHz. Poor efficiency at very low loads. Power saver for low loads (allows for very good low load efficiency) is similar to pulse skipping. OVP. Adjustable-UVLO. Pwr-Good. Enable. Could be used.
Linear LTC3441 DC-DC L-ion to 3.3VDC Buck-Boost Vin(2.4,,5.5)V Vout(2.4,,5.25)V Iout(,,1)A yes Looks good for the post battery supplies sync up to 1.5MHz but would need one for each backed up voltage (not a dual supply)
Linear LTC3442 DC-DC L-ion to 3.3VDC Buck-Boost Vin(2.4,,5.5)V Vout(2.4,,5.25)V Iout(,,1)A sync?
Linear LTC3443 DC-DC L-ion to 3.3VDC Buck-Boost Vin(2.4,,5.5)V Vout(2.4,,5.25)V Iout(,,1)A yes sync up to 1.2MHz but runs at 1/2 that freq.
STmicroelectronics L6924D Linear Charger Vin(2.5,,12)V Vout(4.06,,4.24)V Iout(,,1.045)A N/A Good linear battery charger choice. Very detailed datasheet that is hard to follow.
STmicroelectronics L6924U Linear Charger Vin(2.5,,12)V Vout(4.06,,4.24)V Iout(,,1.045)A N/A Good linear battery charger choice. Very detailed datasheet that is hard to follow. Show minimum layout size with ancilliary parts = 11mmX8mm
National LM3622 Linear Charger Vin(4.5,,24)V Vout(,,)V Iout(,,)A N/A Designed for use in cradle chargers this unit handles larger currents by controlling an external BJT or FET. Only comes in an SOIC.
National LM3658 Linear Charger Vin(4.35,,6)V Vout(,4.2,)V Iout(,,1)A N/A Not much to say here. This is a basic standard timer controlled charger with enable.
National LP3921 Linear Charger Vin(3,,5.5)V Vout(1.5,,3.3)V Iout(,,0.95)A N/A "Almost 1 Amp charging capability7 ""low noise"" LDOs This IC is designed for Cell phones but could be made to work if LDOs are acceptable outputs. Includes I2C control and an onboard audio amplifier that could be used to provide speaker output for warnings and messages (picture a cellular speakerphone). LDOs capable of 3.3V include 300mA. 300mA. 80mA. and 150mA. no 5V LDOs"
National LP3947 Linear Charger Vin(4.3,,6)V Vout(,,)V Iout(,,0.75)A N/A Another I2C charger. Can also act as an LDO if there is no battery. LDO supplies 4.2V at up to 1A
Micrel MIC79050 Linear Charger Vin(2.5,,16)V Vout(,,4.2)V Iout(,,1)A N/A Simple Linear Battery Charger. Needs external circuitry for control and termination.
Micrel MIC79110 Linear Charger Vin(2.5,,16)V Vout(,,4.2)V Iout(,,1.2)A N/A Simple Linear Battery Charger. Needs external circuitry for control and termination.
STmicroelectronics STw4102 Linear Charger Vin(4.5,,16)V Vout(4.1,,4.35)V Iout(,,1)A N/A Charger with gas guage etc. I2C. Looks great with lots of protection features. QFN24 package.

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