Motor driver

la forza dellamore giochi di sala gochi 200 film erotici igiene orale cartoonnetwork it san remo 2002 dalessio provincia mantova it ratchet clank case vacanze affitto piemonte berg nick hofmeister wilhelm friedrich lettore mp3 usb 1gb radio roberto cavalli donna 40 ml clip blue un piacevole imbroglio intestatura imagin hs 801 fs orario company segundo jvc 500 in 3 cuculo illegale hauppauge win tv nova firehouse five plus 2 www chieti it affitto casa vacanza sirmione scopate gratis www musicamp3 com autoradio sony con telecomando offerta auto km 0 hub usb 2 alimentatore casio exilim exz750 doctorate degree chicco triciclo cyclette con programmi broken dei seether luna e stelle sylver shallow water zucchero indaco ca si hong dung medal of honor codici lexar jumpdrive 2 gb prestito pesaro powershot 95 video bluvertigo mx 900 tartaruga giardino altoparlanti per lettori mp3 notizie di cento vetrine ef 28mm f 2 8 bigass cronometro mp3 samsung lettori lanet tunisie petrolmeccanica sor juana ines de la cruz ss rifiuti baby gang il romanista it luli bossa offerte di lavoro brescia fotoannunci ragazze immagini chicchi di caffe terme lusso classe 2000 cocaina a caserta giovane avvocato canzoni d amore straniere fucili subacquei diving pesca wali video orientale (zambia) madonna re invention world tour 2004 notebook 64 bit franco angeli editore digital 5500 hd 200 configurazione siemens sl55 np fp 50 poly boy soluzioni giochi siberia fontane per interni indocina film tradestation chardonnay planeta esploratore tatuaggi maori gratis coriolanus qtec case keyboard switch rio nitrus video poker dowloads immagini diddl desktop tariffe parcheggio www chat su dediche it gallerie gratis donne mature marcia nuziale mendelssohn pagnossin group clubbed to death comune ravenna fortec stars il mare d inverno umorismo bombolo mp3 hp storageworks san tose siamo soli vasco rossi la battaglia di okinawa tomtom maps of western europe emon fuckit in italiano il romanzo di un maestro tutti gli hotel di rimini trallallera quagliata zippo harley billabong beach tour alta marea a mezzogiorno www peepee cordless siemens con segreteria c340 siemens cordless amanti felici eurex vasco buoni sex cartoons clonoa tennis roland garros www grimstveit no fateless sublime directory parola marina roma australia c s a palermo soul to squeeze african art dragostea din tei haiducii vs gabry ponte imposte indirette lo strano percorso accordi converse all star taylor easypack wind mini hifi 2 x 70 watt duns manowar wheels of fire telefoni 3 sony cybershot dscf828 8 megapixel 7x windows mobile 2003 pocket pc gps volo low cost milano new york jota quest heaven philips dvd cinema logic pro sei colpi in canna il richiamo pagano zonda gioco java free download butterflay cd love songs phil veracruz tdk dvd r gli scarafaggi visita ginecologica volo bologna praga webcam com mc and gregory bmw italia ripiani scaffale foto camilla presentatrice love line snuff machinery cd amplificatore amplificatori you can call me al paul simon song s leters attrice italiana g dolby surround amplificatori the mayday laser colore samsung ungaretti giuseppe zion y lenox track 16 hard disk scsi seagate south group health insurance frigoriferi samsung rt62kcmt bitch volley daphnia mostro di sarzana chitarra zen happy days sister acr industria en italia aoc 19 monitor nokia motorola esercizi massa muscolare gambe lastminutes travelmate 4051lmi istituto bancario san paolo max 2005 spartito batteria manuale motorola risotto system utility da nvidia grenada m first love voli varsavia There are many kinds of motor drivers:

• servo motor controller
• stepper motor controller
• DC motor controller ("brushed")
• AC motor controller ("brushless")
• ... (todo: fill in the other kinds) ...

A DC motor controller that is 'reversable' generally uses an 'H bridge'. This 'H-bridge' uses four output drivers in a configuration that resembles an H where the load is the cross bar in the middle. The lines on either side of the load (the downward strokes in the H) represent a series connection of a pull-up driver and a pull-down driver. This allows each terminal of the load to be connected to either the positive supply rail, or the negative supply rail. This allows a positive, negative or zero voltage difference across the load. This load voltage is then utilised to provide the desired control required of the motor. The various combinations can give a 'forwards' torque on a DC motor, a 'backwards' torque on the same motor, can allow the motor to free-wheel (without any applied torque) or can provide a locking of the motor such that it resists any attempt to rotate it.

A single phase AC motor is generally driven in the same way as a DC motor, however instead of operating the motor drive as a constant DC voltage (in either the 'forward' or 'reverse' direction) the AC motor is driven by an approximation to a sinewave. This approximation is created using the H bridge and driving it with a PWM input such that both the positive and negative voltage periods are the same. This is normally acheived either using a sawtooth waveform compared against a sine wave reference, or is done using a lookup table in a microcontroller.

A similar method is used to drive multiphase (3-phase) AC motors, however instead of just using an H bridge, only a half H bridge is used per phase (3 half-bridges). Each phases half bridge is then driven in the same manner as for the single phase motor, with a phase difference between the phases as appropriate.

Most stepper motor controllers uses 2 independent H bridges (4 half-bridges) for the 2 independent coils of a stepper motor. Each possible state (one bridge driving current one way, the other way, or free-floating) of both bridges gives 4 "full steps", 4 "half-steps" between the full steps. The "microstepping" motor controllers use PWM to gradually change from adjacent full-steps and half-steps.

((fill in more details here...))

current sense

Often people want to measure the current going through the motor.

There are 3(?) basic techniques:

• low-side current shunt
• high-side current shunt
• magnetic field sense
• ... (any others I missed?)

Low-side is (electrically) the simplest.

For smaller motors, the current is usually measured by running the current through a shunt resistor, and measuring the voltage across the resistor.

In situations where low-side sensing is difficult ( automobile electronics bonded to the "GND" car frame; other systems where it is inconvenient to put a resistor on the "lo" power wire), we turn to high-side sensing.

side current sense Newark: high side current sense; [http://www.digikey.com/scripts/DkSearch/dksus.dll?KeywordSearch