CN113193799B - Motor drive circuit, vibration device, and electronic apparatus - Google Patents
Motor drive circuit, vibration device, and electronic apparatus Download PDFInfo
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- CN113193799B CN113193799B CN202110509253.1A CN202110509253A CN113193799B CN 113193799 B CN113193799 B CN 113193799B CN 202110509253 A CN202110509253 A CN 202110509253A CN 113193799 B CN113193799 B CN 113193799B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/24—Arrangements for stopping
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Abstract
A motor driving circuit, a driving method, a vibration device, and an electronic apparatus are provided for suppressing reverse rotation of a rotor caused by reverse braking. A control unit (110) generates a drive signal (S3) for controlling the energization of the coils of the motor (2) on the basis of a rectangular signal (S2) indicating the position of the rotor of the motor (2) to be driven. The driving unit (130) drives the coil based on the driving signal (S3). The control unit (110) monitors the period of the rectangular signal (S2) during the reverse braking period, and ends the reverse braking if the period is shortened.
Description
The application is a divisional application of the following patent applications: the application date is 2016, 5 and 18, and the application number is 201610329921.1, and the application is named "motor driving circuit, vibration device and electronic device".
Technical Field
The present application relates to a motor driving technique.
Background
In a drive for a brushless motor, a braking function is often mounted in order to stop a rotating rotor. Braking includes regenerative braking and reverse braking. In regenerative braking, a loop is formed by the output stage of the driver and the motor coil, and a current flows in the loop to dissipate energy of the motor coil.
In the case where it is desired to stop the rotor with a braking force stronger than that of the regenerative braking, the reverse braking is employed. In the reverse braking, the motor coil is driven so that a torque in the opposite direction to the normal driving state (forward rotation state), in other words, the forward rotation direction occurs in the rotor.
[ Prior Art literature ]
[ patent literature ]
[ patent document 1] Japanese patent application laid-open No. 2006-234208
Patent document 2 japanese patent laid-open publication No. 2009-018654
[ patent document 3] Japanese patent laid-open No. 8-191591
Disclosure of Invention
[ problem to be solved by the application ]
The present inventors studied the following control of reverse braking (referred to as a research technique).
In the research technique, the period of the hall signal is monitored during the reverse braking. Then, if the cycle exceeds a predetermined threshold value, the rotor is considered to be sufficiently decelerated and the reverse braking is ended.
In the case of controlling the brushless motor in synchronization with the hall signal from the hall element, the minimum time of the reverse braking is limited by the period of the hall signal. Therefore, when the rotor torque in the forward rotation direction immediately before the reverse rotation braking is small, the torque provided to the rotor by the reverse rotation braking for a certain minimum time or longer may be increased, and as a result, the rotor may be rotated reversely.
Further, immediately 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 the rotor cannot be separated from the reverse braking, and the rotor is further accelerated in the reverse direction.
Further, as a result of examining reverse braking, the present inventors have recognized the following problems. In the case of controlling the brushless motor in synchronization with the hall signal from the hall element, the minimum time of the reverse braking is limited by the period of the hall signal. Therefore, when the rotor torque in the forward rotation direction immediately before the reverse rotation braking is small, the torque supplied to the rotor by the reverse rotation braking for a certain minimum time or longer may be increased, and as a result, the rotor may be rotated reversely. The problem is not understood as a general knowledge of those skilled in the art.
One embodiment of the present application has been made in view of one of the problems in the above-described period, and an exemplary object thereof is to provide a motor drive circuit capable of preventing or suppressing reverse rotation of a rotor caused by reverse braking.
[ means for solving the problems ]
1. One embodiment of the present application relates to a motor drive circuit. The motor driving circuit includes: a control unit that controls energization of a coil of the motor based on a rectangular signal indicating a position of a rotor of the motor to be driven; and a driving unit that drives the coil based on the driving signal. The control unit monitors the period of the rectangular signal during the reverse braking, and ends the reverse braking when the period is shortened.
According to this aspect, the rotation of the rotor in the reverse direction can be immediately detected from the periodic relative change indicating the rotation speed of the rotor, and thus the reverse rotation of the rotor due to the reverse braking can be suppressed.
The control unit may end the reverse braking based on the magnitude relation between the current cycle and the past cycle.
The control unit records the current period as T CUR The past period is denoted as T PRE When the correction value of 0 or more is denoted as TCORR, the correction value may be satisfied
T CUR +T CORR ≦T PRE
When this is the case, the reverse braking is ended.
The control unit records the current period as T CUR The past period is denoted as T PRE When T is satisfied CUR ＜T PRE
And ending the reverse braking.
The past cycle may be the previous measurement cycle. The past cycle may be based on a plurality of cycles measured in the latest predetermined number of times.
In the period of the reverse brake, the control unit may end the reverse brake if the period of the rectangular signal becomes longer than a predetermined threshold value. The control unit may include an edge counter that counts the number of edges of the rectangular signal during the reverse brake period, and may terminate the reverse brake when the count value of the edge counter exceeds a predetermined threshold value. The control unit may include a timer circuit for measuring a period length of the reverse brake, and may end the reverse brake when the period of the reverse brake reaches a predetermined time. The end condition of the reverse brake may be plural in combination.
2. Other aspects of the application relate to motor drive circuits. The motor driving circuit includes: a control unit that generates a drive signal for controlling energization of a coil of a motor to be driven, based on a rectangular signal indicating a position of a rotor of the motor; a hall comparator that generates a rectangular signal; a control unit that controls energization of a coil of the motor based on the rectangular signal; and a driving unit that drives the coil based on the driving signal from the control unit. When a stop instruction of the motor is received in a normal driving state of the motor, the control unit applies a reverse brake at an output corresponding to the normal driving state.
In one embodiment, the control unit monitors a normal driving state before the reverse brake is applied, so that it is possible to estimate how much torque the rotor of the motor has in the forward direction. Therefore, when the estimated rotor has a sufficiently large torque in the forward direction, the reverse brake is applied with a large output, and when the estimated torque in the forward direction is small, the output of the reverse brake is reduced, or the output 0 is set, that is, the reverse brake is not applied, whereby the reverse rotation of the rotor can be prevented.
In one embodiment, the control unit may change the output of the reverse brake according to the number of times of switching the rectangular signal generated in the normal driving state.
If the number of level transitions of the rectangular signal is small, it is estimated that the torque in the forward rotation direction of the rotor is small, and the output of the reverse brake can be reduced.
In one embodiment, the control unit may include an edge counter for counting the number of edges of the rectangular signal in the normal driving state, and may change the output of the reverse brake according to the count value of the edge counter.
In one embodiment, the control unit may reduce the output of the reverse brake when the number of edges of the rectangular signal measured up to this point is smaller than a predetermined threshold value upon receiving a stop instruction of the motor, as compared with the case of the large number of edges.
In one embodiment, the control unit may not apply the reverse brake when the number of edges of the rectangular signal measured up to this point is smaller than a predetermined threshold value upon receiving a stop instruction of the motor.
In one embodiment, the control unit may 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 rotation direction of the rotor is small, and the output of the reverse braking can be reduced.
In one embodiment, the control unit may include a timer circuit for measuring a length of the normal driving state, and may change an output of the reverse brake according to a measurement time of the timer circuit.
In one embodiment, the control unit may reduce the output of the reverse brake when the measurement time is shorter than a predetermined threshold value upon receiving a stop instruction of the motor, as compared with the case where the measurement time is longer than the predetermined threshold value.
In one embodiment, the control unit may not apply the reverse brake when the measurement time is shorter than a predetermined threshold value upon receiving a stop instruction of the motor.
The control unit may end the reverse brake when the period of the rectangular signal becomes longer than a predetermined threshold value during the reverse brake period. The control unit may include an edge counter that counts the number of edges of the rectangular signal during the reverse braking period, and may terminate the reverse braking when the count value of the edge counter exceeds a predetermined threshold value. The control unit may include a timer circuit for measuring a period length of the reverse brake, and may end the reverse brake when the period of the reverse brake reaches a predetermined time. The end condition of the reverse brake may be plural in combination.
In one embodiment, the motor driving circuit may be integrally formed on one semiconductor substrate.
The term "integrated" includes a case where all components of the circuit are formed on the semiconductor substrate and a case where main components of the circuit are integrated integrally, and a part of resistors, capacitors, and the like may be provided outside the semiconductor substrate for adjusting the circuit constant.
By integrating the circuit on one chip, the circuit area can be reduced, and the characteristics of the circuit element can be kept uniform.
Other aspects of the application relate to vibration devices. The vibration device may include a vibration motor having an eccentric weight attached to a rotor, and a motor drive circuit for rotating the vibration motor.
Other aspects of the application relate to electronic devices. The electronic device may also comprise the vibration means described above.
Further, any combination of the above components and the components or expressions of the present application are replaced with each other by a method, an apparatus, a system, or the like, and are also effective as modes of the present application.
[ Effect of the application ]
According to one aspect of the present application, reverse rotation of the rotor associated with reverse braking can be suppressed or prevented.
Drawings
Fig. 1 is a block diagram of a motor drive circuit according to embodiment 1.
Fig. 2 is a block diagram showing a specific configuration example of the motor drive circuit.
Fig. 3 (a) and 3 (b) are operation waveform diagrams of the motor driving circuit of fig. 1.
Fig. 4 is a block diagram showing a configuration example of the reverse brake control unit.
Fig. 5 is a block diagram of a reverse brake control unit according to modification 2.
Fig. 6 is a block diagram of a motor drive circuit according to embodiment 1 of embodiment 2.
Fig. 7 (a) and 7 (b) are operation waveform diagrams of the motor driving circuit of fig. 6.
Fig. 8 is a block diagram of a motor drive circuit of embodiment 2.
Fig. 9 (a) and 9 (b) are operation waveform diagrams of the motor driving circuit of fig. 8.
Fig. 10 (a) is a perspective view of an electronic apparatus including a motor driving circuit, and fig. 10 (b) is a cross-sectional view of a vibration motor unit.
Fig. 11 is a perspective view of an electronic device including a motor drive circuit.
Detailed Description
The present application will be described below with reference to the drawings based on the embodiments. The same reference numerals are given to the same or equivalent components, members, and processes shown in the drawings, and overlapping descriptions are omitted as appropriate. The embodiments are not limited to the application, but are merely examples, and all the features or combinations thereof described in the embodiments are not necessarily essential features of the application.
In the present specification, the term "state in which the member a is connected to the member B" includes, in addition to the case in which the member a and the member B are physically and directly connected, the case in which the member a and the member B are indirectly connected via another member that does not substantially affect the electrical connection state of the members or impair the functions and effects of the coupling of the members.
Similarly, the term "state in which the member C is disposed between the member a and the member B" includes, in addition to the case where the member a and the member C or the member B and the member C are directly connected, the case where they are indirectly connected through other members that do not substantially affect the electrical connection state of them or do not impair the functions and effects of their coupling.
(embodiment 1)
Fig. 1 is a block diagram of a motor drive circuit 100 according to embodiment 1. The motor drive circuit 100 drives a single-phase brushless motor (hereinafter, simply referred to as a motor) 2. The hall element 4 generates 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 phases to each other.
A control command S1 for instructing the rotation/stop of the motor 2 is input to the motor drive circuit 100 from a main processor not shown. When hall signals h+, H-are input to the motor drive circuit 100 and the control command S1 instructs rotation, the coil of the motor 2 is energized in synchronization with the hall signals h+, H-.
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) integrally integrated on one semiconductor substrate. The hall comparator 102 compares the hall signals h+, H-from the hall element 4 to generate a rectangular signal (also referred to as FG signal) S2. The control unit 110 generates a drive signal S3 for controlling energization to the coil of the motor 2 based on the rectangular signal S2. The driving unit 130 drives the coil based on the driving signal S3 from the control unit 110. The configuration of the driving unit 130 is not particularly limited, and a known circuit may be used.
The control unit 110 receives a control command S1 for instructing the rotation/stop of the motor 2. In a normal driving state in which the motor 2 is rotated in a certain direction (assuming a forward rotation direction), the control unit 110 applies a reverse rotation brake when receiving a stop instruction of the motor 2. During the reverse braking period, the control unit 110 monitors the period of the hall signal h+, H-, i.e., the period T of the rectangular signal S2 P (half period in this embodiment), if period T P Shortening, the reverse braking is ended.
The control unit 110 includes an energization control unit 112 and a reverse brake control unit 114. The energization control unit 112 performs a commutation control in synchronization 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 of the rectangular signal S2 during the period of reverse braking P For the current period T CUR And a past period T PRE Comparing, if the current period T CUR Than the past period T PRE Shortening, the reverse braking is ended. This is condition 1. Period T in the past PRE Or may be an immediately preceding period T P . Alternatively, the past period T PRE Or may be based on a plurality of periods T measured in a plurality of past cycles P The calculated value. For example, the past period T PRE May be a plurality of periods T in the past P Is a moving average or an arithmetic average of (a) of (b).
After the start of the reverse braking, the reverse braking control unit 114 starts the reverse braking, and if a predetermined time T elapses END The reverse braking is ended. This is condition 2. When either condition 1 or condition 2 is satisfied, the reverse brake control unit 114 ends the reverse brake.
The application according to embodiment 1 is understood as a block diagram and a circuit diagram of fig. 1, or various devices and circuits derived from the above description, and is not limited to a specific configuration. In the following, more specific configuration examples will be described in order not to narrow the scope of the present application but to assist understanding of the essence of the present application and the operation of the circuit and clarify them.
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 (i.e., the length of each of the high-level section and the low-level section, i.e., the half period) of the rectangular signal S2, and outputs data (period data) S5 indicating the measured period to the determining unit 120.
The determination unit 120 determines the current period T indicated by the period data S5 CUR With a past period T maintained in memory PRE When the magnitude relation of the end signal S7 is set to be active (e.g., high level) if the predetermined condition (condition 1) is satisfied. After the start of the reverse braking, the determination unit 120 determines that the predetermined time T has elapsed END The end signal S7 is asserted. If the end signal S7 is asserted, the energization control unit 112 ends the reverse brake.
Next, the operation of the motor drive circuit 100 will be described. Fig. 3 (a) and (b) are operation waveform diagrams of the motor drive circuit 100 of fig. 1. First, a case where the reverse brake is ended according to condition 2 will be described with reference to fig. 3 (a). At time t0, control command S1 goes high to indicate rotation. Thereby, the control unit 110 starts energization of the motor 2. As the rotation speed of the motor 2 increases, the period of the rectangular signal S2 gradually shortens.
At time t1, when the control command S1 becomes a low level indicating stop, the energization control unit 112 starts reverse braking. The rotor is decelerated by the reverse braking, and the period of the rectangular signal S2 is gradually lengthened. Then, when a predetermined time T elapses from time T1 END At time t2, the end signal S7 is asserted, and the reverse brake is ended.
Next, a case where the reverse braking is ended according to condition 1 will be described with reference to fig. 3 (b). At time t0, control command S1 goes high to indicate rotation. Thereby, the control unit 110 starts energization to the motor 2. Immediately after time t3, before the rotation speed of motor 2 increases, control command S1 goes low, instructing motor 2 to stop, and energizing control unit 112 starts reverse braking.
The period measuring unit 118 measures the period T of the rectangular signal S2 for each cycle P0 、T P1 、T P2 、T P3 …. In the ith cycle, for the current period T CUR (＝T Pi ) And a past period T PRE (＝T Pi-1 ) A comparison is made. Here, assume that the period T in the past PRE Is the period T of the immediately preceding cycle P 。
In a period Ta immediately after the start of reverse braking, T Pi ＞T Pi-1 This is true. That is, the period of the rectangular signal S2 is gradually lengthened, and the rotor is decelerated. If T is detected at time T4 P3 ＞T P2 If condition 1 is satisfied, the end signal S7 is asserted, and the reverse brake is ended.
The above is the operation of the motor drive circuit 100. After the short normal drive, if the reverse brake is continuously applied, the rotor is accelerated in the reverse direction. In contrast, according to the motor drive circuit 100 of embodiment 1, the period T of the rectangular signal S2 is measured P If T is detected CUR ＜T PRE The rotor is regarded as reversing in the reverse direction, and the reverse braking can be stopped immediately.
Fig. 4 is a block diagram showing an exemplary configuration of the reverse brake control unit 114. The determination unit 120 includes a 1 st determination unit 120a and a 2 nd determination unit 120b for determining the 1 st condition and the 2 nd condition, respectively. The 2 nd determination unit 120b includes a timer circuit 160 for measuring an elapsed time immediately after the start of the reverse braking, and for determining that a predetermined time T has elapsed END After that, the end signal S7b is asserted. The predetermined time TEND is set according to the value of the register 162 of the predetermined address. Set time T END It is preferable that the setting can be performed from an external host processor via an interface such as an I2C (Inter IC) bus.
The 1 st determination unit 120a includes a memory 150, a comparator 152, an adder 154, and a register 156. The memory 150 holds a past period T PRE . As described above, the past period T PRE May be an immediately preceding period T P May be a plurality of past periods T P Average value of (2).
Depending on the mounting position of the hall element and the variation of the magnetic field, the period T of the rectangular signal S2 may be the same even when the rotor rotates at a constant speed P Nor is it necessarily variable. This means that the current period T will be Pi And the previous period T Pi-1 If a simple comparison is made, the reverse rotation of the rotor may be erroneously detected. In order to prevent this false detection, the 1 st determination unit 120a corrects the period TCUR.
Adder 154 adds up the current period T CUR Adding correction value T CORR Generating a corrected period T CUR '. Correction value T CORR 0 or more (+.0), is set according to the value of the register 156 of the predetermined address. Specified value T CORR It is preferable that the configuration be possible from an external host processor via an interface such as an I2C (Inter IC) bus. Correction value T CORR The optimum value of (a) may be determined according to the type and the number of poles of the motor 2, the load connected to the rotor, the moment of inertia, and the like.
The comparator 152 corrects the current period T CUR ' and past period T PRE Comparing, when meeting
T CUR ’≦T PRE
When, in other words, satisfying
T CUR +T CORR ≦T PRE
When this is the case, the end signal S7a is asserted.
If at least one of the end signals S7a and S7b is asserted, the end signal S7 is asserted. For example, the logic gate 164 may be constituted by an or gate.
According to the reverse brake control section 114, it can correspond to the correction value T CORR To adjust the sensitivity of the reversal detection of the rotor. By enabling the correction value T to be set from the outside by the register 156 CORR The motor drive circuit 10 can be used0 on the platform.
In the above, a certain aspect of the present application is described according to embodiment 1. Embodiment 1 is an example, and those skilled in the art will understand that various modifications are possible for each component and each process combination, and that these modifications are also within the scope of the present application. Such a modification will be described below.
(modification 1)
In FIG. 4, the current period T is corrected CUR But can also correct the past period T in reverse PRE . In this case, the correction value T may also be subtracted from the value read out by the memory 150 CORR Generating a corrected period T PRE ' and to T PRE And T CUR A comparison is made.
(modification 2)
In embodiment 1, after the start of the reverse braking, if a predetermined time T elapses END The reverse braking is ended, but the present application is not limited thereto. Fig. 5 is a block diagram of an inversion brake control unit 114a according to modification 2. In modification 2, the condition 2 may be that the number of times (the number of edges) of switching of the rectangular signal S2 occurring during the reverse braking exceeds a threshold value.
The 2 nd 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 a predetermined threshold D, and sets the end signal S7b to be active if S4 > D. The threshold D is set based on the value of the register 174 at a predetermined address. The threshold D is preferably set from an external host processor via an interface such as an I2C (Inter IC) bus.
(modification 3)
In embodiment 1, the reverse braking is terminated when either condition 1 or condition 2 is satisfied, but condition 2 may be omitted. In this case, the timer circuit 160 and the logic gate 164 of fig. 4 may be omitted.
(modification 4)
In embodiment 1, the present period T is based on CUR And a past period T PRE The magnitude relation of (a) ends the reverse braking, but the present application is not limited thereto. For example, a plurality of consecutive cycles (for example, 3 or more cycles) may be focused, and when the cycle is found to be prone to be shortened, the reverse brake may be terminated.
(modification 5)
The hall comparator 102 may be built in a hall IC including the hall element 4. Alternatively, the hall element 4 may be incorporated in the motor drive circuit 100.
(modification 6)
In embodiment 1, the motor drive circuit 100 that performs the commutation control using the hall signal from the hall element and performs the control of preventing the reverse rotation has been described, but a signal including rotation speed information other than the hall signal from the hall element may be used instead.
(embodiment 2)
Embodiment 2 will be described with reference to fig. 1. Since the basic configuration is the same as that of embodiment 1, the description of the same points will be omitted and the differences will be described.
A control command S1 for instructing the rotation and stop of the motor 2 is input to the control unit 110. In a normal driving state in which the motor 2 is rotated in a certain direction (assuming a normal rotation direction), the control unit 110 applies a reverse brake at an output corresponding to the normal driving state when receiving a stop instruction of the motor 2.
The control unit 110 includes an energization control unit 112 and a reverse brake control unit 114. The energization control unit 112 performs a commutation control in synchronization 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 driving state before the reverse brake is applied. When the motor drive circuit 100 performs PWM control, the reverse brake control unit 114 can change the output of the reverse brake by changing the duty ratio of the drive voltage vo+/Vo-applied to the motor 2.
The above is the configuration of the motor drive circuit 100 in embodiment 2. The operation will be described next.
During the period in which the control command S1 instructs the rotation of the rotor, the energization control unit 112 performs commutation control based on the rectangular signal S2, and supplies a drive voltage vo+/Vo-having a duty ratio corresponding to the target rotation speed to the motor 2. The duty ratio in the normal driving state may be a fixed value or may be 100%.
The reverse brake control section 114 monitors the normal driving state. The reverse brake control unit 114 can estimate, based on the monitoring result, how much torque the rotor of the motor 2 has in the forward rotation direction. Therefore, when the estimated rotor has a sufficiently large torque in the forward rotation direction, the reverse brake is applied at a large output (rated output), and when the estimated torque in the forward rotation direction is small, the reverse brake is lowered from the rated output, or the output is zero, that is, the reverse brake is not applied.
Thus, the reverse torque applied to the rotor by the reverse brake can be prevented from exceeding the forward torque applied in the normal driving state, and the rotor can be prevented from rotating reversely.
The application according to embodiment 2 is not limited to the specific configuration, but can be grasped as a block diagram and a circuit diagram of fig. 1, or various devices and circuits derived from the above description. In the following, more specific configuration examples will be described in order to clarify the essence of the application and the circuit operation, not to narrow the scope of the application.
Fig. 6 is a block diagram of a motor drive circuit 100a according to embodiment 1 of embodiment 2.
The reverse brake control unit 114a of the motor drive circuit 100a changes the output of the reverse brake according to 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 driving unit 130. The edge counter 116 counts 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 according to the count value S4 of the edge counter 116.
For example, when (i) the control command S1 instructs the motor to stop, the control unit 110 (determination unit 120) applies the reverse brake at the rated output if the count value S4 indicating the number of edges of the rectangular signal S2 counted up to this point is greater than the predetermined threshold value a. For example, the rated output may be a duty ratio in the range of 70 to 100%.
For example, the threshold a may be determined such that the rotor is 1 rotation (mechanical angle 360 °) or less. For example, in a 3-pole brushless motor, 6 edges of the rectangular signal S2 occur in 1 rotation of the rotor, and 3 times occur in half rotation. Therefore, a=3 to 6 may be set. In the 2-pole brushless motor, the edge of the rectangular signal S2 occurs 2 times during 1 rotation of the rotor and occurs 1 time during half rotation, and thus a=1 to 2 may be set.
The threshold a may be determined according to the type and number of poles of the motor 2, the load and moment of inertia connected to the rotor, and the like, and may be set to about 1 to 20.
In contrast, when (ii) the number of edges of the rectangular signal S2 counted up to this point is smaller than the predetermined threshold value a, the control unit 110 (determination unit 120) decreases the output of the reverse brake from the rated output. In the present embodiment, the control unit 110 does not apply the reverse brake when the number of edges of the rectangular signal to be measured is smaller than the predetermined threshold a. That is, the output of the reverse brake is set to the duty=0%.
The period measuring unit 118 measures the period (i.e., the length of each of the high-level section and the low-level section, i.e., the half period) of the rectangular signal S2 while the reverse brake is applied, and outputs data (period data) S5 indicating the measured period to the determining unit 120. When the period indicated by the period data S5 is longer than the predetermined threshold B, the determination unit 120 ends the reverse brake.
The threshold a is preferably set based on setting data stored in a register at a certain address. Similarly, the threshold B is preferably set based on setting data stored in a register at a certain address. Since these thresholds A, B are different in optimum value depending on the type, specification, and use of the motor 2, a designer of the apparatus mounting the motor drive circuit 100 can select the threshold A, B, thereby realizing optimum control for various platforms.
The above is a configuration of the motor drive circuit 100 a. The operation will be described next.
Fig. 7 (a) and (b) are operation waveform diagrams of the motor drive circuit 100a of fig. 6. The vertical and horizontal axes of the waveform diagrams and the timing charts in the present specification are appropriately enlarged and reduced for easy understanding, and the waveforms shown are simplified, exaggerated or emphasized for easy understanding.
Refer to fig. 7 (a). At time t0, control command S1 goes high to indicate rotation. Thereby, the control unit 110 starts energizing the motor 2. As the rotation speed of the motor 2 increases, the period of the rectangular signal S2 gradually shortens. The count value S4 increases with the rotation of the motor 2, and reaches the upper limit value N of the edge counter 116 at time t 1.
At time t2, control command S1 goes to a low level indicating stop. At time t2, since N > a, the reverse brake is applied at the rated output. By the reverse braking, the rotor is decelerated, and the period of the rectangular signal S2 is gradually lengthened. At time T3, the period T of the rectangular signal S2 P When the threshold value B is exceeded, the reverse braking period ends.
Refer to fig. 7 (b). At time t0, control command S1 goes high to indicate rotation. Thereby, the control unit 110 starts energizing the motor 2. Immediately after time t1, control command S1 goes low before the rotation speed of motor 2 increases, and instructs motor 2 to stop.
At time t1, the edge count value S4 is 2 and is smaller than the threshold a (for example, 3). Therefore, the rotor is stopped by regenerative braking without applying reverse braking, or naturally stopped.
The above is the operation of the motor drive circuit 100 a. In fig. 7 (b), the torque in the forward direction of the motor at time t1 is very small. Therefore, when the control command S1 is at the low level, the rotor starts to rotate in the reverse direction when the reverse brake is applied. Further, immediately after the start of the rotation in the opposite direction, the period T of the rectangular signal S2 P If the threshold value B is shorter than the threshold value B, the rotor may not be disengaged from the reverse brake, and the rotor may be accelerated further in the reverse direction.
In contrast, according to the motor drive circuit 100a of fig. 6, when the number of edges of the rectangular signal S2 measured in the normal drive state is smaller than the threshold value a, the torque in the forward rotation direction is pushed sufficiently small, and the reverse rotation of the rotor can be prevented without applying the reverse rotation brake.
In addition, embodiment 1 has the following advantages as compared with embodiment 2 described below. In embodiment 2, the rotation state of the motor in the forward rotation direction is estimated based on the length of the normal driving state, and whether or not the reverse rotation brake should be applied is switched, but when an abnormality such as foreign matter being interposed in the rotor occurs, even if the length of the normal driving state is sufficiently long, the torque in the forward rotation direction is small, and the rotor may be reversed by the reverse rotation brake. In contrast, since the number of edges of the rectangular signal S2 greater than the threshold a is a basis for the motor to reliably rotate in the forward direction, the rotor can be prevented from rotating reversely even in an abnormal state.
Fig. 8 is a block diagram of a motor drive circuit 100b of embodiment 2.
The reverse brake control unit 114b of the motor drive circuit 100b changes the output of the reverse brake according to the length of the normal drive state. The reverse brake control section 114b includes a timer circuit 122 in place of the edge counter 116 of fig. 6. The timer circuit 122 measures the length of the normal driving state, and generates section length data S6 indicating the measured length. The timer circuit 122 may be a digital timer that counts up (or counts down) a clock signal in a normal driving state. In other embodiments, the timer circuit 122 may also be an analog timer. The determination unit 120 changes the output of the reverse brake according to the measurement time of the timer circuit 122.
For example, when the measurement time of the timer circuit 122 exceeds a predetermined threshold value C, the determination unit 120 applies the reverse brake at the rated output, and when the measurement time is shorter than the threshold value C, the reverse brake is not applied or the output of the reverse brake is reduced when the stop is instructed.
The above is the configuration of the motor drive circuit 100b of fig. 8. The operation will be described next.
Fig. 9 (a) and (b) are operation waveform diagrams of the motor drive circuit 100b of fig. 8. Referring to fig. 9 (a). At time t0, control command S1 goes high to indicate rotation. Thereby, the control unit 110 starts energization to the motor 2. As the rotation speed of the motor 2 increases, the period of the rectangular signal S2 gradually shortens. The section length data S6 indicating the length of the normal driving state increases with time. Since the bit width of the timer circuit 122 is limited, when the section length data S6 reaches a certain upper limit value, the count up stops.
At time t2, control command S1 goes to a low level indicating stop. At time t2, since S6 > C, the reverse brake is applied at the rated output. By the reverse braking, the rotor is decelerated, and the period of the rectangular signal S2 is gradually lengthened. At time t3, when period TP of rectangular signal S2 exceeds threshold B, the reverse braking period ends.
Refer to fig. 9 (b). At time t0, control command S1 goes high to indicate rotation. Thereby, the control unit 110 starts energizing the motor 2. Immediately after time t1, control command S1 goes low before the rotation speed of motor 2 increases, and instructs motor 2 to stop.
At time t1, the section length data S6 is smaller than the threshold C. Therefore, the rotor is stopped by regenerative braking without applying reverse braking, or naturally stopped.
The above is the operation of the motor drive circuit 100 b. The motor drive circuit 100b also achieves the same effects as the motor drive circuit 100a of fig. 6.
In the above, a certain aspect of the present application is described based on embodiment 2. Embodiment 2 is an example, and those skilled in the art will understand that various modifications are possible for each component and each process combination, and that these modifications are also within the scope of the present application. Such a modification will be described below.
(modification 7)
In embodiment 2, when there is a fear of reverse rotation, the output of the reverse rotation brake is set to zero, but the present application is not limited to this. For example, in the case where there is a concern about reverse rotation, the output of the reverse rotation brake may be set to a value larger than zero and smaller than the rated output, for example, about 5 to 30%.
(modification 8)
Alternatively, there is a concern that the output of the reverse brake in the case of reverse may be adaptively changed in the normal driving state before. For example, the output of the reverse brake may be reduced as the number of edges of the rectangular signal S2 measured in the normal driving state is smaller, or the output of the reverse brake may be reduced as the length of the normal driving state is shorter.
(modification 9)
In embodiment 2, the period T of the rectangular signal S2 P When the threshold value B is exceeded, the reverse braking period is ended, but the present application is not limited to this. In modification 9, the reverse brake is terminated when the number of times (the number of edges) of switching of the rectangular signal S2 occurring during the reverse brake exceeds the threshold value. When the 9 th modification is applied to embodiment 1 of fig. 6, the number of edges of the rectangular signal S2 during the period of reverse braking may be counted using the edge counter 116. When the number S4 of edges occurring during the reverse braking exceeds the threshold D, the determination unit 120 ends the reverse braking.
In the case of applying the 9 th modification to embodiment 2 of fig. 8, an edge counter 116 may be added to the reverse brake control unit 114 b.
(modification 10)
In modification 10, if the length of the reverse braking period reaches a predetermined time T END The reverse braking is ended. In the case of applying the 10 th modification to the 2 nd embodiment of fig. 8, the length of the period of reverse braking may be measured using the timer circuit 122. The determination unit 120 compares the period of reverse braking measured by the timer circuit 122 with a predetermined time T END A comparison is made.
When the 10 th modification is applied to embodiment 1 of fig. 6, a timer circuit 122 may be added to the reverse brake control unit 114 a.
(modification 11)
The hall comparator 102 may be built in a hall IC including the hall element 4. Alternatively, the hall element 4 may be incorporated in the motor drive circuit 100.
(modification 12)
In embodiment 2, the motor drive circuit 100 that performs the control of performing the commutation control by using the hall signal from the hall element and performing the control of preventing the reverse rotation has been described, but a signal including rotation speed information other than the hall signal from the hall element may be used instead.
Any of the features of embodiment 1 and any of the features of embodiment 2 may be combined, and these combinations are also effective as one embodiment of the present application.
(use)
Next, the use of the motor drive circuit 100 described in embodiment 1 or 2 will be described. Fig. 10 (a) is a perspective view of an electronic apparatus 300a including the 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 device, a controller of a game console, and the like, for example. Fig. 10 (a) shows a typical smart phone.
The electronic device 300 comprises a vibration means 302 and a main processor 304. The vibration device 302 is a vibration motor unit in which the motor 2 and the motor drive circuit 100 are integrally formed and covered with a casing. As shown in fig. 10 (b), the motor driving circuit 100 and the coil 312 are mounted on the substrate 310. Further, a washer 314 is mounted on the spindle 316, and is rotatably supported. An eccentric weight 318a and a rotor 318 having a permanent magnet 318b embedded in an inner peripheral portion thereof are attached to a front end of the main shaft 316. The vibration device 302 is entirely covered by a housing 320.
The motor drive circuit 100 rotates the motor 2 in response to a control instruction S1 from the main processor 304. The host processor 304 may be a baseband processor or an application processor.
Fig. 11 is a perspective view of an electronic device 300b of another configuration. An eccentric weight 306 is mounted on the rotor of the motor 2. The motor 2 is configured so as not to require a hall element.
The above is a configuration of the electronic devices 300a and 300 b. By employing the motor drive circuit 100 according to the embodiment for the vibration device 302, the rotor can be prevented from rotating reversely by the reverse brake, and the vibration can be prevented from being sustained immediately.
The present application has been described with reference to specific users according to embodiments, which are merely illustrative of the principles and applications of the present application, and various modifications and arrangements of the embodiments are possible without departing from the scope of the inventive concept defined in the claims.
[ description of the reference numerals ]
A motor of 2 …, a hall element of 4 …, a motor driving circuit of 100 …, a hall comparator of 102 …, a control unit of 110 …, a driving unit of 130 …, a control command of S1 …, a rectangular signal of S2 …, a driving signal of S3 …, a count value of S4 …, a period data of S5 …, a period length data of S6 …, an end signal of S7 …, a power-on control unit of 112 …, a reverse brake control unit of 114 …, a counter of 116 …, a period measuring unit of 118 …, a decision unit of 120 …, a decision unit of 120a …, a decision unit of 120b …, a decision unit of 122 …, a memory of 150 …, a comparator of 152 …, a adder of 154 …, a register of 156 …, a timer circuit of 160 …, a register of 162 …, a logic gate of 164 …, a counter of 170 …, a comparator of 172 …, a register of 174 …, a 300 … electronic device, a vibration device of 302 …, and a main processor of 304.
Claims (14)
1. A motor drive circuit, characterized by comprising:
a control unit that generates a drive signal for controlling energization to a coil of a motor to be driven based on a rectangular signal indicating a position of a rotor of the motor, and
a driving unit that drives the coil based on the driving signal;
the control unit measures the cumulative switching times of the rectangular signal from the start of the normal driving state, and when a stop instruction of the motor is received in the normal driving state of the motor, the control unit changes the output of the reverse brake based on the measured switching times of the rectangular signal,
the control unit includes an edge counter for counting the number of edges of the rectangular signal in the normal driving state, and changes the output of the reverse brake according to the count value of the edge counter.
2. The motor drive circuit according to claim 1, wherein the control unit, upon receiving a stop instruction of the motor, decreases the output of the reverse brake when the number of edges of the rectangular signal measured up to this point is smaller than a predetermined threshold value.
3. The motor drive circuit according to claim 1, wherein the control unit does not apply the reverse brake when the number of edges of the rectangular signal measured so far is smaller than a predetermined threshold value upon receiving the stop instruction of the motor.
4. A motor drive circuit, characterized by comprising:
a control unit that generates a drive signal for controlling energization to a coil of a motor to be driven based on a rectangular signal indicating a position of a rotor of the motor, and
a driving unit that drives the coil based on the driving signal;
the control unit measures an elapsed time from the start of a normal driving state, and changes an output of reverse braking based on the measured elapsed time when a stop instruction of the motor is received,
the control unit includes a timer circuit for measuring an elapsed time from the start of the normal driving state, and changes the output of the reverse brake according to the measured time of the timer circuit.
5. The motor drive circuit according to claim 4, wherein the control unit, upon receiving the instruction to stop the motor, reduces the output of the reverse brake compared with the case where the measurement time is shorter than a predetermined threshold value.
6. The motor drive circuit according to claim 4, wherein the control unit does not apply the reverse brake when the measurement time is shorter than a predetermined threshold value upon receiving a stop instruction of the motor.
7. The motor drive circuit according to any one of claims 1 to 6, further comprising a hall comparator for comparing a pair of hall signals from the hall elements in mutually opposite phases and generating the rectangular signal.
8. The motor drive circuit according to any one of claims 1 to 6, wherein the period of the rectangular signal is monitored during the period of the reverse braking, and the control unit ends the reverse braking if the measured period becomes longer than a predetermined 1 st threshold value.
9. The motor drive circuit according to any one of claims 1 to 6, wherein the control unit measures the number of edges of the rectangular signal during the reverse braking, and ends the reverse braking if the measured number of edges exceeds a predetermined 2 nd threshold value.
10. The motor drive circuit according to any one of claims 1 to 6, wherein the control section includes an edge counter for counting the number of edges of the rectangular signal in each of the periods of the normal drive state and the reverse brake,
when a stop instruction of the motor is received, the output of the reverse brake is changed according to the count value of the edge counter obtained in the normal driving state,
during the reverse braking period, if the count value of the edge counter exceeds a predetermined 2 nd threshold value, the reverse braking is terminated.
11. The motor drive circuit according to any one of claims 1 to 6, wherein the control unit measures a length of the period of the reverse braking, and ends the reverse braking if the length of the period of the reverse braking exceeds a predetermined 3 rd threshold value.
12. A motor drive circuit according to any one of claims 1 to 6, wherein the motor drive circuit is integrally formed on a semiconductor substrate.
13. A vibration device, comprising:
a vibration motor having an eccentric weight mounted on a rotor;
the motor drive circuit according to any one of claims 1 to 6, for rotating the vibration motor.
14. An electronic device comprising the vibration apparatus according to claim 13.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110509253.1A CN113193799B (en) | 2015-05-25 | 2016-05-18 | Motor drive circuit, vibration device, and electronic apparatus |
Applications Claiming Priority (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2015105729 | 2015-05-25 | ||
| JP2015-105728 | 2015-05-25 | ||
| JP2015105728 | 2015-05-25 | ||
| JP2015-105729 | 2015-05-25 | ||
| JP2016079515A JP6739215B2 (en) | 2015-05-25 | 2016-04-12 | Motor drive circuit, vibration device, and electronic device |
| JP2016-079515 | 2016-04-12 | ||
| CN201610329921.1A CN106208843B (en) | 2015-05-25 | 2016-05-18 | Motor drive circuit, vibration device, and electronic apparatus |
| CN202110509253.1A CN113193799B (en) | 2015-05-25 | 2016-05-18 | Motor drive circuit, vibration device, and electronic apparatus |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
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| CN201610329921.1A Division CN106208843B (en) | 2015-05-25 | 2016-05-18 | Motor drive circuit, vibration device, and electronic apparatus |
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| CN113193799A CN113193799A (en) | 2021-07-30 |
| CN113193799B true CN113193799B (en) | 2023-08-29 |
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| CN202110509253.1A Active CN113193799B (en) | 2015-05-25 | 2016-05-18 | Motor drive circuit, vibration device, and electronic apparatus |
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| JPH0759389A (en) * | 1993-08-13 | 1995-03-03 | Toshiba Corp | Method and equipment for intermittent driving and controlling of motor |
| JP2005057993A (en) * | 2003-07-23 | 2005-03-03 | Matsushita Electric Ind Co Ltd | Motor driving device and disk device using same |
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| JP2012165520A (en) * | 2011-02-04 | 2012-08-30 | New Japan Radio Co Ltd | Motor start-up circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113193799A (en) | 2021-07-30 |
| CN106208843A (en) | 2016-12-07 |
| CN106208843B (en) | 2021-05-18 |
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