JPH0722741Y2 - Audio equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an audio apparatus having a plurality of different reproduction sound sources, such as a radio cassette tape recorder equipped with a compact disc player.

[Conventional technology]

An audio device such as a radio cassette tape recorder equipped with a compact disc player is provided with a plurality of different reproduction sound sources for reproducing media such as compact discs, radio broadcasts, and cassette tapes.
Such an audio device includes, for example, as shown in FIG. 2, a compact disc reproducing section (hereinafter referred to as a CD reproducing section) 21, a tuner 22, and a tape recording / reproducing section 23 as the reproduction sound source. ing.

In the CD reproducing section 21, when the servo circuit 25 controlled by the control circuit 24 outputs the focus signal and the tracking signal based on the light detection signal from the optical pickup (not shown), the coil driver 26 outputs the focus signal and the tracking signal. Are amplified and the focus coil 27 and the tracking coil 28 are driven. And this allows the focus coil
27 and the tracking coil 28 generate an electromagnetic force, and the objective lens 29 is displaced in the focus direction and the tracking direction by the action of this electromagnetic force.

Further, the CD reproducing unit 21 is provided with the coil driver 26, and stabilizing power sources 30 and 31 for supplying electric power to the control circuit 24 and the servo circuit 25. The stabilized power supply 30 includes a transistor Q ₂₁ , a Zener diode ZD ₂₁ , a capacitor C _21, and a resistor R ₂₁ . Transistor Q ₂₁
Has a collector connected to the main power supply 32 and an emitter connected to the coil driver 26. The base of the transistor Q _21, the cathode of the Zener diode ZD ₂₁ - and the anode is grounded through a capacitor C ₂₁ connected in parallel with the Zener diode ZD _21, is connected to one end of a resistor R ₂₁ There is.

On the other hand, the stabilized power supply 31 includes a transistor Q ₂₂ , a Zener diode ZD ₂₂ , a capacitor C _22, and a resistor R ₂₂ . The transistor Q ₂₂ has a collector connected to the emitter of the transistor Q _{21, and} an emitter connected to the control circuit 24 and the servo circuit 25. The base of the transistor Q _22, the cathode of the Zener diode ZD ₂₂ - anode and a zener diode ZD ₂₂ and is grounded via a capacitor C ₂₂ connected in parallel, the transistor Q ₂₁ via the resistor R ₂₂ Connected to the emitter.

The audio device is provided with a function switch 33 for switching connection between the main power source 32 and each of the playback sound sources.
Is provided. The function switch 33 has a CD terminal 33a, a RADIO terminal 33b and a TAPE terminal 33c,
CD terminal 33a is connected to the other end of the resistor R ₂₁ in the stabilized power supply 30, RADIO terminal 33b is connected to the tuner 22, further TA
The PE terminal 33c is connected to the tape recording / playback unit 23.

In the audio device configured as described above, when the function switch 33 is switched from the CD terminal 33a to the RADIO terminal 33b, the transistor Q in the stabilized power supply 31 is
₂₂ does not instantly turn off due to the charging voltage of the capacitor C ₂₂ connected to the base. Therefore, the control circuit 24
High-frequency noise generated by the function switch 33
It will fly to the tuner 22 that is turned on with the switching of, and the reception of the tuner 22 will be impaired.

Therefore, the audio device described above is provided with the inverter 34 in order to solve the above problem, and turns off the transistor Q ₂₂ rapidly. That is, in the inverter 34, as shown in FIG. 2, the output terminal is connected to the base of the transistor Q ₂₂ in the stabilized power supply circuit 31, and the input terminal is connected to the RADIO terminal 33b in the function switch 33. When the inverter 34 is provided in this way, the function switch 33 changes from the CD terminal 33a to the RADIO terminal 33b.
When switched to, the electric charge accumulated in the capacitor C ₂₂ in the stabilized power supply circuit 31 is released via the ground terminal of the inverter 34. Therefore, the transistor Q ₂₂ is rapidly turned off, the power supply to the control circuit 24 is cut off instantaneously, and the tuner 22 is not affected by the high frequency noise of the control circuit 24.

[Problems to be solved by the device]

However, in the above audio device, since the servo circuit 25 is supplied with power from the stabilized power supply 31 together with the control circuit 24, when the power supply is instantaneously cut off due to the rapid turn-off of the transistor Q ₂₂ , Servo circuit
Spike noise called a pop sound is generated in the focus signal and the tracking signal output from 25. Further, at this time, the stabilized power supply 30 has a coil for a while after the function switch 33 is switched from the CD terminal 33a to the RADIO terminal 33b because the transistor Q ₂₁ is slightly turned off due to the charging voltage of the capacitor C _21. Power is supplied to the driver 26. Therefore, the noise is amplified by the coil driver 26, and the focus coil 27 and the tracking coil 28 generate an unnecessarily large electromagnetic force.

As a result, the objective lens 29 displaces abnormally and collides with a lens cover (not shown) to generate a collision sound. Then, such a collision sound causes the function switch 33 to
If it occurs every time when switching from the CD terminal 33a to the RADIO terminal 33b, it may cause the operator to feel anxiety about the operation by associating with the occurrence of failure or abnormal operation, and the reliability of the audio device is impaired. Will be invited.

[Means for Solving the Problems]

The audio device according to the present invention comprises a drive coil for driving an objective lens, a servo circuit for servo-controlling the drive of the objective lens, a drive circuit for supplying a drive current to the drive coil based on the servo control of the servo circuit, and A first control transistor which controls a voltage of a power supply and supplies electric power to a drive circuit, a constant voltage diode, and a capacitor provided in parallel with the constant voltage diode, based on an output voltage of a main power supply. And a second control transistor that operates based on the output voltage of the first control transistor to control the output voltage and supply power to the servo circuit. Disconnect the main power supply from the optical disk playback unit, the receiving unit that receives wireless broadcasting, and the receiving unit such as the first constant voltage circuit or tuner. In the audio device, which is provided with a switching means for changing the second control transistor is rapidly turned off when the connection with the main power source by the switching means is switched from the first constant voltage circuit to the receiving section, Discharging means is provided for discharging the capacitor in the first constant voltage circuit when the connection with the power supply is switched from the first constant voltage circuit to the receiving unit, and the first constant voltage circuit is configured to discharge the discharge. The power supply to the drive circuit is instantaneously stopped when the capacitor discharges by the means.

[Action]

In the above configuration, when the connection with the main power source is switched from the first constant voltage circuit to the receiving unit by the switching unit, the discharging unit discharges the capacitor in the first constant voltage circuit, so that the first control is performed. The transistor turns off rapidly, and the second control transistor turns off together. Therefore, the power supply to the servo circuit and the drive circuit is instantaneously cut off.

Therefore, when the connection of the main power source by the switching means is switched from the first constant voltage circuit to the receiving unit and the receiving unit is turned on, the servo circuit is turned off almost at the same time. Therefore, as in the conventional case, the high frequency noise generated by the servo circuit does not fly to the receiving unit, and the high frequency noise does not impair the reception of the receiving unit.

Further, even if noise is generated in the focus signal and the tracking signal output from the servo circuit due to the second control transistor being turned off rapidly, the power supply to the drive circuit can also be performed by turning off the first control transistor. Since it is cut off, the noise is not amplified by the drive circuit. Therefore, it is possible to prevent the objective lens from being displaced by an abnormally large amount and colliding with the lens cover due to the amplification of the noise by the driving circuit, and as a result, it is possible to prevent the generation of a collision sound that occurs with the collision. You can

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

As shown in FIG. 1, the audio apparatus according to this embodiment includes a compact disc reproducing unit (hereinafter referred to as a CD reproducing unit) 1 as an optical disc reproducing unit, a tuner 2 as a receiving unit, and a tape recording / recording unit. The reproduction unit 3, a function switch 4 as a switching unit, an inverter 5 as a discharging unit, and a main power source 6 for supplying electric power to each reproduction sound source are provided.

The CD reproducing section 1 includes an objective lens 7, a focus coil 8 and a tracking coil 9 as a drive coil, a control circuit 10, a coil driver 11 as a drive circuit, a transistor Q ₁ as a first control transistor, and a first constant voltage. A constant voltage circuit 12 as a circuit, a transistor Q ₂ as a second control transistor, and a constant voltage circuit 13 are provided.

The control circuit 10 includes a control circuit 14 and a servo circuit 15.
It consists of The control circuit 14 is a circuit that controls each control target in the audio device, and is usually configured by an integrated circuit such as an IC. The servo circuit 15 is a circuit that moves the objective lens 7 within a range in which servo control is possible, then closes the servo loop, and performs servo control based on a light detection signal obtained from an optical pickup (not shown). The operation of the servo circuit 15 is controlled by the control circuit 14 so that the control circuit 14
Similarly to, it is usually composed of an IC or the like.

The coil driver 11 is an amplifier that amplifies the focus signal and the tracking signal output for servo control from the servo circuit 15 and drives the focus coil 8 and the tracking coil 9. The focus coil 8 and the tracking coil 9 are coils that generate an electromagnetic force that displaces the objective lens 7 in the focus direction and the tracking direction by driving the coil driver 11.

The transistor Q ₁ has a collector connected to the main power supply 6 and an emitter connected to the coil driver 11. Constant voltage circuit 12, the Zener diode ZD _1, and consists of a capacitor C ₁ and resistor R _1, the cathode of the Zener diode ZD _1, the positive terminal and one end of the resistor R ₁ of the capacitor C ₁ is the base of the transistor Q ₁ It is connected. And
The anode of the Zener diode ZD ₁ and the negative terminal of the capacitor C ₁ are both grounded.

The transistor Q ₂ has a collector connected to the emitter of the transistor Q ₁ and a collector connected to the control circuit 14 and the servo circuit 15 in the control circuit 10. The constant voltage circuit 13 includes a Zener diode ZD ₂ and a capacitor C ₂
And a resistor R ₂ and a Zener diode ZD ₂
The cathode, the positive terminal of the capacitor C ₂ , and one end of the resistor R ₂ are connected to the base of the transistor Q ₂ . Then, the anode of Zener diode ZD ₂ and capacitor C
The negative terminals of ₂ are both grounded, and the other end of the resistor R ₂ is connected to the emitter of the transistor Q ₁ .

The function switch 4 has a CD terminal 4a and a RADIO terminal 4b.
And a TAPE terminal 4c. In the function switch 4, the CD terminal 4a is connected to the other end of the resistor R ₁ in the constant voltage circuit 12, the RADIO terminal 4b is connected to the tuner 2, and the TAPE terminal 4c is connected to the tape recording / playback unit 3. ing. The function switch 4 configured in this way includes the above-mentioned CD terminal 4a, RADIO terminal 4b, and TAPE.
The connection between the terminal 4c and the main power supply 6 can be switched. The input terminal of the inverter 5 is connected to the RADIO terminal 4b of the function switch 4, the output terminal is connected to the base of the transistor Q ₁ , and the ground terminal is grounded.

In the above configuration, when the main power supply 6 and the CD power supply terminal 4a are connected by the function switch 4, the constant voltage circuit 12 in the CD reproducing section 1 generates a constant voltage from the voltage given by the main power supply 6. Turn on transistor Q ₁ . When the transistor Q ₁ is turned on, power is supplied to the coil driver 11, and the constant voltage circuit 13 generates a constant voltage from the voltage applied via the transistor Q ₁ to turn on the transistor Q ₂ . When power is supplied to the control circuit 14 and the servo circuit 15 in the control circuit 10 by turning on the transistor Q ₂ , focus servo and tracking servo can be executed. When the coil driver 11 drives the focus coil 8 and the tracking coil 9 according to the servo control of the servo circuit 15,
The objective lens 7 is displaced by the electromagnetic force generated by the focus coil 8 and the tracking coil 9 so that the objective lens 7 is correctly focused on an appropriate position on the disc (not shown).

By the way, the function switch 4 is switched,
When the main power supply 6 and the RADIO terminal 4b are connected, the inverter 5
Since the voltage of the main power supply 6 is applied to the input terminal of the above and becomes high level, the output terminal of the inverter 5 becomes low level. Then, the electric charge accumulated in the capacitor C ₁ in the constant voltage circuit 13 is released through the ground terminal of the inverter 5, so that the transistor Q ₁ is turned off rapidly.
As a result, the power supply to the coil driver 11 is cut off, the transistor Q ₂ is turned off, and the power supply to the control circuit 14 and the servo circuit 15 is cut off.

If the power supply to the servo circuit 15 is instantaneously cut off, noise will be generated in the focus signal and the tracking signal. However, since the power supply to the coil driver 11 is also cut off, the noise is amplified. Never. Further, almost simultaneously with the connection of the function switch 4 to the main power supply 6 being switched to the RADIO terminal 4b, the power supply to the control circuit 14 is cut off, so that the tuner 2 is affected by the high frequency noise generated by the control circuit 14. It does not extend to

[Effect of device]

As described above, the audio apparatus according to the present invention supplies the drive coil for driving the objective lens, the servo circuit for servo-controlling the drive of the objective lens, and the drive current to the drive coil based on the servo control of the servo circuit. A drive circuit, a first control transistor for controlling the voltage of the main power supply to supply power to the drive circuit, a constant voltage diode and a capacitor provided in parallel with the constant voltage diode, and based on the output voltage of the main power supply. A first constant voltage circuit that applies a constant voltage to the base of the first control transistor, and a second constant voltage circuit that operates based on the output voltage of the first control transistor to control the output voltage and supply power to the servo circuit. An optical disc reproducing section provided with a control transistor, a receiving section for receiving radio broadcasting, and a connection between the first constant voltage circuit or the receiving section and the main power supply are connected. In the audio device, which is provided with a switching means for switching, the second control transistor is rapidly turned off when the connection with the main power source by the switching means is switched from the first constant voltage circuit to the receiving section. Discharging means is provided for discharging the capacitor in the first constant voltage circuit when the connection with the main power source is switched from the first constant voltage circuit to the receiving unit, and the first constant voltage circuit is With the discharging of the capacitor by the discharging means, the electric power supply to the drive circuit is instantaneously stopped.

As a result, even when the connection of the switching means to the main power source is switched from the first constant voltage circuit to the receiving section, the capacitor in the first constant voltage circuit is discharged, and the first control transistor and the second control circuit are discharged. The transistor turns off rapidly. Therefore, as in the case of the conventional audio device, the second control transistor rapidly becomes OF during the switching as described above.
By performing F, the power supply to the servo circuit is cut off, and the reception unit is not affected by the high frequency noise generated from the servo circuit. In addition, even if noise is generated in the focus signal and the tracking signal output from the servo circuit due to the rapid turn-off of the second control transistor,
The noise is not amplified by the drive circuit because the power supply to the drive circuit is momentarily cut off by the rapid turn-off of the first control transistor.

Therefore, it is possible to prevent the objective lens from being displaced more than necessary and colliding with the lens cover due to the noise being amplified by the drive circuit. Therefore, the audio device according to the present invention can prevent the occurrence of the collision noise caused by the above-mentioned collision, eliminate the anxiety of operation, and solve the inconvenience that impairs the reliability of the device. Produce an effect.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention and is a circuit diagram showing a main part of an audio apparatus. FIG. 2 shows a conventional example and is a circuit diagram showing a main part of an audio apparatus. 1 is a compact disc reproducing unit (optical disc reproducing unit), 2 is a tuner (receiving unit), 4 is a function switch (switching unit), 5 is an inverter (discharging unit), 6
Is a main power source, 7 is an objective lens, 8 is a focus coil (driving coil), 9 is a tracking coil (driving coil),
10 is a control circuit, 11 is a coil driver (driving circuit), 12 is a constant voltage circuit (first constant voltage circuit), 13 is a constant voltage circuit, 15
Is a servo circuit, Q ₁ is a transistor (first control transistor), Q ₂ is a transistor (second control transistor), ZD ₁ is a Zener diode (constant voltage diode in the first constant voltage circuit), ZD ₂ is a Zener A diode, C ₁ is a capacitor (capacitor in the first constant voltage circuit), and C ₂ is a capacitor.

Claims (1)

[Scope of utility model registration request] 1. A drive coil for driving an objective lens, a servo circuit for servo-controlling the drive of the objective lens, a drive circuit for supplying a drive current to the drive coil based on the servo control of the servo circuit, and a voltage of a main power supply. A first control transistor for controlling the power supply and supplying power to the drive circuit, a constant voltage diode and a capacitor provided in parallel with the constant voltage diode, and based on the output voltage of the main power source An optical device provided with a first constant voltage circuit for applying a constant voltage and a second control transistor which operates based on the output voltage of the first control transistor to control the output voltage and supply power to the servo circuit. And a switching means for switching the connection between the first constant voltage circuit or the receiving section and the main power source. In the audio device which rapidly turns off the second control transistor when the connection with the main power source by the means is switched from the first constant voltage circuit to the receiving unit, the connection with the main power source by the switching means is the first. Discharging means for discharging the capacitor in the first constant voltage circuit when the constant voltage circuit is switched to the receiving section is provided, and the first constant voltage circuit causes the capacitor to be discharged by the discharging means. An audio device characterized in that power supply to the drive circuit is stopped instantaneously.