CN101185234A - Motor drive circuit and disc unit using the same - Google Patents
Motor drive circuit and disc unit using the same Download PDFInfo
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- CN101185234A CN101185234A CNA2006800185590A CN200680018559A CN101185234A CN 101185234 A CN101185234 A CN 101185234A CN A2006800185590 A CNA2006800185590 A CN A2006800185590A CN 200680018559 A CN200680018559 A CN 200680018559A CN 101185234 A CN101185234 A CN 101185234A
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Abstract
A counter electromotive detection comparator (10) compares counter electromotive voltages (Vu-Vw) with a coil midway voltage (Vn) to generate first rectangular wave signals (Pu-Pw). A mask circuit (12) masks the first rectangular wave signals (Pu-Pw) to output second rectangular wave signals (Mu-Mw). An output circuit (14) supplies, based on the second rectangular wave signals (Mu-Mw), drive currents to coils (50a-50c). A frequency generating circuit (20) generates a frequency generation signal (SigFG) that changes its levels for each of the edges of the second rectangular wave signals (Mu-Mw). A mask signal generating circuit (30) generates a mask signal (MSK) that exhibits a high level for a time period obtained by multiplying a pulse width (Tp) of the frequency generation signal (SigFG) by a coefficient after a level change of the frequency generation signal (SigFG). The mask circuit (12) nullifies the level variations of the first rectangular wave signals (Pu-Pw) while the mask signal (MSK) is exhibiting the high level.
Description
Technical field
The present invention relates to control the motor rotating drive circuit of the motor of the rotor that comprises stator and have magnetic with a plurality of coils.
Background technology
At portable (portable) CD (Compact Disc: device, DVD (DigitalVersatile Disc: digital versatile disc) wait and to have used in the electronic equipment of dish-type medium, for these are spiraled then use brshless DC motor CD).Brushless direct-current (DC) motor generally comprises the rotor with permanent magnet and has by the stator of the polyphase winding of star-like connection, and the electric current that offers coil by control comes coil magnetization, and rotor is driven with the relative rotation with respect to stator.Brushless DC motor generally has transducers such as Hall element, optical encoder for the position of rotation of detection rotor, according to the position that is gone out by sensor, switches the electric current that offers each phase coil, gives rotor suitable torque.
In order to make motor miniaturization more, also propose to have the electric machine without sensor (for example with reference to patent documentation 1) of the position of rotation that does not utilize transducer ground detection rotors such as Hall element.Electric machine without sensor for example passes through the current potential of the mid point wiring of instrumentation motor, and the induced voltage that comes magnetic test coil to produce obtains positional information.
As conduct invention problem to be solved in the patent documentation 2 is illustrated, in such electric machine without sensor, the noise of spike (spike) shape takes place in the induced voltage that exist because induced noise etc. causes each coil to produce, the problem that the rotation of motor becomes unstable such.
Patent documentation 1: the spy opens flat 3-207250 communique
Patent documentation 2: the spy opens flat 10-243685 communique
Summary of the invention
(problem to be solved by this invention)
In order to reduce the influence that causes by this induced noise, the applicant has proposed in above-mentioned patent documentation 2, the transformation of the signal level that is caused by induced noise in the scheduled period inner shield that produces induced noise reduces the technology of this induced noise to the influence of the driving of motor.In the technology that patent documentation 2 is proposed, will be fixed as predetermined value during the shielding induced noise, so take place in the application (application) of bigger variation in rotating speed of motor, the stability of motor also exists treats room for improvement.
The present invention finishes in light of this situation, and its purpose is to provide a kind of energy to remove denoising, makes the motor-drive circuit of the spin stabilizationization of motor.
(being used to solve the means of problem)
The motor-drive circuit that provides drive current to drive to polyphase machine is provided a kind of scheme of the present invention.This motor-drive circuit comprises: the back electromotive force detection comparator, and the induced voltage that coil produced with each phase of polyphase machine compares with each mid-point voltage mutually respectively, generates the 1st square-wave signal of each phase; Screened circuit is removed from the shielding processing of the noise contribution of the 1st square-wave signal of each phase of back electromotive force detection comparator output, as the 2nd square-wave signal output of each phase; Output circuit based on the 2nd square-wave signal of each phase, provides drive current to the coil of each phase of polyphase machine; Frequency generating circuit detects the edge of the 2nd square-wave signal of each phase, and the frequency generation signal that level switches takes place when being created on each detected edge; The shielded signal generative circuit, after the level that is created on frequency generation signal changes, the pulse duration of frequency generation signal multiply by predetermined coefficient during in become the shielded signal of predetermined level.Screened circuit shielded signal be predetermined level during, make the shielding processing of the level variation ineffective treatment of the 1st square-wave signal.
According to this scheme, by during the change ineffective treatment that makes the 1st square-wave signal of shielded signal regulation according to the pulse duration of frequency generation signal, be that rotating speed of motor changes, so taken place in rotating speed of motor under the situation of change, also can from the 1st square-wave signal, remove induced noise etc. well, make the rotation of motor stabilizing ground.
The shielded signal generative circuit also can comprise: counter, and when changing, the level of each frequency generation signal is reset, begin counting; Register, keep by counter count reset the time count value; The pulse duration configuration part, output has the shielded signal that multiply by the corresponding pulse duration of numerical value that is obtained after the predetermined coefficient with the count value that register is kept.
Register also can keep with respect to the shielded signal that will export the pairing count value of previous frequency generation signal.In this case, the motor speed before reflecting in the shielding time is so also can stably drive making under the rotating speed of motor situation jumpy.
When the shielded signal generative circuit also can begin in the driving of polyphase machine, output had the shielded signal of predetermined fixed value as pulse duration.
The pulse duration of fixed mask signal when beginning by the driving at motor can fixed frequency signal.
The motor-drive circuit that provides drive current to drive to polyphase machine also is provided another program of the present invention.This motor-drive circuit comprises: the current/voltage converter section, and the drive current of coil that will flow through each phase of polyphase machine converts voltage to; The pulse modulation comparator will compare from the detection voltage of current/voltage converter section output and the control voltage of command torque; The pulse signal generative circuit, with reference to comparison signal from the output of pulse modulation comparator, be created on from the 1st level of the no power state that detects the coil that becomes each phase of indication in the predetermined deadline that voltage reaches control voltage, become the pulse signal of the 2nd level of "on" position of the coil of each phase of indication in during in addition; The shielded signal generative circuit is created on from pulse signal and becomes the 1st level to through during the 1st predetermined shielding time and from becoming the 2nd level to through during the 2nd predetermined shielding time, becomes the shielded signal of predetermined level; The back electromotive force detection comparator, the induced voltage that coil produced with each phase of polyphase machine compares with the mid-point voltage of each coil mutually respectively, generates the 1st square-wave signal of each phase; Screened circuit, with reference to shielded signal from the output of shielded signal generative circuit, during shielded signal is predetermined level, make from the shielding processing of the level variation ineffective treatment of the 1st square-wave signal of each phase of back electromotive force detection comparator output, as the 2nd square-wave signal output of each phase; Output circuit based on the 2nd square-wave signal and the pulse signal of each phase, intermittently provides drive current to the coil of each phase of polyphase machine.
According to this scheme, the energising of the coil of each phase of polyphase machine can be constant based on deadline, ON time controls according to the pulse signal that torque changes.In this case, by during will being set at shielding during just predetermined shielding time of pulse signal along, negative edge to process respectively, can remove the induced noise that the coil of each phase is produced in the cycle of each pulse signal, set the timing (timing) of switching mutually well.
The 1st shielding time also can be set shortlyer than deadline.In this case, can be arranged on effectively between detection period through the zero crossing that detects induced voltage after the 1st shielding time.In addition, the 1st shielding time also can be set at and be less than or equal to for the 2nd shielding time.
The pulse signal generative circuit can comprise that also the level with comparison signal is changed to the counter circuit of the counting that triggers beginning deadline, output the level from comparison signal change to count finish during in become the 1st level, become the pulse signal of the 2nd level afterwards.
The shielded signal generative circuit also can comprise the triggering that is changed to pulse signal, the counter circuit that the 1st, the 2nd shielding time was counted.
Constitute pulse signal generative circuit, shielded signal generative circuit by the usage counter circuit, can set deadline, shielding time well based on the clock signal of system, and, also be easy to carry out the adjustment of these times.
Pulse signal generative circuit and shielded signal generative circuit can comprise that the 1st counter circuit and the 2nd counter circuit ground one constitute, wherein, the 1st counter circuit is changed to trigger with the level of comparison signal and begins counting, output at the pulse signal that changes through level after deadline with through the 2nd shielding time after the 2nd shielded signal that changes of level; The 2nd counter circuit is changed to the level since the pulse signal of the 1st counter circuit output and triggers counting, the 1st shielded signal that output level after through the 1st shielding time changes; And, the logic operation result of the 1st shielded signal and the 2nd shielded signal is exported as shielded signal.
A kind of motor-drive circuit of scheme can be integrated on a Semiconductor substrate.So-called " integrating ", comprise that all inscapes with circuit are formed on the situation on the Semiconductor substrate, with the situation that main composition key element to circuit integrates, also can a part of resistance, electric capacity etc. be arranged on the outside of Semiconductor substrate for the regulating circuit constant.In this case, can reduce circuit area.
Another program of the present invention is the dish device.This dish device comprises: as the spindle motor of the polyphase machine that makes disc spins; The described motor-drive circuit of above-mentioned arbitrary mode of drives spindle motor.According to this scheme, can suppress the influence of induced noise, make the spin stabilizationization of dish.
(invention effect)
Can in the motor-drive circuit that carries out pulsed drive, remove denoising well by the present invention.
Description of drawings
Fig. 1 is the circuit diagram of structure of the motor-drive circuit of expression execution mode.
(a)～(m) of Fig. 2 is the sequential chart of operate condition of the motor-drive circuit of presentation graphs 1.
(a)～(m) of Fig. 3 is the sequential chart of the operate condition of the motor of the motor-drive circuit of presentation graphs 1 when quickening.
Fig. 4 is the block diagram of structure of the dish device of expression motor-drive circuit that Fig. 1, Fig. 5 have been installed.
Fig. 5 is the circuit diagram of structure of the motor-drive circuit of expression the 2nd execution mode.
Fig. 6 is the block diagram of an example of the structure of indicating impulse signal generating circuit, shielded signal generative circuit.
(a)～(f) of Fig. 7 is the sequential chart of operate condition of the motor-drive circuit of presentation graphs 5.
(a) of Fig. 8 and (b) are the sequential charts of mutually induced voltage of expression U, mid-point voltage, shielded signal.
(a)～(f) of Fig. 9 is the sequential chart that is illustrated in the operate condition of the motor-drive circuit of Fig. 5 under the lower situation of control voltage.
(label declaration)
100 motor-drive circuits, 10 back electromotive force detection comparators, 12 screened circuits, 14 output circuits, 20 frequency generating circuits, 30 shielded signal generative circuits, 32 counters, 34 registers, 40 current/voltage converter sections, 42 pulse modulation comparators, 44 pulse signal generative circuits, 46 the 1st counter circuits, 48 the 2nd counter circuits, 62 OR-gates, 64 shielded signal generative circuits, 50 motors, 200 dish devices, 214 dishes
Embodiment
It is following that the present invention will be described based on preferred implementation with reference to accompanying drawing.For each identical or equivalent configurations key element shown in the drawings, parts, label that the processing mark is identical, and suitably the repetitive description thereof will be omitted.In addition, execution mode is a kind of illustration, and non-limiting the present invention, and all features and combination thereof that execution mode is recorded and narrated are not all to be internal content of the present invention.
(the 1st execution mode)
Fig. 1 is the circuit diagram of structure of the motor-drive circuit 100 of expression the 1st execution mode.Motor-drive circuit 100 provides drive current to non sensor brushless DC motor (being designated hereinafter simply as " motor ") 50, controls its rotation.Motor 50 is the three-phase DC motors that comprise the coil 50a～50c of U phase, V phase, W phase.
Motor-drive circuit 100 comprises back electromotive force detection comparator 10, screened circuit 12, output circuit 14, frequency generating circuit 20 and shielded signal generative circuit 30.Motor-drive circuit 100 is integrated the function IC on a Semiconductor substrate.
Back electromotive force detection comparator 10 compares each the phase coil 50a～induced voltage Vu～Vw of 50c generation of motor 50 and the mid-point voltage Vn of polyphase winding respectively, generates the 1st square-wave signal Pu～Pw of each phase.The 1st square-wave signal Pu becomes high level when Vu＞Vn, become low level when Vu＜Vn.Similarly, the 1st square-wave signal Pv becomes high level when Vv＞Vn, becomes low level when Vv＜Vn; The 1st square-wave signal Pw becomes high level when Vw＞Vn, become low level when Vw＜Vn.
Screened circuit 12 is removed from the shielding processing of the noise contribution of the 1st square-wave signal Pv～Pw of each phase of back electromotive force detection comparator 10 outputs, as the 2nd square-wave signal Mu～Mw output of each phase.Output circuit 14 provides drive current based on the 2nd square-wave signal Mu～Mw of each phase to each phase coil 50a～50c of motor 50.
The pulse width T p that shielded signal generative circuit 30 is created on frequency generation signal SigFG multiply by pre-determined factor during in become the shielded signal MSK of high level.The pulse width T p of so-called frequency generation signal SigFG, being meant changes from signal level plays the time that next time changes.Shielded signal MSK is output to screened circuit 12.
Shielded signal generative circuit 30 comprises counter 32, register 34 and shielding width setup circuit 36.32 couples of clock signal C K from the outside input of counter count.Counter 32 is transfused to frequency generation signal SigFG, the every switching of this signal level once, count value CNT just is reset once, restart the counting.When register 34 is reset at each counter 32, preserve the count value CNT when resetting in turn.36 outputs of shielding width setup circuit with count value CNT that register 34 is preserved multiply by the numerical value that obtains behind the predetermined coefficient α corresponding during become the shielded signal MSK of high level.
Screened circuit 12 after any one of the 1st square-wave signal Pu～Pw changes, shielded signal MSK be high level during, make the shielding processing of the level variation ineffective treatment of the 1st square-wave signal Pu～Pw.That is, shielded signal MSK be high level during, even the signal level change of the 1st square-wave signal Pu～Pw, this change can not be reflected among the 2nd square-wave signal Mu～Mw yet.On the other hand, be between low period at shielded signal MSK, the 2nd square-wave signal Mu～Mw equates with the 1st square-wave signal Pu～Pw respectively.
Drive signal combiner circuit 16 is based on the drive signal Duu～Du1 that generates the grid that will be applied to transistor Tr 1～Tr6 from the 2nd square-wave signal Mu～Mw of screened circuit 12 outputs.
Action to the motor-drive circuit 100 that as above constitutes like this describes.(a)～(m) of Fig. 2 is the sequential chart of the operate condition of expression motor-drive circuit 100.Induced voltage Vu～Vw that the coil 50a～50c of each phase of (a)～(c) expression motor 50 of Fig. 2 is produced, the mid-point voltage Vn of (d) expression coil 50a～50c of Fig. 2, (e)～(g) expression the 1st square-wave signal Pu～Pw of Fig. 2, (h)～(j) expression the 2nd square-wave signal Mu～Mw of Fig. 2, (k) expression frequency generation signal SigFG of Fig. 2, the count value CNT that is kept in (1) expression register 34 of Fig. 2, (m) expression shielded signal MSK of Fig. 2.
Drive current offers coil 50a～50c by output circuit 14, and induced voltage Vu～Vw that its result produced becomes phase place 120 ° the periodic signal that staggers separately from each other.Back electromotive force detection comparator 10 compares induced voltage Vu～Vw and mid-point voltage Vn respectively, generates the 1st square-wave signal Pu～Pw.Produce the induced noise Nv1～Nv3 of needle pattern among induced voltage Vu～Vw, this induced noise also appears among the 1st square-wave signal Pu～Pw as Np1～Np3.
Moment T0 the 2nd square-wave signal Mu from low level when high level changes, frequency generating circuit 20 detects these rising edges (just along), SigFG switches to low level with frequency generation signal.The counter 32 of shielded signal generative circuit 30 is reset when frequency generation signal SigFG changes, begins new counting.
The moment T1 of induced noise Nv1 occurring, shielded signal MSK is a high level.Screened circuit 12 is between high period at shielded signal MSK as mentioned above, makes the level variation ineffective treatment of the 1st square-wave signal Pu～Pw.Therefore, pay close attention to the w phase time, the noise contribution Np1 that occurred among the 1st square-wave signal Pw, the smooth signal of the influence of the induced noise that can be removed in the 2nd square-wave signal Mw, can not occur.
MSK becomes low level at moment T2 shielded signal, becomes low level at moment T3 the 1st square-wave signal Pw.At moment T3, shielded signal MSK is a low level, and the 2nd square-wave signal Mw of the level variation of the 1st square-wave signal Pw is followed in screened circuit 12 outputs, so the 2nd square-wave signal Mw also becomes low level.Frequency generating circuit 20 detects the trailing edge (negative edge) of the 2nd square-wave signal Mw, and SigFG switches to high level from low level with frequency generation signal.Counter 32 is reset once more at moment T3, and before this count value cnt1 is write register 34.This count value cnt1 become with figure in the pulse width T p1 of the frequency generation signal SigFG shown in the Tp1 be worth accordingly.That is, be designated as Tck, then cnt1=Tp1/Tck the cycle time of the clock signal C K of counter 32 if will be imported into.
Shielding width setup circuit 36 (in Tmsk1=α * cnt1 * Tck, makes shielded signal MSK become high level during the corresponding shielding of α * cnt1) with resulting value after the count value cnt1 that is written into shielding width setup circuit 36 multiply by predetermined coefficient alpha.For example, predetermined coefficient α can be set at about 13/16.Produce induced noise Nv2 at moment T4, in the 1st square-wave signal Pv, induced noise Np2 occurs.The moment T4 of induced noise Nv2 occurring, shielded signal MSK is a high level, so noise contribution do not occur in the 2nd square-wave signal Mv.MSK is a low level at moment T5 shielded signal, so screened circuit 12 makes the 2nd square-wave signal Mv become high level the 1st when square-wave signal Pv becomes high level.Frequency generating circuit 20 detects the just edge of the 2nd square-wave signal Mv, and SigFG switches to low level with frequency generation signal.
Like this, according to the motor-drive circuit 100 of present embodiment, make the shielding time T msk of shielded signal MSK according to the pulse width T p of frequency generation signal SigFG, be that the rotating speed of motor 50 changes.As a result, even under the situation of the rotating speed change of motor 50, also can from the 1st square-wave signal Vu～Vw, remove induced noise etc. well, make the rotation of motor stabilizing ground.
And then in shielded signal generative circuit 30, the pairing count value CNT of previous frequency generation signal SigFG that register 34 is preserved with respect to the shielded signal MSK that will export is based on the shielding time T msk of this count value setting shielded signal MSK.As a result, the rotating speed of motor 50 before reflecting among the shielding time T msk is so even making under the rotating speed of motor situation jumpy, also can stably drive.
The sequential chart of the operate condition of motor-drive circuit 100 when (a)～(m) of Fig. 3 is 50 acceleration of expression motor.Fig. 3 (a)～(m) expression respectively with (a)～(m) corresponding waveform of Fig. 2.
Rotating speed rising along with motor 50 provides the time of drive current to shorten gradually to the coil 50a～50c of each phase.As a result, shorten gradually the cycle time of induced voltage Vu～Vw and the 1st square-wave signal Pu～Pw, the 2nd square-wave signal Mu～Mw.When shortened the cycle time of the 2nd square-wave signal Mu～Mw, the time T p of the signal level variation of frequency generation signal SigFG also shortened, and the count value CNT of the counter 32 that register 34 is kept diminishes.As a result, the shielding time T msk by the shielded signal MSK that shields 36 settings of width setup circuit shortens gradually along with the rising of the rotating speed of motor 50.
Shielded signal generative circuit 30 also can irrespectively be set at predetermined fixed value with the shielding time T msk of shielded signal MSK with the pulse width T p of frequency generation signal SigFG when the driving of motor 50 begins.When motor 50 has just begun to drive, do not keep any count value in the register 34.Therefore, with the shielding time T msk of predetermined fixed value, and, from the 1st square-wave signal Pu～Pw, remove induced noise based on the shielding time T msk of this shielded signal MSK as initial value decision shielded signal MSK.Afterwards, by setting the shielding time T msk of shielded signal MSK as described above corresponding to the pulse width T p ground of frequency generation signal SigFG, can from drive beginning to reach desired speed during stably make motor 50 rotations.
Equally, when motor 50 slows down, also can make the shielding time T msk of shielded signal MSK elongated gradually, remove induced noise well by same action.
Next, the application (application) to the motor-drive circuit 100 of present embodiment describes.Fig. 4 is the block diagram of structure of the dish device 200 of expression motor-drive circuit 100 that Fig. 1 has been installed.Dish device 200 be to CDs such as CD, DVD write down, the unit of reproduction processes, be installed in the electronic equipments such as CD Player, DVD player, personal computer.Dish device 200 comprises pick-up (pickup) 210, signal processing part 212, motor 50 and motor-drive circuit 100.
Pick-up 210 writes desirable data to dish 214 irradiating lasers, perhaps reads the data that are written in the dish 214 by the light that reads in reflected back.212 pairs of data by pick-up 210 read-writes of signal processing part are carried out necessary signal processing such as processing and amplifying, A/D conversion or D/A conversion.Motor 50 is the spindle motors that are provided with in order to make dish 214 rotations.Such dish device 200 shown in Figure 4 is required miniaturization especially, so as motor 50, adopt the non-sensor type do not use Hall element etc.The motor-drive circuit 100 of present embodiment can be applicable to the application of the spindle motor that stably drives this no transducer well.
(the 2nd execution mode)
Fig. 5 is the circuit diagram of structure of the motor-drive circuit 100 of expression the 2nd execution mode.Motor-drive circuit 100 utilizes pulse drive mode to provide drive current to non sensor brushless DC motor (being designated hereinafter simply as " motor 50 "), controls its rotation.In the present embodiment, motor 50 is the three-phase DC motors that comprise the coil 50a～50c of U phase, V phase, W phase.
Motor-drive circuit 100 comprises back electromotive force detection comparator 10, screened circuit 12, output circuit 14, current/voltage converter section 40, pulse modulation comparator 42, pulse signal generative circuit 44 and shielded signal generative circuit 64.Motor-drive circuit 100 is integrated the function IC on a Semiconductor substrate.
Induced voltage Vu～the Vw that back electromotive force detection comparator 10 is produced the coil 50a～50c of each phase of motor 50 respectively and the mid-point voltage Vn of polyphase winding compare, and generate the 1st square-wave signal Pu～Pw of each phase.The 1st square-wave signal Pu becomes high level when Vu＞Vn, become low level when Vu＜Vn.Similarly, the 1st square-wave signal Pv becomes high level when Vv＞Vn, becomes low level when Vv＜Vn; The 1st square-wave signal Pw becomes high level when Vw＞Vn, become low level when Vw＜Vn.
Screened circuit 12 uses shielded signal Smsk described later to remove from the shielding processing of the noise contribution of the 1st square-wave signal Pv～Pw of each phase of back electromotive force detection comparator 10 outputs, exports as the 2nd square-wave signal Mu～Mw of each phase.
Drive signal combiner circuit 16 will be synthetic with the pulse signal Vpulse that exports from pulse signal generative circuit 44 described later from the 2nd square-wave signal Mu～Mw of screened circuit 12 outputs by logical operation, and generation will be applied to the drive signal Duu～Du1 of the grid of transistor Tr 1～Tr6.That is, based on the 2nd square-wave signal Mu～Mw, the decision make the transistor turns of which group, to which coil electricity.In the present embodiment, both can carry out 180 degree energisings, also can carry out 120 degree energisings.In addition, in order to regulate conducting and the time ratio that ends based on pulse signal Vpulse, to carry out torque control, can only make transistor Tr 1, Tr3, the Tr5 of high side carry out switch motion, also can only make the transistor Tr 2 of downside, Tr4, Tr6 carry out switch motion, perhaps also can make the both carry out switch motion.
Current/voltage converter section 40 is set between power transistor circuit 18 and ground connection.Current/voltage converter section 40 comprises transfer resistance R1.Transfer resistance R1 goes up and produces and each coil 50a, 50b mutually, the proportional voltage drop of drive current of 50c of flowing through motor 50.Current/voltage converter section 40 is exported the voltage drop that transfer resistance R1 is produced as detecting voltage Vdet.
Non-inverting input of pulse modulation comparator 42 is transfused to from the detection voltage Vdet of current/voltage converter section 40 outputs.The reversed input terminal of pulse modulation comparator 42 is transfused to from the control voltage Vctr1 of the command torque of outside input.Pulse modulation comparator 42 will compare with control voltage Vctr1 from the detection voltage Vdet of current/voltage converter section 40 outputs.Become high level when the Vdet＞Vctr1 from the comparison signal Vcmp of pulse modulation comparator 42 output, when Vdet＜Vctr1, become low level.Be imported into pulse signal generative circuit 44 from the comparison signal Vcmp of pulse modulation comparator 42 outputs.
Pulse signal generative circuit 44 is with reference to the comparison signal Vcmp from 42 outputs of pulse modulation comparator, output change into from comparison signal Vcmp high level to through predetermined deadline Toff during in become low level (the 1st level), become the pulse signal Vpulse of high level (the 2nd level) in during in addition.In other words, pulse signal Vpulse from detect voltage Vdet reach control voltage Vctr1 to through predetermined deadline Toff during in become low level, become high level in during in addition.For example, deadline, Toff was set to several μ s, more specifically as an example, was set to 5.7 μ s.
Pulse signal generative circuit 44 for example can use the level with comparison signal Vcmp to be changed to the counter circuit that triggers the counting that begins Toff deadline.In this case, counter circuit becomes low level in exporting during finishing from level variation to the counting of comparison signal Vcmp, is changed to the pulse signal Vpulse of high level afterwards.
Here, the low level of pulse signal Vpulse (the 1st level) is corresponding with the no power state of the coil 50a～50c of each phase, and its high level (the 2nd level) is corresponding with the "on" position of the coil 50a～50c of each phase.That is, alternately repeat high level and low level by pulse signal Vpulse, electric current intermittently flows through the coil 50a～50c of motor 50, carries out pulsed drive.
Toff deadline of the pulse signal Vpulse that is generated by the motor-drive circuit 100 of present embodiment is constant, and ON time changes according to the control voltage Vctr1 of command torque.That is, pulse frequency modulated (PFM:Pulse FrequencyModulation) mode that changes according to torque of, frequency constant by deadline is carried out pulsed drive to motor 50.
Shielded signal generative circuit 64 generates shielded signal Smsk with reference to the pulse signal Vpulse from 44 outputs of pulse signal generative circuit.Shielded signal generative circuit 64 become from pulse signal Vpulse low level (the 1st level) during through the 1st predetermined shielding time T msk1 in, Smsk is set at high level with shielded signal.And then, this shielded signal generative circuit 64 become from pulse signal Vpulse high level (the 2nd level) during through the 2nd predetermined shielding time T msk2 in, Smsk is set at high level with shielded signal.
In the present embodiment, preferred the 1st shielding time T msk1 sets than Toff weak point deadline.In addition, preferred the 1st shielding time T msk1 is set at below the 2nd shielding time T msk2.In the present embodiment, be set at Tmsk1=Tmsk2=4.7 μ s.
Shielded signal generative circuit 64 for example can comprise the triggering that is changed to pulse signal Vpulse, and the counter circuit ground that the 1st shielding time T msk1, the 2nd shielding time T msk2 are counted constitutes.In this case, counter circuit according to the variation each time of pulse signal Vpulse, promptly be triggering with just edge and negative edge, count 4.7 μ s, make shielded signal Smsk become high level in during counting.
Pulse signal generative circuit 44 and shielded signal generative circuit 64 also can constitute as follows.Fig. 6 is the block diagram of an example of the structure of indicating impulse signal generating circuit 44, shielded signal generative circuit 64.
The pulse signal generative circuit 44 of Fig. 6, shielded signal generative circuit 64 comprise the 1st counter circuit the 46, the 2nd counter circuit 48, OR-gate 62 ground constitute one.The 1st counter circuit 46 is changed to trigger with the level of comparison signal Vcmp and begins counting.The output of the 1st counter circuit 46 from begin to count to pass through Toff deadline during in become low level pulse signal Vpulse.In addition, the output of the 1st counter circuit 46 from begin to count to through the 2nd shield time T msk2 during in become the 2nd shielded signal Smsk2 of high level.
The 2nd counter circuit 48 by the pulse signal Vpulse of the 1st counter circuit 46 output when high level becomes low level, begin counting as triggering.The output of the 2nd counter circuit 48 from begin to count to through the 1st shield time T msk1 during in become the 1st shielded signal Smsk1 of high level.OR-gate 62 is exported with the logic of the 1st shielded signal Smsk1 and the 2nd shielded signal Smsk2 with as shielded signal Smsk.Shielded signal Smsk is output to screened circuit 12.
Screened circuit 12 use shielded signal Smsk remove from the shielding processing of the noise contribution of the 1st square-wave signal Pv～Pw of each phase of back electromotive force detection comparator 10 outputs, as the 2nd square-wave signal Mu～Mw output of each phase.More particularly, it is between high period that screened circuit 12 carries out at shielded signal Smsk, make from the shielding processing of the level variation ineffective treatment of the 1st square-wave signal Pv～Pw of each phase of back electromotive force detection comparator 10 output, as the 2nd square-wave signal Mu～Mw output of each phase.
That is, be between high period at shielded signal MSK, even the signal level change of the 1st square-wave signal Pu～Pw, its change can not be reflected among the 2nd square-wave signal Mu～Mw yet.On the other hand, be between low period at shielded signal MSK, the 2nd square-wave signal Mu～Mw equates with the 1st square-wave signal Pu～Pw respectively.
As above-mentioned, output circuit 14 is based on the 2nd square-wave signal Mu～Mw and the pulse signal Vpulse of each phase, intermittently provides above-mentioned drive current to the coil of each phase of polyphase machine.Drive signal combiner circuit 16 will be synthetic with the pulse signal Vpulse that exports from pulse signal generative circuit 44 from the 2nd square-wave signal Mu～Mw of screened circuit 12 outputs by logical operation, and generation will be applied to the drive signal Duu～Du1 of the grid of transistor Tr 1～Tr6.
Action to the motor-drive circuit 100 that as above constitutes like this describes.(a)～(f) of Fig. 7 is the sequential chart of operate condition of the motor-drive circuit 100 of presentation graphs 5, is illustrated in production burst signal Vpulse in the pulse signal generative circuit 44, generates the situation of shielded signal Smsk in shielded signal generative circuit 64.
(a) expression of Fig. 7 detects voltage Vdet, (b) expression comparison signal Vcmp of Fig. 7, (c) indicating impulse signal Vpulse of Fig. 7, (d) expression the 1st shielded signal Smsk1 of Fig. 7, (e) expression the 2nd shielded signal Smsk2 of Fig. 7, (f) expression shielded signal Smsk of Fig. 7.In the following description, the situation that electric current is flow through coil 50a, 50b describes.
At moment t0, pulse signal Vpulse becomes high level (the 2nd level).When pulse signal Vpulse became high level, drive signal combiner circuit 16 made transistor Tr 1, Tr4 conducting.As for the combination conducting of which group transistor, be that the position according to rotor changes, decide based on the 2nd square-wave signal Mu～Mw.
When transistor Tr 1, Tr4 conducting, drive current flows to the path of transistor Tr 1, coil 50a, 50b, transistor Tr 4 from power line.This drive current begins to rise in time.Drive current flows to ground connection via the transfer resistance R1 of current/voltage converter section 40.It is proportional to detect voltage Vdet and drive current, so begin later on to rise in time at moment t0.
When moment t1 detection voltage Vdet reached control voltage Vctr1, the comparison signal Vcmp that exports from pulse modulation comparator 42 became high level.When comparison signal Vcmp became high level, pulse signal generative circuit 44 made pulse signal Vpulse become low level (the 1st level).When pulse signal Vpulse was low level, drive signal combiner circuit 16 ended transistor Tr 1, Tr4.
Shielded signal generative circuit 64 makes the 1st shielded signal Smsk1 become high level after moment t1 pulse signal Vpulse becomes low level from high level, through the moment t2 behind the 1st shielding time T msk1, the 1st shielded signal Smsk1 is switched to low level.
Pulse signal generative circuit 44 is at the moment t3 behind moment t1 process Toff deadline, and Vpulse switches to high level with pulse signal.At moment t3, transistor Tr 1, Tr4 conducting once more.
Shielded signal generative circuit 64 makes the 2nd shielded signal Smsk2 become high level after moment t3 pulse signal Vpulse becomes high level from low level, through the moment t4 behind the 2nd shielding time T msk2, the 2nd shielded signal Smsk2 is switched to low level.Shielded signal Smsk can be by the 1st shielded signal Smsk1 and the 2nd shielded signal Smsk2 logic and obtain.This shielded signal Smsk is output to screened circuit 12, and it is the shielding processing of the level variation ineffective treatment of high period chien shih the 1st square-wave signal Pu～Pw that screened circuit 12 carries out at shielded signal Smsk.
(a) of Fig. 8 is the induced voltage Vu of U phase coil of expression motor 50 and the sequential chart of mid-point voltage Vn, and (b) of Fig. 8 is the sequential chart of expression shielded signal Smsk.Waveform when Fig. 8 represents to utilize 180 degree energising drive motors 50, but the invention is not restricted to this, also can be 120 degree energisings etc.In the figure, solid line is represented the induced voltage Vu of U phase, and dotted line is represented mid-point voltage Vn.For V phase, W phase, phase-shifted 60 degree ground present same waveform.The cycle of the change of induced voltage Vu is because of different variation of frequency of pulsed drive.Under the situation of carrying out 180 degree energisings, as shown in Figure 8, because the driving condition of V phase, W phase, the induced voltage Vu of U phase is affected.That is, during moment t0～t1, induced voltage Vv, the Vw that repeats V phase, W phase all be low level during 1 and V mutually, a certain person among induced voltage Vv, the Vw of W phase be high level during 2.During moment t1～t2, the induced voltage Vu of U phase is fixed to high level.During moment t2～t3, induced voltage Vv, the Vw that repeats V phase, W phase all be high level during 3 and V mutually, a certain person among induced voltage Vv, the Vw of W phase be low level during 4.
As above-mentioned, the induced voltage Vu that the motor-drive circuit 100 of execution mode is produced based on coil 50a～50c～switch mutually, the motor of the no transducer of driving.Particularly, compare induced voltage Vu and mid-point voltage Vn, generate the 1st square-wave signal Pu by back electromotive force detection comparator 10.
Here, correspondingly produce the induced noise Nx of needle pattern among the induced voltage Vu of Fig. 8 (a) with cycle of pulsed drive.Therefore, because the induced noise of this needle pattern when the magnitude relationship counter-rotating of mid-point voltage Vn and induced voltage Vu, this induced noise also occurs among the 1st square-wave signal Pu.
Shielded signal Smsk becomes high level in the shielding time predetermined from the just edge of the pulse signal Vpulse on the basis that becomes pulsed drive and negative edge shown in Fig. 8 (b).Screened circuit 12 is between high period at the shielded signal Smsk from 64 outputs of shielded signal generative circuit, makes the level variation ineffective treatment of the 1st square-wave signal Pu.Therefore, at shielded signal Smsk the noise contribution of the 1st square-wave signal Pu that occurs between high period, can not appear among the 2nd square-wave signal Mu.As a result, the induced voltage Vu of U phase and the zero cross point that mid-point voltage Vn intersects can be detected well, the switching of phase can be carried out well.
Also carry out same processing mutually for V phase, W, generate the 2nd square-wave signal Mv, the Mw that from the 1st square-wave signal Pv, Pw, have shielded noise contribution.
Motor-drive circuit 100 carries out pulsed drive by carrying out above action repeatedly to motor 50.According to the motor-drive circuit 100 of present embodiment, at every turn switching connection, when disconnecting, generating the shielded signal Smsk that becomes high level in the given time the energising of the coil of motor 50 by pulsed drive.Therefore, can be by become the shielded signal Smsk of high level corresponding to this timing (timing), remove the induced noise that produces owing to the energising of switching the coil of motor 50 well.
In addition, according to the motor-drive circuit 100 of present embodiment, the zero crossing that induced voltage intersects is to take place between low period at shielded signal Smsk, thus can detect this zero crossing reliably, to switching mutually.And then, in the present embodiment, with the 1st shielding time T msk1, be set at Tmsk1 〉=Tmsk2 with the relation of the 2nd shielding time T msk2, so can guarantee reliably that shielded signal Smsk becomes low level detection time.
If with pulse width modulation (PWM:Pulse Width Modulation) mode drive motors, then become and change according to torque deadline.In this case, uprise, deadline is when shortening the setting of the shielding difficulty that becomes in torque.On the other hand,, but adopt the PFM mode,, can set the shielding time reliably so can before the ON time of induced noise occurring, guarantee Toff deadline of scheduled period because the motor-drive circuit 100 of present embodiment is not to adopt the PWM mode.
(a)～(f) of Fig. 9 is the sequential chart that is illustrated in the operate condition of the motor-drive circuit 100 of Fig. 5 under the lower situation of control voltage Vctr1.At this moment, lack than the 2nd shielding time T msk2 the conduction time that becomes the coil of motor 50.Therefore, do not carry out zero cross detection in the ON time.In this case, also be to be set at Toff＜Tmsk1, so during certain before pulse signal Vpulse becomes high level, shielded signal Smsk becomes low level, so can detect zero crossing reliably.
At last, the application to the motor-drive circuit 100 of present embodiment describes.Fig. 4 is the block diagram of structure of the dish device 200 of expression motor-drive circuit 100 that Fig. 5 has been installed.Dish device 200 be to CDs such as CD, DVD write down, the unit of reproduction processes, be installed in the electronic equipments such as CD Player, DVD player, personal computer.Dish device 200 comprises pick-up 210, signal processing part 212, motor 50 and motor-drive circuit 100.
Pick-up 210 writes desirable data to dish 214 irradiating lasers, and the light that perhaps reflects by reading in is read the data that are written in the dish 214.212 pairs of data by pick-up 210 read-writes of signal processing part are carried out necessary signal processing such as processing and amplifying, A/D conversion or D/A conversion.Motor 50 is the spindle motors that are provided with in order to make dish 214 rotations.Dish device 200 as shown in Figure 4 is required miniaturization especially, so as motor 50, adopt the non-sensor type do not use Hall element etc.The motor-drive circuit 100 of present embodiment can be applicable to the application of the spindle motor that stably drives this no transducer well.
More than describe the present invention based on execution mode.These execution modes are illustration, can carry out various distortion to the combination of its each inscape, each handling process, and those skilled in the art can understand these variation and be also contained in the scope of the present invention.
In execution mode, the situation that drives three phase electric machine is illustrated, but the present invention also can be applicable to the driving of three-phase electric machine without sensor in addition well.
In addition, in execution mode, induced voltage Vu～Vw that back electromotive force detection comparator 10 is produced the coil 50a～50c of each phase of motor 50 respectively compares with the mid-point voltage Vn of each coil mutually, but also can use resistance to carry out dividing potential drop as required, by relatively being generated the 1st square-wave signal Pu～Pw by voltage after partial.
The high level of the signal that illustrates in execution mode, low level logic are set a just example, for the structure of logic circuit block, can expect various variation, and these variation are also contained in the scope of the present invention.
In execution mode, the situation that motor-drive circuit 100 is integrated has been described, but the invention is not restricted to this, for example, transistor Tr 1～Tr6, the transfer resistance R1 that constitutes power transistor circuit 18 also can be used as the outside that discrete component or chip part are set at motor-drive circuit 100.
More than describe the present invention based on execution mode, but execution mode is only represented principle of the present invention, application, in the scope of the thought of the present invention that does not break away from claims defined, can carry out the change of various distortion and configuration to execution mode.
(industrial utilizability)
The present invention can be used in the motor-driven technology.
Claims (11)
1. a motor-drive circuit that provides drive current to drive to polyphase machine is characterized in that, comprising:
The back electromotive force detection comparator, the induced voltage that coil produced with each phase of above-mentioned polyphase machine compares with above-mentioned each mid-point voltage mutually respectively, generates the 1st square-wave signal of each phase;
Screened circuit is removed from the shielding processing of the noise contribution of the 1st square-wave signal of above-mentioned each phase of above-mentioned back electromotive force detection comparator output, as the 2nd square-wave signal output of each phase;
Output circuit based on the 2nd square-wave signal of above-mentioned each phase, provides drive current to the coil of each phase of above-mentioned polyphase machine;
Frequency generating circuit detects the edge of the 2nd square-wave signal of above-mentioned each phase, and the frequency generation signal that level switches takes place when being created on each detected edge; And
The shielded signal generative circuit, after the level that is created on said frequencies generation signal changes, after the pulse duration of said frequencies generation signal multiply by predetermined coefficient during in become the shielded signal of predetermined level;
Wherein, above-mentioned screened circuit above-mentioned shielded signal be above-mentioned predetermined level during, make the shielding processing of the level variation ineffective treatment of above-mentioned the 1st square-wave signal.
2. motor-drive circuit according to claim 1 is characterized in that:
Above-mentioned shielded signal generative circuit comprises
Counter is reset when the level of each said frequencies generation signal changes, and begins counting,
Register, keep by above-mentioned counter count reset the time count value, and
Pulse duration configuration part, output have the shielded signal that multiply by the corresponding pulse duration of numerical value that above-mentioned predetermined coefficient obtains with the count value that above-mentioned register is kept.
3. motor-drive circuit according to claim 1 is characterized in that:
Above-mentioned shielded signal generative circuit
When the driving of above-mentioned polyphase machine began, output had the above-mentioned shielded signal of predetermined fixed value as pulse duration.
4. a motor-drive circuit that provides drive current to drive to polyphase machine is characterized in that, comprising:
The current/voltage converter section, the drive current of coil that will flow through each phase of above-mentioned polyphase machine converts voltage to;
The pulse modulation comparator will compare from the detection voltage of above-mentioned current/voltage converter section output and the control voltage of command torque;
The pulse signal generative circuit, with reference to comparison signal, become the pulse signal of the 2nd level of "on" position of the coil of above-mentioned each phase of indication in being created on from the 1st level of the no power state of the coil that becomes above-mentioned each phase of indication in above-mentioned detection voltage reaches predetermined deadline of above-mentioned control voltage, during in addition from the output of above-mentioned pulse modulation comparator;
The shielded signal generative circuit, be created on from above-mentioned pulse signal and become above-mentioned the 1st level, become the shielded signal of predetermined level to through during the 1st predetermined shielding time and from becoming above-mentioned the 2nd level to through during the 2nd predetermined shielding time;
The back electromotive force detection comparator, the induced voltage that coil produced with each phase of above-mentioned polyphase machine compares with the mid-point voltage of above-mentioned each coil mutually respectively, generates the 1st square-wave signal of each phase;
Screened circuit, with reference to above-mentioned shielded signal from above-mentioned shielded signal generative circuit output, above-mentioned shielded signal be above-mentioned predetermined level during, make from the shielding processing of the level variation ineffective treatment of the 1st square-wave signal of above-mentioned each phase of above-mentioned back electromotive force detection comparator output, as the 2nd square-wave signal output of each phase; And
Output circuit based on the 2nd square-wave signal and the above-mentioned pulse signal of above-mentioned each phase, intermittently provides above-mentioned drive current to the coil of each phase of above-mentioned polyphase machine.
5. motor-drive circuit according to claim 4 is characterized in that:
Above-mentioned the 1st shielding time set must be shorter than above-mentioned deadline.
6. according to claim 4 or 5 described motor-drive circuits, it is characterized in that:
Above-mentioned the 1st shielding time set is for being less than or equal to above-mentioned the 2nd shielding time.
7. according to claim 4 or 5 described motor-drive circuits, it is characterized in that:
Above-mentioned pulse signal generative circuit
Comprise that the level with above-mentioned comparison signal is changed to the counter circuit that triggers the counting that begins above-mentioned deadline, output change from the level of above-mentioned comparison signal to count finish during in become above-mentioned the 1st level, become the above-mentioned pulse signal of above-mentioned the 2nd level afterwards.
8. according to claim 4 or 5 described motor-drive circuits, it is characterized in that:
Above-mentioned shielded signal generative circuit
Comprise the triggering that is changed to, the counter circuit that above-mentioned the 1st shielding time, the 2nd shielding time are counted with above-mentioned pulse signal.
9. according to claim 4 or 5 described motor-drive circuits, it is characterized in that:
Above-mentioned pulse signal generative circuit and above-mentioned shielded signal generative circuit comprise that the 1st counter circuit and the 2nd counter circuit ground one constitute, wherein,
The 1st counter circuit is changed to trigger with the level of above-mentioned comparison signal and begins counting, and output is at above-mentioned pulse signal that changes through level after above-mentioned deadline and the 2nd shielded signal that changes through level after above-mentioned the 2nd shielding time,
The 2nd counter circuit is changed to trigger with the level from the above-mentioned pulse signal of above-mentioned the 1st counter circuit output and begins counting, and output is at the 1st shielded signal that changes through level after above-mentioned the 1st shielding time,
And, the logic operation result of above-mentioned the 1st shielded signal and above-mentioned the 2nd shielded signal is exported as above-mentioned shielded signal.
10. according to each described motor-drive circuit of claim 1 to 5, it is characterized in that:
Integrated on a Semiconductor substrate.
11. a dish device is characterized in that, comprising:
As the spindle motor of the polyphase machine that makes disc spins and
Drive each described motor-drive circuit of the claim 1 to 5 of above-mentioned spindle motor.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005179263A JP4890796B2 (en) | 2005-06-20 | 2005-06-20 | Motor drive circuit and disk device using the same |
| JP179263/2005 | 2005-06-20 | ||
| JP305989/2005 | 2005-10-20 |
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| CN101185234A true CN101185234A (en) | 2008-05-21 |
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| CNA2006800185590A Pending CN101185234A (en) | 2005-06-20 | 2006-06-19 | Motor drive circuit and disc unit using the same |
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| JP5125130B2 (en) * | 2007-02-05 | 2013-01-23 | 株式会社デンソー | Rotating machine control device |
| JP4963246B2 (en) * | 2007-03-16 | 2012-06-27 | ローム株式会社 | Motor driving circuit, driving method, and disk device using them |
| JP5087411B2 (en) * | 2008-01-16 | 2012-12-05 | 株式会社リコー | Motor drive device |
| JP6079353B2 (en) * | 2013-03-25 | 2017-02-15 | 株式会社富士通ゼネラル | DC brushless motor control device |
| JP6179416B2 (en) * | 2014-02-06 | 2017-08-16 | 株式会社富士通ゼネラル | Electric motor control device |
| JP5790813B2 (en) * | 2014-03-03 | 2015-10-07 | 株式会社豊田自動織機 | AC voltage period and phase detection apparatus and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH1028395A (en) * | 1996-07-11 | 1998-01-27 | Sanyo Electric Co Ltd | Position detector for dc brushless motor |
| JP3698583B2 (en) * | 1998-02-16 | 2005-09-21 | ローム株式会社 | Sensorless motor driver |
| JP4224738B2 (en) * | 1999-04-12 | 2009-02-18 | ソニー株式会社 | Brushless motor control device |
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| JP2006353057A (en) | 2006-12-28 |
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