JPS61196470A - Power source supply circuit to delay circuit in video disk player - Google Patents

Abstract

PURPOSE:To carry out satisfactorily a dropout compensation by feeding a constantly stable power source to a delay circuit using a CCD and removing a problem that a delay video signal is disturbed and an image quality is lowered by a variation of a power source voltage. CONSTITUTION:A forward lowering voltage of a diode 8 is denoted as VF and a zener voltage of a zener diode 9 as Vz, a voltage VB produced in a base of a transistor 5 becomes a stable voltage VF+Vz by an operation of the zener diode 9 and an operation of an integrator consisting of a resistance 6 and a capacitor 10. Since a voltage VBE between the base and an emitter of the transistor 5 is almost the same as VF, a voltage VE produced in the emitter of the transistor 5 becomes VB-VBE=Vz=+6, even if noise is mounted on a power source +12V, +6V stable in a floating condition is formed. Similar ly, from the power source -12V, also a stable -6V is formed and a delay circuit 3 receives no influence of the noise and can supply a stabled delay video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Technical Field The present invention relates to an improvement in a power supply circuit when a delay circuit using a CCD is used as dropout compensation means in a video disc player.

b. Prior art and its problems In general, if a video disc has scratches, dirt, etc., signal dropouts (dropouts) occur and good image quality cannot be obtained, so video disc players are provided with dropout compensation means. ing.

As shown in FIG. 3, this dropout compensation means includes a detection circuit 1 for detecting a dropout of a detection signal from the disk, and a demodulated video signal outputted via a demodulator 2 during a horizontal scanning period (IH). a delay circuit 3 for delaying the delay;
A switch 4 is provided for switching whether or not to input the demodulated video signal to the delay circuit 3 according to the output of the detection circuit 1, and by utilizing the fact that the video signal hardly changes with the LH time difference, the signal in the dropout section is input to the IH. A system has been put into practical use that allows image quality to be obtained without disturbances due to dropouts by replacing the previous signal. In this type of dropout compensation means, a CCD is often used for the delay circuit 3, but since the CCD is sensitive to power supply voltage fluctuations, the power supply voltage is directly applied to the delay circuit 3 as in the conventional example shown in FIG. The configuration is a switching regulator.

When noise is added to the power supply +L2V due to a motor drive circuit or the like, the effect appears on the IH-delayed video signal, resulting in a problem in that a high-quality reproduced image cannot be obtained.

C0 Purpose The present invention has been made in view of the above-mentioned points.
The purpose of the present invention is to provide a power supply circuit that supplies stable power to a delay circuit using a delay circuit.

d. Configuration of the embodiment The present invention will be described in detail below based on one drawing.

1 and 2 are circuit diagrams showing an embodiment of the present invention.

In FIG. 1, a +12V power supply is connected to the collector of a transistor 5, and a resistor 6 is connected between the base of the transistor 5 and the +12V power supply. The emitter of the transistor 5 is a delay circuit 3 using a CCD.
It is connected to the.

A connection point 7 between the resistor 6 and the base of the transistor 5 is connected to the anode of a diode 8, and the cathode of the diode 8 is connected to the cathode of a Zener diode 9 with a Zener voltage of 6 V, and is connected to GN via the Zener diode 9.
Connected to D.

Further, the connection point 7 is connected to GND via a capacitor 10.
The capacitor IO and the resistor 6 constitute an integrator. On the other hand, the power supply -12V is connected to the collector of the transistor 11, and the resistor 12 is connected between the base of the transistor 11 and the power supply -12V.

The emitter of the transistor 11 is connected to a delay circuit 3 using a CCD. A connection point 13 between the resistor 12 and the base of the transistor 11 is connected to the cathode of a diode 14, and the anode of the diode 14 is connected to the anode of a Zener diode 15 with a Zener voltage of 6 V, and connected to GND via the Zener diode 15. has been done.

Further, the connection point 13 is connected to GN via a capacitor 16.
D, and the capacitor 16 and the resistor 12 constitute an integrator.

A second embodiment of the present invention shown in FIG.
By connecting the cathode of the Zener diode 17 to the cathode of the Zener diode 17 with a Zener voltage of 12 V, and connecting the anode of the Zener diode 17 to the anode of the diode 14, the Zener diodes 9 and 15 of the first embodiment are combined into one Zener diode 17. This is replaced by a diode 17.

It should be noted that the other configurations are the same as those of the first embodiment, so the same reference numerals are given and the explanation will be omitted.

e. Effect of the embodiment Next, the operation of the embodiment of the present invention having the above configuration will be explained.

If the power supply is configured using a switching regulator (not shown), or if the power supply is affected by noise from other circuits (not shown), noise will also be added to the +12V power supply, and this will cause the noise to be lost to the power supply. +12V is applied to the collector of transistor 5 and to resistor 6. Here, if the forward voltage drop of the diode 8 in FIG. capacitor 1
The voltage VF stabilized by the action of the integrator consisting of 0
+Vz. Since the base-emitter voltage VBI- of the transistor 5 is almost equal to vF, the voltage Vε appearing at the emitter of the transistor 5 is V+:= V B V B E = V z = +
6 V, and even if there is noise in the power supply +12V, a stable +6V in a floating state is created with respect to this power supply +12V. Similarly, power supply -1
2V also generates a stable -6V in a floating state with respect to this power supply -12V, and this +6V and -6V
By applying this to the delay circuit 3, the delay circuit 3 can supply a stable delayed video signal without being affected by noise.

Further, in the embodiment shown in the second figure, the Zener voltage 12
Cursed power supply +1 across the Zener diode 17 of V
Since the voltage in a floating state with respect to 2V and -12V appears as it is between the emitters of transistors 2 and 3, the potential difference between these two emitters is always constant 12V even if there is noise on the power supplies +12V and -12V.
By applying this potential difference to the delay circuit 3, the delay circuit 3 can supply a stable delayed video signal without being affected by noise.

f. Effects As described above, according to the present invention, a stable power supply can always be supplied to a delay circuit using a CCO with a simple configuration. This solves the problem of deterioration in image quality and makes it possible to perform dropout compensation satisfactorily. In addition, it is possible to use a switching regulator, which tends to generate noise but has good power efficiency, as a power source for a video disc player, which has a great practical effect.

[Brief explanation of the drawing]

1 and 2 are circuit diagrams showing embodiments of the present invention;
The figure is a block diagram showing an example of dropout compensation means in a video disc player. FIG. 4 is a circuit diagram showing a conventional example. 3: Delay circuit 5, 11: Transistor 6.12
:Resistance 8.14 :Diode 9.15.17
: Zener diode 10, L 6 : Capacitor patent applicant Asahi Optical Industry Co., Ltd.) 1! X t-4t! l

Claims (1)

[Claims] A video disc player equipped with a delay circuit using a CCD as a dropout compensation means, characterized in that the power supply to the delay circuit is set in a floating state by being removed from a noise-containing power supply. A circuit that supplies power to a circuit.