OK, got the SPI working at 1MHz. Shouldn't be much longer now - Cell PWM is not a problem. Can get the on-time to as little as 56us with a 1MHz SPI rate (time config registers for discharging are clocked in to reloading no-discharge configuration). All other calculations can happen in the off time. Given the FETs are the weakest link, and they can handle 10A pulses up to 10ms, going to 0.25ohm current-limiting shunts is feasible for variable cell discharge rates of 0-2.8A via PWM. View attachment IMG_1533.JPG
Linear Tech 12-cell battery monitor/BMS
- Thread starter mike_t
- Start date
I'll be real interested to hear how that works. If you can set up a cell and run it, then you can see how hot the parts get.
Tiberius
10 kW
mike_t said:Nice. I've got my hands on a DC1331 demo board of the LTC6802I also have the DC509 USB board that is used to eval various LTC circuits. I don't have the GUI SW yet, so I'm developing drivers for it on my own demo board using an ATmega168 8-bit uC (http://www.digilentinc.com/Products/Detail.cfm?Prod=NANOCON&Nav1=Products&Nav2=Embedded). Unfortunately the driver writing will be a slow process given I have to work for a living and my C is rusty.
Hi Mike,
Linear have just sent me a DC509, but they say it will be a few weeks before the DC1331 board comes. Apparently demand has been high.....
I'm curious as to why you are using your own controller rather than the DC509 - is there something I should know? Was the installation problem insuperable? I do have a board with an ATmega8 and SPI and USB interfaces on that could be pressed into use, but I'm not a programmer.
Nick
wrobinson0413
1 kW
.
reagle
100 W
Apparently Analog also makes a similar part called AD7280, which looks suspiciously similar, but handles 6 cells per chip only.
http://www.analog.com/static/imported-files/data_sheets/AD7280.pdf
They stack up pretty much the same way (but with more wires) as Linear parts and use what seems to be an SPI link to the micro.
Yay for multiple sourcing requirements
http://www.analog.com/static/imported-files/data_sheets/AD7280.pdf
They stack up pretty much the same way (but with more wires) as Linear parts and use what seems to be an SPI link to the micro.
Yay for multiple sourcing requirements
I finally got back on this project - sorry for the delay! I had some major delays getting a functional Mastech HY5020E power supply (had to send the first 2 back to the factory) I also had a small delay getting a simple solution to throttle the charging current as a single cell reached full charge (I had to switch to a PFET on the high side to keep a common ground between charger and micro to avoid using an opto and a bunch of other components to isolate ground) Long story short I've got everything working now.
FYI I could not get the GUI SW installed on my machine for some reason for the 509 USB board. It wasn't long before I got my micro up and talking via UART to give me status so I haven't tried since or pinged the LT FAE's for an update. Talk to your LT FAE for the latest GUI SW and demo board schematics. These demo boards are not yet technically released so I can't share the materials until they are freely available on their website.
The active cell balancing works fine with the built in resistors as expected (around 240mA). I then got bored and decided to try the PWM of cells again. If you try this just be careful to disconnect your battery from the LTC6802 demo board before downloading FW that controls the LTC6802 while it is on -> With only a 0.25 ohm 2512 current limiting resistor if you freeze the micro with the switch on it takes only a couple seconds to fry the SOT23 FET and 0.25 ohm resistor. It is feasible to have some cells stuck in the high state when the SPI is stopped mid-process. During PWM control it is only on for no more than a 500-1000us in my SW loop before being shut off again so the chances are low, but if it breaks during this on-time you are hosed. When I disconnect the battery first there is no worries as the power source to the fets are obviously gone.
I bought an infrared thermal sensor to measure the heat put off by the factory solution vs the PWM solution and the results were good, though not as much as I'd hoped. At a steady 240mA I measured around 90C the fet and resistor. By PWM'ing the lower 0.25ohm resistor I could get 600-700mA for slightly higher temps of ~100C and held up fine. At the same 240mA (@3.6V per cell) it ran barely above room temp so it definitely is a way to reduce temps if the balancing current at 240mA is OK.
I then got greedy and tried pushing it further to 1.2A and I burnt up a fet (let out the magic smoke! ) The shunt went soon thereafter as the FET failed short. I've got some beefier FETS on order that have an on resistance of less than 50milliohms which is 1/4 of the si2351ds that come with the demo board. This should help me achieve better figures. I also have some more fine tuning to do in the SW algorithm. More to follow...feel free to ask more ?'s as well.
FYI I could not get the GUI SW installed on my machine for some reason for the 509 USB board. It wasn't long before I got my micro up and talking via UART to give me status so I haven't tried since or pinged the LT FAE's for an update. Talk to your LT FAE for the latest GUI SW and demo board schematics. These demo boards are not yet technically released so I can't share the materials until they are freely available on their website.
The active cell balancing works fine with the built in resistors as expected (around 240mA). I then got bored and decided to try the PWM of cells again. If you try this just be careful to disconnect your battery from the LTC6802 demo board before downloading FW that controls the LTC6802 while it is on -> With only a 0.25 ohm 2512 current limiting resistor if you freeze the micro with the switch on it takes only a couple seconds to fry the SOT23 FET and 0.25 ohm resistor. It is feasible to have some cells stuck in the high state when the SPI is stopped mid-process. During PWM control it is only on for no more than a 500-1000us in my SW loop before being shut off again so the chances are low, but if it breaks during this on-time you are hosed. When I disconnect the battery first there is no worries as the power source to the fets are obviously gone.
I bought an infrared thermal sensor to measure the heat put off by the factory solution vs the PWM solution and the results were good, though not as much as I'd hoped. At a steady 240mA I measured around 90C the fet and resistor. By PWM'ing the lower 0.25ohm resistor I could get 600-700mA for slightly higher temps of ~100C and held up fine. At the same 240mA (@3.6V per cell) it ran barely above room temp so it definitely is a way to reduce temps if the balancing current at 240mA is OK.
I then got greedy and tried pushing it further to 1.2A and I burnt up a fet (let out the magic smoke!
) The shunt went soon thereafter as the FET failed short. I've got some beefier FETS on order that have an on resistance of less than 50milliohms which is 1/4 of the si2351ds that come with the demo board. This should help me achieve better figures. I also have some more fine tuning to do in the SW algorithm. More to follow...feel free to ask more ?'s as well.
mike_t said:.... By PWM'ing the lower 0.25ohm resistor I could get 600-700mA for slightly higher temps of ~100C and held up fine. At the same 240mA (@3.6V per cell) it ran barely above room temp so it definitely is a way to reduce temps if the balancing current at 240mA is OK.
I then got greedy and tried pushing it further to 1.2A and I burnt up a fet (let out the magic smoke!
Cool. Gota have smoke to learn. :wink:
So at 240ma, you were using a .25 ohm resistor? What kind of duty cycle was that running?
What got hotter? the FET or the resistor?
Perhaps there's a way to optimize the resistance. I think it would depend a lot on the internal resistance of the cells. What cells are you using?
In a way, this is much like the way I'm PWMing the charge current on my analog BMS. I wasn't sure it would work, but it works well and eliminates a lot of heat. I just didn't think you could get away with it for discharging. Inductance could be an issue if the wires between the cells and the shunts got too long.
You can certainly get FETs with much lower on resistance. And much higher current rating as well. I can already think of an analog way to do this....
Hi Nick,
I don't think the LTC6802 was ever intended to be run by the GUI and DC509 - it is more just a tool to get info from the part and aid in writing code (see the hex values for certain configs, etc). T
The intended application is hooked up to a micro via the SPI interface. The LTC6802 has no way of turning the cell balancing FETs on or off, it just indicates via flags whether a cell has tripped an over-voltage threshold or undervoltage threshold. Alternately you can process the ADC data manually as well and determine a course of action. All the "thinking" occurs in the microcontroller though, and it must determine what to do based on info from the LTC6802. This theoretically could be your PC (via parallel port I suppose) but would still entail programming.
I think the ATmega8 board may be your best bet, but is not a trivial job!
Mike
reagle
100 W
Had a conversation with a Linear app engineer the other day: there is another version of 6802 coming out soon that can run standalone. I guess they added EEPROM to store settings and the internal state machine uses that. That means in many cases you won't need a micro.
Also got the demo boards- application installed just fine
Also got the demo boards- application installed just fine
Helldriver
1 µW
- Joined
- Feb 19, 2009
- Messages
- 3
We've been evaluating both versions of the LTC6802(-1/-2) for some time. DC509 and Windows GUI(downloadable from the Linear site) working fine.
If anybody out there is using Eva Board DC1331B(revison B, i guess also revison A) and wants to cascade another board(s) be warned:
Due to a mistake in the layout(classical RTFM :lol the LTC6802 on the upper board(s) will die miserably after some time(minutes). Contrary to the information in the datasheet the SDO line of the upper board is connected to the daisy-chain line on the lower board. This is fatal. Remove R43 on all boards except the bottom board and everything will run fine. Linear corrected this bug in revision C of the DC1331 :wink:.
We ended up using the LTC6802-2(classical isolated serial communication) cause the daisy-chain interface of version -1 is too sensitive to EMI and is not working reliably (yet). This needs some more development work.
Nico
http://www.erockit.net
If anybody out there is using Eva Board DC1331B(revison B, i guess also revison A) and wants to cascade another board(s) be warned:
Due to a mistake in the layout(classical RTFM :lol
the LTC6802 on the upper board(s) will die miserably after some time(minutes). Contrary to the information in the datasheet the SDO line of the upper board is connected to the daisy-chain line on the lower board. This is fatal. Remove R43 on all boards except the bottom board and everything will run fine. Linear corrected this bug in revision C of the DC1331 :wink:.We ended up using the LTC6802-2(classical isolated serial communication) cause the daisy-chain interface of version -1 is too sensitive to EMI and is not working reliably (yet). This needs some more development work.
Nico
http://www.erockit.net
reagle
100 W
Heldriver,
what version GUI are you using? I grabbed the quickeval from their web page and while it finds the chip, it complains about not having a module for it.
what version GUI are you using? I grabbed the quickeval from their web page and while it finds the chip, it complains about not having a module for it.
Helldriver said:
You mean you are using a separate line for each chip?
What kind of shunt current are you running?
What kind of EMI issues were you having?
(sorry for all the questions... BTW, Welcome!)
wrobinson0413
1 kW
.
Helldriver said:If anybody out there is using Eva Board DC1331B(revison B, i guess also revison A) and wants to cascade another board(s) be warned:
Due to a mistake in the layout(classical RTFM :lol
Nico
http://www.erockit.net
Good to know! Still just using a single board and charging 2 12-cell strings in parallel until I get another board...but I was planning on daisy-chaining them w/ a 2nd board eventually.
Nice prototype pics BTW.
Mike
Helldriver
1 µW
- Joined
- Feb 19, 2009
- Messages
- 3
GUI filename: DC1331...12142007.exe (Version 1.0 - seems not to be relevant); BTW too big for 800*600 screen resolution, not resizable :-(, apparently available only on demandreagle said:
you need to install the drivers for the DC509 Interface board first; our Version is 1.76.0.0
- no, the -2 version uses only one set of spi-lines connected to every chip and individual chips answer to adressed commandsfechter said:
- shunt current? we're currently using the on(demo)board resistors for balancing
- unreliable communication over the spi; in unfavourable conditions(gas discharge lightning near f.e) failing completely
Of course the chips were on different boards(two demoboards) aprox. 100mm part, connected by unshielded flatband cable. An indication that this is not the end of development are the resistors in the daisy chain lines, which have no reference in the datasheet and changed value from DC1331 Rev.B to Rev.C 8) .wrobinson0413 said:
Nico
http://www.erockit.net
toastmaster2k2
1 µW
- Joined
- Apr 2, 2009
- Messages
- 1
Helldriver said:We've been evaluating both versions of the LTC6802(-1/-2) for some time. DC509 and Windows GUI(downloadable from the Linear site) working fine.
If anybody out there is using Eva Board DC1331B(revison B, i guess also revison A) and wants to cascade another board(s) be warned:
Due to a mistake in the layout(classical RTFM :lol
We ended up using the LTC6802-2(classical isolated serial communication) cause the daisy-chain interface of version -1 is too sensitive to EMI and is not working reliably (yet). This needs some more development work.
Nico
http://www.erockit.net
I am about 3 months into my own project with the 6802-1 chip and trying to use Lab View as the controller. A couple successes you have had surprise/ amaze me. I've been working through the Cary sales office talking to John Williams one of their Application Engineers......I was told I could not get a DC 1331 eval board or a 6802-2. How or who did you talk to coax out the hardware ---on the off chance anyone has had this problem and is willing to provide insight --- when I send the start A/D command (using an 8bit 11) ---- there is no change in output on the SDO pin -- it just remains high.
---if any one has suggestions or questions about my set up I'd love to entertain them--Thanks
DavideAndrea
1 µW
I bought 3 each LTC6802-1 by mistake and cannot return them. If anyone wants them, they're free (US only, please). Contact me directly: davide AT
...
elithion.com
...
elithion.com
embeddedmatt
1 µW
- Joined
- Sep 19, 2009
- Messages
- 1
Where can you buy the board? I can see how to buy samples on the LT web site but I don't see how to buy th demo board. Thanks.
Hi guys!
I've just made a board with a single LTC6802-1 and a PIC MCU. I'm having problems with the communication, so If anyone has any experiences in this area I will be very gratefull.
The first task is to write the configuratin register. I send the command + 6 bytes of data. The weird thing is, that I can toggle the GPIOs but none of the DCCs, they just do not respond. Is there any protection mechanism or setting that I've missed?
Thanks!
I've just made a board with a single LTC6802-1 and a PIC MCU. I'm having problems with the communication, so If anyone has any experiences in this area I will be very gratefull.
The first task is to write the configuratin register. I send the command + 6 bytes of data. The weird thing is, that I can toggle the GPIOs but none of the DCCs, they just do not respond. Is there any protection mechanism or setting that I've missed?
Thanks!
Helldriver
1 µW
- Joined
- Feb 19, 2009
- Messages
- 3
Hi folks,
I copied here a private exchange for everybodies benefit. Sorry for the form, but I didn't find a way to publish a sequence of private messages any better.
Regards, Nico
Sent: Thu Nov 12, 2009 11:32 am
by psychoquaker
Hi,
I've read, that you are dealing with ltc6802. What are your final experiences yet? Is this chip worth it or just crap? I've read, that many people had problems with EMI, like in real situations...
Best regards,
Manuel
Sent: Thu Nov 12, 2009 1:55 pm
by Helldriver
Hi,
we're going to use the LTC6802/2 in a custom Battery Managment System(BMS) for our bike and are now entering first small series production with it. We had to deal with a number of EMI problems in the design of the BMS but nothing seriously specific to the LTC chip. As I already wrote in my posts, I strongly recomend to use the /2 version, since the daisy chain version is not EMI proof and I guess will not ever be. Btw. Maxim has released a(very) similar chip with a daisy chain interface which a development engineer at the TTXGP claimed is EMI proof. We have their eva board here but had no time to test it yet.
Best Regards
Nico
p.s. Use the /2 version with icouplers. Somehow expensive, but reliable and simple. Nico
Sent: Thu Nov 12, 2009 5:07 pm
by psychoquaker
Hi Nico,
thanks for the reply - I already expected such a reply
Do you think optocoupler would also be suitable for lower speed requirements? lets say 20kBit?
Or which isolators do you use?
Best regards,
Manuel
Sent: Thu Nov 12, 2009 5:14 pm
by psychoquaker
just forgot something...
what about connecting several LTC6802 to a larger battery pack - I read, that if you unconnect the lowest or highest wire of one LTC, the guy will blow up... is that true? And how can you prevent it?
And do you use the RC-filter at every input, or is noise not a problem in your case... like from motor controllers or chargers...
Best regards,
Manuel
Sent: Fri Nov 13, 2009 11:56 am
by Helldriver
Hi Manuel
psychoquaker wroteo you think optocoupler would also be suitable for lower speed requirements? lets say 20kBit?
Or which isolators do you use?
helldriver wrote:Use the /2 version with icouplers. Somehow expensive, but reliable and simple.
Already answered that. Good for up to 1MBit. Generally limited by the current capability of the LTC's high voltage regulator.
psychoquaker wrote:just forgot something...
what about connecting several LTC6802 to a larger battery pack - I read, that if you unconnect the lowest or highest wire of one LTC, the guy will blow up... is that true? And how can you prevent it?
And do you use the RC-filter at every input, or is noise not a problem in your case... like from motor controllers or chargers...
We have not done testing on the first/last wire issue. But looking at the LTC's internal protection circuitry I'm pretty sure it's going to blow if the supply current has to go through any other wire than the ground connection. We connected 4 LTC's to 36 cells in a row(36s10p) by 4 molex mini Fit connectors(which don't ensure any defined connection sequence) and had no problems.
Just use the rc-filters as described in the datasheet. They don't deteriorate your measurement and give you better noise margin. Motor controller, brush fire(DC Motor) and charger have not been a noise problem but our first DC/DC converter didn't pass EMI test for type approval
Regards
Nico
Sent: Sat Nov 14, 2009 12:10 pm
by psychoquaker
Hi Nico,
thanks for the hints.
So do you have any idea how to do a correct connecting/disconnecting of the LTC6802. Maybe start at GND and then connect first the battery connectors and last the Vcc connector? Or first GND and VCC?
I've not seen any recommendations from LTC side yet... and I'm a little bit confused by the datasheet which says, that there ist protection circuitry to prevent any damage, but everybody tells me, it's going to blow up if you do it the wrong way.
Thanks for your help,
Manuel
Sent: Wed Nov 25, 2009 10:39 pm
by psychoquaker
Hi Nico,
just wanted to ask you my last question, which is still very important for me, as I'm just designing the pcb for the chip.
So do you have any idea how to do a correct connecting/disconnecting of the LTC6802. Maybe start at GND and then connect first the battery connectors and last the Vcc connector? Or first GND and VCC?
I've not seen any recommendations from LTC side yet... and I'm a little bit confused by the datasheet which says, that there ist protection circuitry to prevent any damage, but everybody tells me, it's going to blow up if you do it the wrong way.
Thanks for your help,
Manuel
Sent: Fri Nov 27, 2009 9:26 am
by Helldriver
Hi Manuel,
we didn't care much about connection sequence. We just connected the whole bunch of lines to the battery(GND, Cell1+, Cell2+,....last Cell+) via a molex Mini-Fit connector to the PCB. As I mentioned before, this doesn't ensure any connection sequence, only that they are connected in the time it takes to place the connector. Just remember that you have to connect each cell measurement input of unused cells together to Vcc if you use less than 12 Cells(11s, 10s,...). The chips seam to tolerate a certain time(might not be tooo long) of mising connections(at least 1 sec I guess).
MOST IMPORTANT: Keep the Gnd line AND the Vcc lines up the the actual connection to the battery free fom any current other than the LTC's supply/measurement current !!! These connections MUST be done in a star-like connection as you usually do to prevent ground loops. Any additional current(even for some milli seconds) over these lines(for a DC/DC converter f.e.) gives you a voltage drop which WILL destroy the LTC. We had some reproducible spectacular burn-off's that way. I already suggested Linear to add this to the datasheet but they didn't react. Maxim has a corresponding hint in their sheet for the Max 11068 .
Do you mind if I publish our "private" conversation in the forum? Might be helpfull to evrbody
Regards. Nico
Sent: Fri Nov 27, 2009 7:38 pm
by psychoquaker
Hi Nico,
ok - I must admit, that I'm not totally convinced of that 1sec rule.
BTW: in the datasheet it's mentioned, that for any connection loss within the stack "protection is included within the LTC6802-2 device itself" (see page 25 of datasheet). Also for the case of V- or V+ loss there should be protection by included zener diodes.
What do you think? Is that maybe only working for that 1sec...?
Of course you can publish this conversation - please send me the link then.
Best regards and thanks a lot.
Manuel
I copied here a private exchange for everybodies benefit. Sorry for the form, but I didn't find a way to publish a sequence of private messages any better.
Regards, Nico
Sent: Thu Nov 12, 2009 11:32 am
by psychoquaker
Hi,
I've read, that you are dealing with ltc6802. What are your final experiences yet? Is this chip worth it or just crap? I've read, that many people had problems with EMI, like in real situations...
Best regards,
Manuel
Sent: Thu Nov 12, 2009 1:55 pm
by Helldriver
Hi,
we're going to use the LTC6802/2 in a custom Battery Managment System(BMS) for our bike and are now entering first small series production with it. We had to deal with a number of EMI problems in the design of the BMS but nothing seriously specific to the LTC chip. As I already wrote in my posts, I strongly recomend to use the /2 version, since the daisy chain version is not EMI proof and I guess will not ever be. Btw. Maxim has released a(very
) similar chip with a daisy chain interface which a development engineer at the TTXGP claimed is EMI proof. We have their eva board here but had no time to test it yet.Best Regards
Nico
p.s. Use the /2 version with icouplers. Somehow expensive, but reliable and simple. Nico
Sent: Thu Nov 12, 2009 5:07 pm
by psychoquaker
Hi Nico,
thanks for the reply - I already expected such a reply
Do you think optocoupler would also be suitable for lower speed requirements? lets say 20kBit?
Or which isolators do you use?
Best regards,
Manuel
Sent: Thu Nov 12, 2009 5:14 pm
by psychoquaker
just forgot something...
what about connecting several LTC6802 to a larger battery pack - I read, that if you unconnect the lowest or highest wire of one LTC, the guy will blow up... is that true? And how can you prevent it?
And do you use the RC-filter at every input, or is noise not a problem in your case... like from motor controllers or chargers...
Best regards,
Manuel
Sent: Fri Nov 13, 2009 11:56 am
by Helldriver
Hi Manuel
psychoquaker wrote
o you think optocoupler would also be suitable for lower speed requirements? lets say 20kBit?Or which isolators do you use?
helldriver wrote:Use the /2 version with icouplers. Somehow expensive, but reliable and simple.
Already answered that. Good for up to 1MBit. Generally limited by the current capability of the LTC's high voltage regulator.
psychoquaker wrote:just forgot something...
what about connecting several LTC6802 to a larger battery pack - I read, that if you unconnect the lowest or highest wire of one LTC, the guy will blow up... is that true? And how can you prevent it?
And do you use the RC-filter at every input, or is noise not a problem in your case... like from motor controllers or chargers...
We have not done testing on the first/last wire issue. But looking at the LTC's internal protection circuitry I'm pretty sure it's going to blow if the supply current has to go through any other wire than the ground connection. We connected 4 LTC's to 36 cells in a row(36s10p) by 4 molex mini Fit connectors(which don't ensure any defined connection sequence) and had no problems.
Just use the rc-filters as described in the datasheet. They don't deteriorate your measurement and give you better noise margin. Motor controller, brush fire(DC Motor) and charger have not been a noise problem but our first DC/DC converter didn't pass EMI test for type approval
Regards
Nico
Sent: Sat Nov 14, 2009 12:10 pm
by psychoquaker
Hi Nico,
thanks for the hints.
So do you have any idea how to do a correct connecting/disconnecting of the LTC6802. Maybe start at GND and then connect first the battery connectors and last the Vcc connector? Or first GND and VCC?
I've not seen any recommendations from LTC side yet... and I'm a little bit confused by the datasheet which says, that there ist protection circuitry to prevent any damage, but everybody tells me, it's going to blow up if you do it the wrong way.
Thanks for your help,
Manuel
Sent: Wed Nov 25, 2009 10:39 pm
by psychoquaker
Hi Nico,
just wanted to ask you my last question, which is still very important for me, as I'm just designing the pcb for the chip.
So do you have any idea how to do a correct connecting/disconnecting of the LTC6802. Maybe start at GND and then connect first the battery connectors and last the Vcc connector? Or first GND and VCC?
I've not seen any recommendations from LTC side yet... and I'm a little bit confused by the datasheet which says, that there ist protection circuitry to prevent any damage, but everybody tells me, it's going to blow up if you do it the wrong way.
Thanks for your help,
Manuel
Sent: Fri Nov 27, 2009 9:26 am
by Helldriver
Hi Manuel,
we didn't care much about connection sequence. We just connected the whole bunch of lines to the battery(GND, Cell1+, Cell2+,....last Cell+) via a molex Mini-Fit connector to the PCB. As I mentioned before, this doesn't ensure any connection sequence, only that they are connected in the time it takes to place the connector. Just remember that you have to connect each cell measurement input of unused cells together to Vcc if you use less than 12 Cells(11s, 10s,...). The chips seam to tolerate a certain time(might not be tooo long
) of mising connections(at least 1 sec I guess).MOST IMPORTANT: Keep the Gnd line AND the Vcc lines up the the actual connection to the battery free fom any current other than the LTC's supply/measurement current !!! These connections MUST be done in a star-like connection as you usually do to prevent ground loops. Any additional current(even for some milli seconds) over these lines(for a DC/DC converter f.e.) gives you a voltage drop which WILL destroy the LTC. We had some reproducible spectacular burn-off's that way
. I already suggested Linear to add this to the datasheet but they didn't react. Maxim has a corresponding hint in their sheet for the Max 11068 .Do you mind if I publish our "private" conversation in the forum? Might be helpfull to evrbody
Regards. Nico
Sent: Fri Nov 27, 2009 7:38 pm
by psychoquaker
Hi Nico,
ok - I must admit, that I'm not totally convinced of that 1sec rule.
BTW: in the datasheet it's mentioned, that for any connection loss within the stack "protection is included within the LTC6802-2 device itself" (see page 25 of datasheet). Also for the case of V- or V+ loss there should be protection by included zener diodes.
What do you think? Is that maybe only working for that 1sec...?
Of course you can publish this conversation - please send me the link then.
Best regards and thanks a lot.
Manuel
methods
1 GW
Back up top.
Time to start talking about this chip again.
As far as I am concerned the Max chip is off the table. Nothing pisses me off more than when a manufacturer plays tight-ass with Datasheets and samples. I gave them the 20 pieces of personal information they requested for the datasheet and now I am waiting
I think I am just going to go with the Linear part.
I interviewed at Linear 8 years ago - very cool place to visit - but not such a cool place to work. I got an offer letter - which looked OK - but in my second interview they made it very clear that I would be expected to put in 12 hours of work for 8 hours of pay (in exactly those words). The company works on profit sharing - if your base salary is $100k and the company profits 22% then at the end of the period they cut you a check for $22k. The year I was interviewing they happened to be getting bonuses of over 30%....
I decided to be a lowly government servant instead
Allows me more time to ponder the Electric Revolution. :wink:
So - anyone have any updates to share before I turn this into my personal long-winded LTC6802 build thread ??
-methods
Time to start talking about this chip again.
As far as I am concerned the Max chip is off the table. Nothing pisses me off more than when a manufacturer plays tight-ass with Datasheets and samples. I gave them the 20 pieces of personal information they requested for the datasheet and now I am waiting
I think I am just going to go with the Linear part.I interviewed at Linear 8 years ago - very cool place to visit - but not such a cool place to work. I got an offer letter - which looked OK - but in my second interview they made it very clear that I would be expected to put in 12 hours of work for 8 hours of pay (in exactly those words). The company works on profit sharing - if your base salary is $100k and the company profits 22% then at the end of the period they cut you a check for $22k. The year I was interviewing they happened to be getting bonuses of over 30%....
I decided to be a lowly government servant instead
Allows me more time to ponder the Electric Revolution. :wink:
So - anyone have any updates to share before I turn this into my personal long-winded LTC6802 build thread ??
-methods
