JP3906329B2 - Driving method of electromagnetic actuator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a driving method of an electromagnetic actuator used for an objective lens driving mechanism or the like in a pickup for a CD player. More specifically, the electromagnetic actuator can be operated at a high speed by a voltage higher than a power supply voltage without providing a booster circuit. The present invention relates to an electromagnetic actuator driving method.
[0002]
[Prior art]
As an objective lens driving mechanism for a pickup for a CD player, an objective actuator driving mechanism including an electromagnetic actuator having a plurality of focus coils and tracking coils is known. Since the driving speed of such an electromagnetic actuator is regulated by the power supply voltage, in order to operate at a higher speed, it is necessary to boost the power supply voltage and apply a high voltage exceeding the power supply voltage to the drive circuit of the electromagnetic actuator. .
[0003]
For example, in Japanese Patent Laid-Open No. 11-41984, a voltage of a DC power supply is boosted by a booster circuit (boost DC-DC converter), and a voltage higher than the power supply voltage is applied to a drive circuit of an electromagnetic actuator including a focus coil. Thus, a technique is disclosed in which an electromagnetic actuator is operated at a high speed and the applied voltage is PWM controlled and held at a predetermined value.
[0004]
In this publication, the on / off duty ratio of the PWM signal generator is determined by comparing the voltage of the capacitor, which is the output of the booster circuit, with the maximum value of the voltage required for each electromagnetic actuator by a comparator. As a result, the output voltage of the booster circuit can always maintain the maximum voltage required by each electromagnetic actuator.
[0005]
If the required voltage is lower than the voltage of the DC power supply, the PWM signal off duty of the PWM signal generator is 100%, the transistor is completely turned off, and the directly connected diode in the booster circuit becomes conductive. As a result, the voltage of the DC power supply is applied to the drive circuit of each electromagnetic actuator by bypassing the booster circuit.
[0006]
[Problems to be solved by the invention]
In the driving method of the electromagnetic actuator having the above-described configuration, it is necessary to newly provide a booster circuit in order to operate the electromagnetic actuator at a higher speed, resulting in an increase in circuit elements and an increase in cost.
[0007]
In addition, even when the booster circuit is not used, the actuator drive current flows through the directly connected diode, so that a power loss corresponding to the forward voltage drop of the diode occurs and the power usage efficiency of the electromagnetic actuator is lowered.
[0008]
Further, when a plurality of electromagnetic actuators are provided, it is necessary to individually monitor the voltage required for each electromagnetic actuator, determine the maximum value, and control the booster circuit. This complicates the circuit system and increases the cost.
[0009]
In view of these points, the problem of the present invention is that it is possible to operate the electromagnetic actuator at a higher speed by applying a voltage higher than the power supply voltage to the drive circuit of the electromagnetic actuator without newly providing a booster circuit. The purpose is to propose a method of driving an electromagnetic actuator.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the present invention turns on and off a pair of first and second high-potential side switching elements and a pair of first and second low-potential side switching elements constituting an H-bridge type drive circuit. In the method for driving an electromagnetic actuator that controls and controls energization of a pair of first and second drive coils that are components of the electromagnetic actuator, the first drive coil and the second drive coil are connected in series. The connection point to be used is a neutral point, a direct current power source is connected to the neutral point, the first and second low potential side switching elements are connected to the ground of the direct current power source, and the first drive coil It said first high-potential-side switching element off which is connected to the opposite side of the neutral point, the first low-voltage to be connected to the opposite side of the neutral point of the first driving coil As well as on the side switching element, the second on the second high-potential-side switching element connected to the opposite side of the neutral point of the drive coil, the neutral point of the second driving coil The second low potential side switching element connected to the side opposite to the first side is turned off, and a sink current is caused to flow through the first drive coil, thereby driving the electromagnetic actuator by half-wave energization, and the second the low potential side switching elements of leave the off state, the first low-potential side switching elements in an oN state while the PWM control, if the first low-potential-side switching element is turned off , and performs an operation of turning on the first high-potential side switching elements in the off state to generate a counter electromotive voltage to the first driving coil, above the DC power supply voltage To generate a pressure, by flowing a source current to the second drive coil by using the DC power source voltage or more, is characterized by driving the electromagnetic actuator by pseudo full-wave energization.
[0011]
According to the present invention, attention is paid to the back electromotive voltage generated when the drive coil being energized is turned off by PWM control, and by using this, the DC power supply voltage can be obtained without newly providing a booster circuit or the like. Even getting high voltage. The regenerative current generated by this voltage flows as a source current in the other drive coil. Therefore, the electromagnetic actuator can be operated at high speed without increasing the cost.
[0012]
Here, a capacitor is connected between the first and second high-potential side switching elements and the ground of the DC power supply, and a voltage equal to or higher than the DC power supply voltage formed by the counter electromotive voltage is maintained by the capacitor. It is desirable.
[0013]
Further, in the PWM control for the drive coil in the energized state, a current detection resistor is connected between the first and second low potential side switching elements and the ground of the DC power source, and the coil current is generated by the current detection resistor. When the detected coil current reaches a predetermined target value, the first low potential side switching element in the on state may be turned off. In this case, the first low-potential-side switching element that has been switched off is switched on with the next pulse output from the pulse generator for PWM control as a trigger.
[0014]
Here, PWM control for the drive coil in the energized state is performed by connecting the capacitor to the ground side of the DC power supply via a current detection resistor, detecting the coil current by the current detection resistor, The target value is provided with hysteresis, and when the detected coil current reaches the upper limit value of the target value, the first low-potential side switching element that is in the on state is turned off and reaches the lower limit value of the target value. In this case, the first low potential side switching element can be turned on.
[0015]
In this way, the pulse generator for PWM control can be omitted, and accordingly, the device configuration can be simplified and the cost of the drive circuit can be reduced.
[0016]
Next, voltage limiting means such as a Zener diode is connected between the first and second high potential side switching elements and the ground of the DC power supply to protect the H-bridge type drive circuit from overvoltage. desirable.
[0017]
On the other hand, the driving method of the present invention can also be applied to driving a plurality of electromagnetic actuators. In this case, a drive current may be supplied from the common DC power supply to each of the plurality of H-bridge type drive circuits corresponding to each electromagnetic actuator.
[0018]
In this case, the voltage maintaining capacitor may be provided in each drive circuit, but the first and second high-potential side switching elements in each H-bridge type drive circuit and the ground of the DC power supply It is also possible to connect a common capacitor between them.
[0019]
In addition, instead of connecting the capacitor for maintaining the voltage between the first and second high potential side switching elements and the ground of the DC power supply, the first and second high potential side switching elements are used. And the DC power supply can be connected.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an electromagnetic actuator driving apparatus to which the driving method of the present invention is applied will be described below with reference to the drawings.
[0021]
Example 1
FIG. 1 is a schematic block diagram showing a main part of an electromagnetic actuator driving apparatus according to a first embodiment to which the present invention is applied. The electromagnetic actuator to be controlled by the driving device 1 of this example is, for example, an objective lens driving mechanism of an optical pickup for a CD player. In this case, the electromagnetic actuator includes a pair of focusing or tracking drive coils, and these And a magnet disposed opposite to the drive coil.
[0022]
Referring to FIG. 1, the electromagnetic actuator driving apparatus 1 of this example has an H-bridge type driving circuit 2, and this H-bridge driving circuit 2 includes a pair of high-potential-side output transistors Q1 (first high-voltage output transistor Q1 ). Potential side switching element) , Q2 ( second high potential side switching element), a pair of low potential side output transistors Q3 (first low potential side switching element) , Q4 ( second low potential side switching element), It has. A pair of drive coils L1, L2 are connected in series between the output transistors Q1, Q3 and between the output transistors Q2, Q4.
[0023]
A supply line 4 of the DC power source Vcc is connected to the neutral point 3 of the drive coils L1 and L2 in the H-bridge drive circuit 2 having this configuration, and the low potential side output transistors Q3 and Q4 are connected via the current detection resistor Rs. The power supply ground line 5 is connected.
[0024]
In addition, the driving device 1 includes a control amplifier 10 that amplifies a difference signal between the control signal Cin supplied from the upper side and a preset control reference signal REF, and a high-potential side output based on the output signal from the control amplifier 10. It has an upper pre-driver 12 that controls on / off of the transistors Q1, Q2, and a lower pre-driver 13 that controls on / off of the low-potential side output transistors Q3, Q4.
[0025]
Furthermore, it has a direct PWM control circuit unit 6 for holding the coil current flowing through the drive coils L1, L2 at a predetermined value. The PWM control circuit unit 6 of this example includes an absolute value circuit 11 for generating the current target value CTL based on the output of the control amplifier 10, and a comparator 15 that compares the current target value CTL with a detection voltage by the current detection resistor Rs. A PWM oscillator 16 for generating a pulse signal for PWM control with a constant period, and a current control switch circuit for on / off controlling the low potential side output transistors Q3 and Q4 based on the output of the comparator 15 and the oscillator pulse of the PWM oscillator 16 14. The current control switch circuit 14 of this example also performs an operation of switching on the high-potential side output transistor in the off state when the low-potential side output transistor is turned off.
[0026]
Next, a capacitor Co and a Zener diode Dz are connected in parallel between the high potential side output transistors Q1 and Q2 and the power supply ground line 5.
[0027]
An outline of the operation of the drive device 1 of this example configured as described above will be described. When the relationship between the control signal Cin of the electromagnetic actuator and the control reference signal REF is Cin> REF, the output transistors Q1 and Q4 are turned on via the pre-drivers 12 and 13, and when Cin <REF, the output transistors Q2 and Q3 are turned on. Conduction occurs, and drive currents in both directions flow through the drive coils L1, L2.
[0028]
On the other hand, the output of the control amplifier 10 is also supplied to the PWM control circuit unit 6 and becomes the current target value CTL via the absolute value circuit 11 and is compared with the voltage of the current detection resistor Rs through which the coil current flows by the comparator 15. ing. If the Rs voltage detected by the current detection resistor Rs is higher, the current control switch circuit 14 operates to turn off the low-potential side output transistors Q3 and Q4. At the same time, one high-potential side output transistor in the off state is turned on.
[0029]
The neutral point 3 of the drive coils L1 and L2 is connected to the power supply voltage Vcc, and one drive coil L1 or L2 in which the sink current has flowed is equal to or higher than the power supply voltage immediately after the low-potential side output transistors Q3 and Q4 are turned off. Generate back electromotive force. The high potential side output transistors Q1 and Q2 are in an on state, and a regenerative current flows through them. This regenerative current becomes the source current of the other drive coil L2 or L1 and the charge current of the capacitor Co, and the capacitor Co is charged.
[0030]
The low potential side output transistor is turned on again by the next oscillation pulse of the PWM oscillator 16. At this time, the source current of the drive coil L2 or L1 is supplied by the discharge current of the capacitor Co.
[0031]
By repeating this operation, the drive coils L1 and L2 of the electromagnetic actuator are directly PWM controlled by pseudo full-wave energization.
[0032]
The Zener diode Dz connected between the high-potential side output transistors Q1, Q2 and the power supply ground line 5 is a voltage limiting means for protecting the circuit from the overvoltage of the counter electromotive voltage generated by the drive coils L1, L2. Function as.
[0033]
FIG. 2 shows a regenerative current path when Cin> REF, the output transistors Q1 and Q4 are on, the output transistors Q2 and Q3 are off, and the low potential side output transistor Q4 is off by PWM control. It is. FIG. 4 shows a timing chart of PWM control.
[0034]
In FIG. 2, E1 and E2 are induced electromotive voltages generated by the drive coils L1 and L2, respectively, and R1 and R2 are resistance components of the drive coils L1 and L2.
[0035]
Now, when the low-potential side output transistor Q4 is turned off (time t1 in FIG. 4), a back electromotive voltage eV toward the high potential side is generated in the drive coil L2. Here, since the high potential side output transistor Q2 is turned on, the regenerative current of the drive coil L2 flows as a source current of the drive coil L1 from the high potential side output transistor Q2 via the high potential side output transistor Q1. At the same time, the capacitor Co flows as a charge current. The source current of the drive coil L1 and the charge current of the capacitor Co merge at the neutral point 3 of the drive coils L1 and L2 connected to the DC power source Vcc and return to the drive coil L2.
[0036]
FIG. 3 shows an energization current path when the low potential side output transistor Q4 is on-controlled in the state of FIG. After the high-potential side output transistor Q2 is turned off, when the low-potential side output transistor Q4 is turned on again (time t2 in FIG. 4), a back electromotive voltage eV toward the low potential side is generated in the drive coil L2, and the drive coil The sink current flowing through L2 is gradually increased. The sink current flowing through the drive coil L2 returns to the DC power source Vcc through the current detection resistor Rs, and at the same time becomes a discharge current of the capacitor Co. This discharge current becomes the source current of the drive coil L1 via the high-potential side output transistor Q1, merges with the power supply current at the neutral point 3 of the drive coils L1 and L2, and returns to the drive coil L2.
[0037]
(Example 2)
FIG. 5 is a schematic block diagram showing an electromagnetic actuator driving apparatus according to Embodiment 2 to which the present invention is applied. Since the basic configuration of the driving apparatus 1A of this example is the same as that of the driving apparatus 1 shown in FIG. 1, the corresponding parts are denoted by the same reference numerals, and description thereof will be omitted.
[0038]
In the driving apparatus 1A of this example, the following three items are different from the driving apparatus 1 shown in FIG. The point that the comparator 15 is replaced by the hysteresis comparator 17, the point that the PWM oscillator 16 is eliminated in the PWM control circuit unit 6A, and the connection of the capacitor Co is connected from the power supply ground line 5 to the detection side of the current detection resistor Rs. This is a change.
[0039]
Since the capacitor Co is connected to the detection side of the current detection resistor Rs, the charge current of the capacitor Co flows through the current detection resistor Rs when PWM is off, and the Rs current IRs flowing through the current detection resistor Rs does not become zero. Further, when PWM is turned on, a part of the sink current of the drive coil returns to the capacitor Co, so that the Rs current is smaller than that in the embodiment of FIG.
[0040]
FIG. 6 is a timing chart when the drive coil L2 in the energization period is turned on / off by PWM control. As shown in this figure, the upper limit target value CTL1 and the lower limit target value CTL2 of the Rs current are set by the hysteresis comparator 17, and when the Rs current reaches the upper limit target value CTL1, the PWM is turned off, and when the Rs current decreases to the lower limit target value CTL2, the PWM is performed. Turn on. As a result, the Rs current waveform becomes a sawtooth wave as shown in the figure. If the configuration of this example is adopted, there is an advantage that PWM control of the electromagnetic actuator can be performed without the PWM oscillator 16 that is necessary in the PWM control circuit unit 6 in the drive device 1 of FIG.
[0041]
Next, FIG. 7 is an explanatory diagram showing a regenerative current path when the low potential side output transistor Q4 is off-controlled, and FIG. 8 is an explanatory diagram showing an energized current path when the transistor Q4 is on-controlled. is there. Since these routes are basically the same as those shown in FIGS. 2 and 3, the description thereof will be omitted.
[0042]
(Modification of Examples 1 and 2)
In the first and second embodiments, as shown in FIGS. 2 and 7, in order to secure the regenerative current path, the high potential side output transistor Q2 is turned on in accordance with the low potential side output transistor Q4 being turned off. ing. However, since a parasitic diode exists between the source and drain of the FET used as the output transistor, the operations of the above embodiments can be performed without turning on the output transistor Q2. However, since the forward voltage drop of the parasitic diode is larger than the voltage drop due to the on-resistance of the FET, power consumption increases. Therefore, in order to suppress power consumption, it is effective to configure as in the above embodiments.
[0043]
(Example 3)
FIG. 9 is a schematic block diagram showing a main part of an electromagnetic actuator driving apparatus according to Embodiment 3 to which the present invention is applied. The drive device 20 of this example has a configuration including three sets of H-bridge drive circuits 2 (1) to 2 (3) of electromagnetic actuators. As the control circuit units of these drive circuits 2 (1) to 2 (3), the same one as that of the drive device 1 of the first embodiment can be adopted. Here, in this example, the capacitor Co is shared by the drive circuits 2 (1) to 2 (3).
[0044]
Example 4
FIG. 10 is a schematic block diagram showing a main part of an electromagnetic actuator driving apparatus according to Embodiment 4 to which the present invention is applied. The basic configuration of the drive device 20A of this example is the same as that shown in FIG. 9, but in this example, the capacitor Co is not shared, and each of the drive circuits 2A (1) to 2A (3) has a capacitor Co (1 ) To Co (3) are connected, and the voltages of the respective high potential side output transistors are made independent. In this case, the respective drive circuits 2A (1) to 2A (3) are connected to the diodes D (1) to D (3) so that the maximum value of the voltages of the capacitors Co (1) to Co (3) is subjected to voltage restriction. ) Through the zener diode Dz.
[0045]
(Modification of Examples 3 and 4)
In the driving devices 20 and 20A of Examples 3 and 4, the driving circuits 2 (1) to 2 (3) and 2A (1) to 2A (3) are the same as those of the driving device 1 shown in FIG. The drive is controlled by a simple control circuit portion. Instead of this, it is also possible to apply the control circuit portion having the configuration shown in FIG. In addition, although the configuration includes three sets of drive circuits, it is needless to say that two sets or four or more sets of drive circuits may be provided.
[0046]
(Other embodiments)
In each of the first to fourth embodiments, a configuration in which a capacitor is connected between the high potential side switching element and the ground of the DC power supply in the H-bridge type drive circuit is adopted. Instead, it is also possible to adopt a configuration in which a capacitor is connected between the high potential side switching element and the supply line of the DC power supply.
[0047]
【The invention's effect】
As described above, in the electromagnetic actuator driving method of the present invention, a voltage higher than the power supply voltage of the DC power supply is obtained by using the back electromotive voltage generated in the drive coil that performs PWM control. Accordingly, since it is not necessary to newly provide a booster circuit or the like, the electromagnetic actuator can be operated at a high speed without causing an increase in cost. Further, even when the current power supply voltage is lowered, the operation speed before the power supply voltage is lowered can be maintained.
[0048]
Furthermore, the counter electromotive voltage generated in the drive coil disappears when the PWM control is stopped. Therefore, when the target voltage is equal to or lower than the DC power supply voltage as in the prior art, a bypass circuit composed of a diode or the like for invalidating the booster circuit becomes unnecessary. Therefore, according to the present invention, a simple low-cost circuit system can be realized, and a voltage drop due to the bypass circuit does not occur, so that an efficient circuit can be realized.
[0049]
In the present invention, the high voltage obtained by utilizing the back electromotive voltage generated in the drive coil is maintained by the capacitor, and the high potential side output transistor is moved. Thus, the effect of reducing the drive current can be obtained.
[0050]
Furthermore, when the electromagnetic actuator is conventionally subjected to direct PWM control, the power supply current ripple is normally 100% because the power supply current is cut off when the PWM is off. For this reason, a large-capacity electrolytic capacitor is required on the power supply side, and electromagnetic noise in the power supply line becomes a problem. According to the present invention, the power supply current is not cut off and the ripple rate is small, so that the capacity of the power supply capacitor can be reduced and the electromagnetic noise can be suppressed low. In addition to this, since the peak current value of the ripple is lowered, the current supply capability of the DC power supply can be reduced, and the power supply circuit can be rationalized.
[0051]
Next, in the driving method of the present invention, hysteresis is provided to the target value of the coil current, and the PWM control is automatically performed by making the detected current waveform a sawtooth wave. When this configuration is adopted, the PWM oscillator becomes unnecessary, and accordingly, the cost of the driving device can be reduced.
[0052]
On the other hand, in the driving method of the present invention, the common DC power supply is connected to the neutral point of the drive coil in each drive circuit of the plurality of electromagnetic actuators, so that the drive circuit can Since the voltage required for each electromagnetic actuator can be individually applied to the potential-side output transistor, the function of determining the maximum value of the necessary voltage and controlling the booster circuit is unnecessary. Therefore, a circuit system for driving a plurality of electromagnetic actuators can be realized with a simple configuration and at a low cost.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram showing an electromagnetic actuator driving apparatus according to a first embodiment to which the present invention is applied.
FIG. 2 is an explanatory diagram showing a regenerative current path formed when PWM of the drive device of FIG. 1 is off.
3 is an explanatory diagram showing an energization current path formed when PWM is turned on in the drive device of FIG. 1; FIG.
FIG. 4 is a timing chart showing the operation of the driving device of FIG. 1, and shows the time change of the current flowing through each part at the time of PWM on / off.
FIG. 5 is a schematic configuration diagram illustrating an electromagnetic actuator driving apparatus according to a second embodiment to which the present invention is applied.
6 is a timing chart showing the operation of the driving device of FIG. 5, and shows the time change of the current flowing through each part when the PWM is turned on and off. FIG.
7 is an explanatory diagram showing a regenerative current path formed when PWM of the drive device of FIG. 5 is off.
8 is an explanatory diagram showing an energization current path formed when PWM of the drive device of FIG. 5 is on. FIG.
FIG. 9 is a schematic configuration diagram showing a drive circuit portion of an electromagnetic actuator drive device according to a third embodiment to which the present invention is applied.
FIG. 10 is a schematic configuration diagram showing a drive circuit portion of an electromagnetic actuator drive device according to a fourth embodiment to which the present invention is applied.
[Explanation of symbols]
1, 1A, 20, 20A Electromagnetic actuator drive device 2, 2 (1) to 2 (3), 2A (1) to 2A (3) H bridge type drive circuit 3 Neutral point of drive coil 4 DC power supply Line 5 Ground line 6, 6A of DC power supply PWM control circuit unit 10 Control amplifier 11 Absolute value circuit 12 Upper pre-driver 13 Lower pre-driver 14 Current control switch circuit 15 Comparator 16 Oscillator for PWM 17 Hysteresis comparator eV Back electromotive force voltage E1, E2 Inductive electromotive voltages L1, L2 Driving coils Q1, Q2 High potential side output transistors Q3, Q4 Low potential side output transistors Vcc DC power source Rs Current detection resistors Co, Co (1) to Co (3) Voltage maintaining capacitor Dz Zener diode D (1) to D (3) Diode Cin Control signal REF Control reference signal CTL Current Target value

Claims (8)

A pair of first and second high-potential side switching elements and a pair of first and second low-potential side switching elements constituting the H-bridge type drive circuit are controlled to be turned on and off, and a pair of components constituting the electromagnetic actuator In the driving method of the electromagnetic actuator that performs energization control on the first and second drive coils,
With a connection point where the first drive coil and the second drive coil are connected in series as a neutral point, a DC power source is connected to the neutral point,
Connecting the first and second low potential side switching elements to the ground of the DC power supply;
The first high-potential side switching element connected to the side opposite to the neutral point of the first drive coil is turned off and connected to the side opposite to the neutral point of the first drive coil. Turning on the first low potential side switching element ;
The second high potential side switching element connected to the opposite side of the second drive coil to the neutral point is turned on, and the second drive coil is connected to the opposite side of the neutral point. The electromagnetic actuator is driven by half-wave energization by turning off the second low-potential side switching element and causing a sink current to flow through the first drive coil,
The second low potential side switching element is left in an off state, and the first low potential side switching element in the on state is PWM-controlled , and the first low potential side switching element is turned off. In this case, an operation for switching on the first high potential side switching element in the off state is performed to generate a back electromotive voltage in the first drive coil, thereby generating a voltage higher than the DC power supply voltage. ,
A method for driving an electromagnetic actuator, wherein a source current is supplied to the second drive coil using a voltage equal to or higher than the DC power supply voltage to drive the electromagnetic actuator by pseudo full-wave energization. In claim 1,
A capacitor is connected between the first and second high-potential side switching elements and the ground of the DC power supply, and a voltage equal to or higher than the DC power supply voltage formed by the counter electromotive voltage is maintained by the capacitor. And a driving method of the electromagnetic actuator. In claim 1 or 2,
A current detection resistor is connected between the first and second low potential side switching elements and the ground of the DC power supply, and a coil current is detected by the current detection resistor;
A method for driving an electromagnetic actuator, wherein the PWM control is performed so as to turn off the first low potential side switching element in an on state when a detected coil current reaches a predetermined target value. In claim 2,
Connect the capacitor to the ground side of the DC power supply via a current detection resistor, detect the coil current with the current detection resistor,
Hysteresis is provided to the target value of the coil current, and when the detected coil current reaches the upper limit value of the target value, the first low-potential-side switching element that is in the on state is turned off, A method of driving an electromagnetic actuator, wherein the PWM control is performed so that the first low potential side switching element is turned on when a lower limit value is reached. In any one of claims 1 to 4,
A voltage limiting means such as a Zener diode is connected between the first and second high potential side switching elements and the ground of the DC power supply to protect the H-bridge type drive circuit from overvoltage. Driving method of electromagnetic actuator. In any one of claims 1 to 5,
A driving method of an electromagnetic actuator, wherein a driving current is supplied from a common DC power source to each of the plurality of H-bridge type driving circuits. In claim 6,
Connecting the common capacitor between the first and second high potential side switching elements and the ground of the DC power source in each H-bridge type drive circuit;
In each H-bridge type drive circuit, a voltage equal to or higher than the DC power supply voltage formed by the counter electromotive voltage is maintained by the capacitor. In claim 1,
A capacitor is connected between the first and second high potential side switching elements and the DC power supply, and a voltage equal to or higher than the DC power supply voltage formed by the counter electromotive voltage is maintained by the capacitor. Driving method of electromagnetic actuator.

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