JPH069108U - Flyback transformer - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention relates to prevention of abnormal heat generation of a flyback transformer, and particularly to prevention of overcurrent prevention resistance heat generation connected in series with a high-voltage generating winding. In a laminated winding flyback transformer 11, an overcurrent preventing resistor 18 connected in series with a high voltage generating final winding 19 is used as a diode for accumulating a voltage generated by a high voltage winding 15.
The load current detection circuit block 5 for detecting the input power is provided on the side of the primary winding 12 so that the set operation can be stopped. [Effect] It is possible to prevent the flyback transformer from generating heat and smoking during abnormal conditions.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to prevention of abnormal heat generation of a flyback transformer.

[0002]

[Prior art]

 Regarding the prevention of overcurrent destruction of the voltage stacking diode in the flyback transformer in the prior art, mounting with a resistor is already known, for example, from Japanese Utility Model Publication No. 258-314.

Further, the high-voltage winding is divided into a plurality of winding sections to form winding sections, each winding section is sequentially wound in a laminated manner with an insulating material, and a rectifying diode is inserted in series between the winding sections. The method of mounting the above-mentioned resistors and series diodes in the multi-layer winding flyback transformer constructed as described above is known from FIGS. 5 and 6 of Japanese Utility Model Laid-Open Publication No. 64-12490. Also, regarding the detection of abnormal heat generation of the flyback transformer, an abnormal heat generation detection circuit of the flyback transformer is already known from Japanese Patent Application Laid-Open No. 64-180.

[0004]

[Problems to be solved by the device]

 By the way, in the above-mentioned multi-layered flyback transformer, when the stacking diode for the final stage of the high voltage winding fails in short mode, it is explained in the conventional example in which the diode is connected in series with this diode. In addition to the normally flowing Brown tube anode inflow current, the horizontal pulse voltage generated in the final stage of the high voltage winding is additionally applied to the overcurrent breakdown prevention resistor, which causes more heat generation than usual. The amount of heat generation depends on the resistance value, but is about several watts at a resistance value of, for example, about 4.7 KΩ. With local heat generation of about several watts, reliable protection could not be achieved by the load increase detection that flows into the flyback transformer or the temperature rise detection method found in the conventional example.

As a result, there is a problem that the flyback transformer main body is cracked when used for a long period of time, and its reliability is lowered.

Therefore, in the present invention, even if the final-stage stacking diode of the high-voltage winding fails in a short mode, unnecessary heat generation is prevented, and reliable flyback trance smoke and heat generation are ensured. The purpose is to protect.

[0007]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object of the present invention, according to the flyback transformer of the present invention, an overcurrent protection resistor is provided in the vicinity of the stacking diode of the high voltage winding, which is one before the final winding of high voltage generation. The primary winding side of the flyback transformer is equipped with a detection circuit that detects the input power, so that the set operation can be stopped.

[0008]

[Action]

 By arranging the overcurrent prevention resistor in the vicinity of the stack diode for the high voltage winding, which is one before the final stack winding, when the resistance heats up, the adjacent stack diode is short-moded due to this heat generation. Can be destroyed by heat. As a result, the high-voltage winding pulse voltage to be stacked in this diode is short-circuited through the capacitance between the high-voltage winding stacks. Due to the short circuit current, the coating of this high voltage winding progresses to the melt layer short. The primary winding current increases, and the set operation is stopped by detecting this current.

[0009]

【Example】

 FIG. 1 shows a circuit diagram of an embodiment of the present invention.

In FIG. 1, 1 is a power plug, 2 is a full-wave rectification diode, 3 is an electromagnetic relay, 4 is a smoothing capacitor, 5 is a + B voltage load current detection circuit block, and 6 is a horizontal output transistor. , 7 is a damper diode, 8 is a resonance capacitor, 9 is a horizontal deflection coil, 10 is an S-correction capacitor, 11 is a laminated winding flyback transformer, 12 is a flyback transformer primary winding, and 13 is high voltage generation. 1st layer winding, 14 is 13 generated voltage stacking diode, 15 is high voltage generating 2nd layer winding, 16 is 15 generated voltage stacking diode, 17 is high voltage generating 3rd layer winding, 18 is 16 generating An overcurrent prevention resistor arranged next to the voltage stack diode, 19 is a voltage stack diode 17 generated, 20 is a cathode ray tube, 21 is an ABL resistor for detecting a cathode ray tube beam current, and 22 is 21. This is a smoothing capacitor for the detection voltage detected by the ABL resistance.

In the normal state, the AC power supply voltage is input from the power plug 1 to the full-wave rectification diode 2 through the closed electromagnetic relay-3, and the full-wave rectification diode 2 and the smoothing capacitor are input. The voltage is converted into a DC voltage at 4, and this voltage is supplied to the primary winding 12 of the flyback transformer 11 through the load current detection block 5 to supply energy. The horizontal output circuit composed of the horizontal output transistor 6, the damper diode 7, the resonance capacitor 8, the horizontal deflection coil 9, and the S-shaped correction capacitor 10 generates a horizontal pulse of about 1 Kv between both ends of the primary winding 12. This pulse voltage is generated in each of the high voltage generating windings 13, 16 and 17 as a pulse voltage increased according to the winding ratio to the primary winding. The respective voltages are piled up by the stacking diodes 14, 16 and 19 and supplied as the anode voltage of the cathode ray tube 20 so that the television set is in operation. FIG. 2 shows a cross-sectional structure diagram of the laminated winding flyback transformer. In the drawings, the same parts as those in the other drawings are the same. Reference numeral 23 is a core, 24 is a primary winding coil bobbin, 25 is a high voltage winding coil bobbin, and 26 is an interlayer insulating film that insulates each high voltage winding. Due to the interlayer insulating film 26, interlayer capacitances C ₁ and C ₂ are generated between the high voltage windings.

FIG. 5 shows an electrical equivalent circuit diagram of the high voltage generator of the laminated winding flyback transformer shown in FIG. In the figure, C ₁ and C ₂ are the interlayer capacitances shown in FIG.

The operation of the present invention will be described in detail with reference to FIGS. 1 and 5 in the case where the diode 19 in the flyback transformer 11 is destroyed by a short mode due to some cause at the time of an abnormality.

First, in FIG. 5, in the overcurrent prevention resistor 18, in addition to the current corresponding to the beam current of the normal cathode ray tube 20, an alternating current due to a pulse voltage generated in the final winding 17 for high voltage generation is provided. The current flows through the resistor 18, the diode 19 in which the short is broken, the brown capacitance 20, the ABL smoothing capacitor 21, and the interlayer capacitances C ₁ and C ₂ . As a result, the power consumption of the resistor 18 normally increases from about 0.2 watts to several watts when the resistance value is 4.7 KΩ. The body surface temperature is estimated to be 100 ° C to 200 ° C. By disposing this resistor 18 near and adjacent to the high voltage winding voltage stacking diode 16 immediately before the final winding for high voltage generation, it becomes possible to thermally destroy this diode. When the short mode is destroyed, the pulse voltage generated in the high voltage winding 15 is short-circuited through the shorted diode 16 and the interlayer capacitance C ₂ and a high current flows in the high voltage winding 15. Flowing. This melts the winding coating and advances the layer short.

In FIG. 1, the primary winding current 12 naturally increases. This current is detected by the load current detection circuit block 5, the electromagnetic relay-3 is opened, and the set operation is stopped. This can prevent the flyback transformer 11 from generating heat and smoking.

A mounting example of the resistance mounting of the resistor 18 according to the present invention is shown in the flyback transformer high voltage generating part mounting diagrams of FIGS. 3 and 4.

In the example of FIG. 3, the resistor 18 is mounted side by side with the stacking diode 16.

FIG. 4 shows another embodiment. The resistor 18 and the diode 19 are connected in series by soldering and are arranged side by side with the diode 16. The diode 16 and the resistor 18 are mounted so that they are positioned directly next to each other. ing.

Here, in principle, the overcurrent prevention resistor 18 can be achieved by mounting it near any stacked diode, but in reality, the potential difference between the resistor 18 and the stacked diode is If it is installed in the smallest place, it can be installed closer to it, and the best place is near the high voltage winding voltage stacking diode immediately before the high pressure generating final winding.

[0020]

[Effect of device]

 As is clear from the above detailed description, according to the present invention, the reliability of the flyback transformer can be improved with almost no cost increase.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

FIG. 2 is a cross-sectional structural diagram of a laminated winding flyback transformer.

FIG. 3 is a mounting view of a flyback transformer high voltage generator of the present invention.

FIG. 4 is a mounting view of a flyback transformer high voltage generator according to another example of the present invention.

FIG. 5 is an electrical equivalent circuit diagram of a flyback transformer high voltage generator.

[Explanation of symbols]

5 ... Load current detection circuit block, 11 ... Multilayer winding flyback transformer, 15 ... High voltage winding before the last high voltage generating winding, 16 ... 15 diode for accumulating generated voltage, 17 ...
High voltage generation final winding, 18 ... Overcurrent prevention resistor, 19 ... 17
Diode for stacking generated voltage

Claims (1)

[Scope of utility model registration request] 1. A plurality of high-voltage windings of a transformer wound in a line in the winding axis direction are arranged on a concentric cylinder, and each layer of high-voltage windings is in series with a diode and is oriented so that the generated voltage is accumulated. In the multi-layered flyback transformer connected as shown in the figure, a diode,
The resistors are connected in series, and the resistors are placed next to the stacking diode of the high voltage winding immediately before the final winding, and at the primary winding side, the primary winding input power is detected and set operation is performed. A flyback transformer characterized by being able to stop.