JPS5910842Y2 - television receiver - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a power supply circuit for a television receiver, and is intended to reduce power consumption.

An example of a conventional circuit structure is shown in FIG.

This circuit integrates the parallel type switching regulator shown in FIG. 1 and the horizontal deflection circuit shown in FIG. 2, both of which are well known.

The switching regulator in Figure 1 has Vi as an input.
A DC voltage of

This may be a pulsating flow.

This is applied to both ends of the series connection between the primary winding 2 of the converter transformer 1 and the transistor 3 as a switching element.

The secondary side of the converter transformer consists of a secondary winding 4, a flywheel diode 5, and a smoothing capacitor 6, and a load 7.
, and produces a DC voltage V1 as an output.

A rectangular wave as shown in the figure is applied to the base of the transistor 3 to perform a switching operation.

That is, energy is stored in the primary winding 2 when it is on, and that energy is supplied to the load 7 from the secondary winding 4 via the diode 5 when it is off.

Here, by appropriately changing the waveform applied to the base and changing the duty in response to power supply fluctuations or load fluctuations, it is possible to completely stabilize the output (1).

The horizontal deflection circuit shown in FIG. 2 receives Vi as an input and operates to cause a predetermined deflection current to flow through the deflection yoke 8.

Since this operation is extremely common, it will be omitted here.

In addition, 12 is an output transistor, 13 is a damper diode, 14 is a resonant capacitor, 8 is a deflection coil, and 15 is S
This is a correction capacitor.

On the other hand, a high voltage as the anode voltage of the CRT is provided from the secondary winding 10 of the flyback transformer 9, and is obtained by rectifying the flyback pulse, that is, the pulse during the retrace period.

Further, the primary winding 11 operates as an AC cut choke transformer.

In the circuit shown in Figure 3, the input is unstable Vi, that is,
A voltage similar to Vi explained in FIG. 1 is applied to the converter transformer 16.

A rectangular wave is applied to the base of a transistor 17 as a switching element, and when it is on, energy is stored in the primary winding 18 of the converter transformer 16 by Vi, and when it is off, energy is stored in the primary winding 18 of the converter transformer 16 from the secondary winding 19 to a diode 30 in the deflection circuit.
Supplied via.

The horizontal deflection circuit operates similarly to FIG.

The diode 21 allows the latter half of the deflection current to flow to the transistor 17.

As a result, a waveform as shown in FIG. 4a is generated in the winding of the converter transformer.

Assuming that a waveform 25 occurs in the converter transformer 18 in a steady state, the waveform becomes 26 when Vi increases, and 27 when Vi decreases.

This operation is controlled by the base input of transistor 17.

This also applies to the load side, and is achieved by adding appropriate feedback to the base.

At this time, the flyback pulse 28 shown in FIG. 4b generated in the horizontal deflection circuit is always kept constant.

That is, the operating voltage of the horizontal deflection circuit is constant. A flyback transformer 9 is connected in parallel with the deflection yoke 8, a high voltage is obtained by a voltage winding 10, a reverse pulse is generated by another secondary winding 22, and the scanning period of this is rectified by a diode 23, and the internal A DC voltage with low impedance is obtained.

The circuit shown in FIG. 5 can be made by combining the circuit shown in FIG. 3 with a horizontal oscillation circuit.

In Figure 5, 31. 32 is an AC power supply voltage application terminal;
33 is a rectifying and smoothing circuit that rectifies and smoothes this AC power supply voltage;
34 is the switching regulator circuit shown in FIG. 3, 35 is a horizontal oscillation circuit, and 36 is a horizontal oscillator.

The output of the horizontal oscillation circuit 35 is the horizontal drive transistor 3
It has been added to the base of 7.

The emitter of the horizontal drive transistor 37 is grounded, the collector is connected to the output terminal of the rectifying and smoothing circuit 33 via the primary winding 39 of the drive transformer 38, and the secondary winding 40 is connected to the base of the horizontal output transistor 17. .

The DC power supply voltage vb of the oscillator 36 and other circuits for controlling the pulse width in the horizontal oscillation circuit 35 is the output voltage Vi (approximately 130 volts) of the rectifying and smoothing circuit 33, which is connected to the resistor 4.
1 to lower the voltage to 12 to 20 volts.

However, this circuit has the disadvantage that the resistor 41 consumes 3 to 4 watts of power.

The present invention aims to reduce power consumption, and one embodiment of the present invention will be described below with reference to the drawings.

FIG. 6 shows one embodiment of the present invention, and the same parts as those in FIG. 5 are given the same numbers and the explanation thereof will be omitted.

The circuit shown in FIG. 6 is characterized by having all the internal circuits of the horizontal oscillation circuit 35 floating above the earth ground as a chassis ground, rectifying the pulses of the winding 42 provided in the flyback transformer 9 with a diode 43, and passing the rectified voltage through the capacitor 44. is smoothed to obtain a DC voltage Vc, which is applied to the chassis.

Therefore, this horizontal oscillation circuit 35 is kept completely insulated.

The above Vc is always V even if the AC power supply voltage drops below the normal value.
Set so that i > Vc + Vb is satisfied.

When the turns ratio between the primary winding and the secondary winding of the transformer 16 is 1 or more, that is, when the secondary winding is wound up, when the AC power supply voltage decreases, Vi < Vc may occur; By selecting Vi > Vc regardless of the turns ratio.
can be satisfied.

With this configuration, the voltage drop across the resistor 41 is Vi and Vc.
With only a difference of 10 Vb, it can be set to <10-15 volts and the power consumption can be less than 1 watt.

In addition, as shown in FIG.
It may also be taken out from the DC blocking capacitor 24 inserted between 1 and ground.

As described above, the present invention applies a DC power supply voltage to the horizontal deflection circuit, and also applies the DC power supply voltage to the power supply terminal of the horizontal oscillation circuit via a voltage drop resistor, and connects the ground of this horizontal oscillation circuit to another ground. This is a television receiver in which the DC voltage obtained in the horizontal deflection circuit is applied to the ground terminal of this horizontal oscillation circuit, and the voltage applied to both ends of the voltage drop resistor can be reduced, reducing the voltage drop. The power consumption of the resistor is small.

[Brief explanation of the drawing]

Figures 1 and 2 are circuit diagrams of a portion of a conventional television receiver, Figure 3 is a circuit diagram of a portion of a conventional television receiver that combines the circuits of Figures 1 and 2, and Figure 4 is a circuit diagram of a portion of a conventional television receiver. Figure a,
1) is a waveform diagram for explaining the circuit, FIG. 5 is a circuit diagram of a conventional television receiver, FIG. 6 is a circuit diagram of a television receiver according to an embodiment of the present invention, and FIG. 7 is a circuit diagram of a conventional television receiver. FIG. 7 is a circuit diagram of a television receiver in another embodiment. 33... Rectifier smoothing circuit, 41... Resistor, 34... Horizontal deflection circuit, 35... Horizontal oscillation circuit, 42... Vol. Line, 43...
Diode, 44... Capacitor, 24...
...Capacitor.

Claims (1)

[Scope of utility model registration request] A DC power supply voltage is applied to the horizontal deflection circuit, and the DC power supply voltage is applied to the power supply terminal of the horizontal oscillation circuit via a voltage drop resistor, and the ground of this horizontal oscillation circuit is insulated from other grounds, and this horizontal oscillation circuit to the ground terminal of
A television receiver in which the obtained DC voltage is applied to the horizontal deflection circuit.