JP2892705B2 - Horizontal output circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a high-voltage load current (a flyback transformer 2) of a picture tube high-voltage circuit generated according to the content of a reproduced image in a color television receiver or the like. The present invention relates to a horizontal output circuit capable of correcting an image distortion caused by a fluctuation of a secondary load current.

(Prior Art) Conventionally, a horizontal deflection circuit output stage of a color television receiver is configured as shown in FIG. A series circuit of a damper diode Dd, a resonance capacitor Cr1, a horizontal deflection coil Ly and an S-shaped correction capacitor Cs is connected in parallel between the collector and emitter of the horizontal output transistor Q1,
The collector of Q1 is connected to the DC power supply E via the primary winding Lp of the flyback transformer T1, and a drive pulse having a horizontal cycle is supplied to the base of the transistor Q1 via the drive transformer T2. A ripple removing capacitor C2 is connected to the DC power supply E in parallel. A high-voltage circuit is formed on the secondary side of the flyback transformer T1, and a high-voltage DC voltage is supplied from one end of the secondary winding to the anode of a picture tube (not shown). An ABL circuit (not shown) is formed at the other end of the. The S-shaped correction capacitor Cs is charged from the DC power supply E through the primary winding Lp of the flyback transformer T1 and functions as a substantial series power supply for the horizontal deflection coil Ly.
Resonates in series with the horizontal deflection coil Ly, and superimposes on the deflection current to S
It has the function of improving the linearity of the screen by bending it into a letter shape.

By the way, in the above-mentioned circuit, there is a problem that various distortions are generated on the screen due to the fluctuation of the secondary load current is of the flyback transformer T1 generated according to the content of the reproduced image. For example, when a white rectangular wave signal is received, the secondary side load current is increased, the high voltage of the picture tube gradually decreases, the horizontal amplitude increases with time, and as a result, the white rectangular image reproduced on the screen is reproduced. Become trapezoidal as shown in FIG.
When a white crosshatch signal is received, a vertical line after horizontal line reproduction is bent in the horizontal direction as shown in FIG.

(Problems to be Solved by the Invention) As described above, conventionally, there has been a problem that trapezoidal distortion and horizontal bending occur when a white signal is received.

Accordingly, an object of the present invention is to provide a horizontal output circuit capable of eliminating the above-described screen distortion such as trapezoidal distortion or bending generated on the screen.

[Constitution of the Invention] (Means for Solving the Problems) A first invention according to this horizontal output circuit has a base, an emitter, and a collector, and a drive pulse having a horizontal period is supplied to the base, and a collector-emitter connection is provided. Series circuit of horizontal deflection coil and S-shaped correction capacitor in parallel to
A horizontal output transistor connected to one end of a primary winding of a flyback transformer, an emitter connected to a reference potential point, and the other end of the primary winding of the flyback transformer. A diode connected between the DC power supply and the DC power supply so that the DC power supply side becomes an anode; a first capacitor connected between the cathode side of the diode and a reference potential point; a coil connected in parallel with the capacitor; A parallel circuit comprising a series circuit of capacitors and a second resonance capacitor connected in parallel to a primary winding of the flyback transformer.

A second aspect of this horizontal output circuit has a base, an emitter, and a collector, a drive pulse having a horizontal period is supplied to the base, and a horizontal deflection coil and an S-shaped correction are provided in parallel between the collector and the emitter. A series circuit of capacitors, a first resonance capacitor, and a damper diode are connected, and a collector is a horizontal output transistor connected to a DC power supply via a primary winding of a flyback transformer; an emitter of the horizontal output transistor and a reference potential point. A diode connected so that the cathode is on the reference potential point side, a parallel circuit in which a first capacitor, a series circuit of a coil and a second capacitor are connected in parallel to the diode, It comprises a collector of the output transistor and a second resonance capacitor connected between the reference potential point.

(Operation) In the circuit of the present invention, when the load current on the secondary side of the flyback transformer fluctuates, the resonance pulse voltage generated at both ends of the deflection yoke during the flyback period is obtained by the circuit including the diode, the first and second capacitors, and the coil. And the voltage (average value) across the deflection yoke also decreases. Therefore, when the secondary load current increases, the high voltage decreases and the horizontal amplitude tends to increase. However, since the voltage at both ends of the deflection yoke decreases as described above, it acts in a direction to suppress the horizontal amplitude from increasing, and the trapezoidal shape on the screen Distortion and bending of vertical lines can be reduced.

(Examples) Hereinafter, the present invention will be described based on examples shown in the drawings.

FIG. 1 is a circuit diagram showing a horizontal output circuit according to one embodiment of the present invention. In this figure, the same parts as those in FIG.

In FIG. 1, a damper diode Dd, a first resonance capacitor Cr1, a horizontal deflection coil Ly and an S-shaped correction capacitor Cs are provided between the collector and the emitter of the horizontal output transistor Q1.
Series circuit and second resonance capacitor Cr2 and capacitor C
1 are connected in parallel, the collector of the transistor Q1 is connected to the cathode of the diode D1 via the primary winding Lp of the flyback transformer T1, and the anode of the diode D1 is connected to the DC power supply E. The DC power supply E is connected in parallel with a ripple removing capacitor C3. Also, the second
The series circuit of the coil L1 and the capacitor C2 is connected between the connection point between the resonance capacitor Cr2, the capacitor C1 and the cathode of the diode D1 and the reference potential point (earth), and the drive transformer T2 is connected to the base of the transistor Q1. , A horizontal period drive pulse is supplied. Further, a high voltage circuit is formed on the secondary side of the flyback transformer T1, and a high voltage DC voltage is supplied from one end of the secondary winding to an anode of a picture tube (not shown). An ABL circuit (not shown) is formed at the other end of the.

FIG. 2 is a diagram showing waveforms at various parts of the circuit in FIG. 1, and FIG. 3 is a diagram for explaining one cycle of horizontal operation. In FIG. 2, (a) is a current iLP + iDC flowing through the primary winding Lp of the flyback transformer T1, (b) is a current iD1 flowing through the diode D1, and (c) is a current i1 flowing through a series circuit of the coil L1 and the capacitor C2. , (D) is the voltage V1 at the cathode of the diode D1, and (e) is the current iy flowing through the horizontal deflection coil Ly.
It is. Note that iLP is an AC current flowing through the primary winding Lp of the flyback transformer T1, iDC is a DC current flowing through the primary winding Lp, TH is one horizontal cycle, Ts is a scanning period, Tr is a flyback period,
DC = 0 indicates a DC zero level, and AC = 0 indicates an average level of an AC component.

In FIG. 3, (a) and (b) show the current in the first half and the second half of the scanning period, respectively, and the horizontal output transformer Q1 is turned on. In the first half of the scanning period, the deflection coil current iy, the current iLP flowing through the primary winding Lp of the flyback transformer T1, the current i1 flowing through the series circuit of the coil L1 and the capacitor C2, and the DC current iDC flowing from the DC power source E are 3. Since the current flows in the direction shown in FIG. 3A and the values of the coil L1 and the capacitor C2 are determined in advance so that i1 + iDC> iLP, the diode D1 is in a conductive state, and the cathode voltage V1 of the diode D1 is V1. = E and a constant voltage E is applied to the horizontal output circuit. In the latter half of the scanning period, the currents iy, iLP, i1 flow in the opposite direction to the first half of the scanning period as shown in FIG. 3 (b). However, as in the first half of the scanning period, the diode D1 is in a conducting state, and the horizontal output circuit Is a constant voltage E through a diode D1.
(In the latter half of the scanning period, iLP + iDC> i1
If so, D1 becomes conductive. I1 + iDC as described above
The values of L1 and C2 are selected so that> LP, but iLP + iDC
If a value is selected such that> i1 is also satisfied, the diode D1 will be conductive even in the latter half of the scanning period.) FIGS. 3 (c) and 3 (d) show the current in the first half and the second half of the retrace period, respectively, and the horizontal output transistor Q1 is off. In the retrace period, the circuit enters a resonance operation. In the first half of the retrace period, each current iy, i in the direction shown in FIG.
LP, i1 flows. In the figure, iy = iy1 + iy2, iLP = iLP1
+ ILP2, i1 = i11 + i12. At this time, the inflow current ic1 = iy2-iLP1-i12 is applied to the capacitor C1 in the direction shown in FIG.
And a positive resonance pulse e1 is generated at the cathode of the diode D1 (see FIG. 5 for changes in ic1 and V1 during the flyback period Tr). In the latter half of the flyback period, each current iy, iLP, i1 flows in the direction shown in FIG. Each current at this time flows in the opposite direction on the same route as in the first half of the flyback period.

Here, in FIG. 4, when the high-voltage load of the flyback transformer T1 increases and the secondary-side load current is increases, the amount of iLP1 flowing in the reverse direction through the capacitor C1 increases by an amount corresponding to the increase of is. Current ic1 flowing through C1
(= Iy2-iLP1-i12) decreases from the solid line to the dotted line as shown in FIG. 5 (a). Therefore, the resonance pulse e1 obtained by integrating ic1 also becomes the dotted line from the solid line as shown in FIG. 5 (b). As a result, the voltage 1 across the deflection yoke (= E + ▲)
▼) also decreases, and acts to decrease the extension of the horizontal amplitude due to the increase in the secondary side load current is.

FIG. 6 shows a change in the voltage 1 across the deflection yoke with respect to a change in the secondary load current is. As described above, since 1 decreases when the secondary side load current is increased, it works to reduce the horizontal amplitude. In other words, when is increases and the high voltage decreases, the horizontal amplitude tends to increase, but acts to suppress this.

Accordingly, the trapezoidal distortion of the rectangular image as shown in FIG. 9 can be suppressed, and the bending of the vertical bar after the horizontal white bar as shown in FIG. Work in the direction of decreasing.

 FIG. 7 is a circuit diagram showing another embodiment of the present invention.

In FIG. 7, a series circuit of a damper diode Dd, a horizontal deflection coil Ly and an S-shaped correction capacitor Cs, and a first resonance capacitor Cr1 are connected in parallel between the collector and the emitter of the horizontal output transistor Q1. Is connected to the DC power supply E via the primary winding Lp of the flyback transformer T1. The DC power supply E is connected in parallel with a ripple removing capacitor C3. A diode D1 is connected between the emitter of the horizontal output transistor Q1 and the reference potential point (earth) so that the cathode is on the reference potential point side.
Is connected to the diode D1, a series circuit of the coil L1 and the capacitor C2, and the capacitor C1 are connected in parallel, and a second terminal is connected between the collector of the horizontal output transistor Q1 and the reference potential point.
Is connected to the resonance capacitor Cr2.
Other configurations are the same as those in FIG. Even with such a configuration, the same effect as in FIG. 1 can be obtained.

That is, in FIG. 7, a voltage V2 (negative voltage) shown in FIG. 2 (f) is generated at the anode of the diode D1, and E − (− ▲ ▼) = E + ▲ at both ends of the horizontal deflection coil Ly.
This means that a voltage that becomes ▼ is applied (note that ▲
▼ is the average value of V2). Here, the pulse shown in FIG.
If e2, ▲ ▼ (= ▲ ▼) is e1 shown in FIG.
Similarly, as the high-pressure load of the flyback tons T1 increases, it moves in a direction to decrease. For this reason, the voltage E + ▲ across the horizontal deflection coil Ly also decreases, and as in the circuit of FIG. 1, it is possible to prevent an increase in the horizontal amplitude due to a decrease in high voltage, thereby reducing distortion.

[Effects of the Invention] As described above, according to the present invention, it is possible to obtain a horizontal output circuit having a stable screen with less trapezoidal distortion and horizontal bending generated in a conventional horizontal output circuit.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a horizontal output circuit according to an embodiment of the present invention, FIG. 2 is a waveform diagram showing signal waveforms at various parts of the circuit of FIG. 1, and FIG. 3 is one horizontal cycle of the circuit of FIG. FIGS. 4 to 6 are explanatory diagrams for explaining the operation of FIG. 1 when the secondary load of the flyback transformer fluctuates, and FIG. 7 is a diagram of the present invention. 8 is a circuit diagram showing a conventional horizontal output circuit, and FIGS. 9 and 10 are explanatory diagrams for explaining screen distortion caused by the conventional circuit. Q1: horizontal output transistor, Dd: damper diode, Ly: horizontal deflection coil, Cs: S-shaped correction capacitor, Cr1: first resonance capacitor, Cr2: second resonance capacitor, T1: fly Back transformer, C1, C2 ……
Capacitor, L1 ... Coil, E ... DC power supply, Lp ... Flyback transformer primary winding.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-21777 (JP, A) JP-A-61-174880 (JP, A) JP-A-61-289766 (JP, A) JP-A 64-64 17574 (JP, A) JP-A-2-94963 (JP, A) JP-A-61-174260 (JP, U) JP-B-48-33527 (JP, B1) (58) Fields investigated (Int. ⁶ , DB name) H04N 3/16 H04N 3/22

Claims (2)

(57) [Claims] The present invention has a base, an emitter, and a collector. A drive pulse having a horizontal period is supplied to the base.
A series circuit of a horizontal deflection coil and an S-shaped correction capacitor, a first resonance capacitor, and a damper diode are connected in parallel between the emitters, a collector is connected to one end of a primary winding of a flyback transformer, and an emitter is connected to a reference potential. A horizontal output transistor connected to a point, a diode connected between the other end of the primary winding of the flyback transformer and the DC power supply so that the DC power supply side is an anode, and between a cathode side of the diode and a reference potential point. A parallel circuit consisting of a connected first capacitor, a series circuit of a coil and a second capacitor connected in parallel to the capacitor, and a second resonance connected in parallel to the primary winding of the flyback transformer A horizontal output circuit comprising: a capacitor; And a base, an emitter, and a collector. A drive pulse having a horizontal period is supplied to the base.
A series circuit of a horizontal deflection coil and an S-shaped correction capacitor, a first resonance capacitor, and a damper diode are connected in parallel between the emitters, and a collector is connected to a DC power supply via a primary winding of a flyback transformer. An output transistor; a diode connected between the emitter of the horizontal output transistor and the reference potential point such that the cathode is on the reference potential point side; and a first capacitor, a coil and a second capacitor for the diode. A horizontal output circuit comprising: a parallel circuit in which series circuits are connected in parallel; and a second resonance capacitor connected between a collector of the horizontal output transistor and a reference potential point.