JP2010213541A - Brushless motor drive circuit, motor unit, and electronic equipment using them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor drive technology that can brake a brushless motor. <P>SOLUTION: A decision part 30 receives a pulse-modulated control signal CTL that instructs torque of a vibration motor 1 to decide whether the duty ratio DR of the control signal CTL is in either one of the first status H higher than a predetermined upper threshold value DH, the second status L lower than a predetermined lower threshold value DL, or the third status between the upper threshold value DH and the lower threshold value DL. A control logic part 20 controls an H bridge circuit 10 from the decision result of the decision part 30. The control logic part 20 instructs the H bridge circuit 10 to rotate the vibration motor 1 under the condition of the first status H, to brake backward the vibration motor 1 under the condition of the second status L, or to brake idle the vibration motor 1 under the condition of the third status M. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for driving a brushless motor.

  An electronic device such as a mobile phone terminal or a pager (pager) is equipped with a vibration motor in order to notify the user of an incoming call. In this vibration motor, an eccentric weight is connected to a rotation shaft, and the electronic device is vibrated by rotating the rotor. In such a vibration motor, since a weight connected as a load is eccentric, a drive circuit dedicated to the vibration motor is used. Patent Document 1 describes related technology.

International Publication No. 08/026319 Pamphlet

  The vibration motor includes a brush motor and a brushless motor. When the brushless motor is driven, the rotor position of the motor is detected by a Hall element, and the energization state of the motor coil is controlled by an H bridge circuit. A brushless motor has the advantage of being smaller and having a longer life than a motor with a brush.

  However, a motor unit in which a brushless motor and its drive circuit are integrated is often a two-wire drive system that is driven by being connected to two lines of a power supply line and a ground line. In this two-wire drive system, supply of power from the power supply line is started to start the brushless motor, and supply of power from the power supply line is stopped to stop. Here, after the supply of power is stopped, the number of revolutions naturally decreases due to internal friction in the motor, etc., but the inertia is high because the rotor is heavy due to the eccentric weight, and it takes time to stop. There was a problem that it took. Such a problem can occur not only in a brushless vibration motor but also in other types of brushless motors.

  The present invention has been made in view of such circumstances, and an exemplary object of an aspect thereof is to provide a motor driving technique capable of braking a brushless motor.

  One embodiment of the present invention relates to a brushless motor drive circuit. The brushless motor drive circuit receives a bridge output circuit connected to the coil of the brushless motor to be driven and a pulse-modulated control signal that indicates the torque of the brushless motor, and the duty ratio of the control signal is increased by a predetermined value. A determination unit that determines whether the first state is higher than the threshold value, the second state is lower than a predetermined lower threshold value, or the third state is between the upper threshold value and the lower threshold value; A control unit that controls the bridge output circuit based on the determination result of the unit. The control unit instructs the bridge output circuit to rotate the brushless motor in the first state, instructs the reverse rotation brake of the brushless motor in the second state, and instructs the idling brake of the brushless motor in the third state. .

  According to this aspect, since the motor can be stopped using the reverse brake or the idling brake by appropriately controlling the modulation of the control signal, the rotation state of the vibration motor can be flexibly controlled.

  The control signal input to the control terminal is a control signal used for driving the brushed motor, and is pulse width modulated. The first period and the second period are based on the pulse width modulation period of the control signal. May be longer. In this case, a brushless motor can be driven even on a platform that assumes a motor with a brush.

  Another embodiment of the present invention is also a brushless motor driving circuit. This brushless motor drive circuit includes a bridge output circuit connected to a coil of a brushless motor to be driven, a filter for filtering a control signal indicating the torque of the brushless motor, and output voltages of the filters from the first to the third A determination unit that determines which of the three voltage ranges belongs, and a control unit that controls the bridge output circuit based on the determination result of the determination unit. The control unit instructs the bridge output circuit to rotate the brushless motor in the first state where the output voltage of the filter belongs to the first voltage range, and the second state where the output voltage of the filter belongs to the second voltage range. , The reverse brake of the brushless motor is instructed, and the idle brake of the brushless motor is instructed in the third state where the output voltage of the filter belongs to the third voltage range.

  According to this aspect, when the control signal is pulse width modulated, the rotation state of the motor can be controlled according to the duty ratio, and when the control signal is an analog DC voltage, the motor rotation according to the voltage level. Can be controlled.

  Yet another embodiment of the present invention is a motor unit. This motor unit includes a brushless vibration motor, a Hall element that outputs a Hall signal indicating positional information of the rotor of the vibration motor, and the brushless motor drive circuit according to any one of the above aspects that drives the vibration motor based on the Hall signal. A control signal is inputted from the outside, a control terminal connected to the brushless motor driving circuit, a power supply voltage is applied from the outside, a power supply terminal connected to the brushless motor driving circuit, a ground voltage is applied from the outside, and a brushless A ground terminal connected to the motor drive circuit.

  Yet another embodiment of the present invention is an electronic device. This electronic device includes a communication unit that communicates with a base station and generates a control signal, and the motor unit described above.

  Another aspect of the present invention is a motor unit. This motor unit includes a brushless vibration motor, a Hall element that outputs a Hall signal indicating position information of the rotor of the vibration motor, the brushless motor drive circuit that drives the vibration motor based on the Hall signal, and an external control signal. Is connected to the brushless motor drive circuit, the power supply voltage is applied from outside, the power supply terminal is connected to the brushless motor drive circuit, and the ground voltage is applied from outside to connect to the brushless motor drive circuit. A ground terminal.

  It should be noted that any combination of the above-described constituent elements, and those in which constituent elements and expressions of the present invention are mutually replaced between methods, apparatuses, systems, and the like are also effective as an aspect of the present invention.

  According to an aspect of the present invention, the brushless motor can be braked.

It is a circuit diagram which shows the structure of an electronic device provided with the motor unit which concerns on embodiment. FIG. 2 is a state transition diagram of the motor unit in FIG. 1. It is a time chart which shows the operation example of the motor unit of FIG.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components and members shown in the drawings are denoted by the same reference numerals, and repeated descriptions are appropriately omitted. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. In the drawings, some of the members that are not important for describing the embodiment of the present invention are omitted.

  In this specification, “the state in which the member A is connected to the member B” means that the member A and the member B are physically directly connected, or the member A and the member B are electrically connected. The case where it is indirectly connected through another member that does not affect the state is also included.

  Embodiments described herein relate generally to a brushless vibration motor drive circuit mounted on an electronic device having a communication function such as a mobile phone terminal. Such an electronic device includes a communication unit that communicates with the base station. For example, when an incoming call is detected from the base station, the vibration motor is rotated to notify the user of the incoming call.

  FIG. 1 is a circuit diagram illustrating a configuration of an electronic device 6 including a motor unit 2 according to an embodiment. The electronic device 6 includes a motor unit 2, a communication unit 4, and an antenna 5. The communication unit 4 is connected to the antenna 5 and communicates with the base station. The communication unit 4 rotates the vibration motor 1 when receiving a call, generates a control signal CTL for stopping, and outputs the control signal CTL to the motor unit 2.

The motor unit 2 is a three-terminal device, and specifically includes a power supply terminal P3 that receives the power supply voltage VDD, a ground terminal P4 that receives the ground voltage VGND, and a control terminal P5 that receives the control signal CTL.
The motor unit 2 includes the vibration motor 1 and the motor drive circuit 100, and constitutes one package.

  The vibration motor 1 is a brushless motor with a weight eccentric to the rotor shaft, and is formed such that drive voltages OUT1 and OUT2 can be applied to both terminals P1 and P2 of the coil from the outside.

  The motor drive circuit 100 controls the rotation of the vibration motor 1 based on the control signal CTL. Hereinafter, the configuration of the motor drive circuit 100 will be described.

  The motor drive circuit 100 includes a H bridge circuit 10, a control logic unit 20, a determination unit 30, a hall signal processing unit 40, and a first buffer BUF1, and is a functional IC integrated on one semiconductor substrate.

  The hall signal processing unit 40 is provided to process hall signals H + and H− indicating the position (polarity) of the rotor of the vibration motor 1. The hall signal processing unit 40 includes a hall element 3, an offset cancel circuit 42, an amplifier 44, a sample hold circuit 46, and a comparator 48. In the present embodiment, the Hall element 3 is integrated in the motor drive circuit 100. When the Hall element 3 is built in the IC, the amplitude of the Hall signal is smaller and the offset is larger than when a discrete element is used.

  The hall element 3 has four terminals, which are connected to the offset cancel circuit 42. The offset cancel circuit 42 cancels the offset of the Hall element 3 and generates Hall signals H + and H− having opposite phases indicating the position of the rotor of the vibration motor 1. The hall signals H + and H− have a frequency corresponding to the rotational speed of the motor. Since the Hall signal output from the offset cancel circuit 42 is weak, it is amplified by the amplifier 44 and sampled and held by the sample and hold circuit 46. The comparator 48 compares the sampled and held Hall signals H + and H−, converts them into a so-called FG (Frequency Generation) signal S_FG having a rectangular wave shape, and outputs it to the control logic unit 20.

  The configuration of the block from the Hall element 3 to the comparator 48 via the offset cancel circuit 42, the amplifier 44, and the sample hold circuit 46 may be a known technique, and is not particularly limited in the present invention. Further, when the Hall element 3 is constituted by a discrete element, the amplifier 44 and the sample hold circuit 46 may be omitted.

  The H bridge circuit 10 includes a plurality of switches connected to terminals P1 and P2 of the vibration motor 1 to be driven. Specifically, the H bridge circuit 10 includes a first high side transistor MH1, a second high side transistor MH2, a first low side transistor ML1, and a second low side transistor ML2. The H bridge circuit 10 corresponds to a bridge output circuit for driving the vibration motor 1. The first high side transistor MH1 and the first low side transistor ML1 are connected in series between the power supply terminal P3 and the ground terminal P4. Similarly, the second high side transistor MH2 and the second low side transistor ML2 are also connected in series between the power supply terminal P3 and the ground terminal P4. In the present embodiment, the high side transistors MH1 and MH2 are P channel MOSFETs, and the low side transistors ML1 and ML2 are N channel MOSFETs. These transistors may all be N-channel MOSFETs or may be bipolar transistors.

  A first drive voltage OUT1 at a connection point between the first high-side transistor MH1 and the first low-side transistor ML1 is applied to the first terminal P1 of the vibration motor 1. The on / off states of the first high-side transistor MH1 and the first low-side transistor ML1 are controlled by a first high-side drive signal SH1 and a first low-side drive signal SL1 that are applied to the gates of the transistors. When the first high-side transistor MH1 is on, the first drive voltage OUT1 is the power supply voltage VDD, and when the first low-side transistor ML1 is on, the first drive voltage OUT1 is the ground potential (VGND). When both of the two transistors MH1 and ML1 are off, the first terminal P1 of the vibration motor 1 is in a high impedance state.

  Similarly, the second drive voltage OUT2 at the connection point between the second high-side transistor MH2 and the second low-side transistor ML2 is connected to the second terminal P2 of the vibration motor 1. The on / off states of the second high side transistor MH2 and the second low side transistor ML2 are controlled by a second high side drive signal SH2 and a second low side drive signal SL2 applied to the gates of the transistors.

  In the present embodiment, the vibration motor 1 is driven by setting the high-side transistor MH1 and the low-side transistor ML2 as a pair and the high-side transistor MH2 and the low-side transistor ML1 as another pair and alternately turning on and off these pairs. At that time, the length of the ON period is adjusted based on the pulse signal Spwm.

  The first buffer BUF1 receives the control signal CTL input to the control terminal P5 and outputs it to the control logic unit 20 and the determination unit 30.

  The determination unit 30 receives a pulse-modulated control signal CTL instructing the torque of the vibration motor 1, and a first state where the duty ratio Dctl of the control signal CTL is higher than a predetermined upper threshold DH (Dctl> DH), It is determined whether the second state is lower than a predetermined lower threshold DL (Dctl <DL) or the third state between the upper threshold and the lower threshold (DL <Dctl <DH). . For example, the upper threshold value is set to 60% and the lower threshold value is set to about 30%.

  The determination unit 30 outputs a determination signal Sjdg indicating any one of the first state H, the second state L, and the third state M. The determination signal Sjdg may be, for example, 2-bit data that is [01] in the first state H, [10] in the second state L, and [11] in the third state.

The determination unit 30 includes a filter 32 and a comparator 34. The filter 32 smoothes the control signal CTL subjected to pulse width modulation. The filter 32 includes a second buffer BUF2 and a capacitor C1. By adjusting the capacitance of the capacitor C1, the time constant of the filter can be adjusted. The comparator 34 compares the output voltage Vf of the filter 32 with the first threshold voltage Vth1 corresponding to the upper threshold DH and the second threshold voltage Vth2 corresponding to the lower threshold DL. The comparator 34 may include two comparators.
That is, the determination unit 30 determines whether the output voltage Vf of the filter belongs to one of the three voltage ranges (Vf> Vth1), (Vth1>Vf> Vth2), or (Vth2> Vf).

  The control logic unit 20 refers to the determination signal Sjdg and controls the H bridge circuit 10 based on the determination result of the determination unit 30.

  The control logic unit 20 instructs the bridge output circuit 10 to rotate the vibration motor 1 when in the first state H. Further, in the second state L, the reverse brake of the vibration motor 1 is instructed, and in the third state M, the idling brake is instructed.

  The reverse brake (reverse brake) is executed by applying reverse rotation torque to the vibration motor 1. For example, the transistor of the H bridge circuit 10 is controlled so that the current flows in the opposite direction during the period in which the current flows through the coil of the vibration motor 1 from the first terminal P1 to the second terminal P2. The

When the idling brake is applied, all the transistors of the H bridge circuit 10 are turned off. That is, the first terminal P1 and the second terminal P2 of the vibration motor 1 are in a high impedance state. The coil current of the vibration motor 1 flows through the body diode of the transistor of the H bridge circuit 10.
When the idling brake is applied, both the low side transistors ML1 and ML2 may be turned on. That is, the ground voltage VGND may be applied to the first terminal P1 and the second terminal P2 of the vibration motor 1. In this case, the coil current of the vibration motor 1 flows through the channels of the transistors ML1 and ML2.

  The control logic unit 20 generates drive signals SH1, SH2, SL1, and SL2 for controlling the transistors of the H bridge circuit 10 based on the control signal CTL and the determination signal Sjdg.

  The motor unit 2 changes the following states.

Stop state φ1
The state where the vibration motor 1 is stopped.

Starting state φ2
During a predetermined starting period T _FULL , the vibration motor 1 is rotated at full torque (100% duty ratio).

Normal drive state φ3
The vibration motor 1 is rotated with a torque corresponding to the duty ratio of the control signal CTL.

Reverse brake state φ4
Apply reverse brake to vibration motor 1.

Idling brake state φ5
The idling brake is applied to the vibration motor 1.

FIG. 2 is a state transition diagram of the motor unit 2 of FIG.
In the stop state φ1, when the first state H lasts longer than the predetermined first period T _RISE , the state changes to the start state φ2 (S1).

When the activation time _{T FULL} awake φ2 has elapsed, a transition to the normal driving state φ3 (S2).

In the normal drive state φ3, when the second state L continues longer than the predetermined second period T _FALL , the state changes to the reverse brake state φ4 (S3).

When the reverse brake period _TBRK elapses in the reverse brake state φ4, the state changes to the stop state φ1 (S4). The reverse brake period T _BRK is a period until the rotational speed of the motor decreases to a certain value, or a predetermined fixed time.

In the normal driving state φ3 or the reverse brake state φ4, when the third state M continues longer than the predetermined third period T _MID , the state changes to the idling brake state φ5 (S5).

In the idling brake state φ5, when the first state H lasts longer than the predetermined first period T _RISE , the state changes to the start state φ2 (S6).

  As described above, the determination signal Sjdg is generated by comparing the smoothed voltage of the control signal CTL with the threshold voltage. Therefore, the value of the determination signal Sjdg changes with a delay by the time constant of the filter 32 after the duty ratio Dctl of the control signal CTL changes.

The motor unit 2 in FIG. 1 uses the time constant of the filter 32 as the first period T _RISE and the second period T _FALL described above. For example, it is assumed that the control signal CTL is fixed at a low level as an initial state (Dctl = 0%). From this state, when the duty ratio Dctl of the control signal CTL transits to a state higher than the upper threshold value DH, the filter voltage Vf rises gently, and after the elapse of time T _RISE according to the time constant of the filter 32, The determination signal Sjdg transitions from L to H. That is, when the state of the DCTL> DH continues longer than the first period _{T RISE,} determination signal Sjdg transits to H.

The first period T _RISE and the second period T _FALL , in other words, the time constant of the filter 32 is set longer than the cycle of the control signal CTL subjected to pulse width modulation.

  That is, the control logic unit 20 can execute the state transition of FIG. 2 when the value of the determination signal Sjdg transitions without using a time-lapse means such as a timer.

  The above is the configuration of the motor unit 2. Next, the operation will be described. FIG. 3 is a time chart showing an operation example of the motor unit 2 of FIG.

Prior to time t0, the power supply voltage VDD is supplied, and the motor drive circuit 100 is in the stop state φ1. At time t0, the control signal CTL becomes high level, and the start of rotation of the vibration motor 1 is instructed. When the control signal CTL remains at the high level, the filter voltage Vf of the determination unit 30 increases with time, and at time t1 when the first period T _RISE has elapsed, the filter voltage Vf becomes higher than the threshold voltage Vth1, and the determination signal Sjdg becomes the first state H. When the determination signal Sjdg becomes the first state H, the control logic unit 20 transitions to the activation state φ2. During the startup state φ2, the vibration motor 1 is driven at full torque (100% duty), and its rotational speed increases rapidly.

  At time t2 in the starting state φ2, the duty ratio of the control signal CTL is set to a predetermined duty ratio (for example, 80%). During the startup state φ2, the duty ratio of the control signal CTL is ignored, and the vibration motor 1 is driven at full torque (100% duty ratio).

After the transition to the startup state φ2, the transition to the normal drive state φ3 occurs at time t3 when the startup period _TFULL has elapsed. When transitioning to the normal drive state φ3, the vibration motor 1 is driven with a torque (duty ratio) corresponding to the duty ratio of the control signal CTL. The duty ratio of the control signal CTL and the duty ratio of the drive signals OUT1 and OUT2 applied to the vibration motor 1 do not necessarily need to match. As a result, the rotation speed of the vibration motor 1 is stabilized to a value corresponding to the duty ratio of the control signal CTL.

At time t4, the control signal CTL becomes low level (duty ratio 0%), and the stop of the vibration motor 1 is instructed. When the determination signal Sjdg becomes the second state L at the time t5 after the elapse of the second period T _FALL from the time t4, the state transits to the reverse brake state φ4. During the reverse brake period _TBRK , a torque in the direction opposite to the rotation direction is applied to the vibration motor 1, the number of rotations of the vibration motor 1 rapidly decreases, and the vibration motor 1 stops.

At time t6 in the reverse brake state φ4, the duty ratio of the control signal CTL changes to a certain value (for example, 50%). However, in the reverse brake state φ4, the duty ratio of the control signal CTL affects the driving of the vibration motor 1. Absent. However, the determination signal Sjdg transits to the third state M according to the duty ratio 50% of the control signal CTL. When the reverse brake period _TBRK ends at the time t7, the vehicle shifts to the idling brake state φ5 and enters a standby state.

  Thereafter, when the control signal CTL becomes low level (duty ratio 0%) at time t8, the stop state φ1 is entered.

  The above is the operation of the motor unit 2.

The motor unit 2 according to the embodiment has the following advantages.
1. Since the control signal CTL can use the signal of the conventional brush vibration motor platform as it is, the designer of the electronic device 6 replaces the conventional brush vibration motor unit with the motor unit 2 according to the embodiment. By replacing, a brushless vibration motor can be used easily.

2. The brushed vibration motor does not rotate even if a signal having the same phase is applied to both ends of the vibration motor 1. Therefore, in the conventional vibration motor platform with a brush, the duty ratio and level of the control signal CTL are allowed to fluctuate non-zero when the motor is stopped.
On the other hand, since the brushless motor rotates even when in-phase signals are applied to both ends thereof, a malfunction due to the control signal CTL having a non-zero duty ratio or level becomes a problem. In the stopped state, the motor unit 2 according to the embodiment is mounted on the vibration motor platform with a brush because the vibration motor 1 does not rotate even if the control signal CTL becomes high level for a period shorter than the first period _TRISE. Even if it does not malfunction.

  3. Furthermore, since the motor unit 2 according to the embodiment applies the reverse brake when the duty ratio of the control signal CTL becomes the second state (L level), the motor unit 2 can stop the rotation in a short period of time.

  4). Furthermore, the motor unit 2 according to the embodiment can apply the idling brake when the duty ratio of the control signal CTL becomes the third state (intermediate level M). A state where the idling brake is applied can be used as a standby state, for example.

5). The motor unit 2 according to the embodiment can be mounted on a conventional two-wire type, that is, a brushless motor platform that is operated only by the supply voltage VDD and the ground voltage VGND. In this case, the control terminal P5 in FIG. 1 may be short-circuited with the power supply terminal P3. In this case, when the power supply voltage VDD is supplied, the state transits to the startup state φ2, and subsequently transitions to the normal drive state φ3. When the control signal CTL is the power supply voltage VDD, the duty ratio is 100%. Therefore, in the normal drive state φ3, the vibration motor 1 is driven with full torque. When the supply of the power supply voltage VDD is stopped, a transition is made to the reverse brake state φ4, and the vibration motor 1 is reached in a short time.
The rotation stops.

  6). In the above description, the case where the control signal CTL is subjected to pulse width modulation has been described. However, the motor unit 2 applies a DC voltage having a voltage level corresponding to the motor torque (number of rotations) as the control signal CTL. You can also receive it. In this case, the rotation of the vibration motor 1 can be controlled by changing the voltage level of the control signal CTL. In this case, the control logic unit 20 may include a modulator that receives the DC control signal CTL and generates a pulse signal having a duty ratio according to the voltage level. The control logic unit 20 may switch the H bridge circuit 10 according to the pulse signal.

  Those skilled in the art will understand that the above-described embodiment is an exemplification, and that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. is there.

In the embodiment, the case has been described in which the torque opposite to the rotation is applied at a duty ratio of 100% in the brake period _TBRK , but the present invention is not limited to this. For example, when applying the brake, the control logic unit 20 may monitor the rotational speed of the rotor and adjust the duty ratio so that the speed of the decrease becomes a desired speed. In this case, it is possible to obtain brake characteristics that do not depend on characteristics of the brushless vibration motor to be driven, for example, internal friction.

In the embodiment, the configuration in which the first period T _RISE and the second period T _FALL are measured using the time constant of the filter 32 has been described, but the present invention is not limited to this. For example, a digital or analog timer circuit may be provided to measure the first period T _RISE and the second period T _FALL .

  In the embodiment, the case where the vibration motor 1 is driven has been described. However, the present invention can also be applied to driving a small motor mounted on a remote controller such as an ultra-small fan motor or a game machine.

  In the circuit described in the embodiment, the setting of the high level and low level logic values of the signal is an example, and can be freely changed by appropriately inverting it with an inverter or the like. Further, according to this, replacement of the AND gate and the OR gate can be easily conceived by those skilled in the art.

DESCRIPTION OF SYMBOLS 1 ... Vibration motor, 2 ... Motor unit, 3 ... Hall element, 4 ... Communication part, 5 ... Antenna, 6 ... Electronic device, 10 ... H bridge circuit, 20 ... Control logic part, 30 ... Determination part, 32 ... Filter, 34 ... Comparator, 40 ... Hall signal processing unit, 42 ... Offset cancel circuit, 44 ... Amplifier, 46 ... Sample hold circuit, 48 ... Comparator, 100 ... Motor drive circuit, P3 ... Power supply terminal, P4 ... Ground terminal, P5 ... Control terminal, BUF1 ... first buffer, BUF2 ... second buffer, P1 ... first terminal, P2 ... second terminal.

Claims (15)

A bridge output circuit connected to the coil of the brushless motor to be driven;
Receiving a pulse-modulated control signal indicating the torque of the brushless motor; a first state in which the duty ratio of the control signal is higher than a predetermined upper threshold; a second state lower than a predetermined lower threshold; A determination unit for determining which of the third states between the upper threshold value and the lower threshold value;
A control unit that controls the bridge output circuit based on a determination result of the determination unit;
With
The control unit instructs the bridge output circuit to rotate the brushless motor in the first state, instructs reverse rotation braking of the brushless motor in the second state, and A brushless motor drive circuit that instructs idling braking of a brushless motor. The determination unit
A filter for smoothing the control signal;
A comparator for comparing the output voltage of the filter with a first threshold voltage corresponding to the upper threshold and a second threshold voltage corresponding to the lower threshold;
The brushless motor drive circuit according to claim 1, wherein the third state is determined from the first state based on a comparison result of the comparison unit.   The control unit transitions to an activated state when the first state continues for a predetermined first period in a stopped state, and in the activated state, the bridge output circuit rotates the brushless motor at full torque during a predetermined activated period. The brushless motor drive circuit according to claim 1, wherein:   The control unit transitions to a normal driving state after the start-up period has elapsed, and in the normal driving state, the bridge output circuit rotates the brushless motor with a torque corresponding to a duty ratio of the control signal. The brushless motor drive circuit according to claim 3.   In the normal drive state in which the brushless motor is rotated with a torque corresponding to the duty ratio of the control signal, the control unit transitions to a reverse brake state when the second state continues for a predetermined second period, and the reverse brake 2. The brushless motor drive circuit according to claim 1, wherein the bridge output circuit applies reverse brake to the brushless motor during a predetermined reverse brake period.   The brushless motor drive circuit according to claim 5, wherein the control unit transitions to a stop state when the reverse brake period elapses.   In the normal drive state in which the brushless motor is rotated with a torque corresponding to the duty ratio of the control signal, the control unit transitions to an idle brake state when the third state continues for a predetermined third period, and the idle brake 2. The brushless motor drive circuit according to claim 1, wherein the bridge output circuit applies idling brake to the brushless motor in a state. A bridge output circuit connected to the coil of the brushless motor to be driven;
A filter for filtering a control signal indicating the torque of the brushless motor;
A determination unit for determining which of the first to third voltage ranges the output voltage of the filter belongs to;
A control unit for controlling the bridge output circuit based on a determination result of the determination unit;
With
The control unit instructs the bridge output circuit to rotate the brushless motor in a first state where the output voltage of the filter belongs to the first voltage range, and the output voltage of the filter is set to the second output voltage. Instructing the reverse brake of the brushless motor in the second state belonging to the voltage range, and instructing the idling brake of the brushless motor in the third state where the output voltage of the filter belongs to the third voltage range. A brushless motor drive circuit.   The control unit transitions to an activated state when the first state continues for a predetermined first period in a stopped state, and in the activated state, the bridge output circuit rotates the brushless motor at full torque during a predetermined activated period. The brushless motor drive circuit according to claim 8, wherein:   The control unit transitions to a normal driving state after the start-up period has elapsed, and in the normal driving state, the bridge output circuit rotates the brushless motor with a torque corresponding to a duty ratio of the control signal. The brushless motor drive circuit according to claim 9.   In the normal drive state in which the brushless motor is rotated with a torque corresponding to the duty ratio of the control signal, the control unit transitions to a reverse brake state when the second state continues for a predetermined second period, and the reverse brake 9. The brushless motor drive circuit according to claim 8, wherein the bridge output circuit applies reverse brake to the brushless motor during a predetermined reverse brake period.   The brushless motor drive circuit according to claim 11, wherein the control unit transitions to a stop state when the reverse brake period elapses.   In the normal drive state in which the brushless motor is rotated with a torque corresponding to the duty ratio of the control signal, the control unit transitions to an idle brake state when the third state continues for a predetermined third period, and the idle brake 9. The brushless motor driving circuit according to claim 8, wherein the bridge output circuit applies an idling brake to the brushless motor in a state. A brushless vibration motor,
A hall element that outputs a hall signal indicating positional information of the rotor of the vibration motor;
The brushless motor drive circuit according to any one of claims 1 to 13, wherein the vibration motor is driven based on the hall signal.
A control terminal to which the control signal is input from the outside and connected to the brushless motor driving circuit;
A power supply voltage is applied from the outside and connected to the brushless motor drive circuit;
A ground voltage is applied from the outside and connected to the brushless motor drive circuit;
A motor unit comprising: A communication unit that communicates with a base station and generates the control signal;
The motor unit according to claim 14,
An electronic device comprising:

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