JPH066714Y2 - Thyristor power supply circuit for television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thyristor power supply circuit for stabilizing the output voltage by alternately repeating turn-on and turn-off of a thyristor receiving a DC input voltage in a television receiver.

2. Description of the Related Art A television receiver uses a power supply circuit having a thyristor, but if the receiver becomes larger and power consumption increases, the thyristor generates more heat, so the heat sink may be enlarged. Therefore, various measures must be taken against heat dissipation. By using a plurality of thyristors connected in parallel, the shared current of each thyristor is reduced, so that the amount of heat generated in each thyristor is reduced, and it is convenient because no special consideration is required for heat dissipation.

FIG. 4 shows a general configuration example of the power supply circuit in which the thyristors are connected in parallel as described above. In this figure, first and second thyristors (SR ₁ ) and (SR ₂ ) are connected in parallel between the input terminal (1) and the output terminal (2), and the first and second starter circuits (SR) are connected to the respective gates. 3a) (3b) and gate control circuit (4a)
(4b) are respectively connected as shown. Both of these start-up circuits (3a) (3b) and gate control circuits (4a) (4b) are for turning on the thyristor, but the start-up circuit only works initially, and the thyristor turns on and turns off. The turn-on in the steady state in which the above is repeated is performed exclusively by the gate control circuits (4a) and (4b). On the other hand, turn-off is performed by a turn-off signal given from the outside through the arc-extinguishing windings (L ₁ ) (L ₂ ) connected to each anode of the thyristor.

Problems to be Solved by the Invention However, in the configuration of FIG. 4, since each thyristor is provided with a starting circuit individually, there is a drawback that the number of elements increases and the cost increases. Moreover, since the starting current as a whole increases, there is also a drawback that the power consumption at the time of starting increases.

Therefore, an object of the present invention is to provide a new and effective thyristor power supply circuit for a television receiver, which eliminates the above problems.

Means for Solving Problems The thyristor power supply circuit of the television receiver of the present invention is
A plurality of thyristors connected in parallel between an input terminal to which an uncontrolled DC voltage is applied and an output terminal connected to a horizontal output circuit in a television receiver, and a specific one of the plurality of thyristors are activated. At a timing that is commonly connected to the starter circuit and the gates of the plurality of thyristors, and that corrects the fluctuation of the output voltage based on the pulse obtained from the flyback transformer of the horizontal output circuit and the output voltage of the output terminal. A gate control circuit that outputs a turn-on signal to the plurality of thyristors, and an arc-extinguishing winding that is wound around the flyback transformer and that gives a signal that turns off the plurality of thyristors. It is configured to turn on and off in a cycle.

Action One activating circuit turns on a specific thyristor when the power is turned on. As a result, a voltage is generated at the output terminal, and the gate control circuit starts operation based on this output voltage to generate a turn-on signal. Since the gates of the thyristors are commonly connected to the gate control circuit, all the thyristors other than the activated thyristors are activated by the turn-on signal of the gate control circuit. Therefore, in this configuration, first, only a specific thyristor is activated,
The rest of the thyristors are activated via the gate control circuit that operates with the activation of the thyristors. Therefore, the number of starting circuits can be reduced as much as possible, and the current from the input terminal required for starting can be reduced.

The turn-on signal generated by the gate control circuit is generated by tamming that corrects a variation in the output voltage (variation with respect to a predetermined output voltage value) based on the output voltage and a pulse obtained from a flyback transformer. Further, the turn-off signal is given based on the operation of the flyback transformer.

Examples Hereinafter, examples shown in the drawings will be described. Fig. 1 shows the basic configuration in blocks. Input terminals (1)
Between the output terminal (2) and the first and second thyristor (SR ₁ )
(SR ₂ ) are connected in parallel with each other. Starting circuit (3)
There is only one, one end of which is the input terminal (1)
And the other end is connected to the gate of the first thyristor (SR ₁ ). (4) is the first and second thyristors (SR ₁ ) (SR
It is a gate control circuit common to ₂ ) and operates when the output voltage generated at the output terminal (2) exceeds a predetermined level.
A turn-on signal is given to the gate of the second thyristor (SR ₁ ) (SR ₂ ). (L ₁ ) (L ₂ ) receives a turn-off signal from the outside by electromagnetic coupling, and sends it to the respective thyristors (SR ₁ ) (SR ₂ )
The first and second arc-extinguishing windings are provided for the purpose of correcting the current imbalance.

When the power supply of the device incorporating the circuit of Fig. 1 is turned on, a DC voltage is applied to the input terminal (1), and the starter circuit (3) operates accordingly and the first thyristor (SR ₁ ) is turned on. Let
The starting circuit (3) becomes inoperative after making the first thyristor (SR ₁ ) conductive. During this time, the start signal is not given to the second thyristor (SR ₂ ), so it remains off.
A voltage is applied to the output terminal (2) through the thyristor (SR ₁ ) and the gate control circuit (4) operates, so that it receives a turn-on signal from the gate control circuit (4) and turns on. That is, the second thyristor (SR ₂ ) is activated later than the first thyristor (SR ₁ ). Thus, only the first thyristor (SR ₁ ) is activated by the activation circuit (3), and the remaining second thyristor (SR ₂ ) is activated first.
Since the gate control circuit (4) is operated by the voltage generated at the output terminal (2) by the activation of the thyristor (SR ₁ ), the activation circuit is not necessary for the second thyristor (SR ₂ ).

FIG. 2 shows a power supply circuit in a television receiver of the present invention, which incorporates the structure shown in FIG. here,
(5) is a horizontal output circuit, (6) is a horizontal output transistor, (7) is a damper diode, (8) is a resonance capacitor, (9) is a horizontal deflection coil, and (10) is an S-shaped correction capacitor. 11) is a flyback transformer.

The primary coil (12) of the flyback transformer (11) is connected to ground via a capacitor (C ₃ ). Then, at the connection point between this capacitor (C ₃ ) and the primary coil (12), the power supply circuit (1
The output terminal (2) of 3) is connected. The secondary coil (14) of the flyback transformer (11) acts as a high voltage coil,
The output is supplied to the anode electrode (not shown) of the cathode ray tube through the rectifying element (15). The first and second coils (L ₁ ) (L ₂ ) of the power supply circuit (13) are connected to the flyback transformer (1
It is wound as a tertiary coil on 1) and induces a negative pulse.
Reference numeral (16) is also a pulse coil wound around the flyback transformer (11) and generates a pulse synchronized with the flyback transformer (see FIG. 3A). This pulse (a) is rectified and smoothed by the rectifying diode (D ₃ ) and the capacitor (C ₄ ) to become the power supply voltage of the gate control circuit (4), and as described later, the resistor (R ₂ ) and the capacitor (C ₄ ). It is integrated in ₅ ) and becomes a sawtooth voltage. (17) is an AC power plug of the television receiver, (18) is a power switch,
(19) is a full-wave rectifier circuit, (20) is a smoothing circuit consisting of capacitors (C ₁ ) (C ₂ ) and a coil (L ₃ ), and the input terminal (1) of the power supply circuit (13) is a coil (L ₃ ) is connected to the connection point of the capacitor (C ₂ ). The starting circuit (3) consists of a resistor (R ₁ ), a Zener diode (D _z ), and a backflow prevention diode (D ₁ ) connected in series. The operating condition of this starting circuit (3) is the resistance.
(R ₁ ), the diode (D ₁ ) and the gate-cathode voltage drop of the first thyristor (SR ₁ ) are neglected, the input voltage Ein
And depending on the Zener voltage V _z of the output Eout potential difference and the Zener diode _{(D z), Ein-Eout} > automatically turned on when becomes V _z, a first thyristor by the current flowing therethrough (S
I fire R ₁ ). The first and second thyristors (SR ₁ ) (SR ₂ ) are composed of resistors (R ₁₀ ) (R ₁₁ ) and capacitors (C ₆ ) (C ₇ ) to prevent thyristor current error due to large instantaneous voltage fluctuations. The commutation prevention circuits are connected in parallel.

The gate control circuit (4) changes the voltage of the output terminal (2) to the resistance (R
₃ ) The first transistor (Q ₁ ) to which the voltage divided by (VR) (R ₄ ) is applied to the base, and the second transistor (Q ₂ ) to which the sawtooth voltage is applied to the base, A constant voltage diode (D ₂ ) that connects the emitter to ground, a resistor (R ₅ ) (R ₆ ) (R ₇ ) (R ₈ ), a capacitor (C ₅ ) (C ₆ ), and It is composed of a third transistor (Q ₃ ), of which a resistor (R ₈ ) and a capacitor (C ₆ ) form a differentiating circuit. The output of the gate control circuit (4) is the third transistor (Q
₃ ) Collector and resistor (R ₉ ) to resistor (R ₁₂ ), capacitor
Through (C ₈ ) to the gate of the first thyristor (SR ₁ ), and through the resistor (R ₁₃ ) and capacitor (C ₉ ) the second thyristor (SR ₂ ).
It is given to the gate of.

Next, the operation of FIG. 2 will be described. When the power switch (18) is closed and an AC voltage is applied to the full-wave rectifier circuit (19), a rectified and smoothed uncontrolled DC voltage is derived from the input terminal (1). At this time, since the voltage across the capacitor (C ₃ ) is zero or an extremely small value, the above-mentioned Ein-Eout> V _z
The following condition is satisfied, a current flows through the starting circuit (3), and the first thyristor (SR ₁ ) becomes conductive. This first thyristor (SR
_{When the} capacitor (C ₃ ) is charged to a certain value by turning on ( ₁ ), the horizontal output circuit (5) starts operating. Meanwhile, the starting circuit (3) is turned off. Horizontal output circuit (5)
When the operation starts, the pulse (a) synchronized with the flyback pulse is generated, and the diode (D ₃ ) and capacitor (C ₄ )
The gate control circuit (4) is rectified and smoothed by the power supply voltage. Further, the pulse (a) is integrated by the resistor (R ₂ ) and the capacitor (C ₅ ) and becomes a sawtooth wave voltage as shown in FIG. 3 (b). On the other hand, the voltage (Eou
t) is divided by resistance (R ₃ ) (VR) (R ₄ ) to divide the first transistor (Q ₁ )
The divided voltage value of the output voltage (Eout) is applied to the base affects the level of the sawtooth wave voltage through a resistor from the collector of the first transistor _{(Q 1) (R 5)} . For example, output voltage (Eou
If t) is high, the collector potential of the first transistor (Q ₁ ) is low, so the level of the sawtooth wave voltage (b) is lowered as shown by the dotted line in FIG. 3 (c). Thus, the second transistor (Q ₂ ) is connected to the sawtooth wave voltage (b) and the output voltage (E
The information voltage of (out) is base-driven by the superimposed voltage, and a pulse as shown in FIG. 3 (d) is output to its collector. This pulse (d) is integrated by the resistor (R ₂ ) and the capacitor (C ₅ ) and becomes as shown in Fig. 3 (e). The negative polarity waveform of this differential waveform causes the third transistor (Q ₃ ) Turns on instantaneously and outputs a pulse as shown in FIG. This pulse (f) is applied to the gate of the first thyristor (SR ₁ ) through the resistor (R ₁₂ ) and the capacitor (C ₈ ) and at the same time the second pulse is applied through the resistor (R ₁₃ ) and the capacitor (C ₉ ).
Added to the gate of the thyristor (SR ₂ ). This also activates the second thyristor (SR ₂ ). If the first thyristor (SR ₁ ) is also off, this pulse (f) turns it on again.

On the other hand, when the horizontal output circuit (5) starts operating, the negative pulse synchronized with the flyback pulse is the first and second negative pulses.
It occurs in the arc-extinguishing winding (L ₁ ) (L ₂ ) and this is the first and second thyristor.
Since the anodes of (SR ₁ ) and (SR ₂ ) are set to the low level, the first and second thyristors (SR ₁ ) and (SR ₂ ) are turned off. The first and second thyristors (SR ₁ ) and (SR ₂ ) are gate control circuits (4).
The turn-on by and the turn-off by the arc-extinguishing winding (L ₁ ) (L ₂ ) are repeated alternately. And at that time, turn-off is synchronized with the flyback pulse, but turn-on is the output voltage.
The start time is advanced or delayed according to the variation of (Eout), and thereby the output voltage is stabilized (that is, stabilized). For example, the voltages of (c), (d), (e), and (f) when the output voltage fluctuates in the high direction are in the states shown by the dotted lines. This means that the turn-on start time will be delayed as can be seen from Fig. 3 (f). Therefore, the period from turn-on to turn-off is shortened and the charging time of the capacitor (C ₃ ) is shortened, so the output voltage (Eout) is lowered. The correction is performed in this way.
When the output voltage (Eout) fluctuates in the lower direction, the correction operation is performed to increase the output voltage contrary to the above.

In FIG. 2, the first thyristor (SR ₁ ) is first activated at the time of activation to generate an output voltage, and the first and second arc-extinguishing windings are generated when the flyback pulse is generated due to the operation of the horizontal output circuit (5). line (L ₁₎ (L ₂₎ first thyristor negative pulse is supplied by the (SR ₁₎ also becomes mono-off, followed first by the operation by the gate control circuit (4), the second thyristor (SR ₁₎ (SR ₂ ) is turned on, which also activates the second thyristor (SR ₂ ), but here, the first and second arc-extinguishing windings.
If the negative pulse generation or the negative pulse supply by (L ₁ ) (L ₂ ) is designed to be delayed from the pulse (f) generation of the gate control circuit (4), the second thyristor (SR ₂ ) The first thyristor (SR ₁ ) is turned on when is activated.

In the above, the present invention has been described along with the embodiment, but the present invention is not limited to this embodiment, and various modifications are made within the scope not departing from the gist of the invention described in the scope of claims for utility model registration, It can be modified.

Effect of the Invention According to the present invention, of the plurality of thyristors connected in parallel between the input terminal and the output terminal, only a specific one is activated by the activation circuit, and the remaining thyristors have a voltage generated at the output terminal and a flyback. Since the pulse is obtained from the transformer and is started via the gate control circuit that generates a turn-on signal, the number of starting circuits can be minimized and the starting current can be reduced. Further, since the turn-on signal is also applied to the specific thyristor activated by the activation circuit through the gate control circuit, all the thyristors are turned on / off simultaneously in a horizontal cycle after the activation to affect the generation of the power supply voltage. Therefore, the sharing current of each thyristor is small,
The heat generation of the thyristor is suppressed. Therefore, even if it is used as a power supply circuit of a large-sized television receiver with large power consumption, there is an effect that the heat sink and the like can be small. Also,
Since the extinguishing arc winding is wound around the flyback transformer, the turn-off signal can be obtained directly from the flyback transformer, which simplifies the configuration.

[Brief description of drawings]

FIG. 1 is a block diagram of a thyristor power supply circuit embodying the present invention, FIG. 2 is a diagram showing a concrete implementation circuit example thereof, and FIG. 3 is a waveform diagram of a signal in each part of FIG. FIG. 4 is a block diagram of a conventional example. (1) …… Input terminal, (2) …… Output terminal, (3) ……
Starter circuit, (4) …… Gate control circuit, (5) …… Horizontal output circuit, (11) …… Flyback transformer, (SR ₁ ) ……
First thyristor, (SR ₂ ) …… Second thyristor, (L ₁ ) ……
1st arc-extinguishing winding, (L ₂ ) ... 2nd arc-extinguishing winding.

Claims (1)

[Scope of utility model registration request] 1. A plurality of thyristors connected in parallel between an input terminal to which an uncontrolled DC voltage is applied and an output terminal connected to a horizontal output circuit in a television receiver, and the specification of the plurality of thyristors. And a variation of the output voltage based on the pulse obtained from the flyback transformer of the horizontal output circuit and the output voltage of the output terminal, which is commonly connected to the gates of the plurality of thyristors. A gate control circuit that outputs a turn-on signal to the plurality of thyristors at the timing of correcting, and an arc-extinguishing winding that is wound around the flyback transformer and that provides a signal that turns off the plurality of thyristors. A thyristor power supply circuit for a television receiver in which multiple thyristors are turned on and off in a horizontal cycle.