JP3360305B2 - Television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver, and more particularly to a television receiver suitable for use in a protection circuit of a deflection circuit system.

[0002]

2. Description of the Related Art Conventionally, various circuits used in television receivers have been subjected to short and open tests for testing the short-circuit state, insulation state, and the like of each circuit. In this short / open test, various electric components and I
C and the like become problems. In particular, when a predetermined component causes an abnormality and is short-circuited, it is necessary to take measures to prevent other components related to this component from firing or smoking.

[0003] Various methods have been used as a countermeasure for performing such a short or open test or when an abnormal situation occurs. The main countermeasures are listed below.

(A) Design between components such as a printed circuit board and an IC and a pattern distance so as to satisfy a standard. (B) Use a non-combustible or non-combustible resistor to cut off the resistor (fuse resistor) to prevent burning. (C) Use a resistor having a large power capacity to reduce the heat generation. (D) An overcurrent or overvoltage protection circuit is provided to protect the entire circuit. Etc. are considered.

The example described in the above section (B) will be described with reference to FIG. 5 T indicates a horizontal output circuit of a general television receiver is input pins of the primary side of the drive transformer T in the horizontal output drive transformer is connected to the collector of the transistor to Q ₁ horizontal driving circuit, and the emitter It is grounded and the base is connected to the horizontal drive circuit.

[0006] The input pin of the primary side of the horizontal drive transformer T via the resistor R ₁ is connected to the + B power supply mains 1. The main power supply 1 is operated by a commercial AC power supply 2.

[0007] secondary output pins of the horizontal drive transformer T is connected to the base of a horizontal output transistor Q _2, also the output pin is grounded, the collector of the horizontal output transistor Q ₂ is connected to a damper diode D ₁ and capacitor C ₁ is, the coil L _H of the horizontal deflection yoke by applying a sawtooth wave current for scanning an electron beam in the horizontal direction by a combination of these damper diode D ₁ and capacitor C _1.

Further, flyback transformer (FBT) 2
By generating higher order pulse to the next side high-voltage winding is made so as to supply the anode voltage and the focusing voltage through a diode D ₂ to the CRT.

In the above configuration, the horizontal output transformer T
When a short test is performed between the input pin and the output pin or when an abnormality occurs and a short circuit occurs, the voltage of the + B power supply of the main power supply 1 is set to V. At this time, if the resistance in the short circuit is R ₁ The power consumed here is as follows.

[0010]

(Equation 1)

Therefore, the resistor R ₁ satisfies the rated allowable power in the normal use state and is opened when the short circuit test reaches the value of 1 or does not cause a small heat generation or ignition. A rated resistor must be selected.

Similarly, the resistors R ₁ and R ₄ may be cut off at the input pins and between the output pins and between the input pins and the output pins of the horizontal drive transformer T in the same manner as described above. A short test is performed by connecting a tester. Also, in order to satisfy safety standards that do not affect other components when a short circuit occurs, the same resistor as that used in the short test must be selected.

[0013]

According to the conventional measures,
The number of parts and costs are increased because special parts (expensive) that exceed the standard are used as parts of each circuit, or special protection circuits are assembled with hardware and added to predetermined circuits. In addition to the ineffective use of the substrate area, there are disadvantages such as an increase in design and development time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to use a microcomputer (hereinafter referred to as a CPU) incorporated in a television receiver. Provide a television receiver that can prevent ignition and smoking of the television receiver by detecting the abnormality of the deflection circuit system by software at the time of short circuit or short / open test and shutting off the main power supply. It is assumed that.

[0015]

As shown in FIG. 1, a television receiver according to the present invention comprises a horizontal deflection circuit 6 and a vertical deflection circuit 7, each of which comprises a plurality of types of electric elements. enter the horizontal deflection pulse H _P and the vertical deflection pulse V _P derived from the deflection circuit 6 and the vertical deflection circuit 7, the horizontal deflection pulse generated by a short circuit or open between predetermined terminals of the electrical element H _P or vertical deflection pulse V _P
Abnormality detecting means 3 for detecting an abnormality in the horizontal deflection circuit 6 and the vertical power supply circuit 7 when the abnormality detection means 3 detects an abnormality. It is a thing.

[0016]

According to the television receiver of the present invention, for example, when a short test of a horizontal drive transformer or the like is performed, the horizontal output pulse is automatically stopped and the supply power of the main power supply is cut off. There is no need to worry about causing other connected resistors or the like to generate heat or fire.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The case where the television receiver of the present invention is applied to protection circuits for horizontal and vertical deflection circuits will be described below.

FIG. 1 is an overall system diagram of this embodiment including a main power supply as well as a horizontal and vertical deflection circuit system. Corresponding portions in FIG.

In FIG. 1, a main power supply 1 comprises a horizontal and vertical deflection circuit 4
And 7 is driven by the commercial AC power supply 2 and supplies the power supply voltage + B.
The contact piece S ₁ of the relay RL is connected between the power supply 1 and the main power supply 1.

Reference numeral 5 denotes a microcomputer power supply serving as a power supply for a CPU 3 and a relay drive circuit 6 which will be described later. The power supply 5 is constituted by a normal rectifier circuit and a smoothing circuit.

Between the pins t ₁ and t _{2 of the} CPU 3, a disconnecting means 4 for disconnecting the commercial AC power supply 2 of the main power supply 1 when an abnormality occurs is connected.

[0022] The blocking means 4 is constituted of a transistor Q ₃ and the relay RL relay driving. That is, the relay RL is connected to the collector of the transistor Q _3, the other end of the relay RL is connected to the pin t ₂ of the CPU. In addition, the emitter of the transistor Q ₃ is grounded. A series circuit of a diode D ₄ and a resistor R ₂ is connected to the base of the transistor Q ₃ , and is connected to a pin t ₁ of the CPU 3.

One end of the resistor R ₃ and one end of the capacitor C ₇ are connected between the diode D ₄ and the ground.

[0024] The pin t ₃ of CPU3 is supplied horizontal pulse H _P from the horizontal deflection circuit 6.

[0025] is further supplied vertical pulse V _P from the vertical deflection circuit 7 to the pin t ₄ of CPU 3.

[0026] 8 is a vertical and horizontal drive circuits, perpendicular to the base parallel transformer to Q ₁ horizontal driving vertical synchronizing pulses V _P from the horizontal sync pulses H _P is also vertical pin t ₆ in horizontal pin t ₅ It is supplied to an IC including a vertical output amplifier circuit of the deflection circuit 7.

The horizontal output transistor Q of the horizontal deflection circuit 6
_TwoIs a resistor R_FourThrough the horizontal drive transformer T
In And the horizontal output transistor Q_TwoAnd the base
Resistor R between emitters_FiveAnd the resistor R_FiveContact with
Inductance L between ground₁Is connected.

[0028] The collector of the horizontal output transistor Q ₂ is connected damper diodes D ₁ and D ₃ capacitor to the parallel C ₁ and C _2, these by supplying a sawtooth wave current to the horizontal deflection coil L _H, one horizontal Output transistor Q
Connected capacitors C ₃ and one end ₂ of the collector horizontal pulse H _P is supplied to the pin t ₃ of CPU3 through the resistor R ₆ from the connection point of the series circuit of a capacitor C _4, which is grounded.

The inductance L ₂ is the same as the capacitors C ₆ and C ₈ and the capacitor is the same as the coil for linearity correction.

[0030] primary winding one end of the collector of the horizontal output transistor Q ₂ in the FBT, the other end is connected to the main power supply 1 + B power supply, the + B power primary winding of the horizontal output transformer T It is supplied through the resistor R ₁ to the pin.

The secondary winding of the FBT is configured to extract an anode voltage or the like via a diode D ₂ or the like and supply it to a CRT.

Reference numeral 7 denotes a vertical deflection circuit, and L _V denotes a coil wound around a vertical deflection yoke, and IC denotes a circuit including a vertical deflection output circuit and a voltage pump-up circuit. , The vertical pulse _VP is the resistor R ₇ R
₈ through the capacitor C ₉ or the like in parallel, pin t ₄ of CPU3
Supplied to

In the above-described configuration, for example, when the pins of the horizontal drive transformer T are short-circuited or a short-circuit test is performed as in FIG.
As shown in FIG. 2, a commercial AC power supply 2 supplied to a main power supply 1 is cut off by operating a relay drive circuit by making a judgment by software.

[0034] Hereinafter, by Figure 2, will be described to flowchart <br/> bets in this example. In FIG. 2, in a first step ST ₁ , for example, when a short test or the like for short-circuiting between pins of the horizontal drive transformer T is performed in the television receiver,
Horizontal pulse H _P which is input at pin t ₃ of CPU3 is no longer supplied to stop the horizontal output. So, CPU
3 is "ON" of the main power supply 1 in normal use as a criterion
In taking into account the instability of the time "off", the horizontal pulse H _P
There is returned to the second step ST ₂ the head like a continuously example 5 consecutive stopped whether or not the second in NO determines step ST _2, advances to the third step ST ₃ in YES. Needless to say, the number of pulses in this pulse stop period is appropriately selected.

In the third step ST ₃ , the CPU 3 outputs a low (L) signal to the pin t ₁ , and the driving transistor Q ₃
Is turned on and the relay RL is driven, so that the contact piece S ₁
Is turned off, the AC power supply from the commercial AC power supply 2 to the main power supply 1 is cut off, and the deflection system is stopped.
₁ and R ₄ are fever, without eliciting a fire or the like, it is possible to perform short test.

[0036] While in the above arrangement was set to monitor a predetermined time period whether the horizontal pulse H _P supplied to the pin t ₃ of CPU 3, for example of the vertical deflection circuit 7 short, the open test or a vertical deflection circuit the CPU3 in the same manner as described above even such as when the vertical pulse V _P at short circuit or the like between predetermined pins of the IC is not output by the software to drive the blocking means 4 determines that the predetermined period vertical pulse V _P is not present Thus, it is clear that the main power supply 1 can be turned off.

[0037] Figure 3 differs from FIG. 2 shows another example of a flowchart of this embodiment is the criterion of the second step STE ₂ abnormal.

[0038] That is, rather than the presence or absence of a pulse H _P or vertical pulse V _P in the first other example, the peak value of the pulses H _P or V _P is abnormal when it becomes lower than the predetermined reference threshold Judge. That is, when it becomes lower than the second step STE ₂ in a predetermined threshold value, the commercial AC power source 2 of the main power supply 1 is interrupted. The threshold limit of the peak value recognized as abnormal depends on the output voltage of the CPU 3, but is approximately a predetermined value of 50.
% When it becomes lower.

FIG. 4 shows still another example of the flowchart of this embodiment. The difference from FIG. 3 is that the second step STEP ₂
This is a criterion for determining an abnormality.

That is, in the second other embodiment, the horizontal pulse H
Rather than _P and the threshold of the vertical pulse V _p is the horizontal or vertical frequency fluctuates greater than a predetermined frequency for example 10 to 20
% As it is judged to be abnormal when change is in the manner the second step STEP ₂ frequency blocks the commercial AC power source 2 of the main power supply 1 when the changed significantly from a predetermined horizontal or vertical frequency.

In each of the above-described embodiments, the commercial AC power supply 2 supplied to the main power supply 1 is turned off as the interruption means 4.
Obviously, as a method of stopping the power supply, the + B power supply on the DC side supplied from the main power supply 1 to each circuit may be cut off.

Since the present invention is constructed and operated as described above, the main power supply 1 is shut off in the event of a short circuit, an open test or a sudden abnormality in the horizontal or vertical deflection circuit. It is possible to prevent the generation of smoke and ignition of the circuit, and it is not necessary to deal with the hardware as in the conventional case, so that the circuit can be configured at a low cost without increasing the number of components and the board area.

[0043]

According to the present invention, it is necessary to use a component having a higher degree of safety than the standard, use a special fuse resistor as a component of the test circuit, or provide a special protection circuit in hardware. The protection circuit can be configured by software using a built-in CPU etc. to perform various displays on the CRT, so the number of parts and cost do not increase and the design is performed with a predetermined safety factor even when designing the pattern of the printed circuit board This makes it possible to obtain a television receiver that can very easily cope with secondary defect test measures required by safety standards in each country.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a main part of a television receiver of the present invention.

FIG. 2 is a flowchart showing one embodiment of the television receiver of the present invention.

FIG. 3 is a flowchart showing another embodiment of the television receiver of the present invention.

FIG. 4 is a flowchart showing still another embodiment of the television receiver of the present invention.

FIG. 5 is a configuration diagram of a main part of a conventional television receiver.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main power supply 2 Commercial power supply 3 CPU 5 Microcomputer power supply 6 Horizontal deflection circuit 7 Vertical deflection circuit

Claims (4)

(57) [Claims] 1. Water comprising a plurality of types of electric elements
A flat deflection circuit and a vertical deflection circuit;
And a horizontal deflection pulse and a vertical deflection pulse obtained from the vertical deflection circuit, and a short circuit between predetermined terminals of the electric element.
Or the horizontal deflection pulse or vertical
Abnormality detecting means for detecting an abnormality of the direct deflection pulse, and when the abnormality is detected by the abnormality detecting means, the horizontal deflection
And a shut-off means for shutting off a power supply for supplying a predetermined voltage to the circuit and the vertical deflection circuit . 2. The television receiver according to claim 1, wherein said abnormality detecting means determines that the abnormality occurs when the number of horizontal or vertical deflection pulses does not exist for a predetermined period. 3. The television receiver according to claim 1, wherein the abnormality detecting means determines that the abnormality occurs when the peak value of the horizontal or vertical deflection pulse becomes lower than a predetermined threshold value. Machine. 4. The television receiver according to claim 1, wherein said abnormality detecting means determines that the abnormality occurs when the frequency of the horizontal or vertical deflection pulse fluctuates within a predetermined range.