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Nov 20, 2004, 10:31 PM
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zagisrule!'s Avatar
I know that Allegro has several sensored BL controller IC's and they do provide free samples. http://www.allegromicro.com

Samples are given by just about any company for development purposes.



-Matt
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Nov 20, 2004, 11:36 PM
wsc
wsc
Registered User
wsc's Avatar
Slowflyer -

One thing you have to be careful of when making a logic circuit like you are is that any glitches on the input will cause a corresponding glitch on the output. IE, the hall effect sensors will have some bouncing and jittering on the transitions from one state to another, and these bounces will cause incorrect commutations on the output. I cant say whether or not this will be a serious issue for your design to overcome, but it could cause you some grief down the road. Anyway, good luck. Very simple idea, could come out very nicely.
Nov 21, 2004, 04:51 PM
Registered User
WSC-
I'm not sure if the glitches would affect the controller, but theres one way to find out! If it has problems, buying less sensitive Hall sensors could reduce glitching.
Matt-
I checked out their website and I'm impressed that they give free samples on so many of their products. However, the controllers that use Hall sensors all have a minimum supply voltage of 7v or higher. This would be a problem, as I use 7 cell batteries. The voltage will drop well below 7v before the battery is run down. There is a controller with a minimum supply of 5v, but it uses emf sensing. I could use it if I didn't use any Hall sensors.
Nov 21, 2004, 05:23 PM
"Simplify, then add lightness"
I don't know about Allegro, but my experience lately is that a lot of semi manufacturers seem to be getting a little stingy with the online samples. I have ordered a lot of samples online before that were shipped quickly with no questions asked, but lately it seems that a lot of online sample requests just get routed to a local rep or distributor who calls to verify your needs first. Has anyone else noticed this?
Nov 21, 2004, 06:31 PM
Senior Member
zagisrule!'s Avatar
Yeah,

Samples are a little harder to get, I have had to actually call distributors trying to get samples. All said and done though, I have never not gotten a sample of a product I needed.

My favorites are probably Microchip and ON Semi, both of which are blisteringly fast service-wise. ON requires a $11 shipping fee on all sample orders, but they will allow amazing numbers of samples without any question.



-Matt
Nov 23, 2004, 07:10 PM
Registered User
Well, I've requested Hall sensors from allegremicro yesterday, so I'm expecting them to arrive within a week or two. The questions on the order form weren't too bad and they claim that your order will ship within 1 day of confirmation. When they arrive, I'll post how long it took.
Matt:
I may end up using your simpler design just because its simpler. Another idea is to try both and see which works better. Parts shouldn't be too expensive.
Nov 27, 2004, 02:13 PM
Registered User
Hall sensors arrived yesterday, so shipping only took 5 days . However, it turns out that I requested the wrong type of sensors. The Hall sensors I got were intended for surface mounting, so I requested some with longer leads today.

On a side note, I discovered something interesting this morning. I have a slowstick and was testing how many amps my existing motor would draw. With an 8 cell nihm, it drew around 7 amps. The incredible thing was that my controller was only rated for 2 amps and I have been flying with it for over a year! It just seems odd since I'm obviously pushing it past its limit, but it is rairly even warm after flying long flights at full throttle. Makes me wonder if it's ever going to burn out on me one of these days...
Jun 10, 2005, 04:57 AM
Registered User

circuit deagram


hello sir,
sent me circuit deagram of 9-pole cd-rom brushless esc.
Jun 10, 2005, 07:45 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
A cd-rom motor does not need a special controller, as long as it's a brushless controller it's ok. Several do-it-yourself brushless esc designs, notably the Speedy-BL, the Quax and Takao Shimizu's designs:
https://www.rcgroups.com/forums/showthread.php?t=140454

Vriendelijke groeten Ron van Sommeren
e-motor building tips & tricks
diy outrunner discussion group
int. E fly-in & diy outrunner meet, August 28th, Nijmegen, the Netherlands
Jun 11, 2005, 11:19 PM
Registered User
e-sailpilot86's Avatar
I wish there was a far easier design for brushless controllers... I'd have to take an electronics class to learn this stuff. I haven't even taken Java yet...

R/C microflight had a pretty simple one, easy to understand. Used hall sensors.
Jun 19, 2005, 01:28 AM
Registered User
I hope this thread isn't too old already, but since I've spent a lot of time looking for ICs recently...

I've checked out every datasheet I could find and then some for sensored brushless drivers (trying to make a starter/generator (not hobby related-well a different hobby anyway)). I only payed attention to the full-wave 3-phase pre-drivers. Anyway here's the ICs I like best (mostly because their the simplest without a million pins and features I don't need) some don't have speed control:

NJM2624 - - - 4.5-18V - - - - 16Pins all N-channel Mosfets
NJM2625 - - - 8-18V - - - - - 20Pins
NJM2626 - - - 6-26V - - - - - 16Pins
http://www.njr.com/index4.html

MC33033 - - - 10-30V - - - - 20Pins
http://www.onsemi.com/site/products/summary/0,4450,MC33033,00.html?tax=407

LS7260 - - - 5-28V - - - - - - 20Pins
LS7362 - - - 5-28V - - - - - - 20Pins
http://www.lsicsi.com/products_files/body_products-brushless_dc_motor_controls.htm

I didn't check all of them but the ones I checked are availiable from digikey or mouser for a buck or 2.

For the people that know electronics better than me (I just know what I've learned on the net the last month or so), I was wondering if you can drive mosfets from a non-pre-driver IC. Can you use a P and N totem pole connected to whats supposed to go directly to the motor?

Joel
Jun 19, 2005, 03:32 AM
Registered User

ICs


Some time back I was looking for ICs for an ESC, I found some fro Sanyo. they have brushless,sensorless controller ICs that are voltage controlled and work on voltages from 1.5v to 3v if I remember correctly. I have lost the the part numbers but I think that they were LB16**. I never found a supplier.
cheers,
Robin
Jun 19, 2005, 05:25 AM
We want... Information!
Bruce Abbott's Avatar
It is possible to use a non pre-driver IC with external FETs. Connect a resistor from each motor phase to the supply, and another to ground. Then you can detect three voltage levels using two comparators, one per output FET. This requires 6 comparators and lots of resistors, so is probably more complex than using a pre-driver IC.

I chose the NJM2624 pre-driver for it's simplicity, availability and low cost (just $0.90 each at Mouser Electronics). One thing to watch with this chip is that although it can work down to 4.5V, its outputs can only go up to 1.5V below the supply voltage. Therefore at least a 6V supply may be needed to drive logic-level MOSFETs.

My circuit makes a stock CDROM motor act like a brushed DC motor, which can then be driven by a normal brushed ESC. The breadboard prototype worked very well, so I am now working on a surface mount version. The output switches will be SI4542DY dual N&P MOSFETs, for a total of only 24 parts on the PCB.
Last edited by Bruce Abbott; Jun 19, 2005 at 05:32 AM.
Jun 19, 2005, 11:03 PM
Registered User
Bruce:
Thats the IC I like best and since you have already made a circuit with it and I don't know much about electronics I was wondering why you didn't just use 6 N-channel MOSFETs instead of Ns driving Ps?

Also what hall sensors do I need? I'm guessing bipolar analog? 4pins?

I have a question about mosfets in general too, if you don't mind. Since I'm making a starter/generator, the starting voltage is 12v and the generated voltage could be to about 120v unless the stator saturates before then, not sure how the saturation stuff works, but on to the question.... The generated AC would be rectified by the diodes in the mosfets which is cool, but what if I'm not using any of the power, will the high voltage jump from the source to the gate? Is that what the Vgs is? How would I get around this? Could I just use a shunt regulator to keep the voltage down? I need a regulator to charge the battery anyway. I was gonna have a diode with the regulator in parallel with it so the battery doesn't get the high voltage strait from the generator. I know the Vdss has to be high enough too, but I just need to know if a high enough voltage can go from source to gate?

Thanks,
Joel
Jun 19, 2005, 11:24 PM
Registered User
robinhood:

I haven't looked too much for sensorless drivers since I need the starting torque, but I haven't found a sensorless ic that doesn't need a centertap, or is a pre-driver. I'll probably keep looking though, since I do have several cd-motors.

Sanyo's current sensorless drivers

All Sanyo 3-phase brushless Drivers

Joel


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