TW201703419A - Motor driving circuit, driving method, vibrator and electronic machine capable of inhibiting reverse rotation of a rotor caused by backward braking - Google Patents

Abstract

The purpose of the present invention is to inhibit reverse rotation of a rotor caused by backward braking. Based on a rectangular signal S2 representing the position of the rotor of a motor 2 to be driven, a control part 110 generates a driving signal S3 for controlling energization of a coil of the motor 2. The driving part 130 drives the coil based on the driving signal S3. During the period of backward braking, the control part 110 monitors the period of the rectangular signal S2 and, if the period becomes shorter, terminates the backward braking.

Description

Motor drive circuit, drive method, vibration device, and electronic machine

The present invention relates to a driving technique of a motor.

In the driver for a brushless motor, in order to stop the rotor that normally rotates, there is a case where a brake function is mounted. During braking, there are regenerative braking and reverse braking. In regenerative braking, a loop is formed between the output section of the driver and the motor coil, and a current flows in the loop to dissipate the energy of the motor coil.

Reverse braking is used when the rotor is to be stopped with a stronger braking force than the regenerative braking. In the reverse braking, the motor coil is driven in a reverse phase with the normal driving state (forward rotation state), in other words, the rotor generates torque in the opposite direction to the forward rotation direction.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2006-234208

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2009-018654

[Patent Document 3] Japanese Patent Laid-Open No. Hei 8-191591

Problem 1. The inventors studied the following control of reverse braking (so-called research technique).

In the research technique, the period of the Hall signal is monitored during the reverse braking period. Moreover, if the period exceeds a certain threshold, the rotor acts as a sufficient decelerator and ends the reversal. brake.

When the brushless motor is controlled in synchronization with the Hall signal from the Hall element, the minimum time to reverse the braking is limited by the period of the Hall signal. Therefore, when the torque of the rotor in the forward rotation direction is smaller than the reverse rotation, there is a case where the torque applied to the rotor exceeds the upper limit by the reverse braking over a certain minimum time or more, resulting in a reverse rotation of the rotor.

Further, shortly after the start of the reverse rotation, if the period of the Hall signal exceeds the threshold value, the end condition of the reverse braking is not satisfied, and there is a possibility that the rotor cannot be released from the reverse rotation and the rotor is further accelerated in the reverse direction.

Problem 2. Furthermore, the inventors of the present invention have studied the results of reverse braking and have recognized the following problems. When the brushless motor is controlled in synchronization with the Hall signal from the Hall element, the minimum time to reverse the braking is limited by the period of the Hall signal. Therefore, when the torque of the rotor in the forward rotation direction is smaller than the reverse rotation, there is a case where the torque applied to the rotor exceeds the upper limit by the reverse braking over a certain minimum time or more, resulting in a reverse rotation of the rotor. In addition, the subject matter should not be considered as a general knowledge of those skilled in the art.

One aspect of the present invention has been made in view of any of the above problems, and an exemplary object thereof is to provide a motor drive circuit capable of preventing, suppressing, and preventing reverse rotation of a rotor due to reverse braking.

1. A certain aspect of the invention relates to a motor drive circuit. The motor drive circuit includes a control unit that generates a drive signal for controlling energization of the coil of the motor based on a rectangular signal indicating a position of a rotor of the motor to be driven, and a drive unit that drives the coil based on the drive signal. The control unit monitors the period of the rectangular signal during the period of reverse braking, and ends the reverse braking if the period is shortened.

According to this aspect, based on the relative change of the period showing the number of revolutions of the rotor, That is, the rotation of the rotor in the opposite direction is detected, whereby the reverse rotation of the rotor due to the reverse braking can be suppressed.

The control unit may also terminate the reverse braking based on the magnitude relationship between the current cycle and the past cycle.

The control unit may also set T _CUR +T _CORR ≦T _PRE when the current period is T _CUR , the past period is T _PRE , and the correction value of 0 or more is T _CORR .

At the end of the reverse braking.

The control unit may also set T _CUR <T _PRE when the current period is set to T _CUR and the past period is set to T _PRE .

At the end of the reverse braking.

The past period can also be the period of the previous measurement. The past period can also be based on a plurality of cycles measured over a particular number of times.

The control unit may also terminate the reverse braking when the period of the rectangular signal becomes longer than the specific threshold value during the reverse braking. The control unit may further include an edge counter that measures the number of edges of the rectangular signal during the reverse braking period, and if the count value of the edge counter exceeds a certain threshold value, the control unit ends the reverse braking. The control unit may include a timer circuit that measures the length of the reverse braking period, and if the period of the reverse braking reaches a certain time, the reverse braking is ended. The end conditions of the reverse braking may also be combined in plural.

2. Other aspects of the invention relate to motor drive circuits. The motor drive circuit includes a control unit that generates a drive signal for controlling energization of the coil of the motor based on a rectangular signal indicating a position of a rotor of a motor to be driven, and a Hall comparator that generates a rectangular signal; and a control unit It controls the energization of the coil of the motor based on the rectangular signal; and the drive unit drives the coil based on the drive signal from the control unit. When the control unit receives the stop instruction of the motor in the normal driving state of the motor, the control unit and the normal drive up to this point The corresponding output of the state applies reverse braking.

In a certain aspect, the control unit can estimate how much torque the rotor of the motor has in the forward rotation direction by monitoring the normal driving state before the reverse braking is applied. Therefore, when it is estimated that the rotor has a sufficiently large torque in the forward rotation direction, the reverse brake is applied with a larger output, and when the torque in the forward rotation direction is estimated to be small, the output of the reverse brake is lowered. Or set to zero output, that is, no reverse braking is applied, thereby preventing the rotor from rotating in reverse.

In a certain aspect, the control unit may change the output of the reverse brake according to the number of times of switching of the rectangular signal generated in the normal driving state.

If the number of level shifts of the rectangular signal is small, the torque in the forward direction of the rotor is estimated to be smaller, and the output of the reverse brake can be reduced.

In a certain aspect, the control unit may also include an edge counter that measures the number of edges of the rectangular signal in the normal driving state, and changes the output of the reverse braking according to the count value of the edge counter.

In a certain aspect, when the control unit receives the stop instruction of the motor, when the number of edges of the rectangular signal measured so far is less than a specific threshold, the reverse brake is reduced compared to the larger time. The output.

In a certain aspect, when the control unit receives the stop instruction of the motor, the reverse brake is not applied when the number of edges of the rectangular signal measured so far is less than a specific threshold.

In a certain aspect, the control unit can also change the output of the reverse brake according to the length of the normal driving state.

If the normal driving state is short, it is estimated that the torque in the forward direction of the rotor is smaller, and the output of the reverse braking can be reduced.

In a certain aspect, the control unit may include a timer circuit that measures the length of the normal driving state, and changes the output of the reverse braking according to the measurement time of the timer circuit.

In a certain aspect, the control unit can also receive the stop instruction of the motor at the time of measurement. When the specific threshold is shorter, the output of the reverse brake is reduced compared to the longer period.

In a certain aspect, when the control unit receives the stop instruction of the motor, when the measurement time is shorter than the specific threshold value, the control unit may not apply the reverse brake.

The control unit may also terminate the reverse braking when the period of the rectangular signal becomes longer than the specific threshold value during the reverse braking. The control unit may also include an edge counter that measures the number of edges of the rectangular signal during the reverse braking, and terminates the reverse braking if the count value of the edge counter exceeds a certain threshold. The control unit may include a timer circuit that measures the length of the reverse braking period, and if the period of the reverse braking reaches a certain time, the reverse braking is ended. The end conditions of the reverse braking may also be combined in plural.

In a certain aspect, the motor drive circuit can also be integrated into one semiconductor substrate.

The "integrated integration" may include a case where all of the constituent elements of the circuit are formed on the semiconductor substrate, or a case where the main constituent elements of the circuit are integrated, and a part of the resistor or capacitor is set for adjusting the circuit constant. On the outside of the semiconductor substrate.

By integrating the circuit on one wafer, the circuit area can be reduced, and the characteristics of the circuit elements can be kept uniform.

Other aspects of the invention relate to vibrating devices. The vibration device may further include: a vibration motor that is attached to the rotor with an eccentric weight; and a motor drive circuit that rotates the vibration motor.

Other aspects of the invention relate to electronic machines. The electronic device may also be provided with the above-described vibration device.

Further, any combination of the above constituent elements or constituent elements of the present invention or a method, device, system, or the like, is also effective as an aspect of the present invention.

According to an aspect of the present invention, the reverse rotation of the rotor accompanying the reverse braking can be suppressed and prevented.

2‧‧‧Motor

4‧‧‧ Hall element

100‧‧‧Motor drive circuit

100a‧‧‧Motor drive circuit

100b‧‧‧Motor drive circuit

102‧‧‧Hall Comparator

110‧‧‧Control Department

112‧‧‧Power Control Department

114‧‧‧Reverse Brake Control Department

114a‧‧‧Reverse Brake Control Department

114b‧‧‧Reverse Brake Control Department

116‧‧‧Edge Counter

118‧‧‧Period measurement department

120‧‧‧Decision Department

120a‧‧1st judgment department

120b‧‧‧2nd Division

122‧‧‧Timer circuit

130‧‧‧ Drive Department

150‧‧‧ memory

152‧‧‧ comparator

154‧‧‧Adder

156‧‧‧ register

160‧‧‧Timer circuit

162‧‧‧ 存存器

164‧‧‧Logic gate

170‧‧‧Edge Counter

172‧‧‧ comparator

174‧‧‧ register

300‧‧‧Electronic machines

300a‧‧‧Electronic machines

300b‧‧‧Electronic machines

302‧‧‧Vibration device

304‧‧‧Main processor

306‧‧‧Eccentric hammer

310‧‧‧Substrate

312‧‧‧ coil

314‧‧‧ Washer

316‧‧‧Axis

318‧‧‧Rotor

318a‧‧‧ hammer

318b‧‧‧ permanent magnet

320‧‧‧ Cover

B‧‧‧ threshold

C‧‧‧ threshold

D‧‧‧ threshold

H+‧‧‧ Hall signal

H-‧‧‧ Hall signal

N‧‧‧ upper limit

S1‧‧‧ control instructions

S2‧‧‧Rectangular signal

S3‧‧‧ drive signal

S4‧‧‧ count value

S5‧‧‧ cycle data

S6‧‧‧length information

S7‧‧‧End signal

S7a‧‧‧End signal

S7b‧‧‧End signal

T0‧‧‧ moment

Time t1‧‧‧

Time t2‧‧‧

Time t3‧‧‧

Time t4‧‧‧

During the period of Ta‧‧

T _CORR ‧‧‧revised value

T _CUR ‧‧‧ current cycle

T _CUR '‧‧‧ cycle

T _END ‧ ‧ specific time

T _P ‧‧‧ cycle

T _P0 ‧ ‧ cycle

T _P1 ‧‧ cycle

T _P2 ‧‧ cycle

T _P3 ‧‧‧ cycle

T _PRE ‧‧‧The past cycle

Vo+‧‧‧ drive voltage

Vo-‧‧‧ drive voltage

Fig. 1 is a block diagram showing a motor drive circuit of a first embodiment.

Fig. 2 is a block diagram showing a specific configuration example of a motor drive circuit.

3(a) and 3(b) are diagrams showing the operation waveforms of the motor drive circuit of Fig. 1.

Fig. 4 is a block diagram showing a configuration example of a reverse brake control unit.

Fig. 5 is a block diagram showing a reverse brake control unit of a second modification.

Fig. 6 is a block diagram showing a motor drive circuit according to a first embodiment of the second embodiment.

7(a) and 7(b) are diagrams showing the operation waveforms of the motor drive circuit of Fig. 6.

Fig. 8 is a block diagram showing a motor drive circuit of the second embodiment.

9(a) and 9(b) are diagrams showing the operation waveforms of the motor drive circuit of Fig. 8.

Fig. 10 (a) is a perspective view of an electronic device including a motor drive circuit, and Fig. 10 (b) is a cross-sectional view of the vibration motor unit.

Fig. 11 is a perspective view of an electronic device including a motor drive circuit.

Hereinafter, the present invention will be described with reference to the drawings based on preferred embodiments. The same or equivalent constituent elements, members, and processes shown in the drawings are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. Further, the embodiments are not limited to the invention, and all the features described in the embodiments or combinations thereof are not necessarily essential to the invention.

In the present specification, the term "the state in which the member A and the member B are connected" is in addition to the physical connection between the member A and the member B, and the fact that the member A and the member B are not electrically connected to each other. Sexual influence, or does not impair the function or effect exerted by its coupling, and indirectly connected through other components.

Similarly, the phrase "the member C is disposed between the member A and the member B" includes the case where the member A and the member C are directly connected to each other, and the electrical connection state is not included. A situation in which it has a substantial effect, or does not impair the function or effect exerted by its coupling, and is indirectly connected via other components.

(First embodiment)

Fig. 1 is a block diagram of a motor drive circuit 100 according to the first embodiment. The motor drive circuit 100 drives a single-phase brushless motor (hereinafter simply referred to as a motor) 2. The Hall element 4 produces a pair of Hall signals H+, H- corresponding to the position of the rotor of the motor 2. The Hall signals H+, H- are opposite to each other.

In the motor drive circuit 100, a control command S1 for instructing rotation/stop of the motor 2 is input from a main processor (not shown). The motor drive circuit 100 receives the Hall signals H+ and H-, and energizes the coils of the motor 2 in synchronization with the Hall signals H+ and H- when the control command S1 instructs the rotation.

The motor drive circuit 100 includes a Hall comparator 102, a control unit 110, and a drive unit 130, and is a functional IC (integrated circuit) in which one semiconductor substrate is integrally integrated. The Hall comparator 102 compares the Hall signals H+, H- from the Hall element 4 and generates a rectangular signal (also referred to as an FG signal) S2. The control unit 110 generates a drive signal S3 for controlling energization of the coil of the motor 2 based on the rectangular signal S2. The drive unit 130 drives the coil based on the drive signal S3 from the control unit 110. The configuration of the drive unit 130 is not particularly limited, and a well-known circuit may be used.

A control command S1 indicating the rotation/stop of the motor 2 is input to the control unit 110. When the control unit 110 receives the stop instruction of the motor 2 in the normal driving state in which the motor 2 is rotated in a certain direction (the forward rotation direction), the reverse rotation brake is applied. The control unit 110 monitors the period of the Hall signals H+ and H- during the period of the reverse braking, that is, the period T _{P of the} rectangular signal S2 (in the present embodiment, a half period), and if the period T _P becomes shorter, Then the reverse brake is ended.

The control unit 110 includes an energization control unit 112 and an inversion brake control unit 114. The energization control unit 112 performs the commutation control synchronized with the rectangular signal S2. The reverse brake control unit 114 controls the end of the reverse brake.

Specifically, the reverse brake control unit 114 measures the period T _P of the rectangular signal S2 during the period of reverse braking, and compares the current period T _CUR with the past period T _PRE , if the current period T _CUR and the past When the period T _PRE is shorter, the reverse braking is ended. This is the first condition. The past period T _PRE can also be the previous period T _P . Or the past period T _PRE may also be a value calculated for a plurality of cycles T _P measured by a plurality of cycles that have passed through. For example, the past period T _PRE can also be a simple average or moving average of the past multiple periods T _P .

Further, when the reverse brake control unit 114 passes the specific time T _END after the start of the reverse brake, the reverse brake is ended. This is the second condition. When either of the first condition and the second condition is satisfied, the reverse brake control unit 114 ends the reverse braking.

The invention relating to the first embodiment is not limited to a specific configuration, and is understood to be various devices and circuits that are understood as the block diagram or circuit diagram of FIG. 1 or introduced from the above description. In the following, in order to facilitate understanding of the nature of the invention, and the understanding of the operation of the circuit, and the like, it is not intended to limit the scope of the invention, and a more specific configuration example will be described.

FIG. 2 is a block diagram showing a specific configuration example of the motor drive circuit 100. The reverse brake control unit 114 includes a cycle measuring unit 118 and a determining unit 120. The period measuring unit 118 measures the period of the rectangular signal S2 (the length of each of the high level interval and the low level interval, that is, the half period), and outputs the data (period data) S5 indicating the measured period to the determining unit 120.

The determination unit 120 compares the current period T _CUR displayed on the period data S5 with the past period T _PRE held in the memory, and establishes (for example, the high position) if the magnitude relationship of the equal value satisfies the specific condition (first condition). The signal is terminated by S7. Further, the determination unit 120 establishes the end signal S7 when the specific time T _END has elapsed after the start of the reverse rotation braking. The energization control unit 112 terminates the reverse braking when the end signal S7 is established.

Next, the operation of the motor drive circuit 100 will be described. 3(a) and 3(b) are diagrams showing the operation waveforms of the motor drive circuit 100 of Fig. 1. First, referring to Fig. 3(a), the end of the reverse braking of the second condition will be described. At time t0, the control command S1 becomes a high level indicating the rotation. Thereby, the control unit 110 starts energization of the motor 2. As the number of rotations of the motor 2 rises, the period of the rectangular signal S2 continues to become shorter.

When the control command S1 becomes the low level indicating the stop at time t1, the energization control unit 112 starts reverse rotation braking. The rotor is decelerated by reverse braking, and the period of the rectangular signal S2 continues to be long. Then, at time t2 after the lapse of the specific time T _END from the time t1, the end signal S7 is established, and the reverse braking is ended.

Next, referring to Fig. 3(b), the end of the reverse braking of the first condition will be described. At time t0, the control command S1 becomes a high level indicating the rotation. Thereby, the control unit 110 starts energization of the motor 2. At the subsequent time t3, before the number of rotations of the motor 2 rises, the control command S1 becomes a low level, and the stop of the motor 2 is instructed, and the energization control unit 112 starts reverse rotation braking.

The period measuring unit 118 measures the periods T _P0 , T _P1 , T _P2 , T _{P3 ,} ... of the rectangular signal S2 every cycle. In the i-th cycle, the current period T _CUR (=T _Pi ) is compared with the past period T _PRE (=T _Pi-1 ). Here, the past period T _PRE is the period T _P of the previous cycle.

During the period after the start of the reverse braking, Ta _Pi > T _{Pi-1 is} established. That is, the period of the rectangular signal S2 gradually becomes longer, and the rotor is decelerated. When T _P3 > T _{P2 is} detected at time t4 and the first condition is sufficient, the end signal S7 is established, and the reverse braking is ended.

The above is the operation of the motor drive circuit 100. After a brief normal drive, if the reverse brake is continuously applied, the rotor accelerates in the opposite direction. On the other hand, according to the motor drive circuit 100 of the first embodiment, the period T _P of the rectangular signal S2 is measured, and when T _CUR <T _PRE is detected, it is considered that the rotor is reversely rotated in the reverse direction, and the reverse can be directly stopped. Turn the brakes.

FIG. 4 is a block diagram showing a configuration example of the reverse brake control unit 114. The determination unit 120 includes a first determination unit 120a and a second determination unit 120b that determine each of the first condition and the second condition. The second determination unit 120b includes the timer circuit 160, and measures the elapsed time after the start of the reverse brake, and after the lapse of the specific time T _END , the end signal S7b is established. The specific time T _END is set based on the value of the register 162 of the specific address. The specific time T _END is preferably set by an external host processor via an interface such as an I ² C (Inter IC: internal IC) bus.

The first determination unit 120a includes a memory 150, a comparator 152, an adder 154, and a register 156. The memory 150 maintains the past period T _PRE . As described above, the past period T _PRE may be the previous period T _P or may be the average of the past plurality of periods T _P .

When the rotor is rotated at a fixed speed due to the mounting position of the Hall element or the unevenness of the magnetic field, the period T _{P of the} rectangular signal S2 is not necessarily fixed and may be changed. This case refers to a case where the reverse rotation of the rotor may be erroneously detected when the current period T _Pi and the previous period T _{Pi-1 are} simply compared. In order to prevent this erroneous detection, the first determining unit 120a corrects the period T _CUR .

The adder 154 is tied to the current period T _CUR plus the correction value T _CORR to produce a corrected period T _CUR '. The correction value T _CORR is 0 or more (≧0), and is set based on the value of the register 156 of the specific address. The specific value T _CORR is preferably set by an external host processor via an interface such as an I ² C (Inter IC) bus. The optimum value of the correction value T _{CORR may} be determined according to the type of the motor 2, the number of poles, or the load connected to the rotor, the moment of inertia, and the like.

The comparator 152 compares the corrected current period T _CUR ' with the past period T _PRE and satisfies T _CUR '≦T _PRE

In other words, in other words, satisfy T _CUR +T _CORR ≦T _PRE

The end signal S7a is established.

The logic gate 164 establishes the end signal S7 when at least one of the end signals S7a and S7b is established. For example, the logic gate 164 may also be constructed of an OR gate.

According to the reverse brake control unit 114, the sensitivity of the reverse rotation detection of the rotor can be adjusted based on the correction value T _CORR . The optimum control of the platform used by the motor drive circuit 100 can be achieved by externally setting the correction value T _CORR using the register 156.

Hereinabove, a certain aspect of the present invention has been described based on the first embodiment. It will be understood by those skilled in the art that the first embodiment is exemplified, and various modifications may be made in the various components or combinations of the various processes, and such variations are also within the scope of the invention. Hereinafter, such a variation will be described.

(First variation)

In Fig. 4, the current period T _{CUR is} corrected, but the past period T _PRE can be _reversed . In this case, the correction value T _CORR may be subtracted from the value read by the memory 150 to generate the corrected period T _PRE ', and T _PRE and T _CUR may be compared.

(2nd variation)

In the first embodiment, after the inversion brake is started, if the specific time T _END elapses, the reverse braking is terminated, but the present invention is not limited thereto. Fig. 5 is a block diagram showing the reverse brake control unit 114a of the second modification. In the second variation, the number of times of switching (the number of edges) of the rectangular signal S2 generated during the reverse braking may be exceeded as the second condition as the second condition.

The second determination unit 120b includes an edge counter 170, a comparator 172, and a register 174. The edge counter 170 counts the number of edges of the rectangular signal S2 after the start of the reverse braking. The comparator 172 compares the count value S4 of the edge counter 170 with the specific threshold value D, and if S4 > D, the end signal S7b is established. The threshold D is set based on the value of the register 174 of the specific address. The threshold D is preferably set by an external host processor via an interface such as an I ² C (Inter IC) bus.

(3rd variation)

In the first embodiment, when the first condition or the second condition is satisfied, the reverse braking is ended, but the second condition may be omitted. In this case, the timer circuit 160 and the logic gate 164 of FIG. 4 may be omitted.

(fourth variation)

In the first embodiment, the reverse braking is terminated based on the magnitude relationship between the current period T _CUR and the past period T _PRE , but the present invention is not limited thereto. For example, it is possible to pay attention to a plurality of consecutive (for example, three or more) cycles, and when the shortening tendency is observed in the cycle, the reverse braking is ended.

(5th variation)

The Hall comparator 102 can also be built in a Hall IC including the Hall element 4. Alternatively, the Hall element 4 may be built in the motor drive circuit 100.

(Sixth variation)

In the first embodiment, the motor drive circuit 100 that performs the control of preventing the inversion by using the Hall signal from the Hall element is described. However, instead of the Hall signal from the Hall element, the Hall signal may be used instead. Other than the signal containing the rotation number information.

(Second embodiment)

The second embodiment will be described with reference to Fig. 1 . Since the basic configuration is the same as that of the first embodiment, the description of the common points will be omitted, and the differences will be described.

A control command S1 for instructing rotation/stop of the motor 2 is input to the control unit 110. When the control unit 110 receives the stop instruction of the motor 2 in the normal drive state in which the motor 2 is rotated in a certain direction (the forward rotation direction), the control unit 110 applies the reverse brake to the output corresponding to the normal drive state up to now.

The control unit 110 includes an energization control unit 112 and an inversion brake control unit 114. The energization control unit 112 performs the commutation control synchronized with the rectangular signal S2. The reverse brake control unit 114 controls the output of the reverse brake. Specifically, the reverse brake control unit 114 changes the output of the reverse brake based on the normal drive state before the reverse brake is applied. When the motor drive circuit 100 performs PWM control, the reverse brake control unit 114 changes the duty ratio of the drive voltage Vo+/Vo- applied to the motor 2, and changes the output of the reverse brake.

The above is the configuration of the motor drive circuit 100 of the second embodiment. Next, the operation will be described.

While the control command S1 indicates the rotation of the rotor, the energization control unit 112 performs the commutation control based on the rectangular signal S2, and supplies the motor 2 with the drive voltage Vo+/Vo- having a duty ratio corresponding to the target number of rotations. The duty cycle of the normally driven state can be a fixed value, or can be 100%.

The reverse brake control unit 114 monitors the normal drive state. Reverse brake control unit 114 Based on the monitoring result, it is estimated how much torque the rotor of the motor 2 has in the forward rotation direction. Therefore, when it is estimated that the rotor has a sufficiently large torque in the forward rotation direction, reverse rotation is applied with a larger output (rated output), and when the torque in the forward rotation direction is estimated to be small, the reverse rotation is performed. The brake is reduced to a lower than the rated output, or set to zero output, ie no reverse braking is applied.

Thereby, it is possible to prevent the torque in the reverse direction given to the rotor by the reverse rotation from exceeding the torque in the forward direction given to the normal driving state, thereby preventing the rotor from rotating in the reverse direction.

The invention relating to the second embodiment is not limited to a specific configuration, and is not limited to a specific configuration, which is known as a block diagram or a circuit diagram of FIG. 1 or various devices and circuits introduced from the above description. In the following, in order to simplify the scope of the present invention, and to understand the nature of the invention or the understanding of the operation of the circuit, and to clarify the details, a more specific configuration example will be described.

Fig. 6 is a block diagram showing a motor drive circuit 100a according to the first embodiment of the second embodiment.

The reverse brake control unit 114a of the motor drive circuit 100a changes the output of the reverse brake based on the number of times of switching of the rectangular signal S2 generated in the normal drive state. The reverse brake control unit 114a includes an edge counter 116, a period measuring unit 118, and a drive unit 130. The edge counter 116 measures the number of edges of the rectangular signal S2 in the normal driving state. The determination unit 120 changes the output of the reverse brake based on the count value S4 of the edge counter 116.

For example, when the control unit 110 (determination unit 120) indicates that the control command S1 instructs the stop of the motor, the count value S4 indicating the number of edges of the rectangular signal S2 counted up to this point is larger than the specific threshold value A. In the case, reverse braking is applied at the rated output. The rated output can be, for example, a duty ratio in the range of 70 to 100%.

For example, the threshold A may be set to be less than one revolution of the rotor (the mechanical angle is 360°). For example, for a 3-pole brushless motor, the rotor rotates for 1 week to produce the edge of the rectangular signal S2 six times, and the rotation half-cycle produces three times. Therefore, it can be set to A=3~6. In the case of a 2-pole brushless motor, since the edge of the rectangular signal S2 is generated twice by one rotation of the rotor, and the rotation is performed once every half cycle, it can be set to A=1~2.

The threshold A can be determined according to the type of the motor 2, the number of poles, or the load connected to the rotor, the moment of inertia, etc., and can be set to about 1 to 20.

Conversely, when the number of edges of the rectangular signal S2 counted up to this point (ii) is less than the specific threshold A, the control unit 110 (determination unit 120) lowers the output of the reverse brake from the fixed output. In the present embodiment, the control unit 110 does not apply reverse braking when the number of edges of the measured rectangular signal is smaller than the specific threshold A. That is, the output of the reverse brake is set to the duty ratio = 0%.

The period measuring unit 118 measures the period of the rectangular signal S2 (the length of each of the high level interval and the low level interval, that is, the half period) during the period in which the reverse braking is applied, and displays the data of the measured period (period data). S5 is output to the determination unit 120. When the period indicated by the period data S5 is longer than the specific threshold B, the determination unit 120 ends the reverse braking.

The threshold A is preferably set according to the setting data of the register stored in a certain address. Similarly, the threshold B is preferably set to be set according to the setting data of the register stored in a certain address. Since the thresholds A and B are different depending on the type, the extreme use or the use of the motor 2, the designer of the machine equipped with the motor drive circuit 100 can select the thresholds A and B. The best control is achieved by various platforms.

The above is the configuration of the motor drive circuit 100a. Next, the operation will be described.

7(a) and 7(b) are diagrams showing the operation waveforms of the motor drive circuit 100a of Fig. 6. The vertical axis and the horizontal axis of the waveform diagram or the timing chart in the present specification are appropriately enlarged and reduced for easy understanding, and the waveforms shown are also simplified or exaggerated or emphasized for easy understanding.

Refer to Figure 7(a). At time t0, the control command S1 becomes a high level indicating the rotation. Thereby, the control unit 110 starts energization of the motor 2. As the number of rotations of the motor 2 rises, the period of the rectangular signal S2 continues to become shorter. The count value S4 increases as the motor 2 rotates, and reaches the upper limit N of the edge counter 116 at time t1.

At time t2, the control command S1 becomes a low level indicating the stop. At time t2, since N>A, reverse braking is applied at a constant output. The rotor is decelerated by reverse braking, and the period of the rectangular signal S2 continues to be long. If the period T _{P of the} rectangular signal S2 exceeds the threshold B at time t3, the reverse braking period is ended.

Refer to Figure 7(b). At time t0, the control command S1 becomes a high level indicating the rotation. Thereby, the control unit 110 starts energization of the motor 2. At the subsequent time t1, the control command S1 becomes a low level before the number of rotations of the motor 2 rises, indicating the stop of the motor 2.

At time t1, the edge count value S4 is 2, which is less than the threshold A (for example, 3). Therefore, the reverse braking is not applied, but the rotor is stopped by regenerative braking, or the rotor is naturally stopped.

The above is the operation of the motor drive circuit 100a. In Fig. 7(b), the torque in the forward direction of the motor at time t1 is very small. Therefore, if the reverse brake is applied when the control command S1 is at the low level, the rotor starts to rotate in the reverse direction. Further, shortly after the start of the rotation in the reverse direction, if the period T _{P of the} rectangular signal S2 is shorter than the threshold B, there is a possibility that the rotor cannot be released from the reverse rotation and the rotor is further accelerated in the reverse direction.

On the other hand, in the motor drive circuit 100a of FIG. 6, when the number of edges of the rectangular signal S2 measured in the normal driving state is smaller than the threshold value A, it is estimated that the torque in the forward rotation direction is sufficiently small. The reverse rotation of the rotor can be prevented by not applying reverse braking.

Further, the first embodiment has the following advantages as compared with the second embodiment described below. In the second embodiment, the rotation state of the forward direction of the motor is estimated based on the length of the normal driving state, and whether or not reverse braking is applied is switched. However, even if an abnormality such as foreign matter is caught in the rotor, even the normal driving state is generated. The length is long enough, the torque in the forward direction is also small, and there is also the possibility of reverse rotation of the rotor due to reverse braking. On the other hand, since the number of edges of the rectangular signal S2 is larger than the threshold value A, the motor is reliably rotated in the normal rotation direction, so that the rotor can be prevented from rotating in the abnormal state.

Fig. 8 is a block diagram showing a motor drive circuit 100b of the second embodiment.

The reverse brake control unit 114b of the motor drive circuit 100b is based on the normal drive state. The length changes the output of the reverse brake. The reverse brake control unit 114b is provided with a timer circuit 122 instead of the edge counter 116 of Fig. 6 . The timer circuit 122 measures the length of the normal driving state and generates a section length data S6 indicating the length of the measurement. The timer circuit 122 can also be a digital timer that increments (or counts down) the clock signal in the normal drive state. In other embodiments, the timer circuit 122 can also be an analog timer. The determination unit 120 changes the output of the reverse brake based on the measurement time of the timer circuit 122.

For example, when the measurement time of the timer circuit 122 exceeds the specific threshold C, the determination unit 120 applies the reverse brake to the rated output, and when the measurement time is shorter than the threshold C, the reverse brake is not applied. , or reduce the output of the reverse brake.

The above is the configuration of the motor drive circuit 100b of FIG. Next, the operation will be described.

9(a) and 9(b) are diagrams showing the operation waveforms of the motor drive circuit 100b of Fig. 8. Refer to Figure 9(a). At time t0, the control command S1 becomes a high level indicating the rotation. Thereby, the control unit 110 starts energization of the motor 2. As the number of rotations of the motor 2 rises, the period of the rectangular signal S2 continues to become shorter. The section length data S6 showing the length of the normal driving state continues to increase with time. Since the bit width of the timer circuit 122 is limited, if the interval length data S6 reaches a certain upper limit value, the increment counting stops.

At time t2, the control command S1 becomes a low level indicating the stop. At time t2, since S6>C, reverse braking is applied at the rated output. The rotor is decelerated by reverse braking, and the period of the rectangular signal S2 continues to be long. If the period T _{P of the} rectangular signal S2 exceeds the threshold B at time t3, the reverse braking period is ended.

Refer to Figure 9(b). At time t0, the control command S1 becomes a high level indicating the rotation. Thereby, the control unit 110 starts energization of the motor 2. At the subsequent time t1, the control command S1 becomes a low level before the number of rotations of the motor 2 rises, and the stop of the motor 2 is instructed.

At time t1, the section length data S6 is smaller than the threshold value C. Therefore, the reverse braking is not applied, but the rotor is stopped by regenerative braking, or the rotor is naturally stopped.

The above is the operation of the motor drive circuit 100b. The same effect as the motor drive circuit 100a of Fig. 6 can be obtained by the motor drive circuit 100b.

Hereinabove, a certain aspect of the present invention has been described based on the second embodiment. It will be understood by those skilled in the art that the second embodiment is exemplified, and various modifications may be made in the various components or combinations of the various processes, and such variations are also within the scope of the invention. Hereinafter, such a variation will be described.

(Seventh variation)

In the second embodiment, the output of the reverse brake is set to zero when there is a reverse rotation, but the present invention is not limited thereto. For example, in the case where there is a reverse rotation, the output of the reverse brake may be set to be greater than zero and less than the value of the fixed output, for example, about 5 to 30%.

(8th variation)

Alternatively, the output of the reverse brake in the case where there is a reverse rotation may be adaptively changed in accordance with the previous normal driving state. For example, the smaller the number of edges of the rectangular signal S2 measured in the normal driving state, the lower the output of the reverse braking, and the shorter the length of the driving state, the lower the output of the reverse braking.

(9th variation)

In the second embodiment, when the period T _{P of the} rectangular signal S2 exceeds the threshold value B, the reverse braking period is ended, but the present invention is not limited thereto. In the ninth modification, the number of times of switching (the number of edges) of the rectangular signal S2 generated during the reverse braking is exceeded as the threshold value, and the reverse braking is ended. In the case where the ninth modification is applied to the first embodiment of Fig. 6, the edge counter 116 can be used to count the number of edges of the rectangular signal S2 during the period of reverse braking. The determination unit 120 terminates the reverse braking when the number S4 of edges generated during reverse braking exceeds the threshold D.

In the case where the ninth modification is applied to the second embodiment of Fig. 8, the edge counter 116 may be added to the reverse brake control unit 114b.

(10th variation)

In the tenth modification, if the length of the reverse braking period reaches the specific time T _END , the reverse braking is ended. In the case where the tenth modification is applied to the second embodiment of Fig. 8, the timer circuit 122 is used to measure the length of the period of reverse braking. The determination unit 120 compares the period of the reverse braking measured by the timer circuit 122 with the specific time T _END .

In the case where the tenth modification is applied to the first embodiment of Fig. 6, the timer circuit 122 may be added to the reverse brake control unit 114a.

(11th variation)

The Hall comparator 102 can also be built in a Hall IC including the Hall element 4. Alternatively, the Hall element 4 may be built in the motor drive circuit 100.

(12th variation)

In the second embodiment, the motor drive circuit 100 that performs the inverter control by the Hall signal from the Hall element and performs the control for preventing the inversion is described. However, instead of the Hall signal from the Hall element, the Hall signal may be used instead. Other than the signal containing the rotation number information.

Any feature of the first embodiment can be combined with any of the features of the second embodiment, and combinations thereof are also effective as one aspect of the invention.

(use)

Next, the use of the motor drive circuit 100 described in the first or second embodiment will be described. Fig. 10 (a) is a perspective view of an electronic device 300a including a motor drive circuit 100, and Fig. 10 (b) is a cross-sectional view of the vibration motor unit.

The electronic device 300 is a device having a vibration function, such as a mobile phone terminal, a smart phone, a tablet PC, a portable game machine, a controller of a game console, and the like. In Fig. 10(a), a smart phone is displayed as a representative.

The electronic device 300 includes a vibration device 302 and a main processor 304. The vibration device 302 is a vibration motor unit that is integrally formed by the motor 2 and the motor drive circuit 100 and covered with a cover. As shown in FIG. 10(b), on the substrate 310, a motor drive circuit 100 and a coil are mounted. 312 and so on. Further, a washer 314 is attached to the shaft 316, and is rotatably supported. At the front end of the shaft 316, a rotor 318 having an eccentric hammer 318a and a permanent magnet 318b embedded in its inner peripheral portion is mounted. The entire system of the vibrating device 302 is covered by the cover 320.

The motor drive circuit 100 responds to the control command S1 from the main processor 304 to rotate the motor 2. The main processor 304 can be a baseband processor or an application processor.

Fig. 11 is a perspective view of an electronic device 300b of another configuration. In the rotor of the motor 2, an eccentric weight 306 is mounted. The motor 2 does not require a Hall element.

The above is the configuration of the electronic devices 300a and 300b. Since the vibration device 302 employs the motor drive circuit 100 of the embodiment, it is possible to prevent the rotor from being rotated by the reverse rotation due to the reverse rotation, and the vibration can be immediately stopped.

The present invention has been described with reference to the specific embodiments of the present invention. However, the embodiments are merely illustrative of the principles and applications of the present invention. Many changes or configuration changes.

2‧‧‧Motor

4‧‧‧ Hall element

100‧‧‧Motor drive circuit

102‧‧‧Hall Comparator

110‧‧‧Control Department

112‧‧‧Power Control Department

114‧‧‧Reverse Brake Control Department

130‧‧‧ Drive Department

H+‧‧‧ Hall signal

H-‧‧‧ Hall signal

S1‧‧‧ control instructions

S2‧‧‧Rectangular signal

S3‧‧‧ drive signal

Vo+‧‧‧ drive voltage

Vo-‧‧‧ drive voltage

Claims (33)

A motor drive circuit comprising: a control unit that generates a drive signal for controlling energization of a coil of the motor based on a rectangular signal indicating a position of a rotor of a motor to be driven; and a drive unit based on the above The drive signal drives the coil; and the control unit monitors the period of the rectangular signal during the reverse braking period, and when the cycle is shortened, the reverse brake is ended. The motor drive circuit of claim 1, wherein the control unit ends the reverse braking based on a magnitude relationship between a current cycle and a past cycle. The motor drive circuit of claim 2, wherein the control unit is configured to set the current period to T _CUR , to set the past period to T _PRE , and to set a correction value of 0 or more to T _{CORR CUR} +T _CORR ≦T _PRE ends the above reverse braking. The motor drive circuit of claim 2, wherein the control unit ends the reverse brake when T _CUR <T _PRE is satisfied when the current period is T _CUR and the past period is T _PRE . The motor drive circuit of any one of claims 2 to 4, wherein the past period is the period measured last time. The motor drive circuit of any one of claims 2 to 4, wherein the past period is based on a plurality of cycles measured over a particular number of times. The motor drive circuit of any one of claims 1 to 4, further comprising a Hall comparator that compares one of the Hall signals from the opposite phase of the Hall element to each other and generates the rectangular signal . The motor drive circuit according to any one of claims 1 to 4, wherein the control unit is in a period of reverse braking, and if the period of the rectangular signal becomes longer than a specific threshold, the reverse braking is ended. The motor drive circuit of any one of claims 1 to 4, wherein the control unit includes an edge counter that measures the number of edges of the rectangular signal during reverse braking, if the edge counter is When the value exceeds a certain threshold value, the control unit ends the reverse braking. The motor drive circuit according to any one of claims 1 to 4, wherein the control unit includes a timer circuit that measures a length of the reverse brake period, and if the period of the reverse brake reaches a specific time, the reverse brake is ended. A motor drive circuit according to any one of claims 1 to 4, which is integrally integrated with a semiconductor substrate. A vibration device comprising: a vibration motor attached to an eccentric weight of a rotor; and a motor drive circuit according to any one of claims 1 to 4, wherein the vibration motor is rotated. An electronic machine comprising the vibration device of claim 12. A driving method, characterized in that it is a driving method of a motor, and includes the steps of: comparing one of the inverse elements of the Hall elements from each other to a Hall signal, and generating a rectangular signal; synchronizing with the rectangular signal to the motor The coil is energized; when an instruction to stop the motor is received, reverse braking is applied; and during the reverse braking period, the period of the rectangular signal is monitored, and if the period is shortened, the reverse braking is ended. A motor drive circuit characterized by comprising: a control unit that generates a drive signal for controlling energization of a coil of the motor based on a rectangular signal indicating a position of a rotor of a motor to be driven, and a drive unit that drives the coil based on the drive signal; and the control When the stop instruction of the motor is received in the normal driving state of the motor, the reverse brake is applied to the output corresponding to the normal drive state up to now. The motor drive circuit of claim 15, wherein the control unit changes the output of the reverse brake based on a number of times of switching of the rectangular signal generated in the normal driving state. The motor drive circuit of claim 16, wherein the control unit includes an edge counter that measures the number of edges of the rectangular signal in the normal driving state, and the control unit is configured according to the count value of the edge counter. The output of the reverse brake described above is changed. The motor drive circuit of claim 17, wherein the control unit receives the stop instruction of the motor, and when the number of edges of the rectangular signal measured so far is less than a specific threshold value, The output of the above reverse brake is reduced at a large time. The motor drive circuit of claim 17, wherein the control unit receives the stop instruction of the motor, and does not apply the reversal when the number of edges of the rectangular signal measured so far is less than a specific threshold value brake. The motor drive circuit of claim 15, wherein the control unit changes the output of the reverse brake according to the length of the normal drive state. The motor drive circuit of claim 16, wherein the control unit includes a timer circuit that measures a length of the normal drive state, and changes an output of the reverse brake according to a measurement time of the timer circuit. The motor drive circuit of claim 21, wherein the control unit is configured to receive the above When the motor is stopped, when the measurement time is shorter than the specific threshold value, the output of the reverse brake is lowered as compared with the longer time. The motor drive circuit of claim 21, wherein the control unit receives the stop instruction of the motor, and does not apply the reverse brake when the measurement time is shorter than a specific threshold. The motor drive circuit of any one of claims 15 to 23, further comprising a Hall comparator that compares one of the inverse phase signals from the Hall elements to each other and generates the rectangular signal . The motor drive circuit according to any one of claims 15 to 23, wherein the control unit is in a period of reverse braking, and if the period of the rectangular signal becomes longer than a specific threshold, the reverse braking is ended. The motor drive circuit of any one of claims 15 to 23, wherein the control unit includes an edge counter that measures the number of edges of the rectangular signal during reverse braking, if the edge counter is When the value exceeds a certain threshold value, the control unit ends the reverse braking. The motor drive circuit according to any one of claims 15 to 23, wherein the control unit includes a timer circuit that measures a length of the reverse brake period, and if the period of the reverse brake reaches a specific time, the reverse brake is ended. A motor drive circuit according to any one of claims 15 to 23, which is integrally integrated with a semiconductor substrate. A vibration device comprising: a vibration motor attached to an eccentric weight of a rotor; and a motor drive circuit according to any one of claims 15 to 23, wherein the vibration motor is rotated. An electronic machine characterized by comprising a vibrating device as claimed in claim 29. A driving method, characterized in that it is a driving method of a motor, and includes a step of: comparing one of the inverse elements of the Hall element to the Hall signal, and generating a rectangular signal; energizing the coil of the motor in synchronization with the rectangular signal; and generating the motor if the motor is normally driven In the stop instruction, the reverse brake is applied to the output corresponding to the normal drive state up to this point. The driving method of claim 31, wherein the step of applying the reverse braking is to change the output of the reverse braking according to the number of times of switching of the rectangular signal generated in the normal driving state. The driving method of claim 31, wherein the step of applying the reverse braking is to change the output of the reverse braking according to the length of the normal driving state.