Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
  • H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
  • H02P7/06—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual DC dynamo-electric motor by varying field or armature current
  • H02P7/18—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual DC dynamo-electric motor by varying field or armature current by master control with auxiliary power
  • H02P7/24—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual DC dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices
  • H02P7/28—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual DC dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices
  • H02P7/285—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual DC dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only
  • H02P7/29—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual DC dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only using pulse modulation
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
  • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
  • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
  • G11B7/0925—Electromechanical actuators for lens positioning
  • G11B7/093—Electromechanical actuators for lens positioning for focusing and tracking
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
  • H03K17/16—Modifications for eliminating interference voltages or currents
  • H03K17/161—Modifications for eliminating interference voltages or currents in field-effect transistor switches
  • H03K17/162—Modifications for eliminating interference voltages or currents in field-effect transistor switches without feedback from the output circuit to the control circuit
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
  • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
  • H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
  • H03K17/687—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors
  • H03K17/6871—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors the output circuit comprising more than one controlled field-effect transistor
  • H03K17/6872—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors the output circuit comprising more than one controlled field-effect transistor using complementary field-effect transistors
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K7/00—Modulating pulses with a continuously-variable modulating signal
  • H03K7/08—Duration or width modulation ; Duty cycle modulation
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
  • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
  • H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
  • H03K17/60—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being bipolar transistors
  • H03K17/66—Switching arrangements for passing the current in either direction at will; Switching arrangements for reversing the current at will
  • H03K17/661—Switching arrangements for passing the current in either direction at will; Switching arrangements for reversing the current at will connected to both load terminals
  • H03K17/662—Switching arrangements for passing the current in either direction at will; Switching arrangements for reversing the current at will connected to both load terminals each output circuit comprising more than one controlled bipolar transistor
  • H03K17/663—Switching arrangements for passing the current in either direction at will; Switching arrangements for reversing the current at will connected to both load terminals each output circuit comprising more than one controlled bipolar transistor using complementary bipolar transistors

Definitions

• the present invention relates to a coil load drive circuit that drives a coil load in a positive or negative direction by pulse width modulation (PWM), and an optical disc device that performs focus adjustment, tracking adjustment, and the like using the coil load drive circuit.
• PWM pulse width modulation
• the coil load driving circuit 101 is configured such that the input control voltage V is externally input via an input terminal IN, and the input control voltage V
• Input reference voltage V and output a PWM pulse corresponding to the voltage difference to the first output terminal.
• the motor 5 By applying a voltage between both terminals of the motor 5 via the OUT1 or the second output terminal OUT2, the motor 5 is driven in the forward or reverse direction.
• the motor 5 is driven in the forward direction if the first output terminal OUT1 is positive voltage with respect to the second output terminal OUT2, and is driven in the reverse direction if negative voltage.
• the coil load drive circuit 101 is configured to control the input control voltage V and the input reference voltage.
• Voltage-current converter 131 that outputs a current proportional to the absolute value of the
• the PWM comparator 114 outputs a triangular wave signal TRI to the inverting input terminal, compares them, and outputs a PWM signal PW.
• the voltage V is input to the inverting input terminal, and they are compared.
• a comparator 115 a switch 116 that switches the output of the PWM signal PW to two paths according to the polarity signal PO, and a motor 5 connected to the two paths of the PWM signal PW, respectively.
• a first output buffer 111 and a second output buffer 112 for outputting a PWM pulse to both terminals.
• the above adjustment voltage V is set lower than the lower end voltage TRI of the triangular wave signal TRI.
• the switch 116 switches to output the PWM signal PW to the second output buffer 112 when the polarity signal PO is at a low level, and outputs the PWM signal PW to the first output buffer 111 when the polarity signal PO is at a high level.
• the ground potential is output to the other side without outputting the PWM signal PW.
• the (A) is the input control voltage V
• (b) is the transfer voltage V and the triangular signal TRI
• (c) is the PWM signal.
• the signal PW shows the polarity signal PO
• (e) shows the PWM pulse of the first output terminal OUT1
• (f) shows the PWM pulse of the second output terminal OUT2.
• the pulse width of PW (that is, the high level period) is large.
• the pulse width of the PWM signal PW gradually becomes smaller. Since the polarity signal PO is at a low level, the PWM signal PW is output from the second output buffer 112 as a PWM pulse. At this time, the first output buffer 111 is fixed at the ground potential. Input control voltage V
• the PWM signal PW rises and the pulse width of the PWM signal PW gradually increases. Since the polarity signal PO is at a high level, the PWM signal PW is output from the first output buffer 111 as a PWM pulse. At this time, the second output buffer 112 is fixed at the ground potential.
• the coil load drive circuit 101 determines whether the input control voltage V and the input reference voltage V
• the adjustment voltage V is higher than the lower end voltage TRI of the triangular wave signal TRI.
• a dead zone is created between the voltage and the voltage. In this dead zone, the input control voltage V and the input reference voltage V
• the PW is output from the first and second output buffers 111 and 112.
• Figure 9 (a) shows the difference between the input control voltage V and the input reference voltage V (horizontal
• Fig. 9 (b) is a characteristic diagram showing the relationship between the terminal voltage TRI and the input control voltage V and the input base.
• FIG. 4 is a graph showing input / output characteristics showing the relationship between pressure (output on the vertical axis).
• the coil load drive circuit 101 maintains the monotonicity of the input / output characteristics by providing the dead zone.
• Fig. 10 (a) and (b) The figure is shown in Fig. 10 (a) and (b).
• amplifiers, comparators, voltage-current converters, and the like that compare and output two input voltages have some input offset voltage, but the voltage-current converter 131 in the coil load drive circuit 101
• the input offset voltage of the polarity comparator 115 is relatively shifted from that of the polarity comparator 115, as shown in Fig. 10 (b)
• the difference between the input control voltage V and the input reference voltage V is near 0, and the polarity comparator 115 is incorrectly inverted.
• the adjustment voltage V is
• the lower end voltage of TRI is set lower than TRI by more than the input offset voltage to provide a dead zone.
• the following can be considered as an improved coil load driving circuit.
• the coil load drive circuit 201 inverts the input control voltage V to an inverting input voltage.
• the input reference voltage V is input to the non-inverting input terminal.
• One end is connected to each output of the voltage-current converter 231 that outputs a bipolar current, and the other end is connected to the center voltage V of the triangular wave signal TRI output by the oscillator (OSC) 213.
• the first PWM signal 214 outputs a first PWM signal PW1 to control a first output buffer 211, which will be described later, and the negative output current of the voltage / current converter 231 flows through the bias resistor 233.
• the generated voltage (the second transmission voltage V) is
• a second PWM comparator 215 that inputs the angular wave signal TRI to a non-inverting input terminal, compares them, outputs a second PWM signal PW2, and controls a second output buffer 212 described later, A first output buffer 211 connected to the subsequent stage of the PWM comparator 214 to output a PWM pulse to one terminal of the motor 5, and a PWM pulse output to the other terminal of the motor 5 connected to the second stage of the second PWM comparator 215 And a second output buffer 212.
• the operation of the coil load drive circuit 201 will be described with reference to the waveform diagram of FIG.
• the figure shows the waveforms that occur in each part when the input control voltage V is increased linearly.
• (A) is the input control voltage V
• (b) is the first and second transfer voltages V, V and the triangular wave
• the signal TRI, (c) is the PWM pulse of the first output terminal OUT1 (that is, the first PWM signal PWl), and (d) is the PWM pulse of the second output terminal OUT2 (that is, the second PWM signal PW2). Is shown.
• the difference is larger than the voltage V, the first transfer voltage V becomes higher and the first PWM signal becomes higher.
• the pulse width of signal PW1 (that is, the high level period) is small.
• the pulse width of PWl gradually increases, and the second transmission voltage V increases to increase the second PWM
• the pulse width of the signal PW2 gradually decreases.
• These first and second PWM signals PW1 and PW2 are output as PWM pulses for PWM driving the motor 5 from the first and second output buffers 211 and 212, respectively. Therefore, the input control voltage V is
• the pulse width of the second PWM signal PW2 (that is, high level period)
• the second PWM signal PW2 is larger than the second PWM signal PW2, a period in which a positive voltage is applied between both terminals of the motor 5 is generated, so that the motor 5 rotates in the positive direction and the input control voltage V increases.
• the coil load drive circuit 201 includes the input control voltage V and the input reference voltage V
• the second transfer voltage V that increases and decreases while maintaining monotonicity and linearity with the first PWM signal PW1
• the second PWM signal PW2 corresponding to TR2 is output from the first and second output buffers 211 and 212 as a PWM pulse for driving the motor 5. Since the coil load drive circuit 201 does not use a circuit for determining the polarity as in the polarity comparator 115 of the coil load drive circuit 101, the coil load drive circuit 201 is monotonic or near the point where the input control voltage V and the input reference voltage V become equal.
• the input / output characteristics can be obtained as shown in the characteristic diagrams of Figs. 13 (a) and 13 (b), where the linearity is not lost.
• Patent Document 1 JP 2003-164194 A
• an output buffer that drives a coil load such as a motor and outputs a PWM pulse is a main source of radiation noise having a large current output capability.
• the coil load drive circuit 201 which can be considered as a circuit that ensures the input / output characteristics of the motor, can obtain the input / output characteristics while maintaining the monotonicity and the linearity, but outputs the PWM pulses at both ends of the motor. Since both output buffers are constantly switched, radiation noise increases compared to the coil load drive circuit 101. Especially when the motor is stationary The coil load drive circuit 101 does not output a PWM pulse, but the coil load drive circuit 201 outputs a PWM pulse with a duty of 50% to both terminals of the motor. When used for focus adjustment or tracking adjustment of an optical disk device, the normal state is a state in which the motor is stationary, and even in this case, radiation noise is always generated due to switching of the output buffer. Not much! / ,.
• FIG. 14 shows an example of the optical disk device.
• the focus adjustment coil load drive circuit 511 and the tracking adjustment coil load drive circuit 512 included in the servo circuit 501 are connected to the focus adjustment coil load 513 and the tracking adjustment coil load 514 included in the optical pickup 502. Drive.
• the present invention has been made in view of the above circumstances, and an object of the present invention is to obtain input / output characteristics that maintain monotonicity and linearity, and to stop a motor or the like as a coil load when a motor or the like is stationary. It is an object of the present invention to provide a coil load drive circuit that can suppress the generation of radiation noise when the power supply is in a state.
• a coil load driving circuit applies a PWM pulse between both terminals of a coil load according to a difference between an input control voltage and an input reference voltage.
• a first transmission voltage that increases and decreases around the voltage and a second transmission voltage that increases and decreases inversely to the first transmission voltage around the center voltage of the triangular wave signal output from the oscillator A transmission voltage generation circuit, a first PWM comparator that compares a first transmission voltage with the triangular wave signal and outputs a first PWM signal, and a second comparison circuit that compares a second transmission voltage with the triangular wave signal.
• a second PWM comparator that outputs two PWM signals The logical product signal of the exclusive-OR signal of the first and second PWM signals and the first PWM signal, and the logical product of the exclusive-OR signal of the first and second PWM signals and the second PWM signal
• An output PWM pulse synthesizing circuit that outputs a product signal; and a first output that outputs a PWM pulse to one terminal of the coil load under the control of an AND signal of the exclusive OR signal and the first PWM signal.
• a buffer, the exclusive-OR signal and a second PWM signal And a second output cuffer that outputs a PWM pulse to the other terminal of the coil load under the control of a logical product signal of the output signal.
• the transmission voltage generation circuit desirably includes a voltage-current converter that outputs a current having both positive and negative polarities in proportion to a difference between the input control voltage and the input reference voltage, and one end of the voltage-current converter. And two bias resistors each having the other output and the other end connected to the center voltage of the triangular wave signal. A voltage generated at one end of each of the bias resistors is provided by a first or second transmission voltage. And
• the transmission voltage generation circuit desirably includes a first inversion amplifier that inverts and outputs the input control voltage with reference to the input reference voltage, and a second inversion amplifier that further inverts and outputs the output.
• the center voltage of the triangular wave signal is made equal to the input reference voltage
• the output of the first inversion amplifier is a first transmission voltage
• the output of the second inversion amplifier is a second transmission voltage.
• the coil load drive circuit desirably outputs a ground potential to both terminals of the motor during a period other than the pulse period of the PWM pulse.
• An optical disc device includes the above-described coil load driving circuit, and a coil load driven by the coil load driving circuit and performing focus adjustment or tracking adjustment.
• the coil load driving circuit uses the output PWM pulse synthesizing circuit to use the exclusive OR signal of the first and second PWM signals as a PWM pulse to shift one or the other of the coil load. Output to only those terminals, it is possible to obtain input / output characteristics that maintain monotonicity and linearity, and to suppress the generation of radiated noise when the motor or the like as a coil load is stationary. .
• the optical disk device using the coil load drive circuit can perform stable operation because radiation noise is suppressed.
• FIG. 1 is a circuit diagram of a coil load drive circuit according to a preferred embodiment of the present invention.
• FIG. 2 is a waveform chart showing waveforms generated in respective parts of the above.
• FIG. 3 is a circuit diagram of a coil load drive circuit according to another preferred embodiment of the present invention.
• FIG. 4 is an explanatory diagram illustrating a regenerative current flowing through a motor.
• FIG. 5 is a circuit diagram of a coil load drive circuit according to still another preferred embodiment of the present invention.
• FIG. 6 is a waveform chart showing waveforms generated in respective parts of the above.
• FIG. 7 is a circuit diagram of a conventional coil load drive circuit.
• FIG. 8 is a waveform chart showing waveforms generated in respective parts of the above.
• FIG. 9 is a graph showing the characteristics of the above, where (a) is a characteristic diagram of a transmission voltage, and (b) is an input / output characteristic diagram showing a DC voltage between both terminals of the motor.
• FIG. 10 is a graph showing characteristics to be compared with the above characteristics.
• (A) is a characteristic diagram of a transmission voltage
• (b) is an input / output characteristic diagram showing a DC voltage between both terminals of a motor. .
• FIG. 11 is a circuit diagram of a coil load drive circuit that can be considered to improve a conventional problem.
• FIG. 12 is a waveform chart showing waveforms generated in respective parts of the above.
• FIG. 13 shows the same characteristics as above, (a) is a characteristic diagram of the first and second transmission voltages, and (b) is an input / output characteristic diagram showing a DC voltage between both terminals of the motor. It is.
• FIG. 14 is a block diagram of a general optical disk device.
• FIG. 1 is a circuit diagram of a coil load drive circuit according to a preferred embodiment of the present invention.
• This coil load driving circuit 1 is connected to an input control voltage V via an external input terminal IN and an input control voltage V via an input terminal REF.
• the input reference voltage V is input, and a PWM pulse corresponding to the voltage difference is output to the first output terminal O
• the motor 5 By applying a voltage between both terminals of the motor 5 as a coil load via the UT1 or the second output terminal OUT2, the motor 5 is driven in the positive or negative direction, that is, in the forward or reverse rotation direction.
• the motor 5 is driven in the forward direction if the first output terminal OUT1 is positive voltage with respect to the second output terminal OUT2, and is driven in the reverse direction if negative voltage.
• the rotating motor is described as a coil load.
• the force coil load is not limited to this, and may be a linear or curvilinear one (such as an actuator).
• the coil load drive circuit 1 includes an input control voltage V and an input reference voltage V
• the first transmission voltage V that increases or decreases around the center voltage V of the triangular wave signal TRI output from the oscillator (OSC) 13 according to the difference, and the center voltage V of the triangular wave signal TRI
• the first transmission voltage V and the second transmission voltage V that increases and decreases in reverse
• the transmission voltage generation circuit 17 and the first transmission voltage V are inverted input terminals and the triangular wave signal TRI
• a first PWM comparator 14 that inputs to the non-inverting input terminal, compares them, and outputs the first PWM signal PW1, and a second transmission voltage V is supplied to the inverting input terminal and the triangular wave signal TRI.
• An output PWM pulse synthesizing circuit 16 that outputs a logical product signal of and and a logical product signal of the exclusive-or signal EX and the first PWM signal PW1 are controlled to output a PWM pulse to one terminal of the motor 5.
• the transmission voltage generation circuit 17 converts the input control voltage V into an inverted input terminal
• the voltage-to-current change 31 indicates that the input control voltage V is higher than the input reference
• the voltage (second transmission voltage V) generated in the bias resistor 33 is the center voltage V
• the output PWM pulse synthesizing circuit 16 includes an EOR circuit 21 that outputs an exclusive OR (Exclusive OR) signal EX of the first and second PWM signals PW1 and PW2; An AND circuit 22 that outputs an AND signal of the PWM signal PW1 and an AND circuit 23 that outputs an AND signal of the exclusive OR signal EX and the second PWM signal PW2. Composed. Therefore, the AND signal output from the AND circuit 22 is input to the first output, and the AND signal output from the AND circuit 23 is input to the second output buffer 12.
• the operation of the coil load drive circuit 1 will be described with reference to the waveform diagram of FIG.
• the figure shows the waveforms that occur in each section when the input control voltage V is increased linearly.
• the pulse width (that is, high-level period) of the PWM signal PW1 of 1 is small.
• the second transmission voltage V is lower than the pulse width of the second PWM signal PW2 (that is, the high level period).
• the pulse width of the PWM signal PW1 gradually increases, and the second transmission voltage V increases.
• the pulse width of the second PWM signal PW2 gradually decreases
• the exclusive OR signal EX is output when the input control voltage V is lower than the input reference voltage V.
• the pulse widths of the two pulses coincide with each other with a duty ratio of 50%, the pulse width becomes zero.
• a PWM pulse is output to the first and second output terminals OUTl and OUT2 only on the side of the first and second PWM signals PWl and PW2 having a larger pulse width. That is, when the input control voltage V is lower than the input reference voltage V, the second output terminal OUT2
• a pulse is output, and the second output terminal OUT2 is fixed to the ground potential. At this time, Motor 5 rotates in the forward direction. Then, the input control voltage V is equal to the input reference voltage V.
• the first and second output terminals OUTl and OUT2 are both fixed to the ground potential, and the motor 5 stops. Note that the difference between the input control voltage V and the input reference voltage V increases.
• the pulse width of the PWM pulse output from the first output terminal OUT1 or the second output terminal OUT2 increases, and the torque for driving the motor 5 increases.
• the coil load drive circuit 1 includes the input control voltage V and the input reference voltage V
• the first transfer voltage V increases and decreases while maintaining monotonicity and linearity according to the difference
• This coil load drive circuit 1 has an input control voltage V equal to the input reference voltage V.
• both the first and second output terminals OUT1 and OUT2 are fixed to the ground potential and do not output PWM pulses, so the first and second output buffers 11, 12 are generated by switching. Radiation noise can be suppressed.
• the coil load drive circuit 2 replaces the transfer voltage generation circuit 17 in the coil load drive circuit 1 with the transfer voltage generation circuit 27, and also controls the center voltage V of the triangular wave signal TRI. With the input reference voltage V.
• This transmission voltage generation circuit 2
• a first inverting amplifier 33 for inverting and outputting the output and a second inverting amplifier 34 for further inverting and outputting the output are provided. Then, the output of the first inverting amplifier 33 becomes the first transmission voltage V and the second
• the output of the TR1 inverting amplifier 34 becomes the second transmission voltage V.
• the waveform is similar to that of FIG.
• This coil load drive circuit 2 inputs the center voltage V
• the coil load driving circuits 1 and 2 described above are connected to both terminals of the motor 5 during the pulse period (high level period) of the PWM pulse output from the first output terminal OUT1 or the second output terminal OUT2. A voltage is applied between them, and a current flows in the direction of the voltage. During a period other than the pulse period (low-level period), no voltage is applied between both terminals of the motor 5 because both terminals of the motor 5 are fixed to the ground potential. Since the current tends to continue to flow due to its nature, a so-called regenerative current flows. As shown in FIG. 4, the output transistors on the power supply voltage V side of the first and second output buffers 11 and 12 are
• the star l la, 12a is a P-type MOS transistor and the ground potential side output transistor l lb, 12b is an SN type MOS transistor, it is not a pulse period when a PWM pulse is output from the first output terminal OUT1 During the period (low-level period), the regenerative current I flows from the output transistor l ib of the first output buffer 11 to the output transistor 12 b of the second output buffer 12 through the motor 5.
• an N-type MOS transistor has a lower on-resistance than a P-type MOS transistor, so that when a regenerative current flows through the N-type MOS transistor, power consumption is lower than in the case of a P-type MOS transistor.
• the coil load driving circuits 1 and 2 are more advantageous in terms of power consumption than the coil load driving circuit 201 in which a regenerative current may flow through both the N-type MOS transistor and the P-type MOS transistor.
• the N-type MOS transistor is replaced with an NPN-type bipolar transistor and the P-type MOS transistor is replaced with a PNP-type bipolar transistor.
• the fixed potential of the output from the first output terminal OUT1 or the second output terminal OUT2 is the ground potential in terms of power consumption.
• this it is also possible to modify this to be the power supply voltage V.
• the coil load drive circuit 3 shown in the circuit diagram of FIG. 5 changes the polarities of the input terminals of the first and second PWM comparators 14 and 15 in the coil load drive circuit 1 and exchanges the output PWM pulse synthesis circuit 16 with each other.
• the output PWM pulse synthesizing circuit 26 in which inverters 31 and 32 for inverting the outputs of the ND circuits 22 and 23 are added is replaced.
• the pulse width of the PWM pulse output from the first output terminal OUT1 is controlled by the input control. When the voltage V rises linearly, the voltage gradually increases, and the input control voltage V
• the coil load drive circuit 3 suppresses radiation noise generated by switching of the first and second output buffers 11, 12 when the motor 5 is stationary. Will be possible. Further, the coil load drive circuit 2 can be similarly deformed.
• the coil load drive circuit can suppress generation of radiation noise.
• an optical disc device including the coil load driving circuit and a coil load driven by the coil load and performing focus adjustment, tracking adjustment, and the like can perform stable operation because radiation noise is suppressed. it can.
• the present invention is not limited to the embodiments described above, and various design changes can be made within the scope of the matters described in the claims.
• the same operation can be performed by simultaneously changing the polarities of the voltage-current converter 17 of the coil load drive circuit 1 and the input terminals of the first and second PWM comparators 14 and 15.
• the output PWM pulse synthesizing circuit 16 (or 26) can of course have various logic circuit configurations to synthesize the same output.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Control Of Direct Current Motors (AREA)
• Dc-Dc Converters (AREA)
• Inverter Devices (AREA)
• Control Of Electric Motors In General (AREA)
• Control Of Linear Motors (AREA)
• Optical Recording Or Reproduction (AREA)
• Optical Head (AREA)
• Parts Printed On Printed Circuit Boards (AREA)

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• 2004
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