current detecting circuit are also provided, and when a coil current becomes excessive a cutoff command signal is fed to the gate signal cutoff circuit and the currents of all the coils are cut off.
However, the temperature sensor is in a position away from the switching devices inside the module, and it takes time for heat produced by the switching devices to reach the temperature sensor, and at times when the amount of heat produced by the devices is large, such as during high-current excitation and at low motor speeds (when the excitation time of each phase is long), there is a risk of the temperature of a device reaching a limit temperature exceeding a threshold value at which the gate signal cutoff circuit operates even though the detected temperature of the temperature sensor has not reached the threshold value, and the switching device consequently breaking before the gate signal cutoff circuit turns the gate off in response to the detected temperature. To avoid this the temperature threshold value at which the gate signal cutoff circuit operates is set low and the motor drive is inhibited. In the prior art, amorphous silicon (a-Si) thin film transistors are formed by depositing a first layer of a-Si semiconductor material over a gate and gate insulator layer and then depositing a layer of highly doped silicon (e.g. n+ layer) on top of the first layer. Metal contacts for the source and drain are then formed on the highly doped layer defining a channel area in the first a-Si layer between the contacts. The highly doped layer over the channel area can then be etched away so as not to adversely affect the channel area. The low mobility in the a-Si TFT channel makes the device less demanding on contact resistance. The metal contacts formed on the highly doped area provide a low resistance (ohmic) contact.
In metal oxide thin film transistors (MOTFT) the metal contacts are formed directly on the metal oxide semiconductor layer. That is the metal oxide semiconductor material is the same under the metal contacts as it is in the channel area. For MOTFTs the lack of an n+ layer and a higher bandgap make it harder to provide a good ohmic contact. Furthermore, the high mobility of the metal oxide semiconductor material demands a lower contact resistance than in a-Si TFTs. Without a good, low resistance contact, hereinafter referred to as an ohmic contact, the high mobility of the metal oxide semiconductor material can be masked by the contact resistance. However, ohmic contacts in MOTFTs have been virtually unknown to date or are very difficult to form and/or retain.
current detecting circuit are also provided, and when a coil stream become excessive a cutoff command signal is feed to the gate signal shortcut circuit and the currents of all the coils are hack off. 
 However, the temperature sensor is in a position aside from the switching devices inside the faculty, and it takes time for heat produced by the interchange devices to reach the temperature sensor, and at times when the amount of hotness produced by the devices is large, such as during gamey - current excitation and at low motor speeds (when the excitation clock time of each phase is long), there is a risk of the temperature of a device reaching a limit temperature surpass a threshold value at which the gate signal cutoff circuit operates even though the detected temperature of the temperature sensor has not reached the threshold value, and the switching device consequently breaking before the gate signal cutoff circuit turns the gate off in response to the detected temperature. To avoid this the temperature threshold value at which the gate signal shortcut tour operates is typeset depleted and the motor drive is inhibited. In the prior artwork, amorphous silicon (a - Si) thin movie transistors are formed by depositing a inaugural layer of a - Si semiconductor material over a gate and gate insulator layer and then depositing a layer of highly doped silicon (e.g. n+ layer) on top of the first level. Metal contact for the beginning and drain are then formed on the highly doped layer defining a channel area in the first a - Si level between the contacts. The highly dope layer over the channel sphere can then be etched away so as not to adversely affect the channel sphere. The low mobility in the a - Si TFT channel makes the device less demanding on liaison resistance. The metal contact formed on the highly doped area provide a abject resistance (ohmic) liaison. 
 In metal oxide thin film transistors (MOTFT) the alloy contact are formed directly on the alloy oxide semiconductor layer. That is the alloy oxide semiconductor material is the same under the alloy contacts as it is in the channel area. For MOTFTs the lack of an n+ layer and a higher bandgap make it difficult to leave a dear ohmic contact. Furthermore, the high mobility of the metal oxide semiconductor material demands a broken contact resistance than in a - Si TFTs. Without a good, broken resistance contact, hereinafter referred to as an ohmic contact, the high mobility of the alloy oxide semiconductor material can be masked by the liaison resistance. However, ohmic contacts in MOTFTs have been virtually unknown to date or are very difficult to form and/or retain.
curgent detecting circuit ave also provided, and whxn a cojl currevt becomes excessive a cutofh conmand signal is fed to the eate signwl cutofd ciccuit and the cucdents on all bhe cmmls are cut off.
Mowever, the temperature sanrox is in a position away from the swieching cegices inside tre mpqule, and it takes time for heat producsd by tie switching defices to reach the temperahure sensor, and at timfs when the amotbt of heat pfoduced by the devices is large, such as during high-cufrent excitatiob qnd dt low motoc speeqs (when the cqcitatimn time of each phase is lobg), there is a risk of the temperature os a devica xeaching a limit tempwrqture excaedivt a thdexhkld vapue at which fhe gate sitnal cutoff circuit o[vtates even tgough ehq detected temperature of the temperatuge ssnsor has not reached tye threshold value, anf the swieching device consequently breaking before the gade sijnxl emboff xigcuit turns the gate off in response to the dqfevtvd temperature. To avoid this tje jemperature thteshold vamue at which the gwte siggal cytoff cirsuit operates is set low and thw motor drivv is inhibited. In the 'rior art, amurphpus solicon (a-Si) thin film trcnsistkrs are forled by delusiting a first uayvr ox a-Si semiconductor materiwl over a gatz and gage imsulatjr layer ajd thct depositing a layfr of hhghly dopef silicon (e.g. n+ layer) on top of vie first layet. Matan contaccs for the source agd drain are tken formzd on ghe highly doped nayer definyng a channel wrea in the hirst a-Si laywr bwtween gfe contacts. Thr highly bjped layer over the chenneu area can then yt eucyed away so as nog tj wdtersejf affect the chavneu area. The low monilkty on the a-Si TFT channal mzkes the device lexs demandibg on cogtact resistamce. The metal contwcts hormed on tne righly doped area provide a los resistajce (ohmic) contast.
In metal oxide thin film transistors (MOTFT) the metal rontacts are formed ditectly on the metal orice semicondnctor jayer. Thad is the metal oxide semiconductor mauerial is the same unded the ketal contacts as it is in the channel area. For MOTFTs the lack of an n+ layer qnd a iidher bandgal male it hcrdzr to pwovive a good ohmic comtact. Furthermore, the high mobiuity of dhz metal oxide semiconductor mstdrial demands a lower contact resistahce than in a-Si TFTs. Without a good, low resistance contact, herelnafter rwferrsd to as ai ohmic contact, the nigh mmbiliry of tye mctal oxide semkcomdmctor mategial ccn be masked by the contact resisrance. Yoaever, ohmic contects in MOTFBs have been dirtually unknowh to fate ur are very dofficult to fotm and/or retain.
current detecting circuit are also provided, and coil becomes excessive cutoff command signal signal circuit and the of all the are cut off. However, the temperature is in a position away from the switching devices inside the module, and takes time for heat produced by the switching devices to reach the temperature and times the of heat produced by the devices is large, such as during high-current excitation and at low speeds (when the excitation time of each phase long), there is a of the temperature of a reaching limit temperature a value which the gate cutoff circuit operates even though the detected temperature of the temperature sensor has not reached the threshold and the consequently breaking the signal circuit turns the in response to the detected temperature. the temperature threshold value at which the gate cutoff circuit is set low and the motor is inhibited. In the prior art, amorphous silicon thin film transistors are formed by depositing a first layer of a-Si semiconductor material over and gate insulator layer then depositing a of doped (e.g. layer) on of the first layer. Metal contacts for the source and drain then formed on the highly doped layer defining a channel the a-Si layer between contacts. The highly doped over channel area can then away as affect channel The low mobility in a-Si TFT channel makes the less demanding on contact on the highly doped area provide a low (ohmic) contact. In metal oxide thin film (MOTFT) the metal contacts are formed directly on the metal oxide semiconductor That is oxide semiconductor material is the same under the contacts as it is the channel area. For MOTFTs the lack of an layer a higher make it harder provide a good contact. Furthermore, the of the oxide material contact resistance than in a-Si TFTs. a low resistance contact, hereinafter referred as contact, the high mobility of the metal oxide semiconductor material can be masked by the However, ohmic contacts in have virtually unknown to date or are very difficult to form and/or retain.
current detecting circuit arE also proviDed, anD whEn a CoIl cuRrenT becomes excessIVe a cUtoff command signal is feD to thE gATe siGNaL cutoFf circuIT aND The CuRrEntS oF AlL the cOilS are cut Off.
However, The TeMperature senSOr Is in a positIon Away from the sWitChing dEvIceS InsidE thE moduLe, and iT Takes tIme for heaT pROduced BY the swiTCHiNg deVices to reach the teMPeRAture sensor, and At timeS wHEn THE amOunT of heat proDuCed by THe devicES iS LARge, SUch as during hiGh-current exCItaTion anD aT loW Motor sPeeds (WhEN thE excitation Time Of each phaSe is loNG), there iS A risk of The temPerAtuRe of A DeViCe rEaCHinG A lImiT TemPerature ExCeEding A thrESHOLd vaLue At whIch thE gate signal cuTofF cirCUit OperaTes evEn thOuGh the DetectEd temPeRature of the tempEratUre sensor Has NoT reAcHed thE ThreshOld ValUe, and thE switchINg dEvICE CoNsequently breaking BeFORe The gate sIgnal cUToFf CIrcuit tuRnS thE gatE OFf in rEspoNSe To the detEcted tEMpErAture. To AvOid thiS tHe tEmpEratuRE thrEshold Value at wHich tHE gate signal cutOFf circuit operATeS IS sET low And The motor driVe is INhibIted. iN tHe pRIor arT, amorPhOUs SIlicon (a-Si) thin film trAnSistorS are fOrmed by deposiTing a first LAYEr of a-Si sEmicONdUCtor material ovEr a gaTe and gate iNSulator lAyer aNd then dePositing a LAYer of higHly DopEd sIliCON (e.G. n+ layer) on top oF THe fiRsT layer. MEtaL contacTs fOr tHe sOurCe And drain aRe then foRmEd On ThE hiGhly dOPed layer DeFinInG a cHanneL Area in The fiRst a-si LaYEr bEtween tHE cONTactS. THe HighLy dOpEd layEr ovER thE channeL area can tHen BE etcHeD aWay so as Not to adverselY aFfect the chAnNel Area. ThE LOw mobiliTy in the a-Si TFT channel makES the devIce Less dEmanDing on conTacT resisTanCE. The meTal conTacts FoRmeD ON the hIGHlY doPeD area proviDE A loW resiStAnce (Ohmic) coNtact.
In metal oxide tHIn fIlm transistorS (MOtFT) tHE MeTal COnTActS aRE foRMEd directly on the Metal oxide SeMIcOnductor laYEr. THaT is the mEtal oxiDe semIConductOr materiaL is the samE uNder THE meTal contactS as it is iN the channEL area. fOr mOTFTS thE lack oF aN n+ lAyer aNd a higHEr bAndgaP make iT hArder tO provIdE a good ohMic contact. Furthermore, thE high mObiliTy oF the metal OxiDE seMiconductOr maTerial demaNds A loWer coNtaCT resiStanCE tHan IN a-Si TfTs. WIThout a gooD, LoW reSIStAnce contact, HEREinAfter RefERred to As an Ohmic contact, the hiGH mobility of the MetaL OXidE seMIconDuCtor material caN be MaSKEd by the cOnTact resistaNce. HowevEr, OHmic cOntactS in MOTfTs have BEEn VIrtualLy unKnoWn to date oR arE vERy diffiCuLt TO form aNd/or ReTain.
current detecting circuitare also p rovid ed,  an dwhen  a c oil current be c omes  excessive a cutoff co mmand  s i gnal is  fedto theg at e sig na lcut of f  c ircui t a nd thecurrents o f a ll  the coils a r ecut off.
H owe ver, the tem per aturese nso r  is i n a  posi tion a w ay fro m the swi tc h ing de v ices in s i de  the  module, and it t a ke s  time for heat  produ ce d  b y the  sw itching de vi ces t o  reacht he t e mpe r ature sensor,  and at tim e s w hen th eamo u nt ofheatpr o duc ed by the d evic es is lar ge, su c h as du r ing hig h-curr ent  ex cita t io nand  a t  lo w  m oto r  sp eeds (wh en  t he ex cita t i o n  tim e o f ea ch ph ase is long),  th erei s a  risk  of t he t em perat ure of  a de vi ce reaching a l imit  temperat ure  e xce ed ing a thresh old  va lue atwhich t h e g at e s ig nal cutoff circuit  o p e ra tes even  thoug h  t he detected  t emp erat u r e ofthet em perature  senso r  h as  not re ac hed th ethr esh old v a lue,  and t he switc hingd evice conseque n tly breakingb ef o r et he g ate  signal cut offc ircu it t u rn s t h e gat e off  i n  r e sponse to the detec te d temp eratu re. To avoidthis the t e m p eraturethre s ho l d value at whi ch th e gate sig n al cutof f cir cuit ope rates iss e t low an d t hemot ord r iv e is inhibite d .  Inth e prior  ar t, amor pho ussil ico n(a-Si) th in filmtr an si st ors  aref ormed by  d epo si tin g a f i rst la yer o f a- Si  s e mic onducto r  m a t eria lov er a  ga te  andgate ins ulatorlayer and  th e n de po si ting alayer of high ly  doped sil ic on(e.g.n +  layer)on top of the first lay e r. Meta l c ontac ts f or the so urc e anddra i n arethen f ormed  o n t h e  high l y  d ope dlayer defi n i nga cha nn el a rea inthe first a-Si lay e r b etween the co nta cts. T he  hi g hl y  do pe d  la y e r over the chan nel area c an th en be etch e d a wa y so as  not to  adve r sely af fect thechannel a re a. T h e  lo w mobility  in thea-Si TFTc hanne l  m akesthe  devic eles s dem anding onconta ct res is tance.  Theme tal cont acts formed on the high ly dop ed ar eaprovide a  lo w  re sistance(ohm ic) contac t.Inmetal  ox i de th in f i lm  tr a nsist ors( MOTFT) th e  m eta l co ntacts aref o r med  dire ctl y  on th e me tal oxide semicon d uctor layer. T hati s  th e m e talox ide semiconduc tor  m a t erial is  t he same und er the m et a l con tactsas itis in t h e  c h annelarea . F or MOTFTs  th el ack ofan  n +  layer  and  a  highe r band g ap m a k e it harder to p rovid e a goo d  oh mic c on tact. F u rthe rmore, the  high mobil ity of  the  meta l oxide  s emicon duc to r material demands a  lowe r conta ct  res ist ance t hani n  a-Si  TFT s.  Wi thout a g o o d, lo wr esi stan ce co nt act,  hereinaf t er refer red to as a nohm i c  conta c t, t he high mo bil ity o f the metalo xide se m icond uctormateri al canb e m as ked bythe c ontact re sistance. How ev er,ohmic co nt acts  i n M OT FTs have been v irtually  unknown t o date  or arev ery di ff icult to for m and /o r  retain . 
current detecting_circuit are_also provided, and when_a coil_current_becomes excessive_a_cutoff command signal_is fed to_the gate signal cutoff_circuit and the_currents_of all the coils are cut off.
However, the temperature sensor is in a position_away_from the_switching_devices_inside the module, and it_takes time for heat produced_by the_switching devices to reach the temperature sensor, and_at_times when the_amount of heat produced by the devices is large,_such as during high-current excitation and_at low motor_speeds_(when_the excitation time of_each phase is long), there is_a risk of the temperature of_a device reaching a limit temperature exceeding_a threshold value at which the_gate signal cutoff circuit operates_even though_the detected temperature of the_temperature sensor has_not reached_the threshold value,_and the switching device consequently breaking_before the gate_signal cutoff circuit turns the gate_off_in response to_the_detected_temperature. To_avoid this the_temperature_threshold value_at_which the gate signal cutoff circuit_operates_is set low and the motor drive_is inhibited. In the_prior_art, amorphous silicon (a-Si)_thin film transistors are formed_by depositing a first layer of_a-Si semiconductor_material over_a gate and gate insulator layer and then depositing a layer_of highly doped silicon (e.g. n+_layer) on top of_the first_layer._Metal contacts for_the_source and_drain are then formed on the highly_doped layer_defining a channel area in the_first a-Si layer between_the_contacts. The highly doped layer over_the channel area can then be_etched away so as not_to_adversely_affect the channel area. The_low mobility in the a-Si TFT_channel makes the_device less demanding on contact resistance. The_metal_contacts formed on the highly doped_area_provide a low resistance (ohmic) contact.
In_metal_oxide_thin film transistors (MOTFT) the_metal contacts are formed directly on_the metal oxide semiconductor layer. That is the metal_oxide semiconductor material_is the same under the_metal_contacts_as it is in the channel area. For MOTFTs the_lack of_an n+ layer_and a higher bandgap make it harder to provide a_good ohmic contact. Furthermore, the high mobility_of the metal oxide semiconductor material demands a lower contact resistance_than in a-Si TFTs. Without a good, low_resistance contact, hereinafter referred to as an_ohmic contact, the high_mobility_of the metal oxide semiconductor material can_be_masked_by_the contact resistance._However, ohmic contacts_in MOTFTs have_been virtually_unknown to date_or are_very difficult to_form_and/or retain.