JP2002239458A - Drive circuit for vibration actuator in mobile communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive circuit which stabilizes the operations of a vibration actuator, causes no noise such as collision sound from the actuator and effectively transmits the vibration condition of the actuator to a user by periodically changing the amplitudes of the vibration. SOLUTION: In order to drive an electromagnetic conversion type vibration actuator having nonlinear characteristics, the drive circuit is provided with a pulse train generating circuit 1 which generates two system pulse trains and an outputting circuit 2 which power amplifies the two system pulse trains and makes the trains compatible with the operating voltage and the operating current of the actuator. By the circuit 1, the driving frequency of the actuator is swept in with a prescribed period between a first frequency which is lower than the resonance frequency of the actuator and makes the vibration amplitudes of the actuator smaller and a second frequency which is lower than the resonance frequency and makes the vibration amplitudes larger than the first frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving circuit for an electromagnetic transducer of a vibration type having a mechanical resonance characteristic, and more particularly to a mobile phone or a mobile communication device such as a pager or the like for receiving an incoming call by vibration. The present invention relates to a driving circuit for a vibration actuator in a mobile communication device for effectively driving the vibration actuator when applied to a transmission system.

[0002]

2. Description of the Related Art An electromagnetic conversion type vibration actuator to which the present invention is directed has an inherent resonance characteristic. However, since it includes a spring having a non-linear characteristic, the resonance characteristic has a hysteresis characteristic. The law requires some ingenuity.

[0003] The electromagnetic conversion type vibration actuator which is an object of the present invention includes (1) a weight having a mass m constituted by a permanent magnet and this mounting member, (2) one or two springs for returning the center position, 3) It is composed of a coil for driving a permanent magnet by electromagnetic force and other structural materials, and its vibration model is shown in FIG.

[0004] The spring used in the vibration actuator is a leaf spring.
There is a non-linear characteristic like FIG. 11A shows the relationship between the stress and the displacement characteristic of the spring, and FIG. 11B shows the relationship between the stress and the spring constant of the spring, and shows that the spring constant changes as the stress of the spring increases.

The vibration actuator of the vibration model shown in FIG. 10 shows resonance characteristics in the same manner as the LC resonance circuit, but shows a frequency characteristic having hysteresis as shown in FIG. 12 due to the non-linear characteristics of the spring. The driving frequency f of the coil, starting from a sufficiently low frequency f ₁ than the resonance frequency f _o of the actuator, when gradually increased, the amplitude gradually increases along the resonance curve, through point B resonance Frequency f _o
The moment the robot arrives at the point C, the point jumps to the point D, and the state shifts to a state where the amplitude is small. Here, the drive frequency f is set to f ₀
A decrease than can not return to the big point C prior state of amplitude, to be lowered up to a frequency f ₃ corresponding to the point E,
It has a hysteresis characteristic that it cannot return to a state where the amplitude is large after the point F.

Accordingly, in order to variably to drive the driving frequency of the vibration actuator of the nonlinear characteristics, it is necessary to drive generally frequency f ₂ below having a margin with respect to the resonance frequency f _o.

As another method, US Pat.
There is a technique described in Japanese Patent Application Laid-Open No. 8295, and this patent proposes a method of detecting a state in which the amplitude has decreased after reaching the resonance frequency and returning the state to the state in which the original amplitude is large. But,
In this method, since the driving is performed so as to reach the resonance state, it is considered that the vibration amplitude of the weight increases to a value determined by the Q value (sharpness of the resonance curve) of the vibration actuator. It is easy to change due to individual variations, the structure of the device on which the vibration actuator is mounted, etc., which may vibrate beyond the vibration limit dimensions of the vibration actuator and generate a collision sound or unstable operation. There was a problem that the mode could not be arbitrarily designed.

[0008]

SUMMARY OF THE INVENTION In view of the foregoing, it is a first object of the present invention to drive a vibration actuator in a mobile communication device in which the operation of the vibration actuator is stable and no noise such as a collision sound is generated. It is to provide a circuit.

A second object of the present invention is to provide a driving circuit for a vibration actuator in a mobile communication device capable of effectively transmitting a vibration state to a user by periodically changing the vibration amplitude of the vibration actuator. Is to do.

[0010] Other objects and novel features of the present invention will be clarified in embodiments described later.

[0011]

According to a first aspect of the present invention, there is provided a vibration actuator driving circuit in a mobile communication device for driving an electromagnetic conversion type vibration actuator having a non-linear characteristic. Between a first frequency in a range where the vibration amplitude of the vibration actuator is lower than the resonance frequency of the vibration actuator and a second frequency where the vibration amplitude is lower than the resonance frequency and higher than the first frequency. The driving frequency is swept at a predetermined cycle.

According to a second aspect of the present invention, there is provided a driving circuit for a vibration actuator in a mobile communication device according to the first aspect, wherein the pulse train generating circuit has two signal lines for driving the vibration actuator in a forward direction and a reverse direction. It is characterized by having.

According to a third aspect of the present invention, in the driving circuit for a vibration actuator in a mobile communication device according to the second aspect, a pause period is provided in a period in which the vibration actuator is driven in a forward direction and a reverse direction. And

According to a fourth aspect of the present invention, in the driving circuit for a vibration actuator in a mobile communication device according to the second or third aspect, the pulse train generating circuit has a memory and an address counter, and the driving condition is stored in the memory. By changing the read address of the memory by the address counter, a signal for driving in the forward direction or the reverse direction based on the driving condition is output.

According to a fifth aspect of the present invention, there is provided a driving circuit for a vibration actuator in a mobile communication device according to the second or third aspect, wherein the pulse train generating circuit has a microprocessor, and the microprocessor uses a driving condition based on driving conditions. It is characterized by outputting signals for driving in the forward and reverse directions.

According to a sixth aspect of the present invention, in the driving circuit for a vibration actuator in a mobile communication device according to the fourth or fifth aspect, the plurality of driving conditions are stored in the pulse train generating circuit, and the plurality of driving conditions are stored. And outputs a signal for driving in the forward direction or the reverse direction based on at least one of the above.

According to a seventh aspect of the present invention, there is provided a driving circuit for a vibration actuator in a mobile communication device.
3, 4, 5 or 6 is characterized in that an output circuit is provided which is capable of setting the power supply voltage of the pulse train generation circuit and the power supply voltage of the vibration actuator to different values.

The driving circuit of the vibration actuator in the mobile communication device according to the invention of claim 8 of the present application is the driving circuit of claim 1,
In 2, 3, 4, 5, 6, or 7, the period is a fraction of a second to a few seconds.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a driving circuit for a vibration actuator in a mobile communication device according to the present invention will be described below with reference to the drawings.

A first embodiment of a driving circuit for a vibration actuator in a mobile communication device according to the present invention will be described with reference to FIGS.

FIG. 1 is a block diagram of the overall configuration of the driving circuit, and a pulse train generating circuit 1 for generating a two-system pulse train.
And an output circuit 2 that amplifies the power of the two pulse trains of the pulse train generating circuit 1 and matches the operating voltage and operating current of the vibration actuator. A control signal for controlling ON / OFF of the vibration is input to the pulse train generating circuit 1. The output of the pulse train generation circuit 1 includes two ports, a port A for outputting a first system pulse train and a port B for outputting a second system pulse train. For example, the port A drives the vibration actuator in the forward direction. If it is a signal line, the port B is a signal line for driving the vibration actuator in the negative direction. The output signal of port A is power-amplified by output circuit 2 to become an output signal of output A, and the output signal of port B is power-amplified by output circuit 2 to become an output signal of output B. The output A of the output circuit 2 is connected to one end of the coil 3 of the vibration actuator, and the output B is connected to the other end of the coil 3.

When a mobile communication device such as a mobile phone or a pager enters an incoming call state and notifies the user of an incoming call by vibration, a control signal is turned on (ON) and the present driving circuit is in an operating state. Output signals are output from the pulse train generation circuit 1 to two ports A and B. These output signals are amplified by the output circuit 2 and applied to the coil 3 as signals for driving the vibration actuator alternately in the positive and negative directions. . When the control signal is turned off (OFF), the above operation state ends.

Here, the present embodiment is adapted to the property that a periodically changing vibration stimulus, which is a characteristic of human sensation, is more easily sensed than a constant continuous vibration stimulus. The drive system is used. That is, a sufficiently low lower limit frequency f ₁ than the resonance frequency f _o of the vibration actuator, slightly lower than the resonance frequency f _o, a stable operation in consideration of the variation in the resonance frequency due to the change or variation in characteristics of the vibration actuator external conditions Upper limit frequency f that can be secured
_The drive frequency is set to be swept (swept) at a predetermined cycle in a frequency range between _two . Upper limit frequency _{f 2} is 80 to 90% of the resonance frequency _{f o.} The resonance frequency _{f o}
Operation and too close to the run the risk of becoming unstable, too far from the resonance frequency f _o is the efficiency decreases. Lower limit frequency f ₁ is set to a point where a change in amplitude becomes normal vibration amplitude of a fraction of the upper limit frequency f ₂ to allow sensing in the human body.

FIG. 2 is a timing chart of the entire driving circuit in consideration of these points. When the control signal shown in FIG. 2 (A) is turned ON, gradually increasing the driving frequency f from the lower limit frequency f ₁ as shown in FIG. (B), it reaches the upper limit frequency f _2, gradually lowering the driving frequency f And the lower limit frequency f ₁
Is reached, the above-described increase and decrease of the frequency are repeated again, and this is continued until the control signal is turned off.
As a result, the vibration amplitude of the vibration actuator as in FIG. 2 (C) the upper limit frequency f ₂ approaches the resonance frequency increases, decreases the lower limit frequency f ₁ away from the resonant frequency will vary periodically. The driving frequency f between a lower limit frequency f ₁ and the upper limit frequency f ₂ can be arbitrarily increased or decreased, increasing or falling curve and time of the drive frequency f in one period can be set arbitrarily.

[0025] As an example, in the vibration actuator used in this embodiment, the resonance frequency f _o is about 120
Hz, lower limit frequency f ₁ = 70 Hz, upper limit frequency f
_By setting ₂ = 100 Hz and sweeping the drive frequency f between f ₁ and f _{2 at} a period of a fraction of a second to several seconds (preferably a period of 1 to 4 Hz), vibrations could be sensed effectively.

FIG. 3 is a timing chart of a pulse train output from the pulse train generating circuit 1 to two output ports (ports A and B). When the control signal of FIG. 3A is turned on, the port A of FIG. 3B is turned on (high level) for a certain period of time, then turned off (low level), and then the port A is turned off as shown in FIG. The operation of turning B on for a certain period of time and then turning it off is repeated, and the reciprocal of this repetition period corresponds to the drive frequency. By appropriately increasing or decreasing the repetition period, it becomes possible to change the drive frequency of the output to the vibration actuator coil in FIG. 3D as designed.

The timing charts of the pulse trains shown in FIGS. 4A to 4D are obtained by improving the operation of FIG. 3, and have a fixed pulse pause period (port period) between the ON periods of the ports A and B. A and port B are both turned off). As a result, a pause period is provided during a period in which the vibration actuator is driven in the forward and reverse directions. As a result, the following items can be improved.

(1) Of the semiconductors in the output circuit 2, when an operation delay occurs in the switching from on to off, and at the moment when the switching from off to on is on, both semiconductors are on. A certain period occurs, and a through current flows between the + power supply and the − power supply of the output circuit 2, thereby speeding up battery consumption.

(2) The method of driving the movable portion of the vibration actuator in the positive direction or the negative direction without a pause is to flow a reverse current in spite of the inertial movement of the movable portion. Waste of driving energy leads to faster battery consumption.

The remedy eliminates the disadvantages (1) and (2), and has been realized by employing the following pulse train generating circuit.

FIG. 5 shows a specific example of the pulse train generating circuit 1. After the control signal is turned on, the address counter 10 is counted up by a clock pulse,
The output of the address counter 10 is used as a read address input of a read-only memory (hereinafter referred to as ROM) 11, and data of the ROM 11 specified by the address is read to become data of port A and port B, respectively. If data required for the operation of the actuator is stored in the ROM 11, the intended operation can be performed.

The frequency can be repeatedly swept by clearing the address counter 10 at the address corresponding to the last data of one cycle in which the frequency is swept and writing data to be returned.

At address 0 of the address counter 10,
By writing data to turn off both the port A and the port B, it is possible to prevent unnecessary current from flowing through the coil of the vibration actuator in a standby state or the like.

Needless to say, the components such as the address counter 10 and the ROM 11 are not prepared as dedicated components, but can be incorporated into a part of an LSI or the like on a mobile communication device on which the vibration actuator is mounted. .

Since the size, mass, structure and the like are different depending on the type of mobile communication device such as a mobile phone to which the vibration actuator is attached, if the driving conditions such as the frequency range need to be changed, the data in the ROM is required. Can be dealt with simply by changing the contents of the different circuit parts (hardware)
It is not necessary to prepare several types of. For example, the contents to be written to the ROM as the pulse train generating circuit may be changed, or data of a plurality of driving conditions may be stored in the ROM in advance, and the driving conditions suitable for the mobile communication device may be stored. You may make it select from drive condition data.

FIG. 6 is a timing chart when a specific example of the pulse train generating circuit of FIG. 5 is used. 6A is a control signal, FIG. 6B is a clock pulse, FIG. 6C is ROM data of port A, and FIG. 6D is RO of port B.
FIG. 9E shows a clear signal indicating the end of one cycle of the frequency sweep.

FIG. 7 shows a specific example of the output circuit 2. In this figure, Q1 and Q3 are P-channel FETs, Q2 and Q4
Is an N-channel FET, which connects the gate of Q1 and the gate of Q2 to input a port A signal, and connects the drain of Q1 and the drain of Q2 to output A. Q3 and Q4 are connected in the same manner as Q1 and Q2, and are similarly used as the input and output B of the port B signal. When the signal of the port A of the pulse train generating circuit 1 is turned on, the output A goes to a low level, and when the signal of the port A is turned off, the output A goes to a high level. The same applies to the port B. .

The sources of Q1 and Q3 are connected to the positive side of the vibration actuator driving power supply, and the sources of Q2 and Q4 are connected to the negative side of the vibration actuator driving power supply (coincident with the common power supply of the pulse train generating circuit, that is, ground). Have been.

The power supply voltage for driving the vibration actuator does not need to be equal to the power supply voltage of the pulse train generating circuit 1, and the output circuit 2 can play a role of adjustment when the two voltages are different.

According to the first embodiment, the following effects can be obtained.

[0041] (1) In the case of driving the electromagnetic conversion type vibration actuator having a non-linear characteristic, lower than the resonance frequency, the lower limit frequency f ₁ in the range of vibration amplitude is small,
Lower than this in the vicinity of the resonance frequency, large vibration amplitude, yet between the upper limit frequency f ₂ that ensures a margin in consideration of variations in resonant frequency due to changes in the characteristic variations and external condition of the vibration actuator, driven at a predetermined cycle Because it is configured to sweep the frequency, problems such as instability of operation when driving at the resonance frequency, deformation of the spring, failure, generation of noise, etc. can be solved, and stable and reliable operation without noise is achieved. It is possible. Further, by periodically changing the vibration amplitude, it is possible to surely detect the vibration amplitude by the holder.

(2) As shown in FIG. 4, by providing an idle period during the period when the vibration actuator is driven in the forward direction and the reverse direction, the generation of a through current in the output circuit 2 is prevented, and the inertia of the movable portion of the vibration actuator is reduced. By not exercising against exercise, battery consumption can be reduced.

(3) By using a pulse train generating circuit using a ROM as shown in FIG. 5, various driving conditions can be created, and it is possible to cope with a wide variety of mobile communication devices such as mobile phones. For example, the contents to be written to the ROM as the pulse train generating circuit may be changed, or data of a plurality of driving conditions may be stored in the ROM in advance, and the driving conditions suitable for the mobile communication device may be stored. You may make it select from drive condition data.

(4) By using the output circuit 2 as shown in FIG. 7, the power supply voltage of the pulse train generation circuit 1 and the power supply voltage of the vibration actuator can be set to different values.

A second embodiment of the present invention will be described with reference to FIGS. FIG. 8 shows a pulse train generating circuit having a configuration different from that of FIG. That is, the arithmetic control unit 21, the timer / counter interrupt control unit 22, the memory unit 23 (for example, ROM),
A part of the microprocessor including the input / output control unit 24 and the like is utilized. The configuration of the other output circuits and the like may be the same as in the first embodiment.

The control signal is a timer / counter interrupt control unit 2
2 to detect the situation in which the vibration actuator should be operated, first, the port A of the input / output control unit 24
Time to generate an interrupt to turn on port A, keep port A in the ON state, and when it is time to turn off port A, generate an interrupt to turn off port A and pause the pulse if necessary And the same output as that of the port A is output to the port B, and thereafter, the ports A and B are turned on at an appropriate timing according to the condition of the frequency sweep.

Data for determining the timing of frequency sweeping may be stored in the memory unit 23, and when driving under different conditions in order to adapt to different mobile communication devices as described above, the data is stored in the memory unit 23. What is necessary is just to change the content to be stored. Alternatively, a plurality of driving conditions may be stored in the memory unit 23 in advance, and any one of them may be selected.

As the memory section 23 in the present embodiment, a type of memory whose stored contents are not erased even when the power is turned off is suitable.

The microprocessor is not dedicated for this function, but can utilize a part of the function of the microprocessor originally provided in the mobile communication device.

In each of the above embodiments, the ROM
11 or the memory unit 23 to store data of a plurality of driving conditions, and select from a plurality of driving conditions stored in accordance with the type of incoming call (call, message, etc.) to set the vibration actuator in the forward direction, A configuration for outputting a signal for driving in the reverse direction may be adopted.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and various modifications and changes can be made within the scope of the claims. There will be.

[0052]

As described above, according to the present invention,
Vibration actuator in mobile communication equipment that has stable operation of the vibration actuator, does not generate noise such as collision noise, and can effectively transmit the vibration state to the user by periodically changing the vibration amplitude of the vibration actuator. Can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a driving circuit of a vibration actuator in a mobile communication device according to the present invention.

FIG. 2 is a timing chart of the entire driving circuit according to the first embodiment;

FIG. 3 is a timing chart of the pulse train generating circuit according to the first embodiment.

FIG. 4 is another timing chart of the pulse train generation circuit.

FIG. 5 is a block diagram of a specific example of a pulse train generation circuit according to the first embodiment.

FIG. 6 is a timing chart in the case of the specific example of FIG. 5;

FIG. 7 is a circuit diagram of a specific example of an output circuit according to the first embodiment.

FIG. 8 is a block diagram of a second embodiment of the present invention, showing a part of a pulse train generating circuit.

FIG. 9 is a timing chart of the second embodiment.

FIG. 10 is an explanatory diagram showing a vibration model of an electromagnetic conversion type vibration actuator.

FIG. 11 is an explanatory diagram showing non-linear characteristics of a spring.

FIG. 12 is a graph showing frequency characteristics of the electromagnetic conversion type vibration actuator.

[Explanation of symbols]

 Reference Signs List 1 pulse train generation circuit 2 output circuit 3 coil 10 address counter 11 ROM 21 arithmetic control unit 22 timer / counter interrupt control unit 23 memory unit 24 input / output control unit Q1, Q2, Q3, Q4 FET

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D107 AA06 AA14 AA16 BB08 CC09 CC10 CD01 CD05 CD08 FF10 5H633 BB04 GG02 GG16 GG21 HH03 JA03

Claims (8)

[Claims] 1. A driving circuit for a vibration actuator in a mobile communication device that drives an electromagnetic conversion type vibration actuator having a non-linear characteristic, wherein a vibration amplitude of the vibration actuator is lower than a resonance frequency of the vibration actuator and is smaller than a resonance frequency of the vibration actuator. Wherein the driving frequency is swept at a predetermined cycle between a frequency of the first frequency and a second frequency of which the vibration amplitude is lower than the resonance frequency and higher than the first frequency. Actuator drive circuit. 2. The driving circuit for a vibration actuator in a mobile communication device according to claim 1, further comprising a pulse train generating circuit having two signal lines for driving the vibration actuator in a forward direction and a reverse direction. 3. The driving circuit for a vibration actuator in a mobile communication device according to claim 2, wherein a pause period is provided during a period in which the vibration actuator is driven in a forward direction and a reverse direction. 4. The pulse train generating circuit has a memory and an address counter, and driving conditions are stored in the memory, and a read address of the memory is changed by the address counter. 4. The driving circuit for a vibration actuator in a mobile communication device according to claim 2, wherein the driving circuit outputs a signal for driving in a reverse direction. 5. The mobile communication according to claim 2, wherein said pulse train generating circuit has a microprocessor, and outputs a signal for driving in a forward direction or a reverse direction based on a driving condition by said microprocessor. Drive circuit for vibration actuator in equipment. 6. The pulse train generating circuit stores a plurality of driving conditions and outputs a signal for driving in a forward direction or a reverse direction based on at least one of the plurality of driving conditions. Or a driving circuit for a vibration actuator in the mobile communication device according to 5. 7. The vibration actuator in a mobile communication device according to claim 2, further comprising an output circuit configured to make a power supply voltage of the pulse train generation circuit different from a power supply voltage of the vibration actuator. Drive circuit. 8. The driving circuit for a vibration actuator in a mobile communication device according to claim 1, wherein the period is a fraction of a second to a few seconds.